revvvin7

Alright well I jsut finished a fresh engine install and started tuning this past week or so. I am single turbo to a 3" turbo back and have a agressive street port on the car. Anyways when I start the car I have a big exhaust leak somewhere cause it almost sounds liek the car is camming. I know that a horrible thing to say on a rotary forum but thats the best way i can descibe it.

I have been trying for a week now to narrow down the problem and even went as far as ordering new manifold, wastegate and manifold exhaust gaskets. The problem still hasn't gone away. I was curious if you guys could give me a few pointers here.

Now I am having trouble building boost and it's killing me. The one thing I think it might be is I left one of the bolts out on the back of the turbo that allows the turbo housing to spin for optimal postioning due to it not fitting with my oil return line setup. Could this be the main source of my leak?

Also I have a theory but I had a brand new turbo blanket on the car and during tuning the thing started smoking and almost looked burnt inside. Could this hole where the one 10mm nut needs to go be my exhaust leak and could it have blasted any unburnt gas in my exhaust into the turbo and hense spew out that hole instead of out my tailpipe(running rich)? Anything you gusy could help with would be huge. Thanks all.

Viking War Hammer

iTrader: (8)

Probably leaking from the wastegate flange or from the manifold to engine flange. That will cause you not to boost.

revvvin7

But what about the bolt missing out of the turbo? I am getting some boost.

RacerXtreme7

iTrader: (2)

Ya, that bolt hole dependig on turbo model/make can leak boost. PLUG IT and make sure all your intercooler and intake does not leak along with your exhaust!! You should tune let alone drive a car with those kind of leaks, you can kill an engine or turbo in no time dependant and what kind of leak it is (over rev the turbo).

~Mike..............

revvvin7

Turbo is a GT35/40R
Vacuum leak test is down and it's holding great

The leak is somewhere between the engine - turbo or the wastegate. Any thoughts on what would be good to use for the turbo bolt hole? The normal bolt won't fit...

classicauto

iTrader: (3)

Sometimes you need to play around to get those bolts in. Often when the turbine is in the optimal position the bolt hole is blocked by the return or feed casting on the center section. I normally install all the bolts but don't tighten any (thread them in enough so they will clear the feed/return when rotating the assembly) then position it where I want and sinch them up.

As far as the leaks actually concerned, an exhaust leak should be very easy to spot, especially at the engine like that. If you can't track it down simply by following the noise, start the car stone cold and reach around down there quickly before things get too hot - you should feel the exhaust pulsing on your hand. That said, I've had manifold's leak a tad and the car was still able to boost somewhat.

Viking War Hammer

iTrader: (8)

Another weird one, I've had no boost from over tightening the wastegate. Does your wastegate have a v-band flange ?

revvvin7

It's a HKS Standard with the 4 bolts.

Viking War Hammer

iTrader: (8)

and your name confuses me with 1Revvin7

Viking War Hammer

iTrader: (8)

Ok............. get you a long peice of 3/8 fuel line, fire up the car, put the hose up to your ear like a stethoscope, now roam around the engine with the other end until you hear your exhaust leak.

dragonxbreath

keep us posted on what you find out revvvin7

kenn_chan

souonds like its camming?

This sound slike a vacume leak to me not a boost or exhasut leak. A vacume leak will cause the RPM's to hunt (bounce) and sound like a cammed engine. a vacume leak depending upon where its at will also cause you to get no/low boost.

kenn

88rxn/a

iTrader: (6)

im in the same boat except im not driving the car yet. exhaust leaks SUCK! for the life of me i cannot get the V band for the turbo to DP to seal up right *flanges dont seem bent). then my inlet to flange for the wastegate wont quit leaking either. i been playing tag with tial emailing back and forth why it wont seal. 46MM tial wastegate.
easiest way i found a exhaust leak was to shove a rag in the end of the exhaust and listen. or fire it up cold and spray the parts you think are leaking with soapy water.

revvvin7

OK...so here is a little update. I hunted around the car and looked for any type of black sut that I could find. I found zero...The whole at the turbo was a little rusty inside and really didn't make any difference at all. I could tell exhaust has not been coming from this area. I tried to tighten down the bolts on the manifold a bit more but for the life of me I couldn't budge them any further.

Now could the seel between the downpipe and the turbo cause me to build limited PSI? I mean I am still in the break in phase of the engine so I really can't go out and whale on it but I can get to 1-2 psi but it's having trouble getting there and I can tell the exhuast leak is giving it problems making boost. Other then that it's annoying as *** because the car's exhaust is loud. I wouldn't mind at all if it was coming out the tail pipe but it isn't all coming out from there.

Tonight I will cover the tail pipe and listen with this piece of vacuum hose and see if that will help me to narrow it down...but still could the dp to turbo be causing my problem?

Viking War Hammer

iTrader: (8)

A leak between the Turbo and Downipe won't effect boost.

CarbonR1

iTrader: (2)

I would check your wastegate.

classicauto

iTrader: (3)

If you're breaking this engine in, there's not alot of turbo's that are going to spring into boost from under 3K. My GT3574 on a log manifold will only make 2-3psi at 2500rpm (unless you're jamming it on the highway in 5th or something....)Are you sure there's even an issue? How high are you revving this thing up when judging its ability to make boost?

As mentioned a leaky down pipe won't affect boost, if anything it should increase it being that exhaust can more easily exit the turbine.