Z51 E-diff failure first time at drag strip
Thread Starter
Safety Car
Joined: Jan 2012
Posts: 4,885
Likes: 486
From: Cin City
St. Jude Donor '14
Z51 E-diff failure first time at drag strip
I have thought so far these were pretty bullet proof unless some of the failures hadn't been discussed openly? I know some axles broke but this is the first e-diff to my knowledge? I know in other cars the diffs can bee problematic, but GM's technology on the 4500lb CTS Vs for diffs and axles hardly ever break, so I'm hoping this is just bad luck.
Car:
2014 Z51 7M with Procharger
Craig was having some traction issues with his Michelins so he upgraded to the Toyo R888s on his new wheels and took it to the drag strip to see how his car would do.
Dumped the clutch at 3500 and carnage for the new e-diff and hooking that hard!
Car:
2014 Z51 7M with Procharger
Craig was having some traction issues with his Michelins so he upgraded to the Toyo R888s on his new wheels and took it to the drag strip to see how his car would do.
Dumped the clutch at 3500 and carnage for the new e-diff and hooking that hard!
Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
I did this every 6k to a 66 GTO until they added two more pinion gears to the updated HD unit. I was thinking spider gears were a thing of the past with the E-diff using clutch pack to lock and unlock axles and housing, live and learn I guess! Great to see but not at somebody's expense. Thanks for posting
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Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
Those R888s are sticky but they also have very stiff sidewalls that offer no 'give', the axles and rear diff gets ALL of the hit, especially with a manual trans/clutch.
Not saying that on a drag radial with a softer/tall sidewall that it wouldn't have still broken, but I've seen road race/autocross tires destroy rears in the past as well.
Drag radials (or even D.O.T. street slicks - ET Streets/Quick Time Pros) only along with proper pressures and burnouts for a 'stock IRS' car making this kind of power, in my opinion.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Even a C5 or a C6 with a manual trans was subject to breaking output shafts---This is nothing new for a C7----If you wanna go fast you're gonna break parts---That's why all serious bracket racers go to ford 9" rear ends and heavy duty axles----- A Corvette is NOT a purpose built drag car----Drive it as such you're gonnna break something !!especially if you want to leave hard at 4000 RPM's--
That's why I bought an automatic---The violence at the launch is not as severe ---and these New A6's have the same drivetrain loss as a previous manual trans Like only 10-12 %---------Want to make your manual trans bullit proof ?? And with a SC ?? You must shore up your rear end with heavy duty output shafts and a built rear end and clutch------JMO
That's why I bought an automatic---The violence at the launch is not as severe ---and these New A6's have the same drivetrain loss as a previous manual trans Like only 10-12 %---------Want to make your manual trans bullit proof ?? And with a SC ?? You must shore up your rear end with heavy duty output shafts and a built rear end and clutch------JMO
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
I had actually meant to mention/ask in my post above if there was any wheel hop on this C7 right before (even if it was on a pass or two before) it broke, bad hop will do it every time. 
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
My 2014 shows no wheel hop at all even with the TC off and the Stabilitrack OFF- It will spin the tires badly but not HOP---My quickest runs were made with both the TC and STABILL, TRACK OFF and by trial and error figuring how to do the perfect feathered throttle launch--
Last edited by tblu92; Nov 16, 2014 at 11:24 PM.
Racer
Joined: Feb 2014
Posts: 457
Likes: 10
From: Baxter Kentucky
My 14-3LT-Z51 M7 with magnetic ride , has some wheel hop at the top of second gear for some reason. First gear, not so much if any. This is on stock tires and in sport or track mode.
What does the C7 use for the torque bushing or mount. Maybe need something in the Prothane to stiffen it up. This is my first vet, so im not too familiar with there suspension setup in the rear. Is there a particular air pressure that the tires need for drag racing ?
What does the C7 use for the torque bushing or mount. Maybe need something in the Prothane to stiffen it up. This is my first vet, so im not too familiar with there suspension setup in the rear. Is there a particular air pressure that the tires need for drag racing ?
Last edited by Randy WS6; Nov 11, 2014 at 03:11 PM.
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
Personally, I would lower them to maybe 26psi at the drag strip but again it really makes very little difference.