Jump to content
SAU Community

Recommended Posts

hi all i have recently got a profec b spec 2 ebc installed on my 33gtst and i was pushing 11psi with stock turbo

it was very consistent and stable it stays @ 11psi since 2k + rpm and went on all the way to redline

then the next day i realised the boost wont go over 9+ psi with the same settings (i didnt even touch the controller)

and so i tried to turn the boost controller off and it was only boosting around 5psi instead of 7psi.

i know the profec b increase boost by the % of stock boost

so i reckon the problem lies to my stock boost and thats why its only boosting 9psi with the controller

but anyone can help why issit only boosting 5psi on stock boost?

i read someone bout modding the stock solenoid, the stock boost will stays @ 5psi if the solenoid is not grounded and 7psi if its always grounded.

but it shouldnt affect me since i have an aftermarket bc already. i just thought it might somehow be related.

it was boosting 11psi all the way on the day it was set and everything was good and stable

i dunno what is causing the problem a little help will be very appreciated.

thanks

eskar

Link to comment
https://www.sau.com.au/forums/topic/290436-need-help-with-boost/
Share on other sites

Don't skylines have a two-stage system where they run 5psi at lower revs, then 7.5 at higher revs (when the factory boost controller has power fed to it)? If so, your electronic boost control has probably replaced the factory system, and you get low boost all the time until you power your (aftermarket) boost control solenoid with your new fancy profec b gadget. You'll find 5psi is the wastegate pressure.

this guy is spot on the money. the wastegate pressure on the r33 gts-t and r34 gt-t are 5psi and the solenoid opens at around 4500rpm to increase the boost to 7psi, so if you disconnect the controller and it goes to 5psi then there is no problem.

as for your boost decrease, do you still have the stock solenoid connected or is it disconnected? if it is connected as well as the aftermarket one then there could be an issue there. otherwise it could be one of a few things. could be a leak in the line to the boost gauge or a blockage.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • That's a good point. The rears of the covers themselves have no baffling at all though. Higher up more chance of air for venting the crank case. Lower on the side more likely to be submerged. I might be able to fit them on the sides but with both the sump drain fittings being on the drivers side the passenger one will need to make a U Turn and be nearer the turbo. But it will look neat being not up on top.
    • It won't likely matter where along the cam covers you put the big fittings. I would suggest putting them on the sides if you can, simply because it will reduce the flow up through the baffles and thus reduce the amount of oil that gets put into the foam. It might not matter, but it seems like something to consider as a worthwhile thing to avoid.
    • Well, I have my IM240 results with a cammed LS1... My Nox was 0.11 and my CO g/km was 0.2. Euro4 is 0.08 and 0.1 respectively. I'm gonna say for a stock RB this is actually plausible, BUT in Australia they were complied pre-Euro2, so the limits were: Which as you can see, is way higher. I'd say a stock RB with a new OEM Cat could? actually pass Euro4 for NOX but you'd probably have to do a hell of a lot of testing to prove it, and getting a car emissions tested and carrying a certificate of emissions when/if you get pulled over may be cost prohibitive if it's even allowable to get your car tested and re-classified. You'd have to find out what the UK Govt is using as reference material. It may be non-negotiable.
    • I made a little more progress last night and added some E85 safe fuel tank baffle foam in behind the stock cam cover baffle plate.  It still feels really wrong shoving foam inside the engine but apparently its fine based on it pretty much being the MINES/Hi-Octane RB26 cam baffle kit and the few posts here I have found of people doing it and the lack of posts saying the foam broke down and ruined the motor... Still plan to check it frequently though lol The last step for this round of oil control modifications I plan to make is to add some -12AN fittings to the cam covers and connect them to some (already existing luckily) -12AN fittings on the sump. Basically a sudo head drain/sump breather/pressure equaliser without having to remove the motor and do the one on the rear of the head. My plan is to add them to either the tops or the sides of the cam covers at the back. unless there is a compelling reason to have them at the front on the sides which i have seen a few times though they were all on RB26 cam covers from memory so that may be due to the stock breathers being on the back and the integral baffle being different ?    
×
×
  • Create New...