PSC2 Sizes for GT350 or R for track use?

[cloud9]

I can't wait for the N4SM wheels to arrive to get on track so I'm going to run it like I brung it at the end of April. That means I'll have to run the stock wheels so my plan is to order a set of stock tires since they'll be toast after the three day event. I'm going with the PSC2s instead of the PSS for the added grip. The question is do I go with the OEM sizes 305/295 or the R sizes 315/305? The 10.5"/11" rims will support the larger 315/305 combo, but I need to verify I have enough clearance to the strut up front. Looking for any suggestions from anyone who's run these tires. I'd much prefer to run R7s but I don't want to drop down to a 295 up front with a 315 in back. Even the 295 up front might not work with the bulge and without the longer ARP studs being available I can't run a spacer........

 

[cloud9]

I measured the clearance to the strut at roughly 10mm with the stock 295/30/19 PSS which has a section width of 11.9". The section widths of the tires I'm considering running on the stock wheels are:

PSC2 295/30/19 - 11.9"
PSC2 305/30/19 - 12.3"
Hoosier R7 315/30/19 - 12.5"

I'm pretty sure the PSC2 305 will fit if the overall width is 10mm wider than the 295. I wish I knew if the 315 R7 would clear the strut, but not sure how it will fit on the wheel compared to the PSC2. It's going to be roughly 8mm wider to the inside which would be cutting it pretty close. Does anyone know how much clearance there is on a stock R? If @Black Boss was able to run a 315 R7 on the stock CF wheels, knowing how much clearance there is stock compared to the GT350 should provide the answer.......

 

[VoodooBoss]

I think you can run the R PSC2's on the stock wheels with no problem. Are you going to install CC plates at the same time?

 

[cloud9]

I think you can run the R PSC2's on the stock wheels with no problem. Are you going to install CC plates at the same time?

I'm dropping the car on Saturday so they can put the MM plates on while we're at Track Attack. According to @Black Boss I should be able to get 2+* and will have them set at -2* up front and per Ford's recommendation in the rear.

Per Ford the track specs are:

Front GT350R GT350
Camber -1.5* -1.75*

Caster 6.83* 6.92*
Toe-total 0.06* in 0.10* out

Rear
Camber -1.0* -1.25*
Toe - total -.30* in -.30* in

 

[VoodooBoss]

Are you going to use the R specs in the rear? You are going to use the R tires after all.

 

[cloud9]

Are you going to use the R specs in the rear? You are going to use the R tires after all.

I don't know, you tell me. Is it the tires or the shorter/stiffer springs? I really want to set it up for R7s not the Michelins anyway. Maybe I should just go with the R spec in the rear...... :-\

 

[VoodooBoss]

My bet is those settings are more tire specific than suspension specific. You should call Filip @CorteX Racing and discuss. He has a lot of experience with the S550 chassis. Best not to call him around PWC races as he's usually traveling. CorteX and KohR are setting up a S550 for PWC as I type.