edster75

Hey guys. Left early from work and went to RT66 Raceway today with my 2000 Z28 M6 with 13,750 miles. My best run was the first run 14.157 @ 102.93 hitting 6k in third through the traps. Rt was .541 with a pathetic 60ft of 2.312. Car is stock except for corsa cat back, lid, sfc, phb, lower control arms. I've also got a set of nitto drag radials. It was hot today, 88.5deg, 72% humidity, 29.91in, the DA was 2969.

The DA calculator on dragtimes dot com says with better conditions I would have ran a 13.65 @ 106.8. How reliable are those calculators?

The track wasn't crowded and I made 3 passes in 10min with no cooldown. On the 3rd pass I thought the tires spun in 1st but it was the clutch slipping. It was also hard to shift into 2nd that pass. I finished the run and let the car cool off for about 30 min. I made one more pass after that and the clutch seemed ok. 14.35 at 102.33 with 2.384 60ft, also through the traps in 3rd.

So did I hurt the clutch or just overheat it? How do you guys think the car ran? The driver definitely needs a little practice.

What mods first? Clutch line drill mod or new clutch master cylinder? Gears? It's got the stock 3.42 rearend. Headers and y pipe?

gesto

If your clutch is slipping I'd take care of that first. Since you were hot lapping in heat the clutch fluid was probably pretty hot. I use a turkey baster between rounds to suck the hot fluid out of the reservoir and add new clean cool fluid. You might need a new clutch. Your car will run faster if you let it cool down between runs.

Then tires. I run a bias ply set up on my M6 GTO and I like them. I've heard the newer style soft sidewall drag radials get good results on a stick car but I can't confirm that. Properly set up and driven your car is capable of 1.8x or even 1.7x 60'.

edster75

I never noticed the clutch slipping before. It is the stock clutch and only has 13k miles on it. It seemed fine on the last run when I gave it 30 min to cool off. The clutch fluid is stock so I probably need to bleed it/change the fluid.


I didn't think I'd be hot lapping. I figured I'd get back in the staging lanes and I'd have a few minutes wait until the next run. There was hardly anyone there so as soon as I pulled up they waved me back on the track.


I'm hoping to go back on Aug 4th. They have another race your ride event at RT66. Hopefully the weather will be a little better.


I have Nitto NT555R in the stock size 245 50R16 on the back. They barely spin on the street and they really hooked at the track. I drove around the water box and didn't even need to do a burnout.

gesto

Before you go to the track get a turkey baster or a radiator test sucker thingy, a new bottle of the proper brake fluid, a clean funnel and paper towels. Suck the old fluid out of the reservoir and fill with new. Then pump the clutch 20 - 30 times and repeat until the clutch fluid is clear. This is not the proper way to bleed the clutch but it will clean the fluid and help a lot. I also do this between rounds.

You actually want some controlled wheel spin. Do this by raising the launch rpms and slipping the clutch out of the hole. I try to hold the rpms at 4,500 then floor it and try to slip the clutch enough to not blow the tires off but spin a little while the car is moving. I get my best 60's so far that way. You will have to experiment with your launch rpms and clutch to find your sweet spot.

The reason I recommend bias ply tires for an M6 is they allow better controlled wheel spin and they absorb more drive train shock then radials and are therefore easier on your drive train components.

Cahill93Z28

you should be in 4th by the end of the 1/4, and with your suspension mods and nittos, 1.9 60' should be fairly easy to obtain.

Sounds like you just need some practice.

edster75

Thanks for the replies guys!


I'm going to bleed the clutch and remove the front sway bar and hopefully go back to the track next Friday. If the weather is like it is today the car should run great. Last time I was a little nervous trying to get a good RT and I wasn't able to leave at a consistant RPM. This time I think I forget about RT and just try to get a good launch/60ft.

edster75

Btw, I ran the car on the Dyno a couple days ago.


https://ls1tech.com/forums/chevrolet...yesterday.html

gesto

That's a really nice clean car.

T6Rocket

With 3 passes in 10 min, the clutch (and car) endured a lot of heat. Try to cool down 20-30 min whenever possible.

Going to the track is fun, now you're going to get addicted to it!

Al

dojob

Just swap fluid as shown here:
http://www.rangeracceleration.com/Clutch_Care.html

or if you want to do the drill mod, just buy this clutch line instead (provides the same or better flow):
https://www.summitracing.com/parts/mcl-139212

And use a good brake fluid with high boiling point

JacobChevys

Shift quick and shift into 4th gear do not stay in 3rd. Slip the clutch from 3k RPM when launching (Roll into WOT do not just mash gas unless you have a full drag slick). Shallow stage. ETs will drop drastically.

Denom

iTrader: (2)

Your 60' is costing you. The trap speed seems spot on considering the DA. If you have the stock 3.42 gearing you don't need to shift to 4th. Those gears are stupid long.