ZO6crazy

I have run 2 of the last spring and fall Track Days with West Coast Racing at Willow Springs Raceway in California. Some issues with my 2003 Z06 surfaced at the last event. At the end of the straightaway I was hard on the brakes going into turn 1. I could smell what I assumed were the brake pucks smoking. However, I had a sensation accelerating from turn 1 of a slipping clutch. This "slipping clutch" sensation happened again a few turns later. I had switched into "competition" mode for the first run of the day. The first event I attended, months earlier, I kept it in the default "traction control" setting both days with no ill effects. I spoke to other vette owners at the event and no one could say for sure what the problem may be. I did find out that everyone else was running with all traction and handling controls turned off. So on Sunday, the second day, I also ran with all the contols off. The brakes and clutch problem never returned, but I have to admit I was not running the car as hard. A Mazda Miata I passed had an instructor riding shotgun and he said I was blowing smoke from my exhaust at the end of the back straightaway. Sure enough, my tailpipes had a thin film of soot, but no oil evident. I checked my oil level and it was down almost half a quart. I was told to top it off slightly above the full mark to insure oil pickup with the G's we were getting on the fast sweepers. I left for home before the last run of the day out of concern for my Z06. I did notice, while driving home, that the car tended to pull to the left when hitting the brakes. After a couple weeks of sitting in the garage, the brakes worked fine on a few local runs around town. I want to run the next event Oct 31-Nov 1, so I think I am going to call MotorSport Image in Roseville,Ca. to see what they would charge to give my Z a good checkup. Any thoughts and advice would be greatly appreciated.

zigspeed10

Im no expert but the slipping clutch sensation might be the stability control kicking in. If you feel it going through a turn or exiting a turn it is most likely stability control, if it is when you are going down the straight away shifting through the gears it may be a slipping clutch, or it could be just spinning the tires. Not sure about your smoking issue, hopefully its nothing serious. As far as your brakes go, upgrade your pads, my stock pads could not take it on the track. I now use carbotech XP8 and I only get a little fade close to the end of the session when pushing the car hard. If your mechanically inclined do your brakes yourself, new pads, rotors, fluid(Motul or similar), it will probably fix the pulling issue. Also remember to lube the slide pins on the calipers. If your not up to it let a professional do it, its not worth having brake failure at the track. Have fun and enjoy your new addiction of road racing.

ZO6crazy

Thanks for the advice. The slipping was only out of a few corners with no slipping during shifting. I am going to get professional help with these issues if the price is reasonable.

Dirty Howie

I run competition mode at WSIR and stock brakes on C6Z06

Obviously, your top speed and hardest braking is going into turn1.

What speed and tires are you running and what other turn are you slipping ...... turn 3 and turn 5 I bet.

What is this group you run with? Have you been coming to the 2009 Corvette Challenge ...... next event is October 11 Sunday


DH

96solo

The smell you picking up is the brake pads overheating on competition mode. The Corvette will not allow more than 3 degrees slip angle before compensating by individually controling the brakes to keep the car straight in that mode. I agree that is a weird feeling. It has nothing to do with the clutch unless your slipping the clutch or it is old and overheating on it's own.

It is smart to use the competition mode for a few laps on a cold day, then turn it off when the tires are warmed up.

If you have enough G forces to put enough oil in the right valve cover, oil will over flow into the throttle body burning and causing your smoke. If you are serious at doing track days, get a Moroso catch can (also called a dry sump accumulator). At PIR's Oval I can fill it in 1/2 day of Time Trials. Keep the oil 1/2 a quart above full after the engine is warmed up.

D.J. Covert
2008 NASA-Az TTS Champion
NASA Instructor

longdaddy

you need to pull out brake pads and inspect all of them as a first step.

ZO6crazy

I bought this Z in Jan 08 with 39,000 miles. It had worn front tires, so I replaced all 4 tires with Vedrestrian tires because of the bargain price. They seem to grip very well, but all this high performance car stuff is new to me. The speed at the end of the straightaway is just past 120 mph. I run 36 lbs air cold per advice given to me at the driver's meeting. The other turn I noticed slipping was turn 5, in third gear, just before approaching the rise where I shift into 4th gear. The car kind of slides the rear end out when I let off the gas( no brakes, just engine compression ), and I noticed the slippage when I got back on the gas. I guess the sideways motion might have caused the stability program to go into action. In turn 1, I drift into the apex after getting hard on the brakes and use all the track to the right in 4th gear, getting on the gas again. That is the first time I noticed the forementioned slippage. This never occured with the default setting, or with all traction and handling controls turned off, only in competition mode.
The first fall event, I ran in the "green" group with no problems, using the default mode. The spring event I was moved into the "yellow" group by my request. I later asked Jim Saxton to move me back into the green group after the first run on Sunday, so I could take it a little easier to scope out my difficulties on Saturday.
I don't know what the Corvette Challenge is...!! I only heard about the WSIR POCA event here on the forum. I guess I am a "newbie" in more ways than I want to admit....! Thanks for your reply...........

ZO6crazy

I don't want to convert this car into a "racer", just want to be safe while having some fun without the CHP on my tail. I was looking at brakes at the MotorSportImage.com web site, and I can see that the best is out of my league. I am hoping that they can look at my car and suggest a "working man's" package that I can afford. At the same time, check out the rest of the car for problem areas. Thank you very much for your advice.......

ZO6crazy

I am hoping that I can get new pads that will work well on the street with a little more track performance. I am not able to do any of this work myself since I don't have access to the proper lifts and tools. All my previous history has been in motorcycles, dirt and street. All this car stuff is new territory ! Thanks for your reply and advice.....

AU N EGL

Depending on the speed into that T1 will dertermen what brake pads to get. Unfortunily there really is not a combination brake pad, street and track.

So learning to change brake pads and flush brake fluid will be on your to do list.

DOT4 brake fluid, Motul, SuperBlue are two great brake fluids. and the stock C5Z brake pads for the street and a good race pad for the track. There are several

Hawk HPS or HP+ are not track pads, but very good street pads.

Hawk DTC-70, PFC-01 or 03s, Wilwood H, and many others.

Brake duct cooling would also be a wise addition.

None of these make your Z a race car, but add to your safety and track enjoyment.

Dirty Howie

Check out the SoCal Regional section for all track days at WSIR, BW and ACS.

Here is a link to the upcoming 2009 Corvette Challenge:
http://forums.corvetteforum.com/sout...ober-11-a.html

All levels from beginner with instruction to advanced are available.

Do a search and you will find the previous 4 events.

Feel free to PM me if you have any questions.

Also don't rule out a little fluid on the track if the problem came up out of now where.

And listen to all these experienced guys


DH

Dirty Howie

Tom

WSIR is my home track.

I ran the Hawk HP Plus pads on my old C5 with stroker motor without any fading problems. Just Had DOT 4 fluid.

WSIR is a 2.5 mile high speed track with just a couple of braking zones.

Turn 1 is the only hard high speed braking zone. Then there is LOTS of cooling time.

I was hitting the same turn at 140 without problem.

So I'm sure HP+ will work fine for his level of driving.


DH

Dirty Howie

Changing pads is fast and easy. You need minimal tools and a floor jack. Just find someone local to show you


DH

ZO6crazy

This is just the sort of advice I was hoping for. What kind of trade-offs can one expect on the street with track pads, my car is not a daily driver, just for a fun drive every once in a while, and some track time ? Thanks for your reply.....

ZO6crazy

I did a google search and found your event at WSIR. I hope to come out and see for myself how your event is staged. Unfortunately, I have already mailed my entrance fee to West Coast Racing to be able to run 2 events so close to one another. But there is always next year ! Thanks for all the help and advice. I really like this forum and all the characters associated with it's management and participation. I hope to do business with more of the vendors who support this fine forum......

AU N EGL

You sure DH ?

I burned though a set of HPS in one day and HP+s in one weekend. Right down to the backing plates. The side of my yellow vette was like baby puke

you can change your pads to drive to and from and event. Race pads are not real good at stopping when cold. but if your careful they are OK

Race pads WILL squeak like a SOB when used on the street.

Dirty Howie

I'm sure of my advise above !!!

But that advise is for him at WSIR not YOU running 10/10 at another track


DH

redtopz

Sounds like you are running your car bone stock which is fine the first couple times, but then you need to start addressing the stock brakes. When I started taking my vette to the track I bought some braided SS brake lines, flushed the fluid to high temp brake fluid, and put in some good pads. All you need is a floor jack and some basic hand tools to swap brake pads and bleed brakes. I have a shop in Chowchilla if you need any help shoot me a pm and you can bring your car over. You will be amazed at the difference in performance with these simple mods.

Bill.

Z11409

Also insulate the master brake resevoir and the steel brake lines below the resevoir.
Have a spare set fan belts.
Change PS fluid after every track weekend.
Always carry a large amount of cash or a no limit credit card.

AU N EGL

Me 10/10s ? Never <koff koff.> that was when I was young and stupid. FULL THROTTLE OR FULL BRAKE.

now after banging off a few walls, and various other parts, I am not full throttle, or full brake, but I am faster now. MUCH faster.