Odd Boost Issue

[poo32]

Hey all, my rb20 poped a cooler pipe on a spireted run, so I fixed it up and now im noticing a boost differenc from gear to gear of between 1/2 to a full bar. That just seems to be a bit much. Its stock except int/exh, ball and spring mbc (set to 8 bar, witch was consistant in all gears before the pipe) any info will be appreciated. Cheers.

[DVS JEZ]

Recheck all cooler pipes for splits etc

[poo32]

I went around with a can of carby cleaner and every cooler pipe seem'd fine, the only other thing I touched was the vac lines on the carbon canister but im pretty sure I plumbed it correctly. I dont think that would effect boost though.

[poo32]

Lol just noticed I put 8bar in my post, its .8 that the mbc is set to and it peaks at .8 in all gears but drops to .7 or so.

[DVS JEZ]

Seems normal then

[TurboMick]

Yeah don't see the problem...

[AngryRB]

turbomick, how does your BA differ to the r31?

[TurboMick]

Lol what? They're exactly the same...

???

[poo32]

Fair enough I would have thought being near stock boost it would hold a consistant amount, cheers for the replys guys.

Also what would be the highest acceptable boost drop with a mbc? As my drop is up to 3psi as ive worked it out to.

Edited September 22, 2012 by poo32

[poo32]

ok so i found that the boost gauge line was leaking, fixed that but in the process i found that with a boost leak test (http://www.supramania.com/forums/showthread.php?19718-DIY-Boost-Leak-Tester) that air was leaking from the dip stick, but i have no other symptoms of dodgy rings or anything. any insight would be awesome. cheers.

[HR32GTS 4DOOR]

A bad PCV valve would cause this, but my money is on fried rings.

[poo32]

Catch can is clean, no exhaust out the oil filler cap, no air from the dipstick when running. And ive had my doubts about my pcv as its hard to start cold and idle is a bit dodgy.