Axles - When are they needed?

SpeedRacerX

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Jan 20, 2014
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Is there a rough answer, based on HP or ET or 60-foot, as to when aftermarket axles are needed?

My car currently has a newer Eaton Posi with factory axles. Car makes about 400 RWHP according to the drag calculators, runs 11.8@114-115 with a 1.63 60-foot.

It's about to get a bump in power this Spring and should run into the low 11s (high-mid 10s once I address the heads & cam) so I'm wondering when an axle upgrade might be warranted.

Also, when axles do break, is it the axle just breaking from torque twist or is it weakening clutches in the diff that allow the axle to move outward and then break??

In the Pontiac G8s, the root cause was the latter and we knew the exact recipe (tire, converter, etc.) for when this axle ejection would occur.
 

T- Type Tim

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Jul 8, 2001
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some one is about to say stock axles have been in the 9s......i did mine when i had the rear end apart for gears.....then replaced them again when i put a 9" in...now i know i will never break one
 
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MCH86GN

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Aug 20, 2008
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I've ask the same question as you and I've gotten a couple different answers. One of the answers was I planning on running 1.4 or better 60' times. One person told it depends on the weight of your car and power your making, etc. Never got a straight answer.
You already have the Eaton Posi and with new power level you're going after a good set of after market axles might not be a bad idea. However, if you that far you might as well upgrade the driveshaft with billet yokes, one on the differential and other on the end of the driveshaft. Then you have no weak link in the chain.

Hopefully others will chime in, who have more experience than me and help you make a decision.
 

MCH86GN

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Aug 20, 2008
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Get axles and a good driveshaft. I did run 10.0 with a 1.34 60' on stock axles and driveshaft though.
What was the weight of your car? If you remember. Last time I weighed my car I came in at 3800lbs with me in it. Hopefully, it has lost some weight with GNX knockoff rims and removing the spare tire.
 

dank GN

BlackArts Automotive (661)993-8277
Jan 11, 2009
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I would suggest you get c clip eliminators as well as you will need them once you dip into the 10s . I did moser axels with c clip eliminators a Eaton tru Trac with stock gears and a TA cover . I also welded the tubes while I had it out .
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RUQWKNF

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May 26, 2001
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Years ago ("98-"99) I took my old white "87 T Limited "RARE T" to a best of an 11.07 @ 121, with a 1.52 60ft. Bone stock G80 posi rear end on bias ply ET Streets. This car was a full weight 3950ish with me in it, stock engine, ported M&A aluminum heads, matching intake, TE45 turbo, eastern FM IC, 009 injectors, Bosch external pump and an old school Max Effort chip. Pure C-16, 26* timing in all gears, 27psi and e-brake launching at 14-15psi. It was a blast tearing out in that one as I was street racing it every weekend. I also took my first car, "RU", into the 10.90's with mid 1.5's on a Eaton posi equipped stock rear end. That car was lighter. It was 3675 with me in it. RU eventually got a built 8.5" with c-clip elims, Strange axles, full spool, cover with rear end brace kit and welded axle tubes. I also ran a Denny's driveshaft. It went a best 60ft of a 1.44 with those goodies with old school SSM lower bars, stock upper bars, 1" ATR rear sway bar and dual air bags. That's old school stuff and slow by today's standards though. Seeing how far the cars have gone since then. Especially in H/U racing classes.

With these cars as old as they are now, I'm sure the age will lower the life expectancy of a stock rear. As a bare minimum, I would get Moser stock replacement axles with longer ARP wheel studs.

What they've said is correct, weight, power and 60fts can find the weak link on a stock rear. Sure, some break on 1.80 sixty foot cars as everyone is different. IMHO, if you definitely know you're going to be seeing low 1.50's or quicker short times and the car is heavy, it's not if it will break, but when. Just the axles and wheel studs are peace of mind, until you can spring for all the rest. It's a pay to play ball game at this level. I should know, I'm headed down that old familiar road again myself.
Just my O2's worth.
:D

-Patrick-

RareT.jpg~original.jpg
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Mr.Spool

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Nov 6, 2006
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Is there a rough answer, based on HP or ET or 60-foot,no.power applied to the ground and how many times it's done and age will be your real world factors.i went 16 years 65k on a car that would go 1.4/1.5 60fts @3800+lbs and 10 sec et' s on stock axles and they were really wavey when I pulled them.i think 28 spline upgrade if the car leaves hard would be good enough.if your spinning on the street don't bother:D
 

Mr.Spool

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Nov 6, 2006
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Is there a rough answer, based on HP or ET or 60-foot,no.power applied to the ground and how many times it's done and age will be your real world factors.i went 16 years 65k on a car that would go 1.4/1.5 60fts @3800+lbs and 10 sec et' s on stock axles and they were really wavey when I pulled them.i think 28 spline upgrade if the car leaves hard would be good enough.if your spinning on the street don't bother:D
. I did run 10.0 with a 1.34 60' on stock axles and driveshaft though.
Lol the stock driveshaft is the only thing o. The car I haven't been able to break:eek:
 

TurboWh1

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Upgrade the axles. If nothing else you wont worry about breaking one. There are two types of c-clip eliminators out there. You want the tapered roller bearing version if you want to drive your car on the street.
 

Mr.Spool

Well-Known Member
Nov 6, 2006
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Is there a rough answer, based on HP or ET or 60-foot,no.power applied to the ground and how many times it's done and age will be your real world factors.i went 16 years 65k on a car that would go 1.4/1.5 60fts @3800+lbs and 10 sec et' s on stock axles and they were really wavey when I pulled them.i think 28 spline upgrade if the car leaves hard would be good enough.if your spinning on the street don't bother:D
. I did run 10.0 with a 1.34 60' on stock axles and driveshaft though.
Lol the stock driveshaft is the only thing o. The car I haven't been able to break:eek:
We busted a stock driveshaft in half in a low 10 sec car that only 60' in the mid 1.4s. Most of the time it had street hits, not much track time.
Blew the rear ended out of the car leaving at the track:eek:stock driveshaft survived my friend drew a penis and a king hat on it as a reminder:D
 
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