Discussion in 'Forced Induction' started by import_racer, Oct 16, 2002.
Is it necessary to sleave your block if you are running 9 and under psi on a b16?
psi means nothing. its how much cfms the turbo will flow.
B, I have to say psi has something to do with it.
the more positive pressure you push into the cylinder. the higher the cylinder pressure will be. ther'll be more force on the cylinder walls.
Pressure = Force/Area
Force= Pressure x Area
if your pushin 9psi into a cylinder that's 75mm bore x 84.5 mm stroke (which has a surface area = 2 pi r 2 rh) that's gonna have a good sized reaction force.
r=37.5mm (1.47 in) , h=84.5 (3.32 in), pressure = 9 psi
(9 psi) x ([2 x pi x 1.47 ^2 ] [1.47 x 3.32])
(9 psi) x ([13.57 sq/in] [4.8804 sqin])
9 psi x 18.45 sq/in = 166 lbs/sqin
that's 166 lbs/sqin of reaction force acting on those cylinder walls.
plus whatever forces are already being generated from the stock setup.
I guess the volume of air ther turbo can flow has more of an effect of how much volume of air/fuel mixture gets into the cylinder but pressure has an effect as well
granted-- BUT psi as far as turbo's go is the measurement of air pressure NOT going into the motor. in other words, this psi is seen BEFORE the throttle body.
I swear he just made up that math
9psi = 9psi (pounds per square inch)...not 166 PSI
All you really need to know is what the air pressure is at sea level...which is 14.7 psi
If you were running 14.7 psi of boost to your engine at sea level, you would essentially be doubling the amount of air getting into your engine...if you were running 7.4 psi...you *should* be increasing the air getting into your engine by about 50 percent
So some THEORETICAL numbers for a b16a engine under boost might look something like this:
3.6 psi of boost = a b16a that produces 139 ftlbs of torque/200 crank hp
7.4 lbs of bost = a b16a that produces 166 ft/lbs of torque/240 crank HP
11 lbs of bost = a b16a that produces 194 ft/lbs of torque/ 280 crank hp
and so on and so forth...
When you are putting 7.4 psi of boost into your b16a...you are essentially putting 50 percent more air in the engine...to make 50 percent more power.
Sooo...you are putting about 50 percent more stress on the internals. Hondas are built from the factory to EASILY withstand 50 percent more stress on the internals. You don't get problems with sleeves cracking from the extra power...sleeves crack when you get pre detonation (AKA pinging).
If you have a good intercooler, and run high octane fuel...the chances of running into pre detonation are minimal at 7 or 8 psi. But when you run lower octane fuels and have lots of hot air coming into your engine...your chances for pre detonation increase exponentially...and likewise your chance of blowing the fuck out of your engine.
yes...nevermind that I figured out what you are talking about with that math...the 166 psi comes in after the air has been compressed. but 166 psi should still only be something like 60 percent higher than the compression without the turbo.
Um, yeah, sure, okay!!! lol
Any other ideas? I think mine's right...but I'm open to suggestins
It all has to do with it! Brian is correct. You can think what you want or believe whom you want!
now I get ya B.
makes more sense to me now
you guys did all that math for nothing
yes pissed is right
9 psi on T25 verses 9psi on a T100 are very very different...still 9psi...but the VOLUME of air is far different...so what pissed is saying is....psi don't mean squat unless you know the size turbo!
Separate names with a comma.