Weird boost leak of sorts between 2400-3700rpm ??

[GBC_069]

hey guys, well i have been having some issues with my 3s-gte in the st185.

lately, i am getting this extra weird leak between 2400-3700rpm, when you shift into third at low speeds and try and pick the car up ( do the same in 4th - 5th - on the hwy ) now, what happens is it spools up sooo loudly ( will instantly make 7pound ) and then if you shift when its making so much noise, then it will flutter itself back out the turbo intake !!!!! ?? so if u open the throttle right up, it will instantly spool up really badly !!! and then make a VERY loud flutter back out the turbo/ wastegate, whereever that noise comes from.

however, once you reach 4000rpm, it will continue to make a stable 7pound of boost, with no more noises ???

any ideas ?? i have checked all hose clamps, all vacuum leads etc.

no cigar.

[GU11TY]

u sure its not an exhuast leak. with my old fairlane i had a exhaust leak and between 2000 and 3000 it was dead as

[fixeruperer]

sounds like surge, wich is wierd for a standard turbo that belongs to that engine.
are you using differant comp covers or housings ?

[LeeRoy]

Could also be a broken cat converter clogging the exhaust up. I like the suggestion of a leaking exhaust too - seems like a possible scenario

[Draven]

clogged cat would rob power higher in the RPM band as well (one would assume)

is the car standard, or are there mods?
anything done to it around or before the time this started?

[GBC_069]

well the wastegate had broken off its circlip attachment, i put that back on again, and it started. also , we had to move the actuator itself, as there was no boost being created, wasnt closing properly after it broke off.

its not an exhaust leak, because it sounds like an aeroplane taking off, a real airy hissing noise.

just wondering if anyone knew why on earth it would be happening just when the turbo comes on and then once its gained a bit of steam it goes away.

[GBC_069]

as for mods -

FMIC
computer ( running a muck, but nuttin has changed there recently )
standard ct-26
full exhaust ( new cat )
standard internals

it is funny, because you can be travelling along in third at about 3k rpm, then when you come to go up a hill, and you DONT more your foot, but the car slaves, it starts sucking really badly, like when it is under pressure it causes it to leak out ?

[IN 05 NT]

put it on a dyno..... there you can make the problem happen with the bonnet open....

blake

[LeeRoy]

clogged cat would rob power higher in the RPM band as well (one would assume)

Yeh its weird though, in my corolla which has a habit of destroying cats, when they cave in and block the exhaust they really kill it at around 2-4k rpm but then above that when the car is making more power it is still noticable by a long shot but feels alot more responsive than in the lower rpm. Doesnt make a hissing noise though. It also shudders and feels like its hesitating which is probably the exhaust pressure building and backing up.

[GBC_069]

still have NFI on this leak, gonna throw the car at a shop in the next few days

[BMWTurbo]

Sounds kinda like a leaknig BOV?