Well after taking apart a local turbo tC, we noticed something interesting about the setup. The car ran fine, but acted sometimes like it had a small boost leak and could not figure out why. All pipes and couplers where inspected for boost leaks, but found none. We proceeded to check numerous components and Don had recommended checking the compressor cover, which was a Precision turbo, to see for leaks....

We pulled it apart and saw a nice o-ring sealed compressor cover to the seal plate. This is very nice considering most companies do not do this and the compressor cover would have to be sealed manually. After even further inspection, we realized there was one bolt drilled all the way through the compressor cover to the air channel, which meant a potential boost leak if that bolt hole was not sealed with sealant. We did so, and it made a tremendous difference.

So with that being said, make sure all of you check your compressor cover for the same, and if it does not seal with an o-ring, seal it with sealant. If a hole is drilled into the air channel of the compressor housing, then that bolt hole(s) would have to be sealed as well.

A small tech tip for those DIY turbo setup people.

 

yikes, but good info

 

I noticed the same on Garrett turbos as well

(if you look closely you'll see the bolt end sticking out)

 

hmm.. what exactly are the symptoms of this?

 

good info paul

 

most of the time its very slight and hardly noticable in my exp. but at times it can keep you from reaching the full wastegate spring rateing.

example: tial 38mm wastegate w/.6bar spring (8.7 psi), gauge reads barely 8psi but mostly high 7's.

 

hmm.. could this also cause spiking, unstable boost levels like not bieng able to hold boost.. say i hit 20 then it goes to 18 then 19 then 20 again than 19

 

hmmm...not sure...so far the leaks i have seen have been very small more like a +/- .7 psi...however its not all that impossible.

 

I'm getting a Garrett GT2252 in soon. Should I open the cover and take a look? Never delt with Garrett before so I'm not sure on internal design specifics.

 

you could just look down the the compressor exit and see if that one bolt is sticking out like the pic i posted. if you see that then chances are the rest of em may be like that. not a bad idea to take each bolt out one by one and seal em up as you go.

 

Yes can be a generic symptom, but not always attributed to this. This car showed that symptom.

 

what wastegate spring do you have? ive heard that if the boost pressure is more then double of the spring rate....that will also cause your symptoms.

 

I'm trying to seal the compressor side of my Turbonetics GTK-350, and I don't quite know where you guys are sealing to the backing plate. I took the compressor housing off and see no signs of an o-ring or gasket anywhere. So, I purchased the Turbonetics T3 compressor gasket and I am stuck. You can see in the pic below the size of the gasket compared to the housing... is this the correct gasket? Do I need to seal the outer edge of the backing plate? Or both...

 

t4 compressor

 

OK, the housing I believe is a to4e, so i got the wrong gasket. Anyone know of gaskets made in this size or do I need to buy a sheet and break out a compass? Using rtv sorta makes me nervous.

 

the gasket you have looks like the one that goes between the comp backplate and center section.

the gasket you want should be red in color (so far they have all been red that iv seen and installed) and fairly thin. it will go around the ridge on the front side of the comp back plate (red disc in your pic)

 

part 14 is what im talking about