Standard R32 Boost?

[god's rx]

hey, just put splitfires and NGK iridium plugs into my skyline r32 gtst which has solved my missfire problems instantly

but my next question is about the boost the car is running.

there is an aftermarket boost gauge installed on my car (previous owner) and when im flat chat accelerating in 5th the needle goes up to about 17psi.... could this be misreading?

i havent got an aftermarket boost controller so im interested to know how the car limits its boost levels?

not real cluey on this sorta detail unfortunately, any help appreciated!

mods include: FMIC, Cat Back 3" exhaust, otherwise stock

[OLik]

stock boost is 10psi

[barnoon]

Yeah 10 PSI is stock, id be wanting to get that checked out ASAP because if it is reading correctly your stock turbo wont be lasting too long at 17PSI mate.

[chinkeboi]

10PSI? is this a general consensus? some others say 7psi -_-

10psi sounds more right.. but i've got my self a little boost creep! running 11.6psi (0.8 bar)

[OGR88 R32]

yeah im running 11psi also

[Rolls]

11 here.

Whats the vacuum reading on idle, that will should tell you if its not calibrated correctly, should be about 20

also do you have a bleed valve? it might be malfunctioning.

Edited December 14, 2006 by Rolls

[bubba]

Boost is regulated via the spring in the wastegate actuator. R32 GTSt's run 10psi normally but by freeing up flow in other areas (exhaust) you can gain small increases in boost.

Does it level out at 17psi? or is that all you let it get to before you freak out and shut it down?

[god's rx]

i will check it again 2day, but off the top of my head the VAC is at about 20 on idle....

its only got the stock BOV on it (no aftermarket bleed valve), i will check bout the levelling out but yes it is a bit scary watchin the needle just keep rising.....wood be fine if i knew that the components could handle it, but like u sed it isnt exactly safe

will check back soon after lookin at a few more things 2day

[bubba]

Maybe check the wastegate vacuum hoses before you drive it again.. if it is rising past 17psi I don't think you actually wan't to let it do that to confirm it is a wastegate hose fallen off.. much healthier for your engine to check it first

[Rolls]

i will check it again 2day, but off the top of my head the VAC is at about 20 on idle....

its only got the stock BOV on it (no aftermarket bleed valve), i will check bout the levelling out but yes it is a bit scary watchin the needle just keep rising.....wood be fine if i knew that the components could handle it, but like u sed it isnt exactly safe

will check back soon after lookin at a few more things 2day

By bleed valve I meant boost controller not BOV.

[god's rx]

lol, well i drove it round today and tried not to push it, but i did give it a boot to check and it only goes as high as 17psi n peaks, VAC is 20 at idle....

will check the vacuum hoses n that 2moro but other than that what else could i check?

it doesnt have an aftermarket boost controller, should i maybe invest in one of these to limit the boost level?

thanx for all ur help so far guys

[Rolls]

Bleed valve can only increase boost, can't decrease it. Sounds like you have a crack/split in your waste gate vac line acting the same way a bleed valve does. If its even remotely perished replaced it, if it gets any bigger itll boost infinitely and POP goes your motor.

What is odd though is normally the ECU will just fuel cut or the car would start misfiring badly at that sort of pressure, I really would not drive it until you have sorted the issue.

[Dan_J]

car probly had a 'piggy back' unit on it at one stage den removed, 7psi is stock boost

[bubba]

Pretty sure standard boost on an RB20DET is 10psi. Anyone want to back me up?

[Rolls]

After you put an exhaust on it it will rise, completely dead stock I believe its around 7psi, with full exhaust it will rise to 10-13psi

[god's rx]

k, wont drive it till i get that sorted out...thanx for the help slowly learnin haha

will report how everything goes

[OLik]

Pretty sure standard boost on an RB20DET is 10psi. Anyone want to back me up?

i will back you up. people look at the stock boost gauge and this yeah 7psi. the rb20 actuator doesnt open below 10psi. if you look at the gauge closely the gauge isnt measured in PSI. the gauge is in bar. 0.7bar =10.152642psi

fin...

[Rolls]

Actually you are wrong the gauge is in mmHG x100, while the gauge goes to 7 the needle shouldn't as if it does then you are running 13.5psi

Stock it should go about half way to roughly 4 x 100 mmHg

[bubba]

Well on my aftermarket guage I get 9-10psi with only a cat back exhaust and a split dump (for some stupid reason it still has a stock front pipe and stock cat) so I would imagine it not being much more freed up than it was standard.

Have since put a Turbotech manual boost controller in and think I was hitting R&R around 14psi. I've dropped it back to 11.5-12psi and it seems to go better in the top end, doesn't come on boost as harsh though which was fun but then it didn't really go anywhere.

[lwboosted]

stock boost on a rb20 is def 10 psi!!! that is why when people buy rb25 turbos they put the actulator off the rb20 turbo to run 10 psi... def sounds like u have a split in the hose or something like that... or a faulty guage.