Recommended track tyre pressures for S2?
07-19-2005, 07:52 AM
#1
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Location: Brisbane, Australia (Formerly: Sunnyvale, CA)
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Recommended track tyre pressures for S2?
Hi,
I'm taking my S2 out for some sprints around Morgan Park Raceway
http://www.nmd.com.au/racetracks_detail.cfm?id=16
on Thursday, and was looking for some tyre pressure recommendations.
The factory recommended pressure for a 1990 S2 coupe Australian delivered vehicle is 44 psi (rears), 36 psi (fronts). That's for the original 16" D90 rims, with 8" front tyres and 9" rear tyres.
I've running 17" Mille Miglia turbo twist copies, with 8" front tyres and 10" rear tyres.
I've also got a slightly modded suspension; stiffer springs, lowered 1", bilstein shocks. Put in 968 caster blocks when I rebuilt the ball joints.
My friend Rob in Oz tells me that the 1986 951s recommended 36 psi front and rears; he was a little surprised the spec for the S2 was so different (as was I, thinking the S2 suspension basically was the "early model" 951 suspension.)
Any suggestions or insights appreciated.
-Mark
I'm taking my S2 out for some sprints around Morgan Park Raceway
http://www.nmd.com.au/racetracks_detail.cfm?id=16
on Thursday, and was looking for some tyre pressure recommendations.
The factory recommended pressure for a 1990 S2 coupe Australian delivered vehicle is 44 psi (rears), 36 psi (fronts). That's for the original 16" D90 rims, with 8" front tyres and 9" rear tyres.
I've running 17" Mille Miglia turbo twist copies, with 8" front tyres and 10" rear tyres.
I've also got a slightly modded suspension; stiffer springs, lowered 1", bilstein shocks. Put in 968 caster blocks when I rebuilt the ball joints.
My friend Rob in Oz tells me that the 1986 951s recommended 36 psi front and rears; he was a little surprised the spec for the S2 was so different (as was I, thinking the S2 suspension basically was the "early model" 951 suspension.)
Any suggestions or insights appreciated.
-Mark
07-19-2005, 12:04 PM
#2
Race Director
I have run 34 / 36 to 36 36 on my 88 Turbo S using 225/50 and 245/45 16" street tires.
ON my 944-spec race car I run the same tire pressure at all 4 corner using Toyo RA-1's
ON my 944-spec race car I run the same tire pressure at all 4 corner using Toyo RA-1's
07-19-2005, 12:22 PM
#3
Nordschleife Master
Correct tire pressure is critical to success, and avoidance of failure, at the track. The tire heat up and the air increases pressure during the sessions. This can result in overinflation that causes a loss of grip. And that can coincide with your wanting to go a bit faster.
Best to get in-person advice and help at the track. The methods include using a temp gauge, chalking the edges and measuring pressures after the session.
Best to start low and check how things are going. I'd start with 30-32 psi all around and see how the measurements look and how the car feels.
Best to get in-person advice and help at the track. The methods include using a temp gauge, chalking the edges and measuring pressures after the session.
Best to start low and check how things are going. I'd start with 30-32 psi all around and see how the measurements look and how the car feels.
07-19-2005, 02:13 PM
#4
Race Director
With street tires, I run 34 psi at all four corners.
For track tires, I typically start somewhere between 31 psi and 34 psi cold, with a target of 39/40 psi hot. (Tires are Toyo Proxes RA-1's on 8Jx16 wheels). The starting cold pressure changes according to ambient temps, the track, and other track related factors -- ya know -- that track voodoo magic stuff we all can't really share with the common folk!
-Z-man.
For track tires, I typically start somewhere between 31 psi and 34 psi cold, with a target of 39/40 psi hot. (Tires are Toyo Proxes RA-1's on 8Jx16 wheels). The starting cold pressure changes according to ambient temps, the track, and other track related factors -- ya know -- that track voodoo magic stuff we all can't really share with the common folk!
-Z-man.
