how would i now if i have blowby?

[240cp]

ok i have a supercharged 240 its a 95 model and the reason i am asking this question is i am only seeing about 4 psi and a max of 5 psi at full rpm.

also the car has been intercooled could the prob be that my supercharger is not capable of keeping up? it is a eaton m62 unit out of a nissan frontier.

was wondering cause i thought i should at least be seing aroung 7 or 8 psi and at max power somewhere around 10 psi. the engine does have a bunch of miles on it 147,000 to be exact . thanks for any help!

[nissanfanatic]

The intercooler is more than likely causing a drop in boost pressure. Perfectly normal.

Solution: Smaller pulley.

[480sx]

The only way i know of checking for blowby is to take the pistons out, and see if there is carbon buildup beyond the piston rings(typically, black streaks on your piston). Thats your tell tale sign of blowby. Also a compression check could give you some clues as to how your bottom end is holding up.

[nissanfanatic]

Leak-down test.

[Chezedik]

Lets not forget that the car you got this off of may have made 10psi but had a different size crank pulley than yours. ASP has you covered.

[240cp]

thanks for the reply guys, i was wondering about this because ive seen a few guys with supercharger setups and with the stock crank pulley but where seing boost pressure somewhere around 7 to 8 psi, but that was without the intercooler maybe it is the intercooler dropping the pressure buy i didnt think it would be that bad!

i guess i need to do a compression test and leak down test, just to note the car was alot stronger when i ran it without the intercooler, until the delta temps started to rise as the supercharger really heats the intake charge up!!!! but anyhow thanks for the help guys really appreciate it!!

[S13FX]

Yes,

On a supercharger adding a IC drops the pressure drastically. I also own a miata where SC's are very popular and a lot of people freak out about that. But you don't loose any power so thats a plus.

[Chezedik]

There will be some power loss due to lower cyl pressures. But you would expect that it would be made up for by higher VE. Anyway, you made the right choice with the IC, now get a pulley.