Car Preparation for Track Event

[ZRapid-1]

Hello all,

I am taking my 90 Z to a HPDE at Lime Rock Park next week. Am looking for helpful advice as to car setup and preparation.

I have just replaced the brake fluid with DOT 4. There is no air in the system and the pedal is firm.

The car has new Michelin Pilot Sport PS2 tires (335/35ZR17 on rears). Will bring a compressor and add a few pounds at the track to stiffen the sidewalls.

I have read that the front corner air deflectors should be removed to allow more airflow for front brake cooling. Looks like three bolts holding on each side.

Obvious stuff like making sure the Full Engine Power switch is on, air conditioning is turned off, and radio is off.

Anything else?

Thanks in advance.

[Mr Cool]

I don't really have anything C4 specific to add but that's pretty cool. I've pondered taking my wifes 90 to the track just to try it out if she would let me. I think before I did that I would give the brake system A good work out on a little used road just to see how long it would take to start to see brake fade. I think that would be my biggest concern. I think your gonna be removing air, those tires are gonna heat up fast with that heavy car. I would start 32 cold and and check it after your first session. I really would like to hear your comments after the event.
If this is your first event you may want to reconsider a crack habit would be alot cheaper.

[tomtom72]

Do you have the pizza box? I ask because in it is the ZR-1 owner's manual and it has a section devoted to HPDE's. It has a good amount of info on prep and even some driving tips.

Also, not to be a wise guy, on that other forum there is a section just for road racing. If you log on to their index page after the C1 & C2 forum you will find the "auto cross and road racing" forum.

Good luck, keep her out of the tall grass!:thumbsup:

Yea, I've heard that most drugs like Heroine, cocaine & crack & meth are less expensive habits.....

you need a pit crew?

:cheers:
Tom

[Mr Cool]

I agrre the Autocross Roadracing forum In CF is a good source. Also setup next to other corvette drivers, in the southeast a bunch of us setup together and help each other out or just bs.

[GOLDCYLON]

Anything else?Thanks in advance.

Coilovers? ;)

[lbszr]

Sounds like you already did the most important with flushing the brake fluid. What fluid did you use?

Even if your wheel bearings are tight now, I'd have a spare. Sometimes they only last a day, depending on the brand. I drove mine to the track the first time, blew a front bearing, luckily somebody there had a loaner.

What pads are you running? Spare rotors are good.

I ran mine with the outer air dams off also until installing brake ducts. I don't know if it helped.

As mentioned, 32 psi is probably the most, cause when they get hot the pressure will be about 40 and above that most tires turn to grease. But that pressure will probably help the tire shoulder when the alignment is stock. But less pressure if you want traction.

Keep an eye on the engine oil level. Mine uses about .25 of a quart in 1000 miles on the street. But on the track it uses .25 in 30 minutes. Oil catch can would really be good.

Have fun! As mentioned, I'm thinking crack probably would be the cheaper route though.

Here's a lot of good car setups.
http://www.cardomain.com/ride/418999/1990-chevrolet-corvette

[jrtoffroad]

As mentioned look at your brake pads, I highly recommend HAWK or Cryotech. At my first event I had a set of auto part store pads BADLY glaze and chunk, damaging the rotors.

Be sure you're running high temp brake fluid. I'm using Wilwood 600+, but there are a number of good options. My first event was at a course that is hard on brakes and I had problems boiling the valvoline synthetic I'd just put in.

As lbszr mentioned, start a little low on tire pressure, it will come way up. The front will gain more pressure than the rear. I usually shoot for 36 to 38psi hot as a starting point on the track then tweak from there.

You could also tweak your alignment adding some negative camber for improved traction and more even tire wear at the track.

[Mystic ZR-1]

I tracked my '89 L98 C4 @ Lime Rock about 8 years ago. You'll find that the stock brakes suck after the 1st lap when your slowing from 125+ to about 60 for "Big Bend"... Hawk pads would help. Your wheels will be black from the brake dust. I used the 37/37 psi in the tires, but this may not be the optimal. The main thing is to try to be smooth, you'll feel it in your butt when you get the corner "right". The trick is to get all the corners "right", which comes only with practice (I never came close... I gave up thinking I was cut out to be F1 World Champion that day). My best effort was a 1:08 on a "flyer" that I couldn't ever duplicate, most laps were in the 1:10 to 1:13 range (on the "old" course, no chicane or new corner). I put almost 80 track miles, in several 20 minute sessions, on my car that day, and boy does it use up gas while you're doing this!!! Guaranteed you'll "pucker" cresting the top of hill at the end of "No Name" straight, the car gets VERY light, the wall is VERY close and it's a slight turn to boot... suggest you stay straight and turn late after the cars settles. The downhill turn leading to the main straight is deceptive too.
Save setting "a neeeew track record" for your next visit, concentrate on trying to get it right. Good luck and have FUN!!! Remember, all bets are off with your insurance company while you're doing this...
Doug

[DaveK]

Install the painted roof - it adds rigidity.

Dave

[PhillipsLT5]

Mystic really has it wired
Full tank gas, partial tank will slosh and push car in corners

[Kevin]

don't forget that prolonged running over 5000 (i think) rpms will cause the coolant to bypass the rad and flow back into the motor uncooled.


there's a fix around here somewhere but it involves changing the rad the stat...which I'm hoping to do in a few years...anyone have the how to?

[ZRapid-1]

Lots of good feedback. I really appreciate it.
Every little bit helps and provides a small edge.

Heating of the front brake rotors and pads is my biggest concern.
I tried a number of hard threshold braking stops and drove home. Really built up the heat.
The driving sessions are 25 minutes long and I’ll either be full gas or full brakes.

I have the painted top on already. The mounting screws are fully tightened. There’s a little less room for my helmet but I want the higher stiffness. I don’t have any windshield delamination and this will be a good test.

I’m bringing extra gas to top off at the beginning of the day. But I imagine most of it’ll be gone by the end of the day.

I have also added ZDDP Plus to the Mobil 1 oil to provide some extra wear protection.

Also need to remember not to use the parking brake once I get there. It’s a reflex that will be hard to break so I have to consciously think about not putting it on absentmindedly.

Keep the comments coming.

[Aurora40]

Your wheels will be black from the brake dust.

http://www.zr1.net/forum/showpost.php?p=117651&postcount=3

The stuff is amazing, no lie. My wheels in normal driving would be really dirty in a week with factory pads. At the track I expected them to look powdercoated black. They were clean as a whistle with Armor All Wheel Protectant.

I'm interested to hear about the brakes at an HPDE, though. That would have been my main concern with the ZR-1. But I had no basis for it, they just don't seem big enough for a somewhat heavy car that pulls hard up top.

Did your '89 have J55's?

The driving sessions are 25 minutes long and I’ll either be full gas or full brakes.
Well, or cornering. As a percentage, I think you are on the brakes for not that much of the total time/distance, because the brakes work so much faster than the engine does. But obviously that stuff is really hard on brakes.

[Mystic ZR-1]

Yep, the car had J55, which uses the same crappy stock pads that fade big time. The only real difference between J55 and standard is the larger diameter rotor 13" vs 12" (I know, the caliper is different too, but it's the pads that do the work...)

[lbszr]

Hawk HT-10 pads have worked really well for me with the J55, and brake ducts.

Hawk HP+ did not have high enough heat range, they actually got the car stopped well, faded sometimes, but the biggest problem is a stack of warped rotors I don't know what to do with from the HP+'s overheating. They always burned the dust boots off.

HT-10 pads are about twice the price, but they have saved a lot in the long run with rotors and the pad lasts 5 times as long.

Oil and coolant temp is the limiting factor on mine at the track. Once it's heat soaked, I can only do about 3 or 4 hard laps before backing off. It did seem to help flushing, and adding straight water with water wetter. The big mouth scoop helped also. It was also above 90 degrees. High 70's, it will go a lot longer before backing off.

If heavier braking is used on the J55 from pads that fade, I think they would be more susceptable to spread as they aren't as heavy duty as like the C5 caliper.

[PhillipsLT5]

I think water pump cavitation is at 6200, do not run at that for more than 10SEC, coolant temp will not rise on guage but oil temp will, and then head gasket will blow on overheat

[lbszr]

I think water pump cavitation is at 6200, do not run at that for more than 10SEC, coolant temp will not rise on guage but oil temp will, and then head gasket will blow on overheat

That does seem to make sense, I shift at 6000 normally, but when I take it higher, it cuts the hard run time down fast.

Here's a link to a mod that seems to cure the heating issues.
http://www.cardomain.com/ride/418999/1990-chevrolet-corvette/page-9

[ZRapid-1]

For those interested, there is a turn by turn guide to the track at:
http://www.limerock.com/images/stories/TurnByTurn_ClassicLimeRock.pdf

and

http://www.trackpedia.com/wiki/Turn_by_turn_guide_to_the_Lime_Rock_track


Car setup is mentioned in the small book in the pizza box. They cover removing the corner pieces of the front air dam, tire pressure recommendations and alignment settings.
Tom, thanks for mentioning that as a place to look.

[Tyler Townsley]

I think water pump cavitation is at 6200, do not run at that for more than 10SEC, coolant temp will not rise on guage but oil temp will, and then head gasket will blow on overheat

You are not seeing cavation. What is happening is the radiator bypass that starts at 5200 and all water bypasses the radiator by 5800. You can address by getting a better flowing aftermarket radiator and cutting the spring on the thermostat that closes the water flow through the radiator.

Tyler

[batchman]

Good tips all above. One more is the seat belt. If you don't already keep it all the way back, put it back all the way and push the "cinch" button on the retractor (on the floor). It will latch the belt. Suck in your gut, feed it as much belt as you can (it will ratchet), then use the power seat to push forward until it hurts. At that point it should be almost tight enough...

Have a ball, I've been an LRP fan since the annual pilgramage to see the GTP cars in the 80s. Finally got to drive a Skippy car around it - awesome - and that was before it got paved.

Best,
- Jeff