Weird issue - Help! Turbo sounds different now...

[n20capri]

So I blast through the gears on some open road - all is well - car running strong - full boost set to 19-20psi as usual. Normal driving for a while after that w/o issue....none to light boost as normal. Then, I need to make a lane change so I hit it in 2nd - full boost past traffic to get over...but I notice at full boost this time (same 19-20psi) the turbo now sounds much louder and the "whistle" is much more noticeable. Normally it's fairly quiet and you can only hear it whistle while it's spooling...

The car idles, runs drives and has the same power it did before - just the turbo is now louder only at wot full boost...but as mentioned performance and everything else is the same. I did a quick inspection under the hood and didn't notice anything out of sorts. Sounded normal idling under the hood too.

Normal mods:

• Supposed to have a T3/T4 hybrid but idk for sure
• Gillis (set to 19-20 as mentioned above)
• Forced 4 CAI w/ bypass valve
• TC intercooler w/ forced 4 HD intercooler hoses
• 3" dp 2.5" dual exhaust
• Snow Meth stage III kit

Very weird that nothing is actually wrong except the turbo sounding different...

Anyone experience anything like this or have any ideas of what might be going on?

Thanks,
Mike

[BrianO]

IC boots or in my case the gasket on the inlet to the turbo.

[JTurbo]

I'd check the 4 bolts between the header and the turbo plus all of the header bolts.

[CarverSVO]

If it doesn't seem to be affecting spool up time or performance, it may be an exhaust leak after the turbo. I could hear my turbo spool up from half a mile away when three of the five turbo-to-elbow bolts snapped. Pretty easy to check if those are all in place.

[Erics SVO]

Check maybe for a crack in the manifold also.

[n20capri]

Cool thanks guys...what's the most common exhaust leak area besides a cracked manifold?

Also, iirc, there is no head to exhaust manifold gasket correct?

So just turbo to manifold, turbo to elbo and elbo to dp right?

[NinjaBOY]

If it doesn't seem to be affecting spool up time or performance, it may be an exhaust leak after the turbo. I could hear my turbo spool up from half a mile away when three of the five turbo-to-elbow bolts snapped. Pretty easy to check if those are all in place.

Ditto on this...just had the same problem on my 7B. Go over all four of the nuts that hold the turbo to the manifold, then tighten the 5 bolts that hold the exhaust elbow to the turbo. The 7B was missing two of the 5 bolts, and a third was backing out. The noise will get louder as the problem gets worse...

[n20capri]

Found the leak

I'd check the 4 bolts between the header and the turbo......

Ding, Ding Ding - We have a winner...

Good call Joe! Once I had everything off, nothing that I could get a wrench on was loose...but it looked like a portion of the top of the gasket (between header and turbo) was missing. But I had to figure out how to start the car (without the intercooler) to be sure.

Soooo...I rigged up my trusty ShopVac hose in place and it worked like a charm. Ghetto for sure but it worked for the few minutes I had the car started!

Once I started the car I could easily hear the leak and I could feel a ton of air coming from that spot! So, now it's time to figure out a game plan for replacing it. I'll wait a couple months before I get started - I have a spare E6 that I will most likely port so that will take some time, and I'll order up a 3" elbo from Stinger.

Best way to get to this is to remove the header/turbo as an assembly right? I'm dreading the water lines, the oil line and the EGR fitting! They all look like they don't want to come off - EVER! lol

Pics attached and also, a vid of the air hose setup and the leak itself! Perma link of it on my site...

http://www.mikemartinelli.com/index.php?album=Videos%2F1986+SVO&image=86+SVO+Exhaust+Leak.txt

Anyway enjoy and thanks for all the help everyone!

[NinjaBOY]

Love the shop-vac hose set-up!

Had that problem a lot with my original 84 1C. Re-did the job 4 times before it went to a professional, and then never separated the two after. Here's the trick; both the turbo flange and the exhaust manifold flange need to be machined perfectly smooth. New studs and nuts should be used (be sure to get the correct nuts). Then put the two back together without the gasket; just a little black RTV in between. And as you said, it's a lot easier to remove the manifold and turbo as an assembly.

Also, I took a bolt for the oil return and ground the head off to help guide the flange back on. Once I had the other side tight, I removed that one and replaced it with the correct hex-head bolt.

Hope this helps...

[BINKY]

Mike - glad you found it and really enjoyed your website! Might try the dash repair. Richard

[n20capri]

Thanks for the tips Roger hopefully I'll be able to get it squared away the 1st time! lol

I'm wondering if a copper gasket would work for this application?

Love the shop-vac hose set-up!

Had that problem a lot with my original 84 1C. Re-did the job 4 times before it went to a professional, and then never separated the two after. Here's the trick; both the turbo flange and the exhaust manifold flange need to be machined perfectly smooth. New studs and nuts should be used (be sure to get the correct nuts). Then put the two back together without the gasket; just a little black RTV in between. And as you said, it's a lot easier to remove the manifold and turbo as an assembly.

Also, I took a bolt for the oil return and ground the head off to help guide the flange back on. Once I had the other side tight, I removed that one and replaced it with the correct hex-head bolt.

Hope this helps...

[n20capri]

Mike - glad you found it and really enjoyed your website! Might try the dash repair. Richard

Thanks Richard - I try to do write-ups whenever I can - especially on things I can't find much info on and just dive into!

[JTurbo]

Ding, Ding Ding - We have a winner...

Good call Joe!

Cool, so what did I win????

[n20capri]

Cool, so what did I win????

Joe, I'm going to allow you to come to my house to help me get the job done! How does that sound?

[NinjaBOY]

What's the consolation prize then?