How much tire pressure to add?

[gosu22]

I've got a stock '91 S13 FB, but I'm not sure how much tire pressure is correct. Tire says 40 psi max. All 4 are at 20 now. Is it underinflated? I had a friend tell me that 30-35 is average.

[S13Boosts]

there should be a sticker in ur glove department box

[acheron]

inflate it to about 32-34 psi and you'll be set...

[gosu22]

Gonna check my glove now, thx guys.

[180sx Fan]

20 psi is underinflated i agree with acheron 32-34 is good place to leave tire pressure for daily driving.

[murda-c]

lol glove department box...

[g6civcx]

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=147