fc-racer

I bought my GT3 new five years ago; in 2007, I took the car to EU Autowerks and had them dial in their famous street/track setup. For five years, I've left the setup the same (EU AW setup and Toyos) and have focused on improving my driving by using the AIM data.

At a few of the local tracks, I feel like I'm getting closer to the limits of the car (vs. my limits), so I decided to have some fun and try a set of slicks for the final event before winter hibernation. A fellow rennlister sold me the used slicks for $500.

The slicks are Michelin N1 cup slicks. They're the same OD as the factory 19" tires and fit perfectly on the CCW 18x9 and 18x12 wheels I use for the track. The rear tires look a bit stretched, and were a pain to mount, but they fit the car perfectly.

I tried them out at Shannonville Motorsport Park. I'll openly admit that I'm not fast at this track, having logged a 2:04 on Toyos a few months back. It's a very technical track and I've only been there a few times, so I'm in full-on learning mode. Every lap is a bit of an adventure with the bumps, surface changes, etc.

The weather was not cooperating at just above freezing, and with a killer wind-chill. Mark Wilkins had recommended I do a long warm-up session and keep a close eye on the pressures. I figured these tires would take 3-4 seconds off my Toyo times once I got comfortable with them.

What came next was a huge surprise. The second lap of the second session was already a 1:58, a full 6 seconds faster than my previous best. The tires were astounding, and they weren't even up to temp! They created an additive effect, with higher cornering speeds, the long gearing was less of a hindrance. I did however struggle to get them up to temp and to keep the pressures happy (30 psi).

In the afternoon, I decided to go for broke to see if I could get enough heat in them for a good lap. It took 7 full-on, sliding, scary laps to get some heat into them such that I could lean on the fronts with confidence and power out without big lurid slides. The lap time dropped another 3 seconds to a 1:55. Even then, the slicks felt like they had so much more to give, if only the temps (and driver!) were more favourable.

When I looked at the data, that feeling was verified by the g-forces being only ~1.3g through the corners, so these were operating like a good set of Hoosier R6's in this weather and this driver. I can't imagine the forces and times with a set on a warm day, and with a driver that is comfortable on them.

Unfortunately, I was not able to improve on that time because I did something stupid at the end of that session. I pulled off-line on the straight to let a group of cars go by during my cool down lap, and picked up tons of OPR (other people's rubber). Once the tires cooled off, this rubber hardened and became one with my tires; as a result, the traction dropped dramatically

I took away a few lessons from this first experience:

1. Tire pressures and temperature are critical with slicks. Even a few PSI above the targeted range and the car would get very tail-happy. Straight out of the pits, with near freezing temps, the car was diabolical scary.

2. The car can be throttle steered so much easier with slicks (probably because the front grips so well now). The steering is so wonderfully light that you can use a very light touch on the steering wheel while producing high cornering loads.

3. The Guard diff comes into its own on slicks; the car could be trail-braked deep, deep into the corners with total confidence. Braking is the area I feel that I under-drove the most on the slicks; there's so much more to learn there.

4. It felt like I was beating the crap out of the car on the slicks, with slapping noises (rubber stuck on the tire slapping the wheel arch), banging (rocks flying up), thumping (rubber stuck on the tire) and every bump and groove on the track filtering through. It felt like my entire car was vibrating itself apart.

5. Going off-line with warm slicks is a bad idea. You'll pick up other people's rubber and ruin the traction of your tires. If you do, immediately take the rubber off before it hardens. Once it hardened, nothing I tried got it off; I couldn't generate enough heat for it to melt/peel off. Any ideas what I should have done?

6. Slicks are extremely addictive; I can't imagine going back to Toyos anytime soon...

A decent lap on the slicks:

ivangene

THAT was a good lap - I enjoyed it, thanks for posting

tcsracing1

wow! thanks for sharing!
you got me thinking about slicks now too!!

fc-racer

Are the images showing up upside down for you?

ProCoach

Great post! Congrats on finding that amount of time!

Teams use a heat gun to warm the worms and a wire brush or tire scraper.

http://www.fab-worxinc.com/qmpit.html

paver

Nice post. Thanks for the info. Had you only driven street tires prior to this?

BBMGT3

A blowtorch and a chisel is a good way to get gunk off your slicks.

mooty

yes images upside down
is it due to grippy tires?

mikymu

The only thing better than slicks in certain condition are Hoosier R6 which is great for easy DE and cold weather. Typical "customer" Michelin slicks are not suited for track temperature below 65F and that's when R6 outpace slicks on the same car.

Michelin slicks last and last. I run my slicks way pass 40 heat cycles and they are still decent and fast!

fc-racer

That's great info to know! Thanks for sharing. There was a GT3RS at the track running fresh R6's turning 1:55's as well, so I think you're bang on. What kind of cornering g's do you pull with Michelin's on a warm day?

On the GT3, I've only driven with Toyo R888/RA1 and Michelin Sport Cup. The slicks are on another planet

Brilliant! I'll have to get one for next year. The difference in grip with the worms on the tire was startling. My car transformed into a rally edition

mikymu

Yes, R6 is a fantastic medium fast tire that can be used in wide range of temperature and best of all you can rotate it inside out every 12-14 heat cycles to help improve longevity. At recent Laguna Seca race where the track temp was mid 50-60F my Michelin slick never gain any decent grip and a NSX with Hoosier R6 just kill the rest of the field. I am not sure how much G Michlein slicks generate in my Cup. It has to do with your alignment, track condition and also "*****" which I often forget to bring with me

It's nice to have two sets of track wheels - one with Michelin slicks when temperature is hot and looking to out pace other by 2-3 seconds and another set with R6 for cold weather and easy track days