I'd suggest stock tire pressures to start and maybe tweek a little to dial in the front end.

Biggest needs on track:

• New, clean high temp (Motul RBF for example) brake fluid
• Good brake pads (G-LOC Brakes -)
• Maybe add an extra 1/4-1/2 quart of oil
• SA2010 or SA2015 rated helmet
• Remove floor mats, empty trunk and glove box

Listen to the instructor. Have fun!

Feff
MVP Track Time

 

Thanks for all the input guys.

I received my Porterfields and will be changing them out as well as a brake fluid flush this weekend.

 

I can't talk Jags, but I can add some general track prep information

-1 your car is faster and more capable than you are. This applies to everyone. Relax, have fun, and learn. Don't be that guy that gets mad and goes home after a "lesser" car passes you.

-2 Tire Pressure - this depends on the weight of the car, the track surface, the air temperature, driving style, and a few other things. Cold pressure is irrelevant. The goal is to have even pressure across the surface of the tire so that the all of the rubber is giving you maximum grip when the tire is warm. That's why you're going to start with a higher pressure for a 1-2 minute autocross run than you would for a 15-30 min track session. If you really want to get technical about it, get a temperature probe and measure the temperature of the tire across the tread after your run. If it's hotter or colder in the middle, the pressure is too high or too low. Pay attention to the tire wear, same as temperatures, faster wear in the middle means pressure is too high. You can also tweak the car's handling with tire pressure. Increase the front/decrease the rear pressure to tighten the car up, decrease the front/increase the rear pressure to loosen it up (Same applies to shock/springs/sway-bars). Just make sure you're not trying to fix a driving mistake by changing the car. Learn to drive 1st.

-3 Alignment - driving on a road course calls for a more aggressive alignment than driving on the street. If your car is seeing mixed duty you'll have to find a balance. 1 track day, not worth adjusting anything, but if you get deeper into it, you'll have to find the right balance. With my Corvette, I ran as much caster as they could get evenly on the front tires and just past the factory maximum negative camber (~-1.5') with a bit of toe out in the front. Less camber in the rear (~0.5') because you need camber for the corners, but don't want any when you're trying to put power down after a corner, and a touch of toe-in in the back also helps keep the car stable on corner exit. That was a good balance between track/street use that car saw. For a weekend cruiser it's way too aggressive and would eat the inside edges of the tire tread, but a track only car I would have gone with more camber in the front. You have to work out the details for you and your car and refine it as you go along.

-4 Brake Pads and Fluid. - Brakes fade for 3 reasons, (1) the fluid boils, (2) the pads exceed their operating temperature, (3) new pads aren't bedded in properly. For #1, the pedal will get soft then go to the floor. Take it easy if it starts getting soft, if the pedal goes to the floor, pump the pedal until you get pressure and go bleed your brakes before you continue. For normal use, DOT 3 should be replaced every 2 years, and DOT 4 should be replaced every year. They are both interchangeable and the only difference is the boiling temperatures. If you're shopping for brake fluid, there are 2 temperatures listed, wet and dry boiling points. Dry applies when you crack open the bottle for the 1st time, as soon as you do that, the fluid will start absorbing moisture from the air and will work its way towards the lower wet boiling point. When I was doing regular track time in the Vette, I would bleed the brakes the night before every track day with ATE Type 200 or ATE Super Blue (no longer sold in the US) fluid. The one time I did not do that, I had gone to the Nurburgring on Saturday and was at Hockenheim on Wednesday and I had to back off because of a soft pedal. For your first track day on street tires, it shouldn't be an issue as long as your fluid is reasonably new, but if you're getting into it, be ready and learn how to bleed your brakes. Speed Bleeders are a godsend for that. I'm assuming they're still around or something similar. For pads, the pedal will remain firm, but the car won't slow down as quick as it should. Just make sure they have a high enough temperature rating to deal with the heat you're putting into them. As you get into higher temperature ranges noise and dust come with that. Which gives you another decision to make between street and track use.

-Brake Performance. Unless you have serious issues with your brake system, your tires are the limiting factor in your brake performance. No pads, calipers rotors, brake lines will make you stop any faster no matter what the ads claim. If your current brakes can lock up the tires or engage the ABS, that's all you've got. What brake modifications can do if done right is to make sure you can continue to brake just as quickly over and over. None of this is necessary for your first track day.

-If I were turning a street car into a track car today, I would start with safety, reliability and free stuff. Meaning, oil, transmission and differential cooling, brakes, cage, seat, harness and removing any unnecessary weight. Then wheels/tires & suspension modifications. Then Aero with any suspension adjustments necessary and last, horsepower, but with 500hp not much should be needed in that area with an XKR.

-As you're making adjustments, change one thing at a time, measure the results, then move onto the next change. If you make more than one change at a time you won't know which did what. Be slow and methodical and you'll get much better results. You can't necessarily buy better parts and just expect the car to be better/faster. I did track days and autocrossing on my corvette's factory suspension for 3 years before I made major suspension changes. When I did I invested several thousand dollars in shock, springs, swaybars & bushing. The immediate result was that my car was slower. Not that there was anything wrong with the new stuff, I had just spent 3 years perfecting the old setup and had to figure the new one out. In time it worked out great, but you can't just bolt random stuff on and expect it to work.

That's all I can think of for now. There are whole books written on this subject. I would highly recommend Speed Secrets and its sequels by Ross Bently and Drive to Win and its sequels by Carroll Smith.

 

I take other people with me to the track, and my group allows anyone to bring their own car. I always make a point taking people along on a hot lap in their own car, no matter how unideal their ride is. The point is, that most cars made in the last 15 years are good enough to race. From there, it is up to driver's ability.

In my run group we have an old stooge that would absolutely smoke everyone in his shitty almost-stock Miata. He has been racing since steam engine days and at some point was a professional race driver. That guy is FAST in a slow car.

 

Er, isn't "shitty" and "Miata" redundant?