I just had my exhaust manifold tapped for my EGT gauge and now my boost seems to be down about half of a BAR. I took the car back and explained it to them, thinking that there was an exhaust leak at the probe, and they looked at it and said there would be black sut around the area and that you would be able to hear the leak.

It's incredibly humid out, just rained, so I thought maybe it was the weather, but I didn't think it effected it that much.

Any ideas?

Thanks.

 

Anyone?

 

I think the EGT probe or bung is sitting too much inside the runner causing more backpressure/restriction. Its like when you switch to a 3" exhaust, reducing the back-pressure increases your max boost etc.

The probe tip doesn't need to be in the path of the runner to get an accurate/the same reading.....

 

are you sure you understand how an egt probe works? Its readings will be directly affected by placement. Besides....the small thermocouple probe tip is not going to cause that much of a problem to increase back pressure. I think its more of an install issue. What else was done at the same time (if anything) and also...tell us how the probe was installed. I think that could be the biggest factor here. Metal might be in the turbine housing somewhere causing damage or lodging the wastegate flapper partially open (this is a long shot and just a guess)