OK, I'll list my tire temp procedures and what I try to acheive with a medium horsepower RWD car on a race track. Other racers do things in different ways and achieve the same (or better/worse) results then I do and I'm always willing to listen to the person who achieves better results.

Ultimately what we are trying to achieve with suspension modifications is to make maximum use of the tire without hurting it. One of the best ways to measure how well (or poorly) we are using the tire is to measure the temperature in (not on) the tread. To do that you need:

1. A tire pyrometer that has a sharp probe about 1/4 to 3/8" long.
2. A driver that can consistently drive the car at 10/10ths for a couple laps in a row without going over the limit.
3. A race track.
4. Paper and pen.
5. A pit board or radios.
6. Two crewmembers.

A road racing tire generally works best when its pit lane temps are between 180 and 200 degrees (Hoosier R6s). Each car and driver works better somewhere within that range and other tires work better in slightly different heat ranges. Sometimes, because of the track configuration and/or the length of pit lane you might find that the temp reading is at the low end of the range but the driver is complaining that the tires are greasy. Maybe the tires are getting cooled off because of a long stright before pit entry or you're stuck at the far end of pit lane dealing with a 55mph speed limit. Adjust your ideal range accordingly.

Here's how to check the temps - practice session only.

1. Have the driver go out and warm up the car.
2. After three warm up laps have the driver run two hard 10/10ths laps and immediately come into the pits. Tell the driver during pit entry that the crew will be taking tire temps. Driver stops in the pit box without skidding the tires, puts the car in neutral, leaves engine running, puts his foot on the brakes, and turns the steering wheel to the left 1 turn.
3. Starting at the outside rear tire, crewmember 1 (C1) sticks the probe into the inside 1/3 of the tread and waits for the temp number to stabilize on the meter (2 to 3 seconds).
4. C1 shouts the temp reading to crewmember 2 (C2) who writes the number down.
5. C1 sticks the probe in the middle of the tread and waits for the temp reading to stabilize (2 to 3 seconds).
6. C1 shouts the temp reading to crewmember 2 (C2) who writes the number down.
7. C1 sticks the probe in the outside 1/3 of the tread and waits for the temp reading to stabilize (2 to 3 seconds).
8. C1 shouts the temp reading to crewmember 2 (C2) who writes the number down.
9. C1 runs to the outside front tire and repeats steps 3 through 8.
10. C1 signals the dirver to turn the steering wheel 2 turns to the right. C1 runs to the inside front tire and repeats steps 3 through 8.
11. C1 signals the driver to turn the steering wheel 1 turn to the left (straight ahead). C1 runs to the inside rear tire and repeats steps 3 through 8.
12. C1 then checks air pressures in all 4 tires, in the same order, shouting the numbers to C2 who writes them down.
13. Air pressures are adjusted, if necessary.
14. Driver is released to continue the practice session.

I'll update this post later with what the numbers might mean. Meanwhile, spend money on these according to your budget:

http://www.pegasusautoracing.com/pro....asp?RecId=867

http://www.pegasusautoracing.com/pro...asp?RecId=2515
http://www.pegasusautoracing.com/pro....asp?RecId=869
http://www.pegasusautoracing.com/pro....asp?RecId=875
http://www.pegasusautoracing.com/pro...asp?RecId=2858

--------------

Number Interpretation

So, you've taken tire temps and you have a series of number like this in plan view of the car (the first numbers on the left side tires are the outside of the tread and last numbers on the right side tires are the outside of the tread.)

LF: 215 - 180 - 160 *** RF: 155 - 198 - 180
LR: 200 - 200 - 192 *** RR: 200 - 180 - 169

First thing to look at is what area of each tire is the hottest. That tells you which part of the tread is working the hardest. The second thing to look at is how balanced the temps across the tread face. Actually, you generally want the hottest temps on the inside with a nice 5 degree decrease to the outside. Something like this on a left rear tire is great: 195 - 190 - 185.

LR: Outside tread working hardest, middle is working hard as well, and the inside is working but not as much as the others. This tire has born much of the cornering and acceleration load and is typical on a RWD car racing at a track with mostly right turns. Its borderline overheated and you might want to increase the tire pressure by 2 lbs. I would also add a little more negative camber to try and balance the temps across the tire.

LF: Outside tread is carrying most of the load. This tire will wear out quickly and this is a real problem. Often you see numbers like this if the driver comes into corners too hot, brakes on fire, and then throws in steering to get around the corner. I would definately talk with the driver after seeing these numbers before I adjusted anything. This tire does need more negative camber or some other adjustment to keep it more upright, but the numbers here are junk if the driver is the cause.

RF: Center tread is carrying most of the load. Tire is overinflated. Reduce the air pressure.

RR: Inside tread carrying most of the load. Could be a couple things - too much camber or excessive wheelspin from a failing LSD. Talk with driver about power application and see if he's getting wheelspin. If so, check the diff. If not, reduce camber.

 

Yea - I have done a lot of tire temps with camber changes with the Z. Still found that the Z can handle a ton of negative camber with R-Compounds.

But, haven't done any sway bar changes with tire temps - I think I will try that at Road Atlanta this March. Thanks for giving me more stuff to do at track

 

Somehow I always wind up being the C1 guy.

 

Plenty of good info.

Considering my current setup is not adjustable, I get back to my original question. A-arms or sway bar first? Or, as BetaMotorsport seems to point to, springs? I’m afraid these might make things worst by increasing the load on a front tire that’s not properly positioned to begin with?

In the end, I’m not looking for the perfect setup. A setup that work well (ie better than stock) on the track would do. The car will still be used as a daily driver so I have to keep it civilized.

 

Well - if you want to carry more speed in corners than get the A-arms, but be prepared to either change the camber between street/track or have more tire wear on your street tires.
The sway bars will help on track and you can leave them at the same setting between the street and track, with no real negative effect on the street.
Either way - you will be on your way to building a track monster.

 

I still have a long way to go to match your Manga Z Lol!

Do you drive it on the street? Street racers must stick to you like rice!

 

Updated my previous post.

 

This thread is a keeper. Thanks!

 

I do drive it on the street still since Gerogia doesn't have many laws against modifications and I usually just ignore people that want to race on the street. I find that I drive slower and more conservative ever since I started tracking, and have learned that driving in the paddock and the street is 10X more dangerous than the track!

 

I know what you mean. Once we start to go to the track, “Street Fast” isn’t that fast anymore. The ante gets too high (tickets, accident, manslaughter…) way before things get really interesting.

It’s not like there are fun roads around here either…

 

MoodDude, You coming to the NASA event at RA in March? Stack asked me to come shoot pics & I am planning on it.

 

You will see me there for sure! I used my coupon for the event and will show up on Friday as well to test and tune the car! Can't wait to drive the new surface at Road Atlanta!!!!!

 

damn, kick a$$ post from john coffey. now, if i only had funds to patronize his shop. heh

 

FYI... the tire temp numbers I posted above are just examples and nothing from the real world. If a car I setup came into the pits with those actual temp numbers I would pack everything up and head back to the shop because we missed the setup and are wasting our time at the track.

I take credit cards via PayPal. Keep America Running! Go Into Debt!

 

The ability to pick your collective brains via the internet easily justifies the cost of owning a computer and DSL. All of this information on various posts regarding tires, brakes, and suspension has been helpful for me. I will be anxious to get out on a track and run the new setup once it's complete.




Now you have me looking into Konis and springs, not to mention A arms. Konis will probably come first, so I can adjust to one change at a time.

Anyway, thanks guys!

 

Keep in mind that changing the static camber will change the wear characteristics of your street tires, unless you plan to change back to street settings each time before leaving the track. Adjustable anti-roll bars will provide you with an additional method of altering front-rear balance without much detriment to your ride quality on the street.

 

Terrific supplement to your post John! Thanks for all that went into it.

 

One of the most enlightening threads I have read in a while. I should hang out in the track forum often...

 

Its been mentioned above in this thread, but I think it needs to be more clearly spelled out: while camber and ARBs both affect steady state and transitory behavior, there are subtle differences between how each affects handling.

When I tune a car I tend to adjust transitory behavior using shocks and ARBs. For steady state behavior adjustments I tend to adjust springs, camber, and air pressures. I'm not saying that a camber change won't affect transitory behavior or the an ARB change won't affect steady state behavior. I just tend to focus on certain adjustments to correct certain behaviors. This might be a personal blind spot and I know other racers do things differently, so maybe we can discuss that a bit.

 

Wow - good discussion. After talking to many different race mechanics and doing my own reading, I thought that spings play one of the largest roles in "transitory" behavior. On my next track day I was going to try a different springs on the front to help speed up the wieght transfer to the front (under straight line braking)and slow down the transfer to the rear. Well this and adjusting my shocks and sway bars to fully utilize the new set up.

But you point is great - you have simplified the equation so that you focus on only certain things instead of everything. That being said, what do other think about what the major players are for static and transitory behavior.