?? boost cut in half!??

[Skorj]

hi ppl,

i have a 32 gtr which iwas driving all day today and when i was about 5 min from home i merged onto the freeway doing about 120k in 4th gear prob on full boost... about 0.9bar then boost dropped down to about 0.6 bar...

there were no bangs or noises or any jerks or smoke etc.. nothing at all.. but the car wouldnt boost above about 0.6 bar in any gear after that...

i'm yet to drive the car since this has happened as i'm worried somthing bad may have happened..

anyone have any idea what might have happened? i couldnt have blown a turbo or anything without knowing it could i?

thanks for any help..

p.s 32gtr with full zorst and stock turbo's..

[wrxhoon]

I don't think you busted anything . If you leave the car overnight you will find it will boost again to normal boost . You have a stock ecu , right ? You probably find that it running a little lean at top rpm and the stock ecu nocked boost down to what the actuator is .6 bar .

If you want to make sure you dont have turbo issues try this test . Unplug the hose that goes to your turbo actuators anywhere you get to it , take it for a run BUT CAREFULL , keep an eye on the boost gauge as soon as it hits .9 bar BACK OFF or you nay blow your turbo. If it boosts to .9 then you will know you have no turbo problems .

[Skorj]

thanks for reply,

yes i do have stock ecu.. i was hopeing is was just an electrical problem like that, which will correct itslef when it cools down..

i'l leave it over night and c how it goes tomorro, otherwise i will try the test u mentioned...

thanks agn, much appreciated..

[wrxhoon]

If your turbo let go you would know it , i can assure you first it would be noisy unless the wheel came loose but i doubt that ..

[Skorj]

yeh i took it for a drive yesterday morning and it was all fine.. boosting as normal..

must have just been the computer cutting it back like u said..

is this something that will hapen frequently now? i have had the car about 3 weeks and its the first time its happened...

would u recomend get the car dyno tuned etc..

cheers.

[wrxhoon]

Yes it will and its verry risky . Not because you have no boost , its because it cuts boost for a reason ( knock ) to save your engine .

I don't know if anyone can tune stock ecus but you can get a power f/c and have that tuned .

Check to see if you still have the restrictor in .

As far as boost drop to .6 it will that often but it will go back to normal as soon as its reset itself .

[Skorj]

hmm yeh i have been pricing some power fc's atm, and should hopefully pick one up soonish...

the boost cut has happened another 2 times now... and it is always in a high gear 4th 5th whilst accelerating hard..

i'l take the car in for a service soon and c if i can get a basic tune till i can pick up an aftermarket ecu..

thanks for all ur help wrxhoon,

[wrxhoon]

hmm yeh i have been pricing some power fc's atm, and should hopefully pick one up soonish...  

the boost cut has happened another 2 times now...   and it is always in  a high gear 4th 5th whilst accelerating hard..

i'l take the car in for a service soon and c if i can get a basic tune till i can pick up an aftermarket ecu..

thanks for all ur help wrxhoon,

Try and buy the best fuel you can in the meantime .

You can get a power f/c and hand controlle for $1200 + you will have to pay for someone to tune it , $ 300-400 . In the mean time take it easy on the car .

[Cubes]

Its fairly normal for even the GTS-T's to get that fuel cut in a high gear when running around 1 bar.

My GTST used to do it @ ~5500rpm on around 17psi or on 16psi on a really really cold morning.

Now with the new motor (RB30DET) it does it anywhere from 2500rpm on 8-9psi.

Its not actually maxing out the AFM its more a combination of injector duty cycle & the ecu thinking (hey whats going on here its drawing more air than my map is saying it should be)

[GTRsean]

I was going to say check your piping from turbos to throttle. Hose blew off inter cooler and lost boost quick. But it could be more complex than that.