would somebody explain me what psi means?

[BRSTYLE240SX]

i know it has something to do with pressure.. and also with turbo.. but what is it really? thank you...

Later!

[SSJ2Gohan]

PSI = "Pounds per Square Inch" i believe.  All about pressure.  The more pressure you have the more force you have.  

Shake a can of coke real good and open it up for a quick demonstration on increased pressure.

Comes into play on turbos cause the more pressure you have, the more air you can force into your engine.  Of course the more pressure you have, the greater the strain you put on engine and that is how pistons get fried.

Blow up a balloon until it pops in your face for a quick demonstration of that.

<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[Fourgig]

Actually, pistons usually get fried because of detonation. &nbsp;Too much pressure usually bends/breaks rods.

[AKADriver]

you can get detonation from high cylinder pressure.

[boosteds14]

piston rings get fried from running too hot or too much friction thus being hot.

causes by running too lean or bad gas or engine running too hot

[BlackFox]

At sea level the atmosphere is 1atm or 1.01bar, which is roughly 14.7psi. So as you go up in altitude that pressure drops, hence 'thinner' air up high. So any boost you create is the pressure above the existing outside air pressure.