Chevy Nova Forum banner

1 - 20 of 26 Posts

·
Premium Member
Joined
·
6,277 Posts
Discussion Starter #1
Anyone have a good site to get good explanations on what and how the electronics like stutter step-trans brakes,delay boxes work. I need it in the real simple terms. Want to learn a little more about the stuff.:confused:
Not really confused just sorta ignorant on it.
JR:)
 

·
Premium Member
Joined
·
5,352 Posts
Man thats a good ? I hope some one has an answer for you cause it would help me also.
 

·
Premium Member
Joined
·
11,208 Posts
I know of no site that does that. What exactly do you want to know? The stutter box is actually a 2 step switch. It changes the max RPMs the engine can reach when activated. The trans brake is a solenoid on the trans that activates reverse while the trans is in low gear which locks it into two gears at once when activated so the car can't move. The delay box is basically a timer that delays the release of the transbrake and 2 step switch. All together when you push the transbrake button it activates the trans solenoid and the 2 step switch so the car can't move and the engine can only reach the RPM you have selected in the 2 step switch. You can floor the throttle, the car can't move and the engine only goes to the RPMs you have set. When you release the button the trans unlocks and the 2 step switch allows the RPMs to go max. If you have a delay box connected it will delay the release after you let the button go. Maybe that will help you. RM
 

·
Premium Member
Joined
·
6,277 Posts
Discussion Starter #5
Allright , that's the kinda stuff I need to know Mac. I got a good place to start now.
Thanks
JR:)
 

·
Premium Member
Joined
·
11,208 Posts
I have all those bells and whistles and I use them so if there is a specific question you have I may be able to answer it. RM
 

·
Moderator
Joined
·
6,560 Posts
JR said:
Anyone have a good site to get good explanations on what and how the electronics like stutter step-trans brakes,delay boxes work. I need it in the real simple terms. Want to learn a little more about the stuff.:confused:
Not really confused just sorta ignorant on it.
JR:)
I don't know of any sites but here's what I can tell you:

Stutter step: To me this would be an RPM rev limiter. Ideally each cylinder would recieve a spark when it should each and every time to light the mixture to have the most power. An RPM rev limiter gets a tach signal and at a preset RPM point the electronics inside the limiter box can randomly keep cylinders from firing thus limiting the RPM's. The electronics inside the box monitors how many cylinders do not fire and if the RPM goes above this preset limit, more cylinders are kept from firing to limit the RPM. While I have not looked real close at them I would think that cylinder 1 would be allowed to fire but then skip or not allow 8 to fire, and then allow 4 to fire but then skip 3, allow 6 to fire but skip 5, allow 7 but then not 2, and then on the next set of firing orders reverse what was allowed and not allowed and then reversed again. This would keep one particular cylinder from not being fired more than twice in a row.
RPM rev limiters allow or do not allow cylinders to fire so they have to be controlled by some type of activation on/off type switch. This control wire can be connected to a basic momentary switch to where when it is held down the rev limiter is engaged and the motor can only get up to a certain RPM. When the switch is released all the cylinders are allowed to fire. Some boxes require positive voltage while others a ground. Most single manufacturer's do things one way to where in their product if an activation wire is a ground, other things that require activation also need a ground so they are consistent. The problem a person can run into (and I have before wiring modules up) is that there is no standardization. Some use grounds, some positive voltages and when things do not match up most of the times relays can be used to change a positive voltage to a ground and visa/versa.

Trans brake: To me this is a solenoid that is inside or bolted to the transmission to keep the output shaft from turning while the car is in a forward gear. The solenoid when disconnected from power or ground will allow the output shaft to turn. I'm not for sure which gears get engaged but I think low and reverse are activated inside the transmission to where the equal and opposite forces keep the output shaft from turning.
A problem I have seen with tranny brakes is activating them while the car is in motion and damaging the transmission. Most of the ones I have wired are again wired to a momentary push button and when the button is pushed in the solenoid is activated and when released the solenoid is de-energized. Additional parts can be used to keep the tranny brake from being activated when the car is in motion.

Delay boxes: These are electronic boxes that when activated give you a delayed output. The amount of delay can be adjusted with toggle switches, resistor chips and other means depending on the design.

Ignition Retard box: This is an electronic box that when activated pulls out timing. I normally have wired these up to nitrous systems to where when the nortous solenoids are activated a pre-determined amount of timing is pulled out of the ignition system.

I hope this was simple enough.

Jim
 

·
Premium Member
Joined
·
6,277 Posts
Discussion Starter #8
Yep, Great explanation. Looks like the trans being in 2 gears at the same time would break something, But again I don't know that much about auto trans.
Thanks
JR
 

·
Moderator
Joined
·
6,560 Posts
JR said:
Yep, Great explanation. Looks like the trans being in 2 gears at the same time would break something, But again I don't know that much about auto trans.
Thanks
JR
Neither do I (that's why I have someone else fix mine). I'm not for sure (I just do the wiring for guys that do race) but I think it's all accomplished in the valve body with this solenoid activating two area's in the valve body.
I do know a car I did some wiring on last year he has a tranny brake and when he released it the transmission held up the the gears exploded in the rear end. He found out he couldn't launch at that RPM.

Some shots of his car:

http://community.webshots.com/album/442449169cllDPY

Jim
 

·
Premium Member
Joined
·
11,208 Posts
All the glides I have ever had since the mid 70s used the internal brake and I have never had any problems from the brake. I had a 400 Turbo also in the 1970s with a brake and it burnt high gear clutches about every 25/30 passes. I bought a ,Hipster I think it was, brake that was on the output shaft. It applied a band around a drum which locked the driveshaft but it was so odd I never installed it. The claim was it didn't kill the high gear clutches. I just put a glide in that car too......LOL. RM
 

·
Registered
Joined
·
134 Posts
If you dont' want to spend the money on a transbrake, and still want a two-step to limit your starting line RPM there are a couple of options.

You can set up a button that activates the two step. Then you stage, hold the brakes down, hold the two step button down and floor it. Just release your hand and foot at the same time. Not as complicated as it sounds.

Another option is wiring to the brake light switch, but you will have to setup a relay to shut it off in high gear so you can get on the brakes at the finish line. Some people dont like this because the chevy brake light switch isn't a very positive switch, and it will stutter sometimes off the brakes.

You can set it up to activate off of brake pressure as well, which solves the that problem.

The last option is to drill a hole on one side of your brake pedal, and install a switch directly onto the brake pedal. Don't do it in the middle so you can still hit the brakes at the finish line without activating the two step.

I bought a new car this year and it has a switch installed by the shifter and i have to say, it has never been easier for me to cut a light.
 

·
Premium Member
Joined
·
2,354 Posts
Stuttering the engine is illegal at most tracks and sanctioning bodies. Transbrakes usually don't blow your stuff up. You should have your car set up for a brake if you plan on using one. I run all that crap because it's the only class I'm allowed to run. But if I had my way, all that stuff would be on the bench and I'd be back footin IT. Plus I'd have about a grand extra in my pocket. Dave
 

·
Premium Member
Joined
·
11,208 Posts
Stuttering is illegal going down the race track but it is legal for everything else. RM
 

·
Registered
Joined
·
440 Posts
I'm not an expert on this by any means but....

A two step RPM limiter is not a stutter box. The two step can be used as described above to limit RPM prior to launch.

Stutter boxes (apparently now illegal per above post) were used to precisely dial in the cars ET by activating a lower RPM limit (on a two or three step module) for a precisely adjustable length of time.

This allowed a car to launch at full power (full throttle, without a throttle stop) to achieve the most consistent launch. And allows the driver to dial down the ET by increasing the "stutter" time. Also allowed a bracket car to run hard at the end of the track instead of being on the throttle stop.

These cars were absolutely sickening to watch at the track. Launch hard 60 ft, stutter and pop for a half second or so, then back to full throttle. But man could guys dial in their ET !!
 

·
Premium Member
Joined
·
2,519 Posts
Real McCoy said:
The delay box is basically a timer that delays the release of the transbrake and 2 step switch.
I've been wondering about the delay box since I read your other post about red lighting at night. What is the exact function of the delay box? When do you turn it on?
 

·
Premium Member
Joined
·
11,208 Posts
The stutter box you refer to for ET control we always called a bussbox. It was pretty good but is outlawed and was replaced with the modern throttle contols which are still boring to watch IMO. In the TCI Super Series I run in all automatic timers and throttle controls are illegal. You have to run the number with a mechanical throttle stop or spray the car manually which makes for a much better and entertaining race. I guess the slang terms differ in different places but they refer to the same devices.

Delay boxes delay the trans brake release. They too are illegal in the class I race in because most units today also do many other things as well as delay the trans brake. The more complex units like I own can shift the car, control NOS time, retard timing as well as record your run and play it back in RPMS in hundreds of a second. A basic delay box only delays the release of the brake but most people use the better more complex units. If you want to understand how the box helps I'll explain it the best I can.
Bracket racing requires you to be very quick on the tree with near perfect reaction times. That is very hard to do when lights are flashing everywhere on the tree. The delay box allows you to release the transbrake button when the first or top light comes on and delays the release of the brake for the amount of time you have set it for. This allows you to be more consistant on the light. You jump off the button at the very first sign of light. Now when we race if you dial a 7.00 and I dial a 6.98 your light will come on first but so close to mine the eye can't really see it so the box still doesn't help much. If I have a delay box with what is called a crossover feature I put your dial in into the box, then my dial in into the box. The box adds the differences to the delay time we set for the tree so I can leave when your light comes on. This is a big help and everyone pretty much uses them.
 

·
Premium Member
Joined
·
2,519 Posts
Thanks.

So when the first light becomes lit you hit (or release) the delay box button. The delay box waits a predetermined amount of time and then automatically releases the trans brake and off you go.

So this helps you be more consistent, but that can still vary a little based on wether you release it at the identical time from one race to the next. Gotcha.
 

·
Premium Member
Joined
·
8,051 Posts
I went to the Mid-West Nationals last weekend the Comp Eliminator cars still do the hard launch and almost die at the 60ft mark. The they pick up and scream out the back door. They were running 8.901, 8.902, 8.905 they are down to the hundreth thousand on the ET on those cars. I might be wrong but I think they even called out a couple of 8.9005 and 8.9007.

I don't realy understand the cross over box either, you use your dial in and theirs and your reaction time or something. It has inputs for your side and your competitions.
 

·
Premium Member
Joined
·
11,208 Posts
The cars Nova Guy watched were running off a 8.90 index so they used throttle controls to run that number. They launch full bore then the throttle closes for a set amount of time then go back to full throttle. They run off a 4/10s pro tree and both cars leave together so the cross over is not used. In fact most people doing this don't use a delay box at all since it is hard to cut a great light on a 4/10s tree. Delay boxes and the cross over is used for bracket racing where the cars run a full tree and have staggered starts. It is easier to cut consistant lights when you release the button at the first sign of any light on the tree. You still have to be very focused and being consistant is not easy. With alot of focus and some experience it can be done fairly well by most people. RM
 

·
Registered
Joined
·
1,356 Posts
To make it easier for both cars to release the button on a handicapped tree, they've started using "crosstalk" on the tree. The first yellow light comes on at the same time in both lanes. The slower cars tree then progresses normally at 5 tenths intervals to green while the faster cars second yellow light is delayed the amount of time differnce in dail ins before it lights. This way you don't have to watch the other guys light if you are the faster car but can watch your own first yellow which is easier to see.
 
1 - 20 of 26 Posts
Top