sputtering engine sound only when given throttle.

[dsmAB]

I've recently put on my vrsf fmic, and my evo 3 16g boost creeped to 23psi. I was WOT until I heard some sound like a "whoosh" I thought I blew a coupler off or something but when I got out and checked, all the couplers were on tight. My wideband was still telling me good idle air fuel ratios around 14.7. So it couldn't have been a blown coupler. However there was this weird sputtering/flapping sound when I gave it gas and I also felt that the car had some loss of power.

I thought the head lifted because stock head studs can't take that much boost. So we replaced it with ARP head studs and a OEM composite HG. Started her up and the sound wasn't gone at all, but i could feel the car had power again at lower RPMs.

This sputtering/flapping sound only occurs when I give any bit of gas. I figured that it wasn't RPM related because when i down-shifted, the RPMs would go to 4k and the sputtering/flapping sound didn't occur.

Sounds very similar to this: (this is not my video)
gst 4g63t - YouTube

My dad and I are thinking that it could be an exhaust leak? But can exhaust leaks be throttle related??

Any help/suggestions would be greatly appreciated guys! Thanks in advance.

 

[And_44]

That video does sound like an exhaust leak. But hard to tell with quality of sound recording. But with my experience with an exhaust leak I've had in past is that it depends on where the leak is. After a restriction it's usually in a higher rpm that you hear it (after o2 housing) before a restriction its audible in lower rpms. With it being at an idle could be a preturbo leak. Would explain the low end power loss as well as it would affect the turbo spool up and the light throttle operation with a inadequate o2 sensor reading. Need to have system air tight as possible between maf sensor and o2 sensor.

 

[91mits]

exhaust leak i want to say

 

[dsmAB]

At idle, there is no sputtering sound. It's only when i give it gas. I'll upload my video tomorrow.

 

[GSTurbo1]

spray some soapy water on while it is cool so you can find where the leak is coming from

 

[dsmAB]

i took my turbo out today and saw that the turbine housing was ported too much, and the turbine housing wall was too thin and the heat got the best of it...blow a hole right through it ahhh it was a genuine evo 3 turbine housing too . Going to put on my 6cm hotside from my 14b for now. Thanks for the input guys!