Help! Having trouble diagnosing this one...

[PointFive]

So on Monday I was racing at Brainerd International Raceway, and at some point during my last round of laps two engine manifold bolts had decided to escape, consequently blowing the manifold gasket. As a result my car sounded funny and had a loss in power.
Yesterday I replaced the gasket and the missing bolts, but there still seems to be a loss in power. Where before I was boosting up to 8 PSI, now it only goes to 6 PSI and the turbo seems to be spooling slowly. My gas mileage seems pretty bad as well. No check engine lights, no other obvious sign of anything wrong. Anybody have any ideas?

 

[SCMP3]

are all the bolts are good and tight? also the cold and hot pipe are on tight?

 

[PointFive]

All the bolts are tight and there don't appear to be any leaks in any of the piping.

 

[SCMP3]

Do you have a boost gauge? And if so does it show a boost leak?

 

[PointFive]

No vacuum leak according to the boost gauge, but was only boosting up to 6 PSI instead of the usual 8.

 

[SCMP3]

Well the stock wga is see at 6.5-7. So your closer to stock boost I guess. What all mods are done to the car?


Edit: Just read your mod list. Do you have a boost controller or a after maker wga?

 

[PointFive]

Joe P MBC.

 

[SCMP3]

im assuming you had it set at 8psi?

 

[PointFive]

Yes.

 

[kamon8404]

Try running without the MBC just to see where you are at.

 

[PointFive]

I did that, and it boosts to the stock level, albeit slowly.

 

[kamon8404]

Is your bov stuck open? possible torn diaphragm?

 

[PointFive]

I suppose that's a possibility. Is the stock BPV a sealed unit, or can it be opened up and examined?

 

[SCMP3]

Sealed I'd look at getting another aftermarket bpv or getting rid of it all together

 

[PointFive]

I'm running a dual setup right now with the stock BPV and a GReddy Type RS BOV.

 

[Geezer000]

I believe your wastegate flap is probably stuck against the side on the housing on the inside of the exhaust side of the turbo. It causes the wastegate to stay open enough to only boost a little and not untill high rpm's either.

 

[PointFive]

Well, the BPV seems to be operating fine and the wastegate flap seems to be working as well.

 

[kamon8404]

Well, the BPV seems to be operating fine and the wastegate flap seems to be working as well.

It mean its not as though you can see your wastegate flap with the exhaust on your car, so I'm don't know how you would tell. I know what I just switched back to the stock turbo mine wasn't moving the smoothest and would take some convincing to get it to close until I bent it a hair.

 

[PointFive]

Yeah, I obviously don't anything with certainty unless I were to crack open the turbine housing, but just moving the little arm that the actuator attaches to makes me think it's working properly.

 

[kamon8404]

You can move your wastegate arm freely? Sounds like a bad wastegate. I know I have trouble moving mine.