Chevy Nova Forum banner

1 - 20 of 24 Posts

·
Premium Member
Joined
·
14,614 Posts
Discussion Starter #1
After reading about 66Chevy's driveline incident, I've been considering paying more attention to mine...possibly replacing it since I think it seriously needs a rebalance right now.

What I'm wondering is if I'm going to see any significant amount of improvement using an aluminum driveshaft vs. a HD steel one? Is the extra expense for aluminum worth it on a 12 second car?
 

·
Registered
Joined
·
1,453 Posts
I don't think it is worth it on your car. I would look into having your driveline rebuilt with a new tube and u-joints. There are a lot of ppl running steel drivelines in high HP cars with no problems at all.
 

·
Premium Member
Joined
·
11,208 Posts
I steel shaft costs about $200., and a moly shaft is about $300. then the aluminium is about $400. so what are you willing to spend for some added speed? It will reduce the total weight of your car as well as reduce the rotating mass which is the biggest help IMO. I can't say how much it will help cause I never just changed a shaft from steel to aluminium but you will gain some and the difference costs $200. All new cars I see use aluminium shafts and all new big transfer trucks use aluminium wheels so someone thinks they help. RM
 

·
Registered
Joined
·
9,967 Posts
A good stock one works well in a 12-second car with an automatic tranny. I used a stock one in the DD and never had a problem with it.
 

·
Premium Member
Joined
·
11,072 Posts
I have the factory stock 6 cylinder driveshaft still in mine--never been an issue after thousands of passes with a lot of mid 1.30 60fts. and big wheelies.
I change U-joints about every...............hmmmmm, maybe 8-10 years!
 

·
Premium Member
Joined
·
1,924 Posts
When I needed to replace my yoke, I just went to a local shop. It cost about $80, as I recall it, for them to install 2 new Brute Force joints, a new yoke, and true and balance the shaft. Mine is also just a 6 cyl shaft that is 42 years old and has about 250 passes on it. The guy said the shaft was still within tolerance of a brand new factory shaft but he trued it up anyway. Frankly, I noticed no difference.
 

·
Premium Member
Joined
·
14,614 Posts
Discussion Starter #8 (Edited)
Maybe I phrased my question wrong. :eek: I'm not too terribly worried about the original one failing, but....

If I'm going to mess with the driveshaft and have to remove it anyway, I might as well put the "right" part back in and maybe improve performance in the process.

If we remove imminent failure from the reasons for switching (more insurance is always a good thing though), what does one stand to gain by putting in a lighter driveshaft? 1/10th?? 2/10ths? or not enough improvement to measure on a 12 second car and would be better off putting my money elsewhere first?

Either way, I need a balanced driveshaft. Does it pay to upgrade it at the same time?
 

·
Registered
Joined
·
1,453 Posts
Personally, I would spend the money else where. If an aluminum shaft cost $400, you will get a lot more performance gain out of other go fast parts.

I don't believe you will notice enough gain in relation to the cost.
 

·
Premium Member
Joined
·
11,208 Posts
For everyone who posted that they are running a stock shaft with no problems. I was running a stock shaft in the car my brother had the driveshaft fail in, for many years with 1.30 60 ft times. It never gave a problem til it broke going through the traps at 135 MPH. 2 grand in parts to fix it and fortunately he wasn't hurt, but stock driveshafts can fail. So here's two shafts that did for sure. It probably won't happen to you so you all should be fine. Does that really make sense to you for $200. in cost? JMHO, RM
 

·
Registered
Joined
·
9,967 Posts
I would have a difficult time associating 1.30 60' times with a 12-second car....
 

·
Premium Member
Joined
·
14,614 Posts
Discussion Starter #12
Real McCoy said:
So here's two shafts that did for sure. It probably won't happen to you so you all should be fine. Does that really make sense to you for $200. in cost? JMHO, RM
I would gladly pay an extra $200 to insure against catastrophic driveline failure and avoid a $2000 repair bill regardless of how quick or slow my car is. It won't stay in the mid 12 range forever. I see low 12s or high 11s in the future.

As I've written on my website, I'd rather do it right the first time, and spend a bit extra, rather than do it twice. In this case that might be 1.5 times, since I'm already functional (but not perfect) with the OEM driveshaft. :rolleyes:
 

·
Premium Member
Joined
·
10,210 Posts
would not the moly shaft be both lighter and stronger than the steel one?...it might be a nice compromise between running a steel or aluminum shaft:)
 

·
Premium Member
Joined
·
11,208 Posts
66chevyIISS wasn't having but 1.70 sixty ft times and was going mid 7 second 1/8 from what I read Mike. He started the origional post when his shaft failed just like my brother. Then a guy posted it was a failure of the stock shaft with an explaination of how and why the stock shaft fails. RM
 

·
Registered
Joined
·
362 Posts
IMO, there is no need to run an aluminum shaft. I believe it is similar to your harmonic balancer, yes it is rotating, but it is sprung weight. I would however highly recommend at very least having your shaft replaced. I threw mine 2 years ago, when it let go, the yoke swung enough in 2-3 seconds to shatter a new transmission housing. After we inspected it (it was the original) there were places where it was only .030 thick. Years of rust had ate it down. Simply re-tubing it only cost about $120, balanced. A very cheap investment in your safety.
 

·
Premium Member
Joined
·
11,208 Posts
If you read the cause of failure it is the diameter of the tube according to the post so replacing the stock dia tube is not a fix. I agree the aluminium shaft is not needed but it will make you faster without a doubt, just not sure how much by itself. The engine has to accelerate the weight of the shaft. Why do people use the lightest wheels, drilled rotors and axels, ultra lite spools and such? They are easier to turn and accelerate. Not needed but easier to go fast with. Everyone has opinions and thoughts and everyone doesn't agree on things, which is fine. IMHO spending $200. for a safe 3 in. dia shaft is money well spent. The origional question was, How much would an aluminium shaft help my ET over a steel shaft. That still hasn't been answered by anyone who has converted to one. I'm done now......LOL. RM
 

·
Registered
Joined
·
9,967 Posts
There's more to the aluminum vs steel equation than simply the weight of the shaft. If the aluminum shaft is a larger diameter than the steel one, the weight is farther away from the center of rotation and has more inertia.
I have two driveshafts of similar length to a Nova shaft in my garage, one is aluminum and the other steel. There is about 3# difference between them, but the aluminum one is about 1" larger in diameter.

How about a 2-piece driveshaft like the one on my old BMW?
 

·
Registered
Joined
·
277 Posts
My stock driveshaft let go at approx 142 MPH on the big end back in 97. It destroyed my transmission, converter, stock drive shaft, slip yoke, transmission cross member and put numerous of gouges/tears in my floor.
I went to a Mark Williams 3.5" diameter MMC aluminum driveshaft. On a low 9 second car, I saw approx .03-.05 of a second in ET reduction. Not much "bang for the buck", but it will take all the HP and RPM's I'll ever throw at it (read cheap insurance).
I don't believe 60 foot times are the only/main reason driveshafts fail. I believe that the RPM the shaft is seeing (critical speed) on the big end matters most.
 

·
Premium Member
Joined
·
9,228 Posts
I had to have a new driveshaft anyway, and found that it was about $100-$125 more for an aluminum 3.5" through Inland Empire Driveline vs their steel ones. I got the 1350 U-joints etc. It's definitely lighter than my old stock steel one and of course a lot beefier.

Since I had to get a new one anyway I felt it was worth the difference in this case.
 

·
Premium Member
Joined
·
14,614 Posts
Discussion Starter #20
Seattle_Mike said:
I had to have a new driveshaft anyway, and found that it was about $100-$125 more for an aluminum 3.5" through Inland Empire Driveline vs their steel ones. I got the 1350 U-joints etc. It's definitely lighter than my old stock steel one and of course a lot beefier.

Since I had to get a new one anyway I felt it was worth the difference in this case.
Thanks for that comment Mike.

If we can get past the nitty-gritty on the actual material used in the driveshaft (excluding OEM-type steel) and concentrate on any new driveshaft's delivered weight, are the only benefits going to be additional strength and maybe .03-.05 off an ET?
 
1 - 20 of 24 Posts
Top