Advice on slicks/semi slicks for stock 15/16 and running multiple classes

[Scin]

I am going to be running the NSX in a new time trial series in the Texas area. I plan on running two classes, the first is showroom stock and the second prepared. Show room stock is not particularly stock since they allow coilovers, sways, exhaust and a few other things.

I will be running the AD08 for SS 215/40/17 and 255/35/18, then plan to do a tire change to either a slick or semi slick for the prepared class. The tire size is limited to +10 width over stock, with no limit on the wheel size.

Does anyone have experience with the Hankook Z214 C71 compound? I am basically looking at choosing either the Z214 C71 or the Hoosier A6 (I know it's autox, but it can turn a faster lap for a time trial).

The tire is unlimited in the prepared class, so I could also run a full slick, but I have no idea where to buy a set for the stock 15/16 wheels. My plan is to run a 205/50-15 up front and a 245 tire in the rear, I am not sure if I need a 245/50/16 or a 245/45/16.

If anyone has experience switching between R Comps (I know AD08 aren't R comp, but they are pretty close) and Slicks let me know what to expect, particularly which direction to tune the suspension... I am guessing a little stiffer, but I am not sure what will happen to the front/rear balance.

I am hoping to take some time to test the car before the first event, hopefully I can get a good balance after the tire change by adjusting the JRZ dampers a click or two. My spring rates are pretty moderate, 550 front and 450 rear. The track is really bumpy and this works great on street tires, may be a little under sprung for slicks.

 

[CL65 Captain]

I am going to be running the NSX in a new time trial series in the Texas area. I plan on running two classes, the first is showroom stock and the second prepared. Show room stock is not particularly stock since they allow coilovers, sways, exhaust and a few other things.

I will be running the AD08 for SS 215/40/17 and 255/35/18, then plan to do a tire change to either a slick or semi slick for the prepared class. The tire size is limited to +10 width over stock, with no limit on the wheel size.

Does anyone have experience with the Hankook Z214 C71 compound? I am basically looking at choosing either the Z214 C71 or the Hoosier A6 (I know it's autox, but it can turn a faster lap for a time trial).

The tire is unlimited in the prepared class, so I could also run a full slick, but I have no idea where to buy a set for the stock 15/16 wheels. My plan is to run a 205/50-15 up front and a 245 tire in the rear, I am not sure if I need a 245/50/16 or a 245/45/16.

If anyone has experience switching between R Comps (I know AD08 aren't R comp, but they are pretty close) and Slicks let me know what to expect, particularly which direction to tune the suspension... I am guessing a little stiffer, but I am not sure what will happen to the front/rear balance.

I am hoping to take some time to test the car before the first event, hopefully I can get a good balance after the tire change by adjusting the JRZ dampers a click or two. My spring rates are pretty moderate, 550 front and 450 rear. The track is really bumpy and this works great on street tires, may be a little under sprung for slicks.

I can tell you that R-Comps/Slicks like the Nitto NT01, Hoosiers Toyo RA1, R888, etc like a lot of camber. I was running 2.8 deg on the front and am switching back to street tires this year and dialing it back to 1.5 deg. The R-Comps just wore too quickly for my HPDE use. Add in the fact that I instructed/ran at 16 events last year and it got awful expensive, awful fast.

 

[Scin]

I completely understand, I learned this pretty quick. My yearly karting budget was enough to buy a nice used NSX: multiple sets of new tires per weekend, travel, temperamental Italian Engines that cost $3,000 and had to be re-built every 5 or 6 hours, etc... it's not cheap to run at the front.

I usually just use the NSX for fun at local track days. I run the Dunlop Star Spec Direzza's like you and like them very well--although it is possible to get decent mileage out of some of the R Comp's like the NT01.

I am going to try the AD08's for the time trial street class since they are rumoured to be slightly faster and are even more reactive to turn in etc., which is what I like (altho the direzza's are pretty amazing for this). The class has a 140 treadwear limit. If anyone can suggest a better 140+ treadwear tire, let me know!

The problem is once you start running competitive series, you really need to have the best equipment, particularly tires. With the Hankooks or Hoosiers, I'm hoping to get a few practice laps to tune the car with and have them last long enough for two or maybe three time trials events.

I currently run -2.2 front camber and -2.8 in the rear.

 

[FXMDBilly]

As far as 'street'-classed tires, the AD08 is currently at the top, followed very closely by the StarSpec. The Federal ___ 'RSR' -i forget the specific name are also very quick. All three are very close in performance only a couple seconds off an NT01.

For autoX go with the C91 or R6. Those are far stickier than most slicks in an autoX or 2-lap environment and in some cases have been recorded as 3-5 seconds faster than the NT01 on a 2 minute track.