Coldmale

Hi

I participate in sprints, ie individual time trials. The time trial is 2 laps, from a standing start. The total time is expected to be 2min and 40 secs

We get 2 practice sessions, each of 10-12 laps so total track time is expected to be under 15 minutes. There is approximately 1 hour between each practice session then 1 hour again to and between each time trial. In the practices, as many as 30 cars are on track at same time.

OK

I have been using MPSCs for 18 months and am nowing making the switch to the A6s as a number of you favour that tire. Its a 2007-z06 and I will use the 295x30x18 fronts and 345x30x19 rears.

Questions

1. First heat cycle. I propose to drive for about 30mins on the road taking it easy, not getting the tires above 45deg C (115f), then letting it sit for 24hrs
2. I drive to the track on race day, again easily
3. I have seen Frank and others recommend a 28F/26R cold pressure. This is where I will start from home on race day
4. For the 1st practice session, I will follow the hoosier advice and start easy and build up times by say 2 secs a lap, with my last lap being a flyer
5. I check the temperatures and look for an even spread across the tires and being an A6, hope that they do not exceed say 150F. [That was typically the temp of the MSPCs after practice]
6. I currently run 2deg 30min neg camber front and 2deg raer

Do you all agree? Is there a better way?
It takes 30 mins to drive to the track and I need that to warm up the motor, brakes etc, so I wont be using a trailer to save the tires

Thanks for any input

Ait temp on the day is likely to be around 75deg F

John

LehmanZ06

1) Buy an extra set of wheels

2) Don't drive to the track on A6's

3) Do the practice on your other set of tires and use the A6's for your competition runs-----otherwise your A6's will take too much wear from the practice.Also if you do this your A6's will last for many more events.

4) Increase your front camber and decrease your rear camber.......2.5 front to 1.5 rear or so.

5) You will love the a6's....

Oh yeah Don't need to heat cycle the A6's.....you will just use up your tires faster. Skip it

6) Where the hell is where you are ?

AU N EGL

LehmanZ06

Don't heat cycle the tires. These tires only last about 60 to 120 min....at speed don't waste them heat cycling them. Try to avoid driving them on the street.

THEY ARE FLYING FAST !

LehmanZ06

Enlist a buddy with a pickup to shelp your extra set of wheels.

Maybe pickup a co-driver to do this.

Or be like a lot of us idiots and get a truck and a trailer.....and become INSANE.

SLandstra_Z06

I think your plan sounds good John. A couple of comments.

1. Hoosier recommends heat cycling, but as others have said above, heat cycling will use up some of the limited life of the tires.

2. For heat cycling the Hoosiers, I would suggest running them a bit harder. Driving around on the street won't get any heat in them. Instead, I would suggest leaning on them a bit harder. Maybe take some exit ramps at a good clip, run some circles in both directions in an empty mall parking lot or some other safe place. Then take the wheels off the car, or put the car on 4 jack stands to take the weight off of the tires. Let them sit this way for a day or two.

3. Hoosier A6's can operate effectively at temps higher than 150 degrees. You'll know if they are overheating if they start to get slippery. Frank and I run pretty hard for 20-25 minute sessions and rarely do I feel like I've overheated them.

4. As you've indicated, work them up to temp over a few laps to get a feel for the tires as you reach the limits of adhesion. They have a pretty abrupt falloff at the edge of the friction circle, but easy to control, once you test the limit.

5. The starting pressures you plan are a good guide, but we find those pressures to be a little higher than what we run on hot days when pushing hard. The goal is hot pressures of 38-40 psi.

6. I run 2.75-3.0 degrees of camber in front and 1.5 degrees in the rear. But my car is trailered and never driven on the street with street tires.

You'll love the awesome grip of the Hoosier A6. Hoosier R6 is nearly as good, but offer longer tire life. If you want the ultimate grip for a time trial, the A6 is the way to go. For track day guys, I would suggest the R6 is a good choice for most.

Have fun...

Steve

LehmanZ06

----I don't think you need 30 min to warm up the car----

let it idle or drive for 5 to 10 min before your practice at most----and then let er rip !

LehmanZ06

My opinion Steve-O- is that he shouldn't run the A6's hard on the street---why use up the tires, and also kind a hard to feel the tires really work in a safe enviroment on the street-----

A6's don't need a 30 min heat cycle-----or much of any really.

Why use up the tires on the street for no reason ?

Stick with the A6's and destroy the competition !

LehmanZ06

My ***** are itchy

Coldmale

Actually - I do

I run the ARE Stage 3 dray sump with the 10.5quart tank with a dewitts rad and twin fans

It takes ages to warm up - but - it takes ages to get hot. This is the result of 18 months testing and let me tell you - it needs time to get all that glorius thick Redline 15W50 oil circulating. - so no trailer.

Coldmale

Steve. Thanks for that
I also do full bore track days which entail 7 sessions of 7 laps at 2min 20secs per lap

I'll stick with the MPSCs for that as the A6 would hardly last the day

I always started the Cups at 26F/28R as the heat from the brakes brought them both up the 34 or 35. In starting the A6 as high as 28, dont they get very hot compared to the rears?

Cheers

John

drivinhard

I'd run them sticker (no HC) and cold pressure 24/22 (+/- 1) for what you are doing.

SLandstra_Z06

The fronts definately get hotter than the rears. I sometimes see pressures as high as 45 psi after a hard session. So, that's why I suggest even lower starting pressures, if running hard on a hot day.

Let us know how it works out for you on the Hoosiers.

Steve

C66 Racing

I'm with those that would be very uncomfortable running the A6s on the street. Back when I was running my car in DEs on DOT track tires, I usually had my wife come along in her SUV with my track wheels/tires. When she couldn't, I'd probably run my street tires.

I'm also a believer in the long warm up required to get oil temp up.

Coldmale

This is where I am:--

http://www.youtube.com/watch?v=1Vteu...eature=related

The car is a full race Lumina with a restricter on an LS1 putting out about 380hp at the wheels. The tires are full slicks. The driver is just about the fastest we have in Bahrain

My z is 520hp at the wheels and shed loadsa Torque. Up the S/F straight he maxs at 213, me at 220, but at the entry he is 67 and me at 55 (see my avatar). At the exit of that straight he is 96 and me at 85. The difference in time is 1 sec faster for me

Round the back its a different story. Watch him pulling more than 1.4g everywhere, I can just manage 1.2/1.25

Thats the time to beat

Enjoy racing in the sand and sun

John

davidfarmer

2deg 30min = 2.5deg doesn't it??

TedDBere

Jason

Yup. I'd run scuffs for practice. Way low pressures for the 2 lap blast. Use the 1st TT lap to get them up to temp, lean on them hard but don't slide, and then just hammer them. Use those tires as your scuffs next event.

Coldmale

ok - so how low is way low?

remember that after a 1 hr break the tires will have cooled a fair bit

J

Everett Ogilvie

The manufacturer of my car says 22 rear and 20 front starting pressures on A6s (rear engine car, reverse the numbers for the Vette).

Watching the Rolex 24 shows the incredible 1st lap strength and forgiveness of the A6 - the best drivers in the world are losing it leaving the pits on real racing slicks. With the A6 you can go for it in the 2nd turn - the A6 will cover up your mistakes and lack of experience - believe me, I know.