34 Gt-r Boost Issue

[Duncan1]

I was driving the car through a mountain section of road one evening through the week and the car was making really good [too much for stock turbo's] boost. say 1.15bar. then i pulled up at the next set of lights. as i accelerated away from the lights the car felt really doughy. it was not pulling more than about .7 bar of boost. this continued and i wondered what was wrong. on the way home, i put the car in 4th at low speed and heard the turbos spool up [much louder than i normally do]. i figured i had a small crack in a hose or something.

Then this morning i drove the car again.... Made lots of boost around 1 bar and i put the foot down in the lower gears about 5 times.. all perfect! on the second to last lot of maximum acceleration in made 1.19 bar!!! Then it did the same thing again and boost didnt want to go over .7bar. i doesnt sound today like there is a cracked pipe though [no excessive noise from the turbo at all?!?!?!?!

If anyone can help me identify what the problem/solution is that would be great. is it a faulty actuator/cracked pipe/ecu drama/safe mode? who knows??? you guys do, thats why im here!!!

[Duncan1]

Need your help guys...

[cefiro]

Mate sounds like Rich and retard mode, do a search, basically your ecu knows its runing either too much boost or AFM maxing out and retards the timing and maps to safer levels.

[Duncan1]

Mate sounds like Rich and retard mode, do a search, basically your ecu knows its runing either too much boost or AFM maxing out and retards the timing and maps to safer levels.

Thanks mate, how would i know if this is the case?? Im not sure the cars output is enough to max out the afm though???

[Johnny]

dude for some reason my car did that too at the beginning, even with my ebc it seemed to jump around abit.

using some logic from science gas laws, specifically that a gases pressure directly relates to the force of the container the gas is stored in.

in certain gears the engine is sucking in more gas and hence will lower the measurement of boost, in lower gear with less engine requirement, the whole intake system is pressurized more due to the force exerted back on the gases reading higher boost.

the gtr mfd only registers the highest boost recorded before the bov and wastegates can stabilize the pressure

[Duncan1]

dude for some reason my car did that too at the beginning, even with my ebc it seemed to jump around abit.

using some logic from science gas laws, specifically that a gases pressure directly relates to the force of the container the gas is stored in.

in certain gears the engine is sucking in more gas and hence will lower the measurement of boost, in lower gear with less engine requirement, the whole intake system is pressurized more due to the force exerted back on the gases reading higher boost.

the gtr mfd only registers the highest boost recorded before the bov and wastegates can stabilize the pressure

Yeah true it only stores the peak boost figure, but it does show instant boost pressure and generally speaking it will peak at a bit over 1.1 then it will flicker around 1 bar through the rpm range. but since this infrequent strangeness has occured it will only peak at .7 and flicker around that region. like i said its not all the time and its only just started to happen. Im still none the wiser???????? Any more thoughts Johnny or anybody?

[Johnny]

Yeah true it only stores the peak boost figure, but it does show instant boost pressure and generally speaking it will peak at a bit over 1.1 then it will flicker around 1 bar through the rpm range. but since this infrequent strangeness has occured it will only peak at .7 and flicker around that region. like i said its not all the time and its only just started to happen. Im still none the wiser???????? Any more thoughts Johnny or anybody?

I dunno ben, bit stumpt now as my car does/did it too.

personally, my ebc is tuned for .85bar but makes .97 bar. strange huh?

do you have an ebc man? maybe take it to a tuner and get a dyno run to check boost in all gears

[Duncan1]

I dunno ben, bit stumpt now as my car does/did it too.

personally, my ebc is tuned for .85bar but makes .97 bar. strange huh?

do you have an ebc man? maybe take it to a tuner and get a dyno run to check boost in all gears

Just drove the car home, made 1.15 bar peak then 1.1 bar consistantly. no problems whatsoever. it seems that it only happens after it over-boosts. given that i think it must be a safe mode on the ecu. any thoughts???

[Duncan1]

Have driven the car a few times now, no issue whatsoever!! must just of being a safe mode. will invest in an ebc this week to keep the boost under control....

[Johnny]

Im with you ben, still confused as mine did it again yesterday.

im going to buy a new ebc and run it on the dyno again to fine tune everything as im too paranoid to give it the beans now.

Please keep me updated with yours and ill let u know of mine, goodluck mate.

[Duncan1]

Im with you ben, still confused as mine did it again yesterday.

im going to buy a new ebc and run it on the dyno again to fine tune everything as im too paranoid to give it the beans now.

Please keep me updated with yours and ill let u know of mine, goodluck mate.

Thanks mate, will do!!

[SXR]

I had a similar situation with customers R34. On the dyno makes 1.2 bar, drove it on the street 0.7....finally realized it had the ARC radiator deflector plate so hardly any air wasn't going into the airbox. So we removed the bottom section of the airbox which now grabs air through the fender...all sweet.

[Johnny]

I had a similar situation with customers R34. On the dyno makes 1.2 bar, drove it on the street 0.7....finally realized it had the ARC radiator deflector plate so hardly any air wasn't going into the airbox. So we removed the bottom section of the airbox which now grabs air through the fender...all sweet.

ohhh, mine has the arc deflector as well, what a cowinkedink.

I will try that or mayb get a pod kit!

thankyou

-Johnny