dbratten

After running a HPDE at Buttonwillow Saturday and an autox Sunday I feel a better differential is needed. With Kumho 710 335s it is spinning the inside tire in the corners way too much. The OEM unit was rebuit by the dealer under warrantee with new clutches not too many races ago but just doesn't seem up to the task.

I find a Quaife available for the C6Z but nothing for the base/Z51 models. I have the A6 which may also matter. Does anyone know of a good option for the C6?

TIA,

--Dan

davidfarmer

DTE, Zip, etc can beef the clutches up as much as you want. I don't autocross, but I've never had that kind of problem with these cars.

Zip Corvettes

I have a Quaife for a standard C6 in stock.

gkmccready

Dig up the thread LG posted in about checking the clutch pack lockup torque, etc...

dbratten

Thanks to everyone.

Justin, I sent you an email.

--Dan

0Louis @ LG Motorsports

VERY important!! It can really wreak havoc on the handling and setup on the car if it is out of whack!

dbratten

I searched for the thread and couldn't find it. Can you provide me with the link or the information again?

Thanks.

--Dan

BrianCunningham

Did they ever come out with one for a C4 D44?

C6400hp

What are the options when it is out of whack? If I jack up one side of my car and put the torque wrench on the axle nut with the car in neutral, i only get 60-65# before the clutchpacks break free. On standing starts it seems to lay 2 tracks of rubber just fine and I dont think i am getting the one wheel peeler.
Anyone have estimates for the labor to replace the clutch packs with the Quaife unit?
Is the Quaife piece worth the price over clutch packs rebuilt to more aggressive specs?
Other options?

0Louis @ LG Motorsports

That break away level is happy medium for corner entry, and not much push on corner exit. You will have to drive it in the corner, as with that preload (not much) its going to walk around trying to get it to the apex.

The tighter you make it, 90-110, 110-130, its going to be very stable in and push out ( more and more like a spool, the tighter you make it)

The car will get goofy on corner exit like the OP stated when break away torque is low.

As for the Quaife, we tested it, Lou went quicker by .5 compared to a perfectly setup clutch pack diff, but he could not drive it in the corner with out it snap oversteering. The potential for a spin was much greater. In a race, + .5/lap means nothing, if you cannot keep the car under control.

Use the quaife at your own risk, many many love it and swear by it, we tried it in 05, and couldnt use it.

Hope that helps.

Louis

C6400hp

Everyone go check your diff and see at what torque it breaks free, lets have a comparison.

jiggyracing

the differential on my c6 z-51 PTA/ST-2 car was breaking loose and the car was awful coming out of a turn. i was losing huge amount of ground exiting turn #9 to enter the NASCAR track at PIR. the car was, however, very stable under braking.

i now have a quaife rear differential. i have not yet pushed the limits on breaking. i go to Cal Speedway end of July and this should be a good test on the exit of the NASCAR oval and onto the inner track.

in terms of "slow in, fast out" the quaife seems to have its advantages.

it's a little hard for me to tell as in addition to replacing my broken diff with the quaife, i went from leaf springs to your coil overs - which i have been very happy with by the way.

Louis, are you saying that in terms of outbreaking maneuvers the quaife is a problem? how will the quaife perform in the high banking/high speed NASCAR turn at Cal Speedway?

relatively new to the sport, am i thinking about all of this correctly? please correct if wrong.

JIGgy racing
Tucson AZ

OKsweetrides

^^^
My opinion:
The propensity to spin when diving into a corner is higher with the Quaife. It's a hard feeling to describe, but it does not like to be unloaded. It's a power-on style diff if that helps.

gkmccready

87# on my '06 C6 Z51.

dbratten

I can't find an answer from my dealer techs or a couple of rearend shops I've called locally. Can my base model A6 diff be adjusted for higher breakaway torque?

I'd check the current torque but never bought an axle nut socket during the panic a couple of years ago.

--Dan

0Louis @ LG Motorsports

The only way for it to be adjusted is removing the diff, and shimming the clutch packs. Different styles of washers also determine how aggressive it is on break away and how long you can keep it in the window of acceptable break away torque ( IE endurance race, etc)

0Louis @ LG Motorsports

It was stable under braking due to the diff being near open. The unstableness on corner exit, was due to the diff....Being near open. Its a happy medium.

I cannot comment on how the car will react with the Quaife, As OKSweetrides commented, it doesnt like to be unloaded on corner entry, so trailbrakers may have some issue with it.

Again, if you are in search of the perfect differential, you need to test what works for you. Its not cheap, which, if you go with a built stock unit, its hard to go wrong as far as driving.

Like I said, it all depends on how you drive. Leighton loved it, and thats where ZIP started making them fit. We tried it, It didnt work for us . Just because it didnt work for us, doesnt mean it cant work for you.




Bingo.

C6400hp

Can you adjust the clutch pack breakaway by altering the amount of sliplock additive? Any downside to doing so? Louis, what is the cost of rebuilding / shimming the clutchpacks? Is it something you guys do inhouse?

Thanks

0Louis @ LG Motorsports

Less friction modifier= less break away, more = more, and it does have an impact on how the car drives!! Take note= Some oils have SOME friction modifier in them, others do not. Redline does, and we add one bottle of modifier to it.

Ill have anthony send you a PM

C6400hp

Thanks, Are you saying that if I use less additive the clutch packs will break away at a higher torque number? Any idea how much one can change the breakaway torque by adjusting modifier amount? 10#20# more? Any damage to components from doing so?