Tire PSI - TriStateTuners.com :: Home of Tristate Auto Enthusiast

evogsrviii · 12-03-2008, 10:49 PM

What kind of PSI is everyone running in their tires for draging? Usually I like to keep it safe in the 32-38 range, but I see people run mid 20s and lower with higher hp Evos. I also heard to run higher in front and lower in the back, not sure why.

The Captain · 12-03-2008, 10:58 PM

38? hot damn that's high. I thought 32 was the suggested operating psi, so any higher i would figure would just hurt you.

Mid 20's sounds right.

And if it helps, i know for fwd, you want low in front (obviously) and higher in the back because u're just draggin the rear wheels around so you want them to be dragged as easily as possible. Is the Evo a 50/50 split for power?

blewby u · 12-03-2008, 11:30 PM

32 in the front, 29 in the back

enigma · 12-03-2008, 11:33 PM

I'd run them at stock tire pressure, and learn how to launch real well, then play with tire pressure from there, buuuuut-
Problem with radial tires is that when you lower the tire pressue you change the contact pattern that the tread makes with the ground, lower tire pressure makes the inside ring of the tire collapse, and you are running mostly on sidewalls(more drag, but more contact patch with slicks/dr's), and higher pressure makes the inside bulge out, less contact with road, and less drag. Slicks are a different beast, they expand and contract more freely as the tire rotation increases/decreases.
Dropping the tire pressure a pound or slightly more on DD street tire may help a bit, but any lower will hurt you.
When i was racing my truck, dropping the rears more than 5 lbs hurt my launch, but that was on a RWD truck ,so tire pressure is even more critical.

lawdogg · 12-03-2008, 11:37 PM

I pull 1.6x 60's in my VR-4 with my tire pressure around 36psi front & rear. I never changed it between autocrosses when I hit the track. I have 245/40/18 Aziens RT-615s.

evogsrviii · 12-04-2008, 10:17 AM

yea, upper 30s is a little on the high side. i usually only run that in the summer when the track is prepped really well. i feel its safer to spin then end up breaking something. Last time i went, i was running 38/36 and pulled a 1.73 60. Ill probably drop it to around 30 since its colder and will work around from there.

peteyturbo · 12-06-2008, 02:16 PM

22 front and 19 in the back...Still spins like crazy though

12-03-2008, 10:49 PM	#1
evogsrviii Tri-State Addict Join Date: Mar 2008 Location: CMCH, NJ Member #7186 My Ride: 05 TB Evo VIII GSR iTrader: (0)	Tire PSI What kind of PSI is everyone running in their tires for draging? Usually I like to keep it safe in the 32-38 range, but I see people run mid 20s and lower with higher hp Evos. I also heard to run higher in front and lower in the back, not sure why.

12-03-2008, 10:58 PM	#2
The Captain Tri-State Post Whore Join Date: Jan 2007 Location: West Philly - FBG$ Member #3369 My Ride: Prelude iTrader: (2)	38? hot damn that's high. I thought 32 was the suggested operating psi, so any higher i would figure would just hurt you. Mid 20's sounds right. And if it helps, i know for fwd, you want low in front (obviously) and higher in the back because u're just draggin the rear wheels around so you want them to be dragged as easily as possible. Is the Evo a 50/50 split for power? __________________ Thank you for flying Air force Airlines. Oh me? They call me The Captain. - "America is all about speed - hot, nasty bad-ass speed." Eleanor Roosevelt (1965)

12-03-2008, 11:30 PM	#3
blewby u Tri-State Addict Join Date: Oct 2008 Location: Waterfront Square, Philadelphia Member #9461 My Ride: 2012 Audi S5, 2007 Lotus Exige 240S iTrader: (0)	32 in the front, 29 in the back __________________ current: 2012 Audi S5, 2007 Lotus Exige 240S

12-03-2008, 11:33 PM	#4
enigma Tri-State Addict Join Date: Oct 2006 Location: Glenolden ,PA Member #2659 My Ride: Hoopties galore iTrader: (0)	I'd run them at stock tire pressure, and learn how to launch real well, then play with tire pressure from there, buuuuut- Problem with radial tires is that when you lower the tire pressue you change the contact pattern that the tread makes with the ground, lower tire pressure makes the inside ring of the tire collapse, and you are running mostly on sidewalls(more drag, but more contact patch with slicks/dr's), and higher pressure makes the inside bulge out, less contact with road, and less drag. Slicks are a different beast, they expand and contract more freely as the tire rotation increases/decreases. Dropping the tire pressure a pound or slightly more on DD street tire may help a bit, but any lower will hurt you. When i was racing my truck, dropping the rears more than 5 lbs hurt my launch, but that was on a RWD truck ,so tire pressure is even more critical. __________________ 2001 Dakota Quad Cab, 1996 Ford F250, 1993 Honda Civic, 1991 Eagle Talon, 1970 Plymouth Duster.

12-03-2008, 11:37 PM	#5
lawdogg Tri-State Addict Join Date: Aug 2007 Location: Chicago, IL Member #5674 My Ride: seat of my pants iTrader: (0)	I pull 1.6x 60's in my VR-4 with my tire pressure around 36psi front & rear. I never changed it between autocrosses when I hit the track. I have 245/40/18 Aziens RT-615s. __________________ 2001 Audi allroad 2.7T 6mt: DD - 1991 Mazda Miata: track rat - 1992 Dodge Stealth RT/TT: now with VR-4's drivetrain - 1994 Mistubishi 3000GT VR-4: 11.8 @ 116: RIP

12-04-2008, 10:17 AM	#6
evogsrviii Tri-State Addict Join Date: Mar 2008 Location: CMCH, NJ Member #7186 My Ride: 05 TB Evo VIII GSR iTrader: (0)	yea, upper 30s is a little on the high side. i usually only run that in the summer when the track is prepped really well. i feel its safer to spin then end up breaking something. Last time i went, i was running 38/36 and pulled a 1.73 60. Ill probably drop it to around 30 since its colder and will work around from there.

12-06-2008, 02:16 PM	#7
peteyturbo Tri-State Post Whore Join Date: Feb 2006 Location: NE Phila. Member #1450 iTrader: (0)	22 front and 19 in the back...Still spins like crazy though __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures. To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures. To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures. To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

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