McRat

CCB ZR1:

OK, ready for an AutoX (Calspeedway) with an 1800 mi car that wasn't driven hard.

Brakes:

I went from 60/65 to 20 mph just under the ABS limit, occasionally barely hitting it. Repeated 30-40 times before a cop showed up. About 15 minutes worth. The pedal was hard, then got very soft, then firmed up again. Smoke was coming off the fronts. I cooled down for 10 miles. Very light coat of white on pad edges.

Yes, I had to cut it short. Feels OK.

Is that enough? Or should I try again?

Oil hot is 1/4" over full on the stick.

Flushed clutch fluid with DOT 4, until clear.

Factory alignment to start.

OE PS2 tires at 34psi hot all corners.

Am I forgetting something?

05dsom

^^ haha, love it.

that is the street burnishing process done well if they were smoking, stinking and you got the white outline at the outer edge of the pad (do a search on the ZR1 forum about this topic).

GM also recommends the "track burnish" procedure for road racing ? HPDE, but it may apply to AutoX as well....it is also in the owners manual.

McRat

Well, after 8 runs, the clutch sent me home, sticking pedal. Brakes were fine.

For OE PS2 runflats, 32-34psi is the best. No understeer even at 32psi front.

Apocolipse

Seems like an excessive amount to bed pads...Do those take longer than most?

05dsom

http://forums.corvetteforum.com/c6-c...urnishing.html

mountainbiker2

That actually looked like a fun track. How did you do?

Steve

McRat

Well, I can tell you what I did worked great. Brakes of Death. Good feel, tons of power, no ABS hassles.

We did not bed the OE Brembo steel rotors and pads on our CTS-V. I drove that the second day. DAMN, what a difference. I had thought the CTS-V brakes felt fine until the ZR1 spoiled me.

McRat

Track was short by SCCA standards, median time was probably 40 seconds for fast cars.

So-so. First lap, 38.0 (PTM level 3), best 36.1 (ALL OFF).

But I had a blast. 32-34 PSI was all that was needed on the OE Michelin PS2 runflats. I looped it once (full 360° and no cones), and still put down a 42.x lap.

I did not change alignment specs or anything. Felt good.

ALL OFF is the way to go. Not just because it's faster, but because it's easier to drive that way. I did not loop it in ALL OFF mode. I looped it with the babysitter on 4 or 5.

37.1 was the time for the CTS-V. Trans overheat sent me home.

sd7ss

Looks like you did great! Thanks for the posts and video. Interesting.

Skylane spent Saturday and Sunday getting up to speed at Qualcomm.
He's going to be really good when he gets used to the car. Went from rank novice to really respectable in about ten laps. Paid attention, listened, and learned fast. Consistently getting better with each run.

Short course for us. Times in the high forties and low fifties, all turns.
No problems with the Z/28 at all. Maxed out the camber full negative, about 2 degrees I'd guess, and ran the Pirellis hard to save the edges.

You said the clutch sent you home. Were you using it much? Interested in the story there. Been reading about the Z/28 clutch problems, and very interested in the causes and possible solutions to the issues, in case I pop for a 1LE any time soon. Some people seem to have no trouble at all; others seem to be dogged by it.
Let us know how it goes. Be really interesting to see how it would do with some fresh rubber on a little faster track where you could get into the power and brakes a bit more more.

Stay with it!
Best Regards,
John

05dsom

McRat

Thanks!

The car had barely been driven (1700 easy miles) and still had **** on the tires.

On the way home, the pedal stuck to the floor in stop and go traffic. Had to get towed to the dealer. They replaced the master.

I get it home, and did a couple of 3000 rpm launches on the street, and a PTM "Launch Control" test.

Everything OK. Replace the fluid again. Clear.

Take it to the AutoX, and I launch at about 2500, then short shift into 2nd. Engine has enough power to oversteer at 3000 in corner. Never touch the clutch again during a run.

On run 8, when I went to the 1-2 shift, the pedal was stuck 2/3's the way down, and barely disengaged for the shift. I could smell clutch.

By the time the run was over, the pedal popped back up. I'm thinking it's the slave sticking? Dunno. I'm just going to replace the clutch, pressure plate, flywheel, hydraulics, and pilot bearing, and try again.

I'm familiar with LSx clutch hyd issues. But usually it takes a lot of use to make it kick in. AutoX is not normally hard on clutches, and certainly 8 passes isn't a lot in 3 hours.