Turbo Problem

[SirRacer]

My rb30 has recently been rebuilt due to a cracked oil pump. Engine was running fine today (has maybe run an hour since rebuild) and then i got a bang (backfire sort of noise) when driving it on boost. From there on the turbo didnt seem to spool, bov didnt work etc and boost wouldnt register on the gauge. The turbo is a 3540r from GCG.

The engine still seems to run fine, however im not getting any boost. I dont have any black smoke at all from the exhaust (indicating oil) and when i took the air filter off to turbo spun freely. It spun almost too freely.

Any ideas, or do you think i should pull it off and check it physically?

The vacuum hoses could probably be a smaller size, however when i first drove it down the road it went well, so im certain its not them. All other hoses seem to be installed fine.

Some ideas would be great on the likely symptoms of a turbo failure. If so, what do you think it is likely to be, and how can i fix it?>

Cheers

Byron

Edited November 11, 2010 by SirRacer

[Trozzle]

Perhaps exhaust wheel has come off somehow? Otherwise boost leak, but that would suggest black smoke (fuel, white = oil) as would be running rich unless you're running a MAP sensor ECU

[Lithium]

Hey Byron - thats no good. Have you idled it with the inlet pipe off the turbo to see if its actually spinning from exhaust flow? Seeing as you had your filter off it should be pretty easy to test, that should rule out any rotating assembly issues. I'd think something on your intake side has given up...

[Beer Baron]

sounds very much like a blown off hose somewhere between turbo compressor outlet and the throttle inlet. very common, hear a big bang or pop, loose boost etc. 9 times out or 10 a hose will have popped off. sometimes they can be hard to spot as they will look like they're still on but there is a gap on the back etc. check all the hose joiners before you start looking at the big ticket failures.

[kwickr33]

might have a popped cooling piping. If not, the turbo probably have lost its rear wheel or broke its main shaft.

[R31Nismoid]

as you said a cracked oil pump, what exactly?

did you loose pressure when driving etc?

I'm with the others, cooler piping is most likely.

otherwise id say a collapsed cartridge due to low oil supply/pressure due possibly the pump issue also mentioned.

i highly doubt a wheel has come off or similar.

[SirRacer]

The cracked oil pump was a r33 gtr pump that simply cracked as the n1 ones do. I had the car on the dyno getting ready to tune, and it simply just lost oil pressure on the first pull. We quickly shut off the engine and the damage was limited to that. The rebuild was done with a brand new oil pump and new acl bearings.

The only thing i think that may be related to a potential turbo failure could be some crap in the oil blocking the hose. The hose, however is a -6 one so its pretty big and would take a lot to clog.

Id be very keen if it was a loose hose somewhere, however then the car would idle poorly wouldnt it? Ive had intercooler hoses come off before and the car barely runs. The car seems to run fine at the moment. Beer Baron- will this stop the turbo boosting really at all? Ive had plenty of hoses come off and the turbo still boosts. The intercooler/wastegate hoses are definitley connected tight.

Boost was around 15psi when i had my issue.

Whats a replacement cartridge worth?

Edited November 11, 2010 by SirRacer

[Lithium]

however then the car would idle poorly wouldnt it? Ive had intercooler hoses come off before and the car barely runs. The car seems to run fine at the moment. Beer Baron- will this stop the turbo boosting really at all? Ive had plenty of hoses come off and the turbo still boosts. The intercooler/wastegate hoses are definitley connected tight.

You have a Link now eh? I've popped an intercooler hose completely off with Moby and it drove fine, just never hit positive pressure. There was nothing at all to indicate anything was up other than that. Different story if you have an ECU which relies on an airflow meter however. Did you try what I mentioned above? Start it with the intake pipe off the turbo- make sure there is no way of any shit going in there. If the turbo spins, that's not your problem. Easiest way to rule that out. It should even twitch in desire to go just from cranking...

[R31Nismoid]

on the line size... that won't make a difference because...

the issue with blocked lines will again be at the cartridge. the internal restrictor is tiny and won't take much to block and thus a dead cart due to oil starvation

[Lithium]

Wouldn't it either hardly spin, or spin very noisely? The stuffed BB cores I've heard are quite "clicky"

[SirRacer]

Didnt quite think of the map sensor vs AFM but that would explain potentially why its idling rough.

Will go and trace all the vacuum lines tomorrow and check the intercooler piping. Didnt look like that but i could have been more thorough. Theoretically it shouldnt be stuffed (the turbo) as it hasnt done more than 1500kms.

[R31Nismoid]

Wouldn't it either hardly spin, or spin very noisely? The stuffed BB cores I've heard are quite "clicky"

when mine died due to the cart/bearings the turbo span reasonably well.

it was just slightly off balance and hitting the housing a tiny bit as it wasn't huge failure.

would get worse if i left it running of course.

[SirRacer]

when mine died due to the cart/bearings the turbo span reasonably well.

it was just slightly off balance and hitting the housing a tiny bit as it wasn't huge failure.

would get worse if i left it running of course.

What was the cartridge cost to replace?

[R31Nismoid]

$1100 trade from Garrett.

Comes with everything and balances so just dropped into my housings and off I went.

Comp housing needed minor machining, was around $100 I think.

So a rebuilt GT3040 for $1200, i was happy.