Chris Edwards

Is there any advantage at all for an open track car to "upgrade" to a C6 Z06/ ZR1 diff and TR6060, or is an MN12 T56 and 3-Rib diff with the cooling setup for each perfectly sufficient?

Chris Edwards

Anyone have insight?

C5 Hardtop

The C6 and C5 diffs are one of the best pieces of the pie. Both put the power down on track. The drag strip? Not sure, but I've always had "posi" burnout marks. Never a peg-legger!

After tracking 2 C5's and 2 C6's including both gen Z06es, I can't tell there is zero difference because every one of them was flawless. Never needed to think about it. Rather, enjoy excellerating out of a corner putting the power down. Ahh!!!! So fulfilling

One or both gens did have rear end noise around a corner driving in the streets when new that was attributed to a lack of friction modifier. Completely benign. I guess Bowling Green forgot to add that.

If you have a C5, stick with that rear. I understand both diffs (not counting half-shafts) are Getrag with kick-*** clutches.

0Anthony @ LGMotorsports

Early C5 diffs are almost worthless and not to much point in building

The later C5Z06 cases are better and we ran them for years without to much of an issue (DOT R tires, 470 rwhp, 3100lbs). Diffs were rebuilt 6-8 races (50 min races)

Later as the cars got more power and traction control started we started to crack the cases. The 2006 and up C6 cases have a bit more material and will hold up much better. Diffs were rebuilt 2-3 races (50 min races)

By the time we were in GrandAm we used ZR1 diffs with the Emco sequential boxes because of the larger ring/pinion, larger output shaft/ and stiffer case. Diffs were done after 3-4 races (endurance events....so 2-5 hr races)

The C6ZR1 is by far the strongest one of the bunch but you are limited to a 3.42 gear set.

Chris Edwards

Anthony, thanks for the post. What wear items are replaced when the diffs get rebuilt every few races?

0Anthony @ LGMotorsports

We were still using clutch pack diffs, so the clutches were typically the first part that went. After that we started to mileage out gears and cases.

Chris Edwards

So a Quaife is actually a good way of extending gear/bearing/case longevity due to the fact that clutch material doesn't start circulating through the diff over time?

0Anthony @ LGMotorsports

Doubt it would help gear life....but it would completely stop having to rebuild the diff for a weak clutch pack.

Only thing we had found is that not all drivers like that style of diff so to some degree it is up to the driver.

C5 Hardtop

I think there are contradicting experiences with the diff quality (LG Motorsports and I). To add clarity, I want to add context to my previous post that was stating the diff kicked *** which I still believe.

The usage was driving showroom stock Vettes (except brake modifications & shifter) on street tires at HPDE events frequently through the seasons. Not racing like Lou does.

Each Vette was a daily driver in Seattle (Redmond). They were driven to the race tracks, lapped all day and some times back-to-back days. Then driven back home as far away as T-Hill in central(ish) CA which was a 1,370 mile journey. There was a time when fluid blew out the GetRag bleeder in the C5 Z and made a mess. The fluid spew occurred "canyon carving" through the Siskoues (sp) and various mountain ranges/passes that span between OR and CA with ambient temps over 110F.

0Anthony @ LGMotorsports

The rebuild times I am speaking of are in a WC GT car.

490-500 rwhp
3100 lbs
at the time on Toyo RA1 shaved tires....and we did have standing starts.

ratt_finkel

Anythony, what are the weight differences between the diffs?

For sprint racing with no launches, would a C5Z diff with a quaiffe be reliable? Rcomps, 2800lbs 800whp.