Gears & Axles - Time to spend some money :(

I broke my draveshaft last year and evidently the pass before it, i broke something in my trutrac as well. after I got the new driveshaft in it I noticed some loud popping in the rear when i would make sharp turns but let it ride and just assumed the trutrac was on it's way out. Well, I went to the track last night and noticed only one wheel was spinning in the burnout box. Time for a new unit. Im going to go with a wavtrac for obvious reason. My question is this. The rear has 31 spline axles in it now. Would I be stupid not to upgrade to 35 splines now that i have to buy a new unit? The car is a M6 with a Moser 9", aluminum center section and 3.80 gear with no tcs ect. Car has a procharger and makes just under 600 to the tires and will make a good bit more once I build a motor and up the boost. It is a weekend beater and goes to the track a few times a year. Im not rich by any means and don't want to spend the money for new axles but then again I don't want to be replacing broken 31 spline axles either. What should I do?

I believe the strange strac is 31 spline and if it breaks they will replace it I think it's in the $750 range. So if you have the green I would look at that route...

I believe the strange strac is 31 spline and if it breaks they will replace it I think it's in the $750 range. So if you have the green I would look at that route...

Both the Strac and Wavetrac come in 31 and 35 spline axles. My question is, I have 31 spline axles now. Should I just buy the 31 spline unit and be done or should I buy new 35 spline axles and the 35 spline unit? I'm not worried about breaking the diff, i'm worried about breaking a axle. And they are a good bit more than $750 unfortunately :mad:

31 spline should be fine IMO but give eric at MWC a call he will be more help than me haha

I have an almost identical car. And almost identical situation. I sold the Tru-trac before it broke and replaced it with a 31 spline spool. I want to ditch the spool and use the S-track, though, which is 35 spline. I want the Strange Hybrid case too. I'll probably sell all the 31 spline stuff. I need to save a a few bucks first, so I can afford the new parts. Let us know what you decide.

I have an almost identical car. And almost identical situation. I sold the Tru-trac before it broke and replaced it with a 31 spline spool. I want to ditch the spool and use the S-track, though, which is 35 spline. I want the Strange Hybrid case too. I'll probably sell all the 31 spline stuff. I need to save a a few bucks first, so I can afford the new parts. Let us know what you decide.

I would like to keep using my 31 spline axles and just use the 31 spline wavtrac to save money but I don't want to regret not going 35 spline on down the road. I'm waiting for Bob's input or someone with a strong knowledge of this to chime in before I make my decision.

Anyone else?

In my opinion, once you upgrade all of the other parts to bulletproof status, then the axles will start to fail with that much power. Do yourself the favor and spend the extra few hundred bucks on at least 33 spline axles if not the 35's. I had my 9" built with 35's just so I know I wont ever have to mess with them again. It also allows for further power gains if you want to in the future. Do it once and it will save you money in the long run.

In my opinion, once you upgrade all of the other parts to bulletproof status, then the axles will start to fail with that much power. Do yourself the favor and spend the extra few hundred bucks on at least 33 spline axles if not the 35's. I had my 9" built with 35's just so I know I wont ever have to mess with them again. It also allows for further power gains if you want to in the future. Do it once and it will save you money in the long run.

Im thinking this too but want some solid proof of they will or they probably won't break makeing x amount of power. I think the axles are going to set me back another $370 on top of the already hefty price tag of the Wavtrac.

I would do 35 splines if your M6 JMO.

If you goto brutespeed's website they have a formula on there on the axel page that lets you calculate how many splines you need.

I'm going to be right at 600rwhp on spray and 700 over the limit on the 31 spline axles.

If your going to drop the cash on the Wave/S-trac you would be better off just opting for the 35 splines because you will end up regretting paying that much money on a 31 spline unit.

But check out that formula it will give you the answer your seeking about the limits on the spline counts.

There is also the problem of axle flex/bend, not necessarily breakage. These cars are heavy enough, make enough power, and most are being hit with a 5000rpm shock of a clutch.

It only makes sense to use 35 spline axles if doing a swap, but chances are if you have a 31 spline setup now that the center section case is a 3.06 bore, and the side bearing size keeps you limited to 31 spline unless using a spool. Wavetrac is available in 31 spline, S-Trac is 35 only.

Each individual person will have to make their own decision, but chances are you will get better returns out of a complete center section and axles as a set. Someone looking to save a few bucks on upgrading to a 9 inch will make use of your parts, and only need to purchase a new housing then. This way you can step up to a 35 spline package which will be good for pretty much anything that is able to be street driven.

I just did this exact swap for a customer that was in need of a better setup than originally purchased, and now will never need to look back. If anyone with a 9 inch rearend- no matter of brand- is looking to make a upgrade, MWC has more options for center sections and axles than anyone else, and as always the best prices. Whether it's a S-Trac, Wavetrac, iron or aluminum, 3ch or 4ch abs MWC has you covered. We can even setup 3ch abs on any 9 inch rearend, even if it wasn't originally equipped with the option.

Im in the process of putting a 9" in my Camaro... I went ahead and took the plunge and am going with a 35-spline wavetrac setup as well. Want to build the sucker right the first time, and not look back.

So I found the axle strength site:

http://qp.doonce.com/axle_tech.htm

From what I can tell making roughly 525 TQ to the wheels right now with a 3.80 gear useing their formula it comes to 4776 which is well below their 7000 rating for a 31 spline axle. The problem is im not sure if they are useing the TQ rating at the flywheel or at the wheels. If its at the wheels im good, if its at the flywheel then not so much. Any input?

First multiply your engine's torque by its First gear ratio, its ring-and-pinion ratio, and 0.90 to account for driveline loss. This is per Bob's website.

FORMULA

Torque at
rear axles = Torque x First gear
ratio x Rear gear
ratio x 0.90

Equals= 5492

That taking your 525 and just adding %15

Yeah thats the formula I found. Problem is I dont know exactly how much I am making at the flywheel. Would that 15% be pretty acurite with it having a procharger on it? I know the axles are good now. My concerns come into play when I build a motor and make 650-700 tq to the wheels.

Yeah thats the formula I found. Problem is I dont know exactly how much I am making at the flywheel. Would that 15% be pretty acurite with it having a procharger on it? I know the axles are good now. My concerns come into play when I build a motor and make 650-700 tq to the wheels.

I put in 600 when I did it for me as a round up for when I hit the juice and it was in the 7700 range using a 4.10 gear for reference.

I have an almost identical car. And almost identical situation. I sold the Tru-trac before it broke and replaced it with a 31 spline spool. I want to ditch the spool and use the S-track, though, which is 35 spline. I want the Strange Hybrid case too. I'll probably sell all the 31 spline stuff. I need to save a a few bucks first, so I can afford the new parts. Let us know what you decide.

I guess i'm just going to stick with my 31 spline axles and just put a 31 spline wavtrac in. I wish i could do 35 spline now but i can't afford to right now. Now I just got to save some coin so I can order the diff and get it in.