Someone educate me on torque converters (merged)

[WhitecatD]

What is the need for different stall rpms? What does the stall mean? I feel like I should know this but I dont:o . Could some one please educate me on torque converters!

[taz3]

Stall RPM is the RPM the engine will get to before the t/converter will engage the trans an the car will begin to go.A 3500 stall will allow you to be on the line holding the brake and bring RPM to 3500 also known as preload without the car moving untill after 3500 RPM.It works like a manual trans rev it up and let the clutch out.The advantage is you can leave the line harder with RPM's up tipically the more gear the more stall can be used,but vehicle weight and max RPM all will predict how much stall you should use as well as a host of other things,but theat is the basics of a stall converter.At low RPM it feels like the trans is slipping untill it reaches it's stall then it feels pretty much normal.Hope that answers your question some of the drag racers here maybe able to explain it better.

Paul

[Mike Goble]

The 'stall' in stall speed refers to the rpm's at which the motor stalls against the load of the converter and chassis. The same converter will stall the motor at different speeds depending on the applied torque and the load.
Stall speed does not refer to the rpm's you must be going to get the car to move, nor does it refer to some magic happening inside the converter causing it to suddenly work.
These sites have some pretty good explanations of stall speed:

www.converter.com
www.converter.cc

[NovaNate]

In simple terms Tax3 is right, it is the rpm the converter must be spinning before it engages the trans. But Goble is right too, this stall will change depending on the weight of the car and the load. If you chained your car to an achor in cement it is the speed that the engine would begin to feel the load of the car and in theory stall if the car didn't move. So it is somewhat dependant on load. But in simple terms if you held the input shaft of a converter in your left hand and the output in your right. Stall speed is the rpms you would need to spin the input shaft in your left hand before the output tried to turn in your right. This is the way I understand it, but I'm no professional.

The following website had the following definition (and a cool exploded view of a torque converter.

http://www.tciauto.com/tech_info/torque_converters_explained.htm

Stall speed --- the rpm that a given torque converter (impeller) has to spin in order for it to overcome a given amount of load and begin moving the turbine. When referring to "how much stall will I get from this torque converter", it means how fast (rpm) must the torque converter spin to generate enough fluid force on the turbine to overcome the resting inertia of the vehicle at wide open throttle. Load originates from two places (1) From the torque imparted on the torque converter by the engine via the crankshaft. (This load varies over rpm, i.e. torque curve, and is directly affected by atmosphere, fuel and engine conditions.) (2) From inertia, the resistance of the vehicle to acceleration, which places a load on the torque converter through the drive train. This can be thought of as how difficult the drive train is to rotate with the vehicle at rest, and is affected by car weight, amount of gear reduction and tire size, ability of tire to stay adhered to ground and stiffness of chassis. (Does the car move as one entity or does it flex so much that not all the weight is transferred during initial motion?)

[taz3]

The 'stall' in stall speed refers to the rpm's at which the motor stalls against the load of the converter and chassis. The same converter will stall the motor at different speeds depending on the applied torque and the load.
Stall speed does not refer to the rpm's you must be going to get the car to move, nor does it refer to some magic happening inside the converter causing it to suddenly work.
These sites have some pretty good explanations of stall speed:

www.converter.com
www.converter.cc
Thanks Mike I just kept it simple wasn't sure how to better define it.

[NovaNate]

also relavant from same website listed above....this is probably more of what Goble was refering to.

"While referring to the resistance of the vehicle to move while at rest, the torque converter's stall speed and much of its characteristics for a given application are also affected by the vehicle's resistance to accelerate relative to its rate of acceleration. This resistance has much to do with the rpm observed immediately after the vehicle starts moving, the amount of rpm drop observed during a gear change and the amount of slippage in the torque converter (turbine rpm relative to impeller pump rpm.) A discussion involving how resistance to acceleration affects a torque converter involves more theory than fact and must involve all the dozens of other variables that affect rpm and slippage. The primary thing we want to remember about torque converter stall speed is that a particular torque converter does not have a "preset from the factory" stall speed but rather its unique design will produce a certain range of stall speeds depending on the amount of load the torque converter is exposed to. This load comes from both the torque produced by the engine and the resistance of the vehicle to move from rest. The higher this combined load the higher stall we will observe from a particular torque converter, and conversely, the lower the load, the lower the stall speed. Naturally, if the engine is not at wide open throttle we will not expect to observe as high a stall speed as we would under a wide open throttle."

[WhitecatD]

why then, do some camshaft grinds require a higher stall?

[Mike Goble]

why then, do some camshaft grinds require a higher stall?

As the duration and overlap of the cam increase the motor will produce less torque at low rpm's. In order to get the engine into the power producing higher rpm range you should install a converter with a higher stall speed. Again, the engine and load determine the stall speed, so what stalls at 3500 rpm behind a torquey 406 may only stall at 2500 behind a high rpm 283. This is why converter manufacturers like to know all about your engine, tranny and chassis.

To reiterate, stall speed has nothing to do with how fast you need to rev the engine to get the car to move. My converter stalls about 3600 rpm in my 406/700R4 setup, yet I can easily achieve freeway speeds without exceeding 2500 rpm's.

[arndog]

I kind of get it :D. Take a given car 3000 pounds 283 (200hp,150ft/lbs @ 2500rpm) with a 2500 stall. Lets say the car start to moves at exactly 2500 rpm. Now say theoretically the motor goes to 250hp,250ft/lbs .... what happens ... Does the car move at 2000rpm?


For a driver Im thinking what you don't want to happen is step on the gas .... torque converter engages and motor bogs ... on the other side you don't want to step on the gas .... wait until motor hits 3500 rpm ... and start to move (unless of course you are racing).

arndog

[Paul Wright]

For a driver Im thinking what you don't want to happen is step on the gas .... torque converter engages and motor bogs ... on the other side you don't want to step on the gas .... wait until motor hits 3500 rpm ... and start to move (unless of course you are racing).

I think you are assuming a torque converter is like a centrifugal clutch on a mini bike. It's not.
Here's how they work:
If you take a running desk fan and point it at non running desk fan, the blades will begin to spin.
A torque converter works in much the same way. You have two sets of blades (curved to capture and direct the fluid) pointing at each other. Instead of air as the medium you have thicker transmission fluid. When the engine side (the impeller) turns, it causes the transmission side (the turbine) of the converter to spin also. There isn't a direct connection between the engine and the transmission and this is why the engine can still run while stopped at a light in gear. The torque converter can slip. If you take your foot off the brake the car will creep forward but not like you "let the clutch out" on a manual car. A higher stall speed will still creep but you'll notice the rpm goes higher when you accelerate.

There is a third component called a stator. This fits inbetween the impeller and turbine. It redirects and accelerates the fluid force leaving the impeller. This adds torque multiplication much like a lower gear ratio does.
Stall speed is adjusted by fine tuning the mechanical relationships of the impeller, turbine and stator. Some cheaper converters just cut open the unit, tweak the blades and weld it back up. More expensive converters are often more efficient and reduce power robbing high rpm slippage while maintaining the correct stall speed for the application.

All torque converters slip to some degree even when past the stall speed unless it's has a lock up converter which incorporates a mechanical clutch. The amount of slippage varies depending on the speed and load, not to mention the design and clearances of the torque conveter. A torque converter with less slippage at stall speed is more efficient. Slipping creates heat because the fluid is shearing between the blades. This is why you need additional cooling with performance coolers or when towing (increased load means more slippage).

I hope this explains it simply and accurately enough.
As far as what the driving sensation is with a high stall converter it's might be more educational if you just find someone with one and see if you can drive it. You'll then say "oh, I get it".

[Mike Goble]

The converter doesn't engage and disengage. As soon as you drop your car in gear it is transmitting torque to the tranny. If you let your foot off the brake, your car will roll slowly. As you increase the rpm's the car will accelerate even though you are far below the stall speed. If you suddenly mash the gas from a standing start, the converter will flash up to the stall speed and you will be transmitting a lot of torque to the tranny.

Another feature of a torque converter is the torque multiplication at low stator speeds, usually about 2:1. This is why an automatic car can leave so hard.

[joey d]

So if you had a small cam(about 212@50)that makes good botom end torque with a stall that was too big it would act even bigger and you would never even see most of the power band because you spin the engine righ out of it? I think i have this problem right now.

[NovaNate]

Wow, I think I had the wrong idea all along. I used to think that with a high stall converter, when you pushed down on the gas, the car wouldn't move until you hit the "stall" rpm. And then your car would lurch forward? People used to say "XZY stall gives a performance advantage but still allows for tolerable street driving" I used to think they meant it wouldn't yank your neck with the lurch when you were leaving every stop light.

Now I think I'm starting to understand that no matter what stall speed you have, your car still starts to pull away when you step on the gas??

And it sounds like in a way the torque converter is a multiplyer, like a gear, a higher stall speed increases the multiplication of the input torque, but also has greater slipage under high acceleration so you see higher RPMs? Is that right?

[taz3]

Oh yeah! the data posted is great,You really have to drive one to understand what it's doing.

['74hatchback]

just thought i'd pipe in and say this post has been super edjumacational. i've been meaning to ask how convertors work for a long time. glad someone finally brought it up. it's all getting a little clearer now.

[bowtie0069]

The converter in my car goes to 6000+ on the transbrake, but I can drive around at 2000rpm with no trouble. With the little 350 in it now, it'll go to about 4500.
A few years ago I borrowed a converter from a blown big block powered car to try; it went to 6000 with the big block--when I put it in gear with my small block, it stalled the engine! After turning the idle way up, I drove it down the street, it felt like driving with a clutch! The engine just lugged down like shifting too early with a stick. I'd never noticed how little torque my engine produced, because it had always flashed right thru that area.
As for slippage with a loose converter, my expensive 8" piece slips less at low speeds than the average 10" 3500 cheapie-Most of them are junk-spend the money on a quality piece, you'll be happier in the long run. Most 10" cheapies will slip enough to actually slow your mph at the track.

[Cool II]

I have run a small 8" converter on the street a few years now. It is rated 4800~5200 stall. It acts like any other automatic. When you put it in gear you will feel a load placed upon your engine. It won't be the 'clunk' you are used to, it will be milder. You will still feel it. The idle in drive RPM's won't change much, but the engine seems to idle easyer. At a traffic light next to a patrol car you can easily pull away with no drama. With a light throttle, the bugger lets your trans shift normal. You don't have to rev the pee out of it to get the car moving. BUT YOU CAN if you want to. The more you get into it, the more it will let you rev depending on your traction. Without traction, I would have to say stall speed is theory. The stall speed I spec'd earlier is with a trans brake. This means the car can not move when the trans brake is engaged. The car can not move because the trans is engaged in first gear and reverse gear at the same time as long as you have the trans brake buton engaged. The drive train from the trans back is at idle, just waiting. At this point you may be able to experiment with stall speed. Let go of the trans brake button and the reverse servo dumps, wham. Like dumping a clutch at (choose your stall speed). Build torque converters to make us happy.

[Fatcat]

Whitecat, lot of great posts here, but the why of the "stall" convertor seems cloudy. A 550hp motor is making very little hp at 1200 rpm. If you have a stock type convertor and floor it, it will accellerate the car briskly, if you however have a 4500 stall convertor and floor it from a standstill, the motor will rev up into a rpm range where the motor is producing very strong power and torque and the car will accellerate at an enormously increased rate, providing adequit traction has been allowed for. As with everything there is a price to pay, in mileage, heat, etc, but to really unlock the potential of a performance oriented car, a compatible convertor is manditory.

[NOVACA1N]

I have a B&M holeshot 3000 converter which has minimal run time on it. However, I'm skeptical about putting it in my car. 1) I'm not sure if it will be enough stall. 2) I've heard nothing but bad things about those converters, plus it has no anti-balloon plate. I really don't want to put this in and have it blow up and then I'd have to redo my fresh manual valve TH350. A 383 with ATLEAST 450 hp is goin in, 10:8:1, custom ground comp solid, world heads, etc. It will have 28''-29'' tires and 4:10s. I'm just not sure 3000 stall is enough. I've heard NOTHING but good things about redneck converters so I figured if all else failed, I'd get one from them. What do ya think? How big of a converter/gear ratio do you drive daily and/or drive often?

[novaboy009]

I think 3000 is getting pretty close, but it should be okay if you aren't buzzing down the highway a lot and have a good tranny cooler. DriveWFO and others have had good luck with redneck, I think I may order my converter from them when the time comes for the PW Claimer 350.

Kev

[jacobgiles]

call the company of choice for your converter and tell them all your specs. they will build you a converter that is right for your car. like this- http://www.bteracing.com/ApplicationSheet/default.asp


not having the plate on the converter isnt going to let your converter blow up. i spray the hell out of my car and have yet to have a converter issue.

[Mike Goble]

The PI Vigilante converter in my driver/tow car stalled the engine at about 3600 rpm.

[69NovaSS]

IMO you can drive whatever stall you need to on the street...its not like you have to rev the car up to the stall speed before the car moves...Now as was said already a good tranny cooler will be needed as the higher the stall the more heat the convertor creates..just my 2 cents.:)

[71Novacaine]

I have a Redneck convertor in my car right now I have a th350 with a hardened powerglide input shaft. It is a 2800 stall and I drive it everyday!! I love it!! It came with anti ballooning plates and was shipped fast and great condition. They are the best and cheap as hell too. Go redneck and you won't regret it.

[67Canso]

This may sound stupid but I have a 2spd. powerglide with a 2800 stall and I always assumed that with a stall converter the car would not really move until that rpm. I don't really understand were the stall converter really works.

[Mike Feudo]

With 4.10s you should be fine. My 67 has a 2800 and 3.08s. you must be very carefull about leaving it in 3rd gear going up hills at 35-40 mph. It flat fried everything untill I took the cooler out of the radiator and got an external with an electric fan on it.

[bowtie0069]

I've mentioned this before but, I drove my car on the Power Tour
(L.A.-Nashville) with a 6000rpm 8" converter and 3.73 gear. No trouble with trans or converter, I had a very small cooler at the time.

[LIL NOVE]

i have a glide and on the brake it flashes 4000, and doesnt feel like i have a stall on the street. but then again my converter is custom built fo rmy motor. if u talk to Mike @ Mike transmissions, he has guys w/ over 5500 on the street w/ no problems. a trans temp gauge will tell ya a lot also.

[Racinfan83]

How do you know if you have a "stall converter"? My car was built by a guy to race - and then it was "cleaned up" to the present street/strip combo it is now. It has a pretty potent 396 in it and a lot of other goodies that make me think it should have a stall in it. I have not had one so I don't know what to look for. I have noticed that when standing on the gas from a dead stop it goes 10 feet or more and then breaks the tires loose. I don't think this is a tranny problem as it is built also. If it does have a stall in it - do you just power brake the car up to 2500 or so and then let off the brake to launch it??

[DriveWFO]

TCI can it explain it for you: http://www.tciauto.com/tech_info/torque_converters_explained.htm

[69NovaSS]

all convertors have "stall" or your car would stall (stop running) when you stopped your car at a stop light....

[The Dude]

There's no such thing as a "stall converter." "Torque converters," however, are rated to stall at different RPM.

DriveWFO posted a good site for info.

If I ever go into the torque converter business I swear I'm going to name the company "Stall" or "Stahl" or somesuch.

[Racinfan83]

Maybe I didn't explain myself well. I know the basic idea of how they work - but how do you determine if you have an aftermarket "stall" converter and what rpms it "locks up" at?? I see and hear all the time that cars have 3500, 2500, 3000, etc stall converters in them. How do you use these to launch the car? Power brake it and run it up til it starts to move and let off the brake?? For example: if I just step on the gas on mine off idle (1000 rpm) the car will take off but after about 10 feet or so it just lights the tires up like something locked up and made it hook up, thus burning my little tires off. Yesterday I stopped at a stop sign and power braked it and slowly added rpms, at about 2300 the brake wouldn't hold it anymore and I let off and stomped it - the tires lit up instantly. Thats why I am wondering what I have and how to best use it. Sorry to keep asking dumb questions - but this is my first real performance car I have owned......

[Paul Wright]

What you should be saying is: "how do I know if I have a higher stall speed converter."

The terms "Stall converter" or "Stahl" converter is basically car idiot talk. This web site trys to eradicate misnomers, misleading and false information.
The first step to being smarter about automatic transmission torque converters is to know the correct terminology.

[novaboy009]

Peg the accelerator from an idle and see where the rpms jump to before you start moving.... that's called flash stall.

Footbraking the car is inaccurate if you roll through your brakes.

Kev

[DriveWFO]

You can obtain true stall using a transbrake (which locks 1st & reverse).

[69NovaSS]

You can obtain true stall using a transbrake (which locks 1st & reverse).

ummm....I could be wrong but I dont think it "locks" first and reverse what I think it does is puts the car INTO both first and reverse at the same time with cancels out both gears and keeps the car stationary without using the brakes even though you are hard into the trottle at the moment...

[69NovaSS]

Peg the accelerator from an idle and see where the rpms jump to before you start moving.... that's called flash stall.

Footbraking the car is inaccurate if you roll through your brakes.

Kev

yep.....this will work...:)

[DriveWFO]

ummm....I could be wrong but I dont think it "locks" first and reverse what I think it does is puts the car INTO both first and reverse at the same time with cancels out both gears and keeps the car stationay without using the brakes even though you are hard into the trottle at the moment...

Geez, it's too early in the morning to argue semantics :rolleyes: :p

[69NovaSS]

If I ever go into the torque converter business I swear I'm going to name the company "Stall" or "Stahl" or somesuch.

that second one is already in use by Jere Stahl he has a Header Company...they make, from my understanding AWESOME headers:) .....link below;)

http://www.stahlheaders.com/

[NOVACA1N]

that second one is already in use by Jere Stahl he has a Header Company...they make, from my understanding AWESOME headers:) .....link below;)

http://www.stahlheaders.com/
Yes they do, there's a set in my dads monte that fit like a glove.

[Paul Wright]

Jere makes great headers, but no "Stahl converters".

[65NovaSSman]

Fellow Nova lovers-Help!
I am first of all, not that knowledgable on High Stall torque converters and their characteristics. Here is my problem. I am running a 355 that has a radical idle cam with a TCI Streetfighter 350 trans, 3:73 gears. I talked with Summit Racing before I bought the Hughes 2500 rpm torque converter they recommended based upon my set up. I do not know what cam I have, brand, lift or duration because the engine was built by the guy I bought the car off of 5 years ago. I had at the time a 4 speed in it and have now went to the auto trans. The engine idles at 1200 rpm, not too high or not too low, just right for this cam. Again, very choppy idle, sounds like the Comp Cam Xtreme cam sound bite that is on Comp Cam's web site. When I first start the car and it is cold, if I put it in gear it seems to have the stall capabilities, it moves slowly until you get up the rpms. But, after it warms up or you have got the rpms up to engage the torque converter it acts like you have a stock torque converter the rest of the time, no slipping. The engine/trans is under stress all the time, the car wants to die when you have it in gear. I don't know what a high stall converter should act like because this is my first experience with one. My car is a show/street use machine, not for the drags. I need the car to be able to idle without having to work both the brake and gas to keep it running while in gear and without having the trans under stress because the torque converter is not slipping. Has anyone got advice for a beginner when it comes to the high stall converters? Should I go with a higher stall 3000 or 3500? Thanks again Nova lovers, sorry for this being so long.
Gene-65 Nova SS

[novaboy009]

I'd bump up the initial timing and get the carb idle mixture dead on. You might need 16-18 degrees initial and you might need to change vaccum canisters. It should be able to idle. If I can get a 246/246 @ .050 .544/.544 lift cam to idle at 900-1000 rpm, so can you.

Kev

[65NovaSSman]

To tell the truth, I do not have a clue about the way this engine was set up by the original owner. The distributor is an HEI unit set up with mechanical advance. When I set the distributor where the engine is running it's best and then check the timing on the harmonic balancer, the timing mark is at 12 o'clock position. Not down where the timing indicator is. When set up this way, this engine screams. It is not a matter of getting the car to idle, at the 1100 to 1200 rpm idle the car sounds just right. Not too high and not too low. Anything below 1100 the car wants to load up and die, too much cam to be much lower. I have even tried leaning out the carb, but when I do that, I lose performance. I know I am looking for that needle in the haystack because I do not have the cam specs, and I do not want to take my engine apart just to check the cam and get the specs for it. I love the way this engine performs, I just need to know what kind of torque converter stall speed I will need in order to keep the idle there and not put stress on the trans and engine.

[nova10sec]

Here is my suggestion>>> Make a decision.. Do you want all out performance or a compromise....

Performance-- Match the converter to your peak tq.. put the car in high gear, rolling about 25mph, mash the gas and watch the tach. It should be fairly obvious where the pk tq is, it will be where the car really starting pulling, based on the limited info you provided, I would guess its in the 3700-4200 range...

Compromise>>> Live with what you got, if you step up in converter you economy will suffer, diverability will diminish.. Is this worth .5-.7 et gain???

[tpinovaII]

What kind of carburetor do you have? Has anyone checked the float level(s)? The last time I wrenched on a car with the symptoms you are describing, the floats were way too high.
Once you step up to a larger camshaft and the vacuum at idle drops, tuning the carb gets a little more involved. This could be a big factor in your idle quality. I may get crucified for saying this but sometimes changing to a smaller camshaft can make for a more enjoyable car to drive.

[monzaz]

Well to tell you the truth here...You need to know all that info or you are just shooting money out the window here. Sounds like you do not even know if the timing mark is in the correct spot 12 or 2-3 o'clock. If you do not have the timing correct or the hei is not working right. Your done. You will NEVER get it right. You can guess all you want but if you do not have the right starting reference points you can not time the car...Only by ear at best.

You could just have the car totally retarded and looking at the timing mark you think is correct will be 20-30 degrees off from 12 -3 o'clock. see how that works. So if the car you think is at 12 degree before top dead center TDC really is 20 degrees of and is really running the car at 8 degrees ATDC your going to have a car that will shut down under load at ideal and run sluggish .

And then there is the parts...What if you just installed a part wrong and just is not working right to begin with. You'll never know cause your dealing with too many different variables from other problems.

Get that info right first...timing mark, what your full advance is at 3000 rpms to see if the distributor is working properly, and CAM specs. Good luck, Jim

[Dan_Lebherz]

It also sounded like you were saying the distributor is a fully mechanical HEI. IF you want the thing to run right on the street I'd consider a distributor with vacuum advance. Read the article in Best of Tech on this subject.

[tpinovaII]

To tell the truth, I do not have a clue about the way this engine was set up by the original owner. When I set the distributor where the engine is running it's best and then check the timing on the harmonic balancer, the timing mark is at 12 o'clock position. Not down where the timing indicator is. When set up this way, this engine screams.


I gave this some more thought. It is possible that the previous owner installed a late model harmonic with an early model indicator. Chevrolet moved the timing indicator to the twelve o'clock position on later models. (Can't remember the year of the change. I know that it is where they were in the eighties.) This doesn't mean that replacing the harmonic or indicator will solve your problem but it could add a piece to the puzzle and be a step in the right direction. If you have access to an older harmonic balance, check the position of the keyway and timing mark. Then compare their spacing to one another to your present balancer.

[NovatoriusRex]

I gave this some more thought. It is possible that the previous owner installed a late model harmonic with an early model indicator. Chevrolet moved the timing indicator to the twelve o'clock position on later models. (Can't remember the year of the change. I know that it is where they were in the eighties.) This doesn't mean that replacing the harmonic or indicator will solve your problem but it could add a piece to the puzzle and be a step in the right direction. If you have access to an older harmonic balance, check the position of the keyway and timing mark. Then compare their spacing to one another to your present balancer.

This might also be a good time to suggest finding Top Dead Center (TDC) with a piston stop in order to see how the TDC mark on the balancer matches up with the pointer on the timing tab. This will be the best/easiest/quickest way to see if it's off.

This will let you know if the existing pointer is wrong relative to the balancer. Knowing that will allow you to choose the appropriate pointer.

[jjyoung909]

I think tpinovaII has is right. I have a later model balancer with an early style pointer and I had to put a degree tape on the balancer so I could get timing readings that made sense. Should be a easy fix for that part of the problem.

In the past I have run roller cams with a decent amount of lift and duration, and been able to get them to idle lower than 1200 without loading up. Get the timing where it should be first then you can start working on the other things.

Good Luck
james Y.

[68chevyll]

If the car was fine with the four speed I'd say that converter is to tight. I had the same problem in the past. All the timing and carb adjustments did nothing. As soon as I changed the converter car was sweet. From what you described that motor sounds like it needs more than a 2500 converter.

[1quik69]

Still being new to automatic cars with high stall converters, is it true that with a high stall converter it will make the shifts if you are in drive softer/harder to detect. We are still working on my friends 68 Camaro. We finally replaced the modulator and the car will shift fine manually. When you put the car in Drive it still seems like it has only one gear. We still can't detect any normal shift pattern.

[Jason628]

Greetings,

When I went from a 2500 stall to my 3500 stall there was a noticable difference when it came to the firmness of shifts. I couldn't feel the shifts at all right after I did the swap. So, I bought a TCI adjustable modulator and even with it turned the maximum 4 turns I can feel it shift but it's nowhere near as hard as when I had the 2500 stall in it. When I manually go through the gears, it's a whole other story as it is nice and firm.

Jason

[68chevyll]

Yup what he said.

[nabit]

I am looking at buying a new converter from a guy that states it is a vega converter that was cut open rebuilt,cleaned up and set for 3700stall and it is a 10inch 350 converter. My question is I can't find any info on a vega converter, company or anything. Is it a chevrolet vega stock converter that was rebuilt and changed or is there and actual company called vega converter?
Thanks!!

[Mike Goble]

Vega (as in Chevrolet Vega) converters were a common way to get a higher stall speed in the day of the Vegas, 1970's and early 80's. They fit right on a Powerglide. I had a Vega converter rebuilt by Rossi behind a 454" BBC in the late 1970's.

[Pick]

My guess would be it's a Chevy Vega convertor that he's saying he's beefing up and rebuilding. Back several years ago when aftermarket converters were very pricey and poor boy racers like me used to run them because you could get a lot of stall out of them. They often didn't last long, but they were cheap.

There are a lot of pretty good, pretty affordable converters out there these days from reputable companies and shops, so I'd research what this guy is selling before I'd buy.

[Real McCoy]

Lots of us use to run Vega converters. They were good in their day but we sure could break them preety esay. They hate being loaded up against the brakes and fail easily and often. We have run they behing big motors with some success if you leave at an idle and just hammer the throttle but if you load the suspension against one it got ugly quick. They use to cost less than 30 bucks so they were a deal. I would never run one again. Just way to many cheap better converters available today. JMO. RM

[DriveWFO]

set for 3700stall and it is a 10inch 350 converter

Set for 3700 stall behind what motor? That thing could stall at 3000 behind your motor or 4000...who knows? Is that 3700 true stall with a transbrake or flash stall?

My $.02 says you don't wanna skimp on a converter.

[monzaz]

yES THEY WERE fACTORY gm VEGA converters. Behind a sbc chevy you could get about 2500 stall. Normally used on small 4 cylinder motors that need to rev to get moving...lol. They came with a heat shield tack welded to the front pump facing area.

I did use one on the street when I did not know anybetter year ago. It actually did work and it servived. Again you are throwing the dice each time.

Now as for rebuilding it...??? It is possible. I just do not know what to tell you on this. How well do you know the guys where was it done? etc. Ask alot of questions and if the asnswer do not add up or you do not get them...Skip it and move on. All depends on the price and how NEW your tranny is. I would not chance it on a new tranny. Just my thoughts. Take or leave it. Jim >Happy Holidays<

[Pwrtrip75]

Wow, did these things slip like crazy on the high end? How efficient were these things?

[Pick]

I used one behind a 461 and after 10 passes it would stall about any where you wanted it too. I can remember leaving at 4000, shifting at 7000, and the rpm would drop maybe to 6000 after a shift - efficient they were not, but they were cheap and plentiflul back then.

[bowtie0069]

Being the cheap SOB that I am, low cost parts are my specialty. The torque converter is one area where I would say to spend as much as you can afford.
I use a Munsinger(of course I got it used for $200!) they are around $700+ new, but if you give Mike all the correct info on your combo, he can build one to do just what you want it to do.
When I bought my used one, I called to ask him about what the stall would be--after I gave him all the info, he said it should be about 6000 rpm. When I put it in the car, it went to 6200--a lot closer than most converter builders I've seen.
I've run cheap converters before and all I can say is, DON'T, you'll be happier in the long run if you spend the money once on a good one.

[nabit]

Thanks I will pass on it..

HAPPY HOLIDAYS!!

[novaracer1]

Not to hijack this thread but, what about Redneck converters, are they any good? Anybody using them?

[Nova_Guy]

Not to hijack this thread but, what about Redneck converters, are they any good? Anybody using them?I have one of them in my car. It seems to work Ok for me. I plan on using it in the T-400 this spring. I'm running it in a glide now. It spins the tires right at 3000 and flashes right at 3500. It does exactly what they said it would. Dave (DriveWFO) had one in his car for a while.

[nabit]

Not to hijack this thread but, what about Redneck converters, are they any good? Anybody using them?
I have talked to them a few times and he said he can tailor a converter to my application, he even gave the code to use if I buy it on ebay so that he can change it up for my car compared to the one I buy. He is a very nice guy and is about 2 hours away from me.. I will probably be using them since they have such a good warranty, price and guarntee of what it will do.

I was asking about the vega one b/c it was very cheap, but I will be getting the redneck most likely since he will make it for my car for the same 255 he quotes on ebay..

[bowtie0069]

I plan on using it in the T-400 this spring. I'm running it in a glide now.
Does the Glide have a TH input shaft or vice versa? Different spline ya know.

[Nova_Guy]

Does the Glide have a TH input shaft or vice versa?Yes I had a hardened Turbo splined input shaft installed durning the rebuild. The turbo convertors are cheaper, easier to find and they input shafts are stronger.

[cmthomp2]

What would you all recommend Stall Converter wise for a street car...little strip? and do you guys like your current set up?

[Mike Goble]

Every converter is a 'stall' converter, some will stall the engine at a greater rpm than others. If you are selecting a converter you will want to talk to a converter manufacturer about your engine and chassis specifications and the projected usage of your car.

[74 hatchback]

2500-3000 stall is good for street/strip, but you must match this with your cam .

[nova73harley03]

I've got a Hughes GM25 which should stall around 2500 rpm. It's behind a 350 hp 350 sb with a very streetable cam and actually flashes around 2200 rpm. It's also pretty affordable...$180.

[Pwrtrip75]

What engine size, cam, compression, gears, car weight, intake, carb??

My 3400lbs Nova with 3.50 gears and a 377 ran a 4800 stall and drove it as a daily driver. And it drove around almost like stock.

For anything unless you have a turbo car I would not get less than 3500 stall. Anything under that you wont feel much or even notice a whole lot. And everyone I know thats gotten a smaller one than that sold it and went bigger.

[74 hatchback]

I've got a Hughes GM25 which should stall around 2500 rpm. It's behind a 350 hp 350 sb with a very streetable cam and actually flashes around 2200 rpm. It's also pretty affordable...$180.

nice car lets see some pics please!

[Jeremy77nova]

Every converter is a 'stall' converter, some will stall the engine at a greater rpm than others. If you are selecting a converter you will want to talk to a converter manufacturer about your engine and chassis specifications and the projected usage of your car.

I think Mike is dead on.Talk to a manufactor and give them your specs.

[cmthomp2]

Thanks fellas....the trans and the rear are currently in the works....im just tryin to get some feedback on how others have their cars set up....mine ain't no racecar but i like to get some smoke rollin every once and awhile

[ProchargedchevyI]

Look into a company called Redneck Performance Transmissions out of Texas. I think they have an Ebay store, but I bought my 3000 stall from them and I am very happy with it. It can handle up to 800hp and it has an anti ballooning plate for nitrous applications. And it only cost me about $300.00.

Check it out. :D

[USMCNOVA]

I have a question concerning converter choice. I understand the need to run the trans cooler with the higher stall, and know that the converter should be matched to such things as cam specs, and rear end gear. But what would be the effects of having too much stall speed? I am looking at picking a torque converter to run behind a "slightly warmed over" 283, but will only run that engine until rebuild of the 350 is complete. Nothing too outrageous, most likely with the Edelbrock Performer RPM package components. Just wondering what a good stall speed to look at might be so I don't have to replace the converter twice.

[Pwrtrip75]

The actual rpm band of the 283 will be much higher than advertised, most advertise general cubes of around 350. Too high of a stall is like on a big block when you make 500# torque from 2000-4000 rpms and you have a 4000 stall. On a 283 you dont really have any torque so going too high shouldnt effect anything, unless you got a stock cam....and even then shouldnd hurt it.. It would be fun.

[USMCNOVA]

The actual rpm band of the 283 will be much higher than advertised, most advertise general cubes of around 350. Too high of a stall is like on a big block when you make 500# torque from 2000-4000 rpms and you have a 4000 stall. On a 283 you dont really have any torque so going too high shouldnt effect anything, unless you got a stock cam....and even then shouldnd hurt it.. It would be fun.

So what might be a good converter to run? I was originaly looking at the B&M Torkmaster 2000, but now maybe am thinking the Torkmaster 2400? Maybe even more so it will work better with the 350? What do you think?

[69NovaSS]

USMCNOVA make sure your convertor will match the 350 you plan on installing. When you go to order the convertor tell the vendor the specs for the 350 and any other info they ask for. that should help you get a convertor that Will work well with your future motor.

While the 283 is in the car since it will likely have much less torque then the 350 will the convertor will act like it has less stall then it will when you have the 350 in the car. (stall is directly related to torque) Though it would not be ideal for the 283 it will work good enough until you can get the 350 in the car. Good luck

[USMCNOVA]

USMCNOVA make sure your convertor will match the 350 you plan on installing. When you go to order the convertor tell the vendor the specs for the 350 and any other info they ask for. that should help you get a convertor that Will work well with your future motor.

While the 283 is in the car since it will likely have much less torque then the 350 will the convertor will act like it has less stall then it will when you have the 350 in the car. (stall is directly related to torque) Though it would not be ideal for the 283 it will work good enough until you can get the 350 in the car. Good luck

69NovaSS, Thanks for the info. That will help out alot. I amm guessing with the Performer RPM package, 64cc aluminum heads, and matched cam to that package I should look at around a 3000 RPM stall speed or more. But will most certainly talk to the vendor. Thanks again.

[69NovaSS]

69NovaSS, Thanks for the info. That will help out alot. I amm guessing with the Performer RPM package, 64cc aluminum heads, and matched cam to that package I should look at around a 3000 RPM stall speed or more. But will most certainly talk to the vendor. Thanks again.

Your welcome.(NPHNP) They should ask stuff like the cam specs, rear diff gear, etc, etc, etc.......

[Pwrtrip75]

B&M torkmaster converters are junk and not for modified engines. I had one last an hour before it sounded like a bunch of BBs in a bread pan. That was just a small cammed 350. I'd go with a TCI streetfighter, or their breakaway one at the least. If you dont get at least a 3000 stall you wont even feel it and it wont do anything for you.

[youngin69nova]

ok i'm still stressing the whole what stall to go with and i cant sleep so i thought i would post.... but anyways i'm getting the th350 installed next friday and he said he wouldnt go anything bigger than a 2200 with that cam and everyone on here recs a 2800 or a 3000 correct? and he said he had a 3000 at hs shop that i could use but he doesnt think its a good idea i know or think that the torque converter will help a lot with a 1/4 mile time how much time do you think the difference would be and what do you guys think about the idea of the 2200 -thanks

[74 hatchback]

if you like the feel of a good hard shift go with the 2200, the 3000 will soften your shift kit, i had a 11" 2400 and it would only stall to 2000 in my 350 with a 222 degree @ .050 cam (2400-5400 power band) . my 10" 3000 stall only went to 2500 with a 230@.050 cam (3200-6200) so small blocks stall at the low side of a convertors range, the 3000 will make more heat with that small gear, so its a matter of taste. if it was my car i would go for the 2200 just because of the shift kit and i would get 3.55 gear with that cam.

[Pwrtrip75]

Anything under 3000 stall will drive like stock and not even be noticable to anyone other than you because you know you put it in. When I built my first engine I ran into all those skeptics also....."thats way too big" Turns out the torkmaster i baught was junk and like stock, I went with a TCI breakaway in a cammed 350, and it was pretty good. I'll never go under 3500 again though, unless its a turbo application where things are a little different.
2200 stall would probably make no difference in the 1/4, if you want a difference get a good converter. You can run a big stall on the street and it drives normal. They dont rev like in neutral and then hit at the stall speed. You can take your foot off the gas and it will roll and you can start out slow and go normal. Its when you mash the gas is when it flashes to the stall speed.
If your cam is to 2000-6000 power band, even a 3500 stall is good, then your dead into your power when it hits. And most the time you need to get up to that to get it motivated.
If the guy is telling you a 3000 is WAY too big, I'd question if he knows the slightest of what hes talking about. If you had a big block with 500# tq then you can afford to go smaller. But you have a 350, right?
350+small or mild cam= minimum 3000 stall.

[6471nova]

B&m Torkmaster 3000 Is Great Stall Had A Few In Different Novas Worked Great Summit Or Jegs Has Them Around 220 Dollars Stall 2800-3200 Depends On Motor And Gears

[big dog ss]

i prefer a flash higher in the power band. if your motor is making power from 2500-6000 then i would get a 3500. you want to get the rpms up in the power band for a better launch.. imo

[novaboy009]

I run a 3800-4000 stall in mine. It's probably a little much, but it sure does get up and go! As others have said, you can't really tell it's there until you mash the gas.

Kev

[Bscman]

I'd got higher than that 2200...I put a holeshot 2,000 in my '72 w/ mild 350 and was a little disappointed. I could tell the difference over stock--but a bit more would be nice.

IIRC this is mostly a street driven car (daily driver?)
If that's the case, I'd comprimise a little between best converter for acceleration vs. driveability/reduced heat of a lower stall.

A converter advertised at 3,000 will probably stall around 2,500-2,600 behind your 350 in your fairly light nova...Like in your last post, I'd say that 2,500 or so would be a great compromise for a daily driver....

I wouldn't want a true 3,000-3,2000 in my nova. I do a lot of highway/freeway driving between 2,500-3,000 and having that converter slipping for prolonged periods like that creates a LOT of heat.

Make sure you get a good (large) tranny cooler, as I've seen a lot of transmissions die because of the excessive heat of high-stall converters.
Just my opinion, YMMV.

[Pwrtrip75]

I Had a 4800 stall in my nova drove it on the highway every day to work. If you want your tranny to last get a huge cooler regardless if you have a stall or not. And Do NOT use the cooler in the radiator, eliminate it all together, that is a heater for the tranny fluid since your radiator coolant is 180+.
Overheating is the number 1 reason for auto tranny failure.

[bowtie0069]

I use an 8" 6000 rpm in mine; have for many years. 2 Power Tours, cruising in traffic, you name it, no problems. But then, I do things a little different than some.

[youngin69nova]

i found a flex-a-lite trans cooler that is 7.5 x 20.5 inches for only $40 is this a big cooler like you guys are talking about

[tsimpson]

I'm a little confused on stall converters. How do you determine the correct stall converter for particular application? Is it based on HP of the engine?
I'm confused and would like more info. Thanks

[leejoy]

I'm a little confused on stall converters. How do you determine the correct stall converter for particular application? Is it based on HP of the engine?
I'm confused and would like more info. Thanks

there is lots of information out there on this - search the internet. It is not based on horsepower, rather it is based on the performance RPM range of your engine setup and where that range starts - determined largely by the cam. For example, if your cam has a performance range from like 2500 to 5500 rpm, you want a stall converter with a "stall" rating of about 2500. If you have a racing engine (high rpm most of the time) with a racing cam, and a performance rpm range of 4000 to 6500, then you need a converter with a stall rating of 4000.

also, big block engines have more torque, and therefore will engage the torque converter "earlier" than the equivalent HP small block motor would. So if you have a big block, you will want a converter with a slightly higher stall rating than a small block with the same HP.

that's my understanding anyway.

Most street performance cars have converters with stall ratings of about 2500 to 3000. Most drag racing cars have stall ratings of like 4000 and higher.

also seems like the higher the rating the more expensive it is.

Lee

[tsimpson]

Thanks for the info. My engine is the GM Performance HO 350 330 HP
Based on what you said, I would be better off with a 2500 stall. Is that correct? I do have all of the specs on the engine. They are listed on GMs web site. I also had my car dynoed last year and it is what it is:) Thanks for the help

[Jeremy77nova]

This is from a drag racing online site,not sure which one.

Drag race torque converters: Love them or hate them, but if you select the wrong converter for your race car, you'll end up with a slug at best and an unraceable car at worst. What's the purpose of increasing the stall speed of the converter? For street-strip use or dedicated drag racing, increasing the stall speed allows the car to leave the starting line at a higher rpm, usually at a point where a modified engine is producing more torque. That translates into quicker elapsed times and increased speeds. Because of this, the most critical component in the performance mix of an automatic-transmission-equipped car is the torque converter. That should be no secret to most of you. The real secret is the way converters are rated and how the ratings affect the performance of your car.

When discussing torque-converter stall speed, two terms, and, consequently, two entirely different numbers are used: "rated stall," commonly called "footbrake stall," and "flash speed." What's the difference? Footbrake stall is just that. You load the converter by stomping one foot on the brake and the other on the gas. Watch the tach. The rpm at which the converter overpowers the brakes is footbrake stall.

Flash speed is quite different. Flash occurs the instant you release the footbrake and the rotating inertia, which is stored in the engine-flexplate-converter, is released. In many cases, this flash speed can be anywhere from 500 to 2,500 rpm higher than the footbrake stall speed. Often, a racer will stage at idle, hold the brakes, and "flash" the converter by flooring the gas pedal the instant the last yellow on the Christmas Tree comes on.

B&M points out that flash stall can be changed just by reworking the load of the converter. For instance, if a car has a 4.10 rear-axle ratio and a flash stall of 2,800 rpm on launch, a change to a 3.90 gear might increase the flash speed to 3,000 rpm. Why? B&M points out that the effective load on the converter went up. It also works the other way. If the same car used a 4.30 rear gear, the flash stall speed would go down. B&M explains this is because the converter has begun to couple up progressively as its load decreases. Thus, the combination with the 4.30 gear would make the car easier to move than the 4.10 and 3.90 combinations.

So far, so good, but herein lies the grief: Some converter manufacturers advertise the stall speed of their converters using the footbrake figure, and some use the flash-speed figure. As can be imagined, this causes no end to confusion - and it's compounded even more by the complex array of variables that contribute to converter stall speed.

Generally speaking, the larger the torque converter, the more torque and horsepower it absorbs. Because of this, a larger converter usually has less stall speed than a smaller-diameter converter. The variable is, of course, the fin angle inside the converter. Because of fin-angle changes, it is possible - in theory and in practice - to produce a converter in, for example, a nine-inch size that actually has more stall speed than an eight-inch converter. The stall-speed changes to be gained by reworking fin angles obviously are limited. The stall speed can only be increased so far before a smaller-diameter converter is necessary.

Many factors besides the converter have a direct impact on stall speed. ATI points out that engine type, engine power characteristics (and, more important, engine torque characteristics), bore, stroke, induction system, cylinder-head modifications, altitude, chassis weight, chassis modifications, tires, header tube diameter, and even body style affect stall speed. As an example, a converter that stalls at 2,500 rpm in a lightweight roadster with a small-displacement mouse engine might stall at close to 4,000 rpm in a '55 Chevy with a 454. Place one car at sea level and the other in high altitude, and a whole new range of stall speeds will result.

TCI concurs with ATI and stresses the importance of knowing complete car specifications before contacting the converter manufacturer. TCI added that nitrous-oxide, supercharged, or turbocharged applications also have a large influence on the size and type of torque converter required.

Basically, when selecting a converter, the converter stall speed should be coordinated to the engine-torque curve. It should come as no surprise that a high-revving, peaky, three-inch-stroke small-block will require a much looser converter than an oval-port, lumbering, four-inch-stroke rat engine.

Optimism, especially in the area of engine output, can be detrimental to converter selection. Turbo Action notes that inaccurate engine power and torque estimates provided by racers can seriously affect the performance of the torque converter. The same applies to optimistic dyno tests. To combat this, Turbo Action maintains that a converter manufacturer can never have enough information. It's up to you to supply it.

A-1 Automatic Transmissions agrees and notes that racers have a tendency to use torque converters with stall speeds that are too high. Said A-1's Marvin Ripes, "When recommending torque-converter stall speeds, we tend to be conservative. In order to come up with a stall speed for a given combination, we rely upon years of experience with countless different automatic-transmission combinations. There are some trends that appear in the torque-converter selection process that tend to influence the selection of stall speed. For example, a three-speed-automatic combination prefers a converter designed to work at peak engine torque. On the other hand, a Powerglide combination prefers a converter designed to work above peak engine torque." Ripes agrees with the other manufacturers with regard to information: Supply everything the manufacturer requests, and don't fudge on the specs.

As can be gathered, specifying a stall speed for any given converter is virtually impossible due to the wide array of probable engine and torque curve combinations. What about the stall-speed numbers published by converter manufacturers? Almost all manufacturers will tell you to consider these as guidelines only for stall-speed potential.

Before taking a closer look at the overall converter-selection process, one more item should be considered when dealing with high-stall-speed torque converters: efficiency. Typically, as stall speed increases, overall converter efficiency decreases - though, to some degree, this relationship has been tightened in recent years. For example, a small-diameter performance converter will almost always slip more than a large, tight OEM converter. In most cases, a typical performance converter will slip from 3 percent to 5 percent at coupling (part-throttle conditions). When a high-stall-speed converter is installed, the engine rpm increases under certain conditions, as does the ATF, or automatic transmission fluid, temperature. That's why a large, high-capacity cooler is almost mandatory in an application that experiences regular hot-lapping.

So how do you know which converter is right for your application? Frankly, it's impossible to buy a converter off the shelf and expect it to be right for your modified car. The only way to tailor the converter to your combination is to check with the experts: the converter manufacturers. ATI, for example, builds hundreds of different eight-inch race-converter combinations and has taken the time to computerize more than 7,000 vehicle combinations so that the right converter is manufactured for your car.

Hughes makes a valid point about the converter-selection process: "Be sure to spell out and understand the real application for the converter. A Super Gas or Super Comp car doesn't need a converter designed to squeeze the last tenth or mile-per-hour out of the combination. Instead, the combination needs a converter that's engineered for consistency."

The criteria for selecting the right converter are many and extremely important. Before selling a converter, ATI requires the following information; all serious aftermarket transmission and converter manufacturers will require similar information.

Chassis
Vehicle weight: The weight tells the converter manufacturer how much work is needed to reach a certain elapsed time. It affects gear ratio and helps indicate what converter flash rpm can be used in your combination.

Body style: An initial calculation of the horsepower/gear ratio will be made and may be adjusted if the car has a large frontal area. This gives the manufacturer an idea of how much air the car is pushing as it enters speed traps.

Performance
Class or bracket: The manufacturer needs to qualify your needs as accurately as possible; it might already have significant information about your type of combination on file. Additionally, converters for class or bracket racing or street-strip duty have major differences.

Average e.t., speed, 60-foot times, and rpm at the e.t. light: The manufacturer wants to know the present performance rating on your car. How efficient is your converter? How efficient is your entire combination? If you're building a new car, the manufacturer can estimate how fast the car will run and help to choose the right combination of components before mistakes (often expensive) are made.

Engine
The following information is required to evaluate the combination:


Bore and stroke
Type of cylinder heads
Cam lift, lobe centerline, and duration at .050-inch
Carburetor and manifold
Compression ratio
Primary header-tube diameter
Gear ratio
Type of transmission: Once the manufacturer knows which transmission is in your car, it knows what low-gear sets are available for your combination. Tail-housing length can help identify the transmission.

Rear-axle ratios and tire size: This information is required to calculate the actual output gear ratios (overall ratios in the respective gears), engine rpm, and vehicle mph. It is possible to have a good elapsed time and high trap speed but still have a torque converter that is all wrong for your car. Trap-speed rpm will tell you if the converter is operating efficiently when going through the traps. Typically, 100 rpm of torque-converter slippage equates to a loss of 1 1/2 mph through the traps. In essence, too much slippage means that you're throwing away usable horsepower and elapsed time.

Suspension and tires
Type of rear suspension: This information is especially helpful in diagnosing problems with your car or combination. In some cases, a loss of performance has nothing to do with the transmission or torque converter - it's in the chassis.

Tire size and code: Through extensive testing and racer feedback, racing-converter manufacturers have identified the characteristics of many tires. Tire growth, sidewall characteristics, and compounds are taken into account when selecting a torque converter. This testing has also determined which tires work and which don't with automatic-transmission combinations.

Miscellaneous
In addition, the manufacturer will request information on fuel type and ask if nitrous oxide is used. The tach type is considered, and information will be requested on motor-mount midplates, flexplate bolt circle, past performance, past equipment tested, and so on. Expect a barrage of questions before the right converter is selected.

One size doesn't fit all when it comes to torque converters. What's the bottom line? Contact manufacturers directly for an exact recommendation based on your combination. Remember to provide accurate information about your own combination. If you fudge the numbers, you'll end up with the wrong converter, and you won't be happy. That's one thing that can be guaranteed.




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