My car is a 95 Z28, Advanced Induction Econport heads, GM847 cam and all the essential bolt ons. Last year through the stock 10-bolt with 4.11 gears and a T56 with a mcleod clutch it made 404.8rwhp, 365.1rwtq, SAE corrected of course.

New setup is a built 4L60E, PI Vigilante 3500 stall, same rear-end, driveshaft, wheels, PCM tune and mods. Yesterday it made 368.0rwhp and 353.9rwtq

So there it is, 36.8rwhp and 11.2rwtq loss between a T56 and an A4 with an unlocked converter, atleast in my car. In both cases hp peaked at 6400rpm. But with the T56, peak torque was at 3800rpm and with the A4, peak torque is at whatever rpm you nail itbecasue of the stall converter. I was going to have track results today but the track was closed due to an IHRA event.

Those 4.11's haven't been breaking stuff. A guy told me not to put 4.10's in with a stock setup. What kind of tires are you running?

4.11s are stronger than 4.10s. I broke a couple of 4.10s but since I swtiched to 4.11s I've been lucky. Tires are BFG Drag radials 275/50R-15. Insane traction. I drive everywhere with them.

what #'s did u put down, when the converter was locked?

I never locked the converter. When I wired in the 4L60E harness I marked the TC solenoid wire but since I have a built TH400 waiting to go in I didn't wire in a switch.

Interesting. My setup, at the 486 flywheel HP level showed 12.6% drivetrain loss (425rwHP) with the Street Twin/steel flywheel, T56, 3" chrome moly DS (19#), 3.73 Strange 12-bolt and 17x11/BFG DR's. Loss was calculated by comparing an engine dyno with full intake and exhaust to a chassis dyno pull.

Switching to the TH400 with a loose, non-locking convertor increased the drivetrain losses to 19.8% (390rwHP), with an additional 35HP lost in the drivetrain. Numbers seem similar. Will be interesting to see what happens when you install the TH400.

now i'm kinda happy I switched from an A4 to a M6, since I AM a dyno-racer

Let's see how it runs though.

Do those 4.11's whine more than the 4.10's did? I have heard it is harder to setup the 4.11's quietly than 4.10's.

4.11s don't necessarily make more whine than 4.10s. It depends on the gear brand and installer more than the ratio. I had Richmond 4.10s that whine alot more than the GM Motive 4.11s I use now.

Cool, well if that's the case, and that 4.11's are stronger gears, then 4.11's will be the gears that I will be going with.

Let's see the track results in comparison!
I went from stock A4/ST3500 to a Th350/Vig 3500 and picked up some ET.
12.3s were my best with the A4, finally ran 12.0s consitantly with the TH350 but that is a tough comparison b/c I dont have the DA on all runs but the weight would have been close to the same.

Now I have track results. Previous best with the 6-speed was

60ft – 1.874
330’ – 5.184
1/8 ET – 7.912
1/8mph – 90.03
1000’ – 10.222
¼ ET – 12.189
1/4mph – 116.64

Last night at the same track and same weather conditions with the A4 leaving at 1500rpm it ran

60ft – 1.690
330’ – 4.974
1/8 ET – 7.771
1/8mph – 87.60
1000’ – 10.134
¼ ET – 12.160
1/4mph – 112.57

So its slightly faster at a much lower ET, but waaaay more consistent. Damn near all my runs were within 1 tenth of each other and less than 1mph apart. On the dyno it ran too lean, 14.0:1 air/fuel ratio and on my runs it was pulling out timing. I’m getting an update from PCMforless and hopefully this thing will run 11s. On the dyno it also picked up 11rwhp and 20rwtq by removing the crappy 2.5” Y-pipe I have on the car so I’ll be looking into getting a 3” Mufflex. And the last thing, 4.11s are too much gear for me. I was shifting into overdrive before the end of the track. I lost 2 tenths on one running by leaving it in 3rd gear.