Turbo problems: what the hell is this noise?

[SHIFT_*grind*]

Mistakenly edited away the original post. :(

Basically, I installed a new manifold/T28/elbow and the car sounds like shit. Please see last post for more info.

[jskateborders]

mine did that. Had no shaft play. Now its got no play at all... It seized. Although it wouldnt even make 0 vacuum when it was making that noise

[DJ_Sunrise]

Every time you do something with the turbo.. you should prime it. When you replaced it, you drained the oil.. So theres a chance you could have fried it, or are frying it. Be more specific with chainsaw noise.. I don't understand it. Coming from the cabin, under the hood, I dunno.. be more specific.

-Bart

[SHIFT_*grind*]

The noise sounds like it's coming from under the hood, or possibly from the exhaust. I'm not sure how else to describe it...other than it sounds like a chainsaw :( It's not high-pitched, as I would imagine grinding turbine blades would sound.

And I forgot to mention, I primed the turbo before I started everything up. Disconnected the CAS and the injectors and cranked it for a few seconds.

[SHIFT_*grind*]

Also, I didn't point this out explicitly, but the turbo boosts fine. Pretty damn hard, actually...

[Chrischeezer]

push the impeller blade to the edge and see if it locks up.

i have seen turbos with no shaft play but they wouldn't spin if they were pushed to the edge of the housing.

[S14DB]

Could be your WG door flapping around.

[KwKouki]

Make sure your manifold is nice and tight, mine is loose right now and it makes what you could call a chainsaw sound.

[SHIFT_*grind*]

Torqued the manifold bolts to ~40 ft/lbs, with the factory locking nuts/washers.

What would cause the WG door to be flapping around?

If the impeller were locking up wouldn't it not boost? Same thing with WG door opening prematurely?

[SHIFT_*grind*]

Any other ideas?

The manifold bolts are at ~40 ft/lbs because I saw that people have problems with breaking studs at much more torque than that.

The turbo boosts hard so I don't think the WG door would be flapping around...or would it? And it also wouldn't be boosting if it were locking up...?

[Soup Nazi]

Mine did that same thing after i installed my exhaust. But mine ended being because the Bolts started to back out from the Turbo/Mani.

[TTrx7Pete]

Usually a chainsaw noise is like the others have said, a bad turbo. When my FD's factory twins started to go out they started whirring like a chainsaw. When I removed the turbos they still had zero shaft play. The turbos still boosted. Upon taking them apart I found that the back end of the blades were starting to deform and bend. However, the exhaust heat on a rotary is a lot higher than your standard piston engine.

Another thing to check would be that your manifold is tightened all the way down. You could possibly have a metal gasket flapping or something of that nature.

Check for any other exhaust leaks.

[SHIFT_*grind*]

Thanks for all the input guys. I'm pretty certain I have a leak between my turbo and dump pipe, so maybe the gasket's flapping around. I've had exhaust leaks before and they didn't sound like this, but maybe it sounds worse since it's that much closer to the manifold/turbo.

[Clowny]

i too have had that sound come from my old sr. it turned out it was a leak from between the turbo and manifold and the gasket was just flapping. so definitely start there. good luck and let us know what fixed your issue.

[jskateborders]

with a ball bearing turbo, It should still spin a little after you turn your car off. What does that sound like? Or does it even spin?

[SHIFT_*grind*]

I wasn't listening for anything when I shut it off.

[WoolyS14DET]

Kinds sounds like the blade on the compressor wheel is contacting the housing under boost conditions ?? Happened to me on a POS Ebay turbo that I bought !! (I learned my lesson the hard way). Pull the intake pipe off and look at the housing and see if the compressor blade is contacting the housing and see if their is scratch marks !!

Just My Opnion

[SHIFT_*grind*]

OK. Here's where I'm at:

-Bought new turbo elbow that actually fits. Bolted cleanly to the turbo and downpipe, so I know there's no leak there.
-Picked up some SS hose for the catch can. No more melting vinyl hose.
-Checked the intake and the compressor wheel; still no oil in hot pipe, little/no shaft play on turbo.
-Manifold bolts are all tight, turbo-->manifold bolts are all tight as well. Gaskets are all metal, and fairly new. (couple thousand miles, at the most)
-Adjusted the wastegate actuator down to ~10 psi.

The chainsaw-ish noise is still there. The car also doesn't run right. It's *very* rough when it starts up, sputtering, almost stalling, idle going up and down. Then after a few seconds it smooths out and stabilizes, but still sounds rough. Meaning, the idle stays right around 850 but I can hear it missing. Driving, it boosts fine (hits 10 psi with no problem), but the power isn't there. It hesitates and jerks a little, and doesn't pull very hard even though it's boosting. And of course it still makes that fucking noise.

I could have probably just kept using the old elbow =-\

I can think of 2 possibilities:

1) My timing is off. I'm pretty sure this would explain the poor idle, rough start, hesitation/jerking, boost but no power. I think I remember seeing in other threads that bad timing would also cause the car to sound like shit, but I might be wrong.

2) Turbo-->manifold leak. I didn't see how this could be possible, since the bolts are all tight and the metal gasket is almost new. But, it dawned on me that when I had the manifold surface machined, where it bolts to the head, I didn't think to have them machine the manifold-->turbo surface as well. I didn't think it was warped, but now I'm not so sure. This would definitely explain the noise, the poor idle/etc, and could also throw my timing off (right?).


UGH.

[jskateborders]

If you could get a sound clip or video up of the noise, that would be great.

[SHIFT_*grind*]

I'm not sure if that'll help much; it's really only audible on boost, which is when i'm in the car driving. A sound clip from inside the car wouldn't be very telling :(

I could try revving it a bit sitting still and recording that...

[TTrx7Pete]

I'm not sure if that'll help much; it's really only audible on boost, which is when i'm in the car driving. A sound clip from inside the car wouldn't be very telling :(

I could try revving it a bit sitting still and recording that...

Try to record the sound from inside the engine bay by strapping down the recording equipment to something. Go around the block, boost, get a good recording and then see what that gives you. Usually there is a place to strap it down with a good ol' zip-tie somewhere.

[SHIFT_*grind*]

Just to update...the noise is gone. I discovered that the 3-layer metal gasket I was using has these little slightly raised rivet-type things between the runners, and my aftermarket manifold has a one piece flange with the runners connected. Whereas the stock manifold runners aren't connected. So I'm thinking the little rivet things (or whatever you'd call them) were keeping the manifold from sealing tight against the head. Also there was some gasket material I had missed when I installed it the first time, so maybe that did it :tardrim:

Scraped the head and gasket with a razor, wiped everything down really well with acetone, and bolted a stock manifold on (because I didn't feel like tracking down a different gasket, and maybe I'll save money this way). All is well.

So I can safely say that the noise was caused by a small exhaust leak between the head and the manifold.

Still runs rough though......the only other thing I did was change my spark plugs. Maybe I fucked that up somehow... :(