Boost not holding above 5000rpm

[Kaido_RR]

Hey,

Im having with boost dropping off above 5000rpm, it only happens from 3rd gear up. Im running a Profec A Ebc (im pretty sure it was tune, still unsure of that).

Im running 0.8bar but when i hit 5000rpm the boost drops to 0.5/0.4bar. Is this a ebc related problem? should i get it retune or is something else affecting the boost?

Car is r33 gts-t rb25det

mods: fmic, exhuast (stock dump), air filter, bov

Cheers Michael

[Zahos]

Standard turbo cannot flow enough air to make desired boost pressure.

A 76+mm dump + front pipe may help you a little, but the turbo is the major bottleneck for that much airflow...

[rob82]

Sounds like an EBC problem get it check and if it looks ok check the Duty cycle to solenoid at the point it drops off.

[Wazz]

simply sounds like stock turbo limits with that exhuast.. mates got the same problem with his sr stock turbo

15psi... than slowly bleeds to 12 psi

as its maxxing the turbo

he thought it was his ebc aswell but its not

[JH32]

michael is your turbo smaller than stock?

[Kaido_RR]

JiMiH, it has never been check out it seems to be the size of an rb20 turbo, as it makes no where near the power it should at 12psi if it was an rb25 turbo.

Would this have an affect on the boost dropping? Im also 100% the ebc was tune when i had it on the dyno after my fmic was installed

[Jolinator]

look on the compressor cover of the turbo, if its an rb20 unit it will have a nipple on it, were as the 25 turbo uses the intake piping for reference