Which diff for 600hp?
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 2,412
Likes: 3
Which diff for 600hp?
Does anyone beef up diffs around here other than Toms? What type of diff or diff service should I spring for for 600hp (450 - flywheel) motor (150) nitrous without slicks (275 z rated tires)? I saw that Toms has a 12 bolt diff, would that be over kill for me? Also is the 4 series carrier different from the 3 series in terms of strength?
Also if it's an option I would like to send out my stock diff to get built up. To save on cost.
Also if it's an option I would like to send out my stock diff to get built up. To save on cost.
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I just have a series 4 with richmond gears and Tom's super main caps, $700 posi unit, custom hardened yokes.
But then your into it so much that the smart guy would buy a 9 inch or 12 inch IRS.
Why are you only going for 600 hp? You really need about 550 crank and 250 shot to make a Vette a fun car to drive.
But then your into it so much that the smart guy would buy a 9 inch or 12 inch IRS.
Why are you only going for 600 hp? You really need about 550 crank and 250 shot to make a Vette a fun car to drive.
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 2,412
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I might have gone a little crazier with the vette when I built the motor but when I built the stroker it was my daily driver. After the nitrous and the diff I plan to do some headwork and portmatching, maybe a bigger cam if I can convince myself.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
My upgraded drive train has just amazed me because of how long the parts have lasted. I just spent two track days with 12 inch road racing slicks and lots of miles of either stomping on the brakes or petal to the metal. I do shift quick, but nice to not abuse my tranny.
Melting Slicks
Joined: Dec 2005
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Melting Slicks
Joined: Jan 2006
Posts: 3,028
Likes: 2
From: North NJ
If your planning on dropping the clutch hard and running slicks I'd convince myself to go with the 12 bolt from Toms. It'll take anything you throw at it. You might just have to indent your battery/storage box. At that point your diff won't be the weakest link and you have to start looking at half shafts, I beleive toms also has a kit that works with the 12bolt that upgrades the halfshafts and Ujoints. You need special/larger ujoints with the 12bolt flanges.
If your not running slicks and repeadedly dropping the clutch you can rebuild your stock diff and beaf it up to handle the power. Toms rebuilds, as well as Gary (GTR1999) and a member in texas (can't remember his forum name at the moment).
I know Gary is very busy, but PM him and check his availability.
He does amazing work.
If your not running slicks and repeadedly dropping the clutch you can rebuild your stock diff and beaf it up to handle the power. Toms rebuilds, as well as Gary (GTR1999) and a member in texas (can't remember his forum name at the moment).
I know Gary is very busy, but PM him and check his availability.
He does amazing work.
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Team Owner
Joined: Jul 2001
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
For a stick shift high HP car with slicks there are no cheap solutions.. The total cost of the upgrade will be at about $5k or so if you do all the work and a few hundred more if you'll have it done.. If you wanna play, you gotta pay.. That's life..
With any other commonly available setup, it's gonna be a ticking time bomb and it's only a matter of time unitl any of the rear end components breaks..
Last edited by GrandSportC3; Apr 16, 2007 at 05:57 PM.
Le Mans Master
Joined: Oct 2002
Posts: 5,714
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From: Silver City NM
St. Jude Donor '05-'07
And the answer is...
Even Tom's has been known to shear axles.
And yes...the above setup is on a C3 Vette.
http://cgi.ebay.com/ebaymotors/MOTIO...QQcmdZViewItem
Dep
Even Tom's has been known to shear axles.
And yes...the above setup is on a C3 Vette.
http://cgi.ebay.com/ebaymotors/MOTIO...QQcmdZViewItem
Dep
Last edited by DJ Dep; Apr 16, 2007 at 06:17 PM.
Pro
Joined: Apr 2005
Posts: 591
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From: Batavia IL
Now I maybe missing something here, but It seems to me that installing a 12 bolt ring and pinion yourself would not be too hard of a task. Tom's differentials sells the special 12 bolt ring and pinions seperatly. after that you just need to grind out with carbide cutters the clearance for the larger ring. Then add those heavy duty caps and get a set of 30 spline axles from van steel. Set up the gear mesh right and your good to go. Using a spool would be cheaper or maybe a locker. I calculated it would cost half less than having Tom's do it for you.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
And the answer is...
Even Tom's has been known to shear axles.
And yes...the above setup is on a C3 Vette.
http://cgi.ebay.com/ebaymotors/MOTIO...QQcmdZViewItem
Dep
Even Tom's has been known to shear axles.
And yes...the above setup is on a C3 Vette.
http://cgi.ebay.com/ebaymotors/MOTIO...QQcmdZViewItem
Dep
For example Greg Eaton!
http://home.earthlink.net/~geaton
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Solid axles are great.. However, my 12-bolt IRS had been holding up great and there are cars much faster than mine running one too..
For example Greg Eaton!
http://home.earthlink.net/~geaton
For example Greg Eaton!
http://home.earthlink.net/~geaton
Dep
Drifting
Joined: Jul 2002
Posts: 1,995
Likes: 110
From: Garland Texas
Torqvette,
The 4 series carrier is margainally stronger than the 3 series. The outer edge is thicker at the ring gear but that has never been a weak point. The 71-newer posi cases and internal gears are stronger than the earlier ones. All stock cases have casting defects. New replacement cases are stronger but you need to use the 10-17 gears, not the new replacement gears. Where are you located?
Mike
The 4 series carrier is margainally stronger than the 3 series. The outer edge is thicker at the ring gear but that has never been a weak point. The 71-newer posi cases and internal gears are stronger than the earlier ones. All stock cases have casting defects. New replacement cases are stronger but you need to use the 10-17 gears, not the new replacement gears. Where are you located?
Mike
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
From the files of the "BTDT Department"... For 600hp, even a strong 10-bolt setup just isn't going to go the long haul (I've wasted several with a good deal less hp than that, on street tires). And, on the other hand, with a proper 12-bolt IRS being capable of handling 1000+hp, there's no need to unnecessarily ruin the handling of your Vette with a solid axle chop job. Personally, I've also been the course of having a local shop convert an IRS to a Moroso posi based 12-bolt, only to end up happier with the Tom's (then Henry's) Eaton piece.
If this is the beginning of a truly hardcore drag project, you could always just call Mark Williams and be done with any diff. problems once and for all.
In any event, before finallizing your decision you owe it to yourself to read this, if you haven't already:
http://www.hotrod.com/techarticles/1...e_irs_buildup/
btw... my 12-bolt IRS is behind a rather stout BB and a Muncie, not an automatic. After going to the HD stubs w/1/2" lugs, I never had any more troubles back there, though I broke a T-10. But, that's another story...
If this is the beginning of a truly hardcore drag project, you could always just call Mark Williams and be done with any diff. problems once and for all.
In any event, before finallizing your decision you owe it to yourself to read this, if you haven't already:
http://www.hotrod.com/techarticles/1...e_irs_buildup/
btw... my 12-bolt IRS is behind a rather stout BB and a Muncie, not an automatic. After going to the HD stubs w/1/2" lugs, I never had any more troubles back there, though I broke a T-10. But, that's another story...
Last edited by TheSkunkWorks; Apr 30, 2007 at 08:05 PM.
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Well, I'm running auto but will run the transbrake with my new setup that should get me into 8's on a 250 shot...
A transbrake is just as violent on components like a stick shift car. I believe that Greg Eaton is leaving off the transbrake...
A transbrake is just as violent on components like a stick shift car. I believe that Greg Eaton is leaving off the transbrake...
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
The bigger axles require bigger bearings and a trailing arm rebuild is required.. It doesn't make sense to have a 3rd member that hold sup to 1200 HP if the axles and half shafts will break at 550 HP.. In order to have lasting fun, you need to fix all weak links instead of shifting the weak link from one component to another one..
Oliver - has a very true statement. I completely wasted my stock outer axles and trailing arms. When I took them off for a rebuilt/refurbish the axles were rotated nearly a whole spline from the years of pounding. I do not know what kept them from shearing.
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
What RPM are you bringing it up to (or however it works, I never ran an auto) before the shock hits the rear tires?