AusS2000

Just venting because I have almost definitely stuffed another turbo.

I was running in a new diff today so driving up a freeway sedately varying speed from 95 to 100kph (55-62Mph). Car felt nice and strong. After an hour I stopped and took this pic:



This in on a little bit of bendy road where I pulled off the freeway. After taking the picture I followed the road for a few kilometres then saw the turn off for the freeway and gunned it through a couple of gears. Damn it felt good. I braked for the left bend onto the feeder road and accelerated again and nothing. At least not by boosted standards. I tried a few times and heard something of a rattle or whistle. I figured I had burst a charge pipe connection. No big deal so I just drove to the next service centre.

I checked the charge pipes and all looked in order. I started the engine and that's when I heard it. A rattling from the turbo. Like someone shaking a tin with a few nuts and bolts in it.

I took a long cut home via the turbo shop where I bought my last two turbos after various failures (may or may not be related). They looked at my coolant lines and oil feed. Said they looked pretty good. They think it is oil starvation and suggested a bigger gauge oil feed line (mine is -3). I mentioned that I had bought a feed restrictor from them on their recommendation so wouldn't a thicker feed line would be pointless?

Other salient points:
There is no smoke. So I'm guessing it's not seals.
The tuning is rich in vacuum. Most of the drive up there was in vacuum.
I recently replumbed my oil feed line. It used to come from the point on the block where the pressure switch sits. It now comes from the side of the Canton oil filter re-locater screwed onto the block.
My water lines use the old water lines that used to go to the OEM oil cooler.
My oil return exits the bottom of the turbo and goes straight down to a connection welded into the top of the sump. I mention this because the problem happened directly after a hard left turn.

AusS2000

Tomorrow I'll post some pics of the set up under the bonnet. The water oil lines.

slappynuts

Here is the problem. S2000s run high oil pressure under high load. The oil pressure at idle however is the same as any other car.When you restrict the oil feed your doing this across the board and then you end up starving the turbo at idle and low load.

AusS2000

Interesting theory. I will look into that.

rsmatti

6th doing 45mph I see 80psi of oil pressure. Keep in mind the turbo is not spooling, and im running a .065 restricter. my precision 5857JB has been fine for 10000 miles and going strong. and i do aloott of crusing in vacuum. I would think something threw off the balace in the turbo?

EngineerX

Other possible cause could be a clogged restrictor, though that's probably unlikely because most of us running turbos change oil/filter every 3k ~ 5k miles.
What size restrictor are you running? What turbo?

Yes, a larger -AN hose wouldn't make a difference since the restrictor is the bottleneck for flow.

05TurboS2k

I had a fireman explain to me that water/oil would only flow just so fast through a given size diameter hole no matter what the pressure was. Didn't make much sense to me because I would think more pressure = higher speed and thus more flow.

However is he's right that would disprove slappynuts' theory.

Not sure, maybe some research on that would be a good diea for someone to make.

AusS2000

The fact that the turbo is noisy suggests oil starvation. And as the turbo is not blowing oil that also supports the idea. And the turbo shop suggesting a larger flow line.

So that leads me to think the restrictor they sold me is too small. I'll have to check the size.

Revenge

what kind of turbo, if its a percision you may just want to switch over to a garrett

AusS2000

Garrett GT3071R unfortunately.