Track Day Tires

[Kawman]

Has anyone tried racing slicks on your CT4-V Blackwing for track days?

I'm trying to get confirmation on what fits these cars. Seems like 25/64 should fit the front and 27/65 might fit the back. Can anyone confirm?

Thanks

 

[Super Saloon]

What kind of racing are you doing that you need slicks? Have you tracked on the OEM tires yet?

 

[poor-sha]

John Heinricy was running Hoosiers on the 4BW he campaigned in T2. I believe there was another thread a while back about slick sizes where several of us had done some research.

 

[Kawman]

Just regular track days and maybe time trial events.

I did the Cadillac Academy at Spring Mountain, NV. Since then 1 day at Lime Rock, 2 days at Palmer Motorsports and 1 day at Watkins Glen.

I tend to always want more, so figured I go all the way to the Michelin Cup N2's.

 

[AC2024]

If youre pushing that hard and adding slicks you going to be VERY fast and limit handling is going to be scary. I wouldn’t do this in a car without a roll cage. If youre putting slicks on a 3800lb sedan i think that means you bought the wrong car!

 

[poor-sha]

Heinricy demonstrated it could run a full T2 race and win on Hoosiers - so it certainly can handle stickier tires. I always tracked my 5BW on stock tires because frankly they are very good and I didn’t see a reason to add more grip.

Both John and I also ran dedicated track alignments, so frankly that’s the cheapest handling mod if you haven’t already and it’ll help with tire life on track.

It’s up to you, but with a total of 6 days of track experience, I’d focus on learning how to maximize lap time on the stock tires. Your biggest gains will be through the driver mod.

 

[Kawman]

Yeah, I'm pushing it pretty hard. As a friend said who I took for a ride at Palmer, "driving it like you stole it".

I'm dinging 1.1-1.2 on the G-force gauge in most turns. I hit 136mph on the back straight at Watkins Glen last year. I think I should be able to reach 145mph this year.

Camber had been increased to -1.8 front and -1.4 rear last year. For this year I'm going to -2.4 front and -1.8 rear. I just switched to Castrol SRF brake fluid. I will use Porterfield Racing brakes and the brake deflector cooling fins that come with the car for track days this year.

Well, I pulled the trigger and ordered a set of Michelin Porsche Cup N2 racing slicks. I'll post if they work out in a few months. Both the 25/64's and 27/65's are designed to be front tires.

I don't know how good this may or may not be, but I ran 1 minute, 55 seconds at Palmer in either direction last year. With more camber, more brakes and more tires, I'm hoping to break into the 1:49"s this year. I'm also going to start using the "no lift shift" feature this year that I never tried last year.

 

[Kawman]

If youre pushing that hard and adding slicks you going to be VERY fast and limit handling is going to be scary. I wouldn’t do this in a car without a roll cage. If youre putting slicks on a 3800lb sedan i think that means you bought the wrong car!

Well, I might be getting a 2016 Corvette from an estate sale. That would be a 3,300lb car with slicks, better? The problem is the thing is an automatic, arrghh!

 

[poor-sha]

Do you have the PDR and did you record any sessions?

This data dive was with my 5BW, but might be useful for understanding how to improve lap time.

 

[AC2024]

Well, I might be getting a 2016 Corvette from an estate sale. That would be a 3,300lb car with slicks, better? The problem is the thing is an automatic, arrghh!

I guess i would generally say that if you are running slicks without a roll cage you should think about things.

Either youre too slow for slicks (ref: driver mod). Or if youre fast enough (based on your comments you seems to be in this category). to be a the limit on a very capable mps4s you may have a death wish…

I think i am more irresponsible than most but i would never go the speeds you mention without a 5 point and roll cage. I just turned 40 so perhaps i am just getting old…

 

[Kawman]

Do you have the PDR and did you record any sessions?

This data dive was with my 5BW, but might be useful for understanding how to improve lap time.

Yes, I have the PDR. I watch the videos over and over and over and over looking for areas for improvement.

At Watkins I was slowing to 90mph entering turn 2. From watching the videos and the G-force meter and considering the slicks, I know I'll be over 95mph entering turn 2. I was entering the Esses at 100mph and exiting them onto the back straight at 115mph. I anticipate this year entering the Esses at 110, exiting at 125 and doing better than 145 on the back straight. I was downshifting to 3rd going into the bus stop and staying in 3rd until the Boot straight. This year I plan to stay in forth through the bus stop and around the Outer Loop, then down shift to 3rd going into the Chute.

I'm doing the same kind of analysis, I just a bit low-tech

So, are you going to take a drive up to the Northeast for a "Blackwing Racing" event?

 

[Kawman]

I guess I would generally say that if you are running slicks without a roll cage you should think about things.

Either you're too slow for slicks (ref: driver mod). Or if you're fast enough (based on your comments you seems to be in this category). to be at the limit on a very capable mps4s you may have a death wish…

I think i am more irresponsible than most but i would never go the speeds you mention without a 5 point and roll cage. I just turned 40 so perhaps i am just getting old…

I just turned 60 and recently bought the first new car of my life. Feeling like the "kid in the candy store" driving this thing. Always wanted to try driving something on a track.

There's plenty of stock "Showroom floor" cars going faster than me.

No death wish here, it's called being an adrenaline junkie.

So, you're in MA, coming to play at Palmer July 15th?

 

[poor-sha]

Yes, I have the PDR. I watch the videos over and over and over and over looking for areas for improvement.

At Watkins I was slowing to 90mph entering turn 2. From watching the videos and the G-force meter and considering the slicks, I know I'll be over 95mph entering turn 2. I was entering the Esses at 100mph and exiting them onto the back straight at 115mph. I anticipate this year entering the Esses at 110, exiting at 125 and doing better than 145 on the back straight. I was downshifting to 3rd going into the bus stop and staying in 3rd until the Boot straight. This year I plan to stay in forth through the bus stop and around the Outer Loop, then down shift to 3rd going into the Chute.

I'm doing the same kind of analysis, I just a bit low-tech

So, are you going to take a drive up to the Northeast for a "Blackwing Racing" event?

Most time is going to be found by when and how you pick up the throttle, as well as managing your speed heading to the apex (e.g. rolling more speed longer). It’s very tough to see this through video.

I’ve been to WGI a couple of times and would like to go back, but I doubt I’d bring the Blackwing.

This was my fastest lap there in my C7 ZR1. Still a lot of time to be had though. They say lap times at VIR and WGI are very similar, but I was 4s faster at VIR because I had a lot more laps there.

 

[Kawman]

I can watch that all day! 115mph through turn 2, into the Esses at 120 and coming out at 145 before hitting 160 on the back straight.

What group were you in? That looked like a combination of B and C groups. I only know the HOD system, which goes:
A-Novice (with instructor)
A-Solo
B
C
D

My drives look much the same but slower. Front end pushing at times, rear end trying to come around at times. I leave my nanny controls on. I think it saved me one time when I started going sideways in the left hander at the end of the straight at Palmer when driving CCW. If you're not driving near the edge what fun is it?

What were you running for tires? Was that a stock ZR1? Oh what 300lbs lighter, 250 more hp, more suspension, more brakes and more tires can do. Why wouldn't you bring the Blackwing to the Glen? If not the Blackwing, bring the ZR1!

You use the curbing more, especially through the Bus Stop. I use them a bit, but stay away from the harsher ones like through the Bus Stop, worried about my carbon fiber splitter.

 

[poor-sha]

I instruct for them. One benefit is that I can go out whenever I don’t have a guest/student.