I am looking at going to my first track day at Nelson Ledges in July with the 68, and I was hoping to get some suggestions on things to do/watchout for. As this will be my first track day I plan to be conservative and ease up to the cars potential, but I want to prepared for potential issues.

From what I have read, the brakes are the most suspect component when doing any extended track driving. I am definitely going to get some better brake fluid (Probably ATE super blue) and possibly a set of Hawk HP+ brake pads to help curb some of these issues. I have also read that brake ducting may be necessary, but I am not planning on it for this event.

I have autocrossed this car before and one of the unsettling things was under heavy braking (trail braking) the back end would come out really bad which I believe is a somewhat inherent trait of our suspension due to the toe out under suspension unloading. Since autocrossing I have lowered the car and raised the differential to reduce this impact. I also tried to get the rear to 0toe when I aligned it. Hopefully this will help.

Current mods on the car:
SPC Adjustable upper front A-arms
Extended upper ball joints
Bump steer blocks
1 1/8" swaybar
"big block" springs (500lb/in I believe)
Adjustable rear fiberglass spring
Modified camber strut rods to improve camber curve
Differential raised ~1"
Bilstein shocks
16"X8" wheels with Eagle F1 tires

I am excited about doing this event, I am just trying to be as prepared as possible, so any advice or expericence would help.

Thanks,
Matt

 

You want at least 1/8 rear toe in.

Remove the stock dust covers from all four wheels. They hold the heat in. run 580 -600 degree brake fluid. two inch air ducting is easy to do to the front brakes. Three inch is a little tougher to fab up

As your speed goes up and your tires get better. Your brakes will fail within a few laps even with all the above. In my research I came across titanium modified thermal blocking pistons in J-56 brakes. I next came across Wilwood brakes with Thermloc pistons. So I went to bigger rotors and bigger calipers and now I can finally use my brakes as hard as I want to and not baby my Vette around the track

Invest in a good IR heat gun and pressure gauge

 

Gkull

after my last test with rear toe , i've found that 1/4" is perfect with my set up

about brakes. if by rules i can't go for aftermarket calipers, what's best?those titanium you say? what stock cars road racers use?

 

http://www.duntovmotors.com/brakes.php

All of our shop historic racing vets use these.

B039 One Axle Set Twin Pin Calipers w/ Titanium Insulators

 

thanks Gkull
wanting to go step by step ($$$) is it a stupid thing to do the twin pin calipers conversion just in the front , leaving the single in the back?

 

You're off to a good start with the mods. With rear oversteer I do all braking in a straight line before turn in and get on the gas as I turn in. It's the way to do it just parking brake pins.more critical to combat oversteer in my car. Yeah dust covers should go and on rear I left the part for pins. Good harness is a good thing

 

Biggest thing you want to do on your first track day is gain confidence in the car so you can actually begin to focus on improving both driver technique and chassis tuning. To that end, if you're not already familiar with how your car handles at 10/10ths of its cornering limits (which may well be different than indicated on the road where leaving some margin is prudent or with what you've done in auto-x) I'd suggest working your way from softer rear spring adjustments to firmer, as IMCO you'll be better off having to deal with and solve for understeer than struggling with oversteer.

Print out several copies of the track map so you can make fresh turn-by-turn debriefing notes after each session (one map per). You'll have trouble accurately re-constructing all of these details after the day is over, and you'll likely feel it less of a blur if you download your brain ASAP upon getting back to the paddock (after taking tire temps, of course). I like making baseline setting notes on the back of the first, writing any setup and/or technique changes on each subsequent map rather than trying to collate such info from separate notes latter.

I consider having a good pyrometer and pressure gauge as track-side necessities. An IR gun is good for general use, but if you're going to track regularly I'd also get a quality tire probe type one along with some tire temp note pads to help keep your data organized. Tire temps are a perishable commodity, so unless otherwise required don't do cool off laps and don't delay taking tire temps immediately, if not sooner, upon pitting. Not only will studying this info help you determine proper inflation, but it will also help you diagnose camber and other settings as you become practiced at reading temps. You might want to staple these to your individual session note maps, along with any lap time charts.

If you plan on taking any alignment tools (or know how to string up), I'd figure out some way of creating a level "pad" on which to make adjustments and maybe carry a set of poor man's floating tables (4 pairs of commercial vinyl tiles w/a little grease between). Should you be able to talk someone with a set of scales into letting you, I'd get your corner weights (with you in the car).

Too bad you don't have adjustable shocks (or a differently valved set) and a couple of different front anti-roll bars to play with, but experimenting with such is probably best left to future track days when you've had a chance to get better aclimated anyway. That said, don't lock yourself into only following pre-concieved notions (yours or anyone else's) of what is the best way to go about fine tuning your setup. Be cautious when testing different settings and/or components (one change at a time), but by all means test!

Most of all, enjoy the day. If you feel like you're spending more time catching up to the car than having fun, there's no disgrace in hitting the pits to settle one's self. IMHO you'll actually earn more respect doing so than by staying out and having a "big one". Best of luck, and post up. Hope some of that's worth something to you.




Aldo, if you need a pair of J56 type front caliper braces let me know and I'll PM you a couple of sources.

 

Thanks for everyone's input. I have been looking at getting a set of the Wilwood 4 or 6 piston calipers, but I just couldn't justify it over some of the other things I have done. Atleast not yet

I like the comments about taking notes between sessions. We would do a similar thing between runs/session at bigger autox events. It would really help out the co-driver and even your next runs when you force yourself to talk through your lap.

Anybody have any experience with the Hawk HP pads? Unfortunately I can't remember what pads I have on the car now but I believe they are Performance Friction pads from autozone. They haven't been the greatest on the street especially without power brakes.

Thanks again for the input.

 

Ive run both the Hawk and performanc friction pads. If you can get a set of the Perf friction Z rated pads. I found that once the Z rated pads are warmed up they grab a whole lot better than the Hawks

 

.........

 

hoping to help in the discussion... i post the pics of this car i like very much, and i have some question about it for road course experts










i found these pics in an old thread where it was said that this car is very fast.
this car is somewhat my model because is not overmodded and it's a set up that i could reach with my car without going too deep into mods ( no fender flares,no fia headlights, nice air dam , front bumpers still there, not huge, very invasive roll cage...)
but i have some questions:

-half shafts. they are straight horizontal. shouldn't they be slightly down externally to avoid excess toe steer?
-what size tires? they are quite fat but stay into the fenders. offset trailing arms there?
-who makes that air dam-chin spoiler. diy?

any more input on this car (bad and good things) is welcome

 

J&L is one of sister shops in in the historic racing world. We pit by them often so I will take a look at this car at on of the next events.

That car has a history, but not big name or a company. It is more of you personal race car from the 70's Everything is home made. Including those boxed a-arms. There was no Vette Brakes back then to sell you stuff.

It has period correct wheels so they are 15X8 front and 15X10 rear with probably 25X9 fronts and 26X10.5 rear grooved slicks

To get the car low the half shafts went up. the fix is a raised pumpkin.

How do you like the rear end and tranny cooler where the rear lic. goes

 

This is about tires. When i was jumping through the SCCA hoops to get my driving instructor credentials I decided to take my 2002 Firebird for a class and track day to keep miles off my Vette.

I put on a set of BFG G force sports in 255/50/16. Really nice tire. Very little ware or feathering of the edges of the tread blocks. I usually start tires out about 6-8 psi under max sidewall listed pressure and see how they do.

You want to set the front end with something like "Zero toe" and lots of castor. My firebird has aftermarket struts. So I had them set near 6 castor and .50 degrees neg camber. Like my Vette I use more rebound than compression. You want the tire to compress like when you hit the rumble strip and rebound slow so it holds your car down.

I had the VB&P 550# front coils and I never thought that they were enough for track use. You get to much nose dive when on the brakes.

 

Gkull ,
thanks for the various inputs.
are those 26X10.5 rear tires about same size of 295/50/15?
if i'll decide to go ahead in the mild-racing prep of my car , i would possibly go for Avon Cr6ZZ 295/50/15 hoping that they don't stick out too much from fenders. there are also CR6ZZ in 275/55/15 size but the tread is not much more than my current 245/60/15.
of course i'll go for suitable rims ( TTD or Minilite) and works on the brakes. I already see my wallet lighter...
on monday i'm going to have my very first lesson at the racetrack on a C6 Z06. Then I'll decide if to stay with a vintage corvette or go for the new. it will depend on which will give me more emotions , regardless of lap times...

 

My first drives in Z0-6's was a let down. You always have the Late model Vette group guys at the track days there for HPE or PDX. They are always talking big, but they never have transponders to be able to tell what lap times they are actually getting.

So my first time driving one of the older 405 hp Z0-6's with lots of mods was very disapointing. It reminded me of a Miata because you had to have you foot on the floor all the time to get it moving. Then within a couple of laps I had to slow down because the car was filled with burnt brake smoke.

Now the 427 ci Z0-6 are actually kind of fun, but they only have 505 hp. It was also filled with burnt brake smell in a couple of laps and I really think that if pushed hard that they would fail within 4-5 laps.

Oh, have them show you how to take off traction control. It really sucks when you have the wheels braking and engine misfiring because it thinks that it is smarter than you. It is a device for old men and woman that really don't how to drive in the first place

 

Gkull
actually i will be in the car with the driver for all the track time and if time left , i will try to drive the car. never been at a race track and i'm quite anxious. but i will study all that the driver makes and he will explain.there will be lot of trackside work : tuning suspensions, alignment...pyrometer, transponder... just a start for me and i have lot to learn.
I already drove a Ls7 z06 on the street for few minutes but i was not exhactly impressed by the engine. I confirm the brakes issues with the Z06 : just few laps then fading.
no traction control of course

 

look again....

 

^^^ true true true ^^^

 

Not maybe those tires, but most of us are using Roger Kruase hand grooved slicks that look very much like treaded tires.

http://www.rogerkrausracing.com/

 

I think that we are bringing 5-6 cars to Portland Internation Raceway for the Historic event July 17 - 20th. Stop by and say hello at the Intrepid racing team transporter.