Boost leak test results....blown compressor seal and its effect on performance

[gtfrede]

Car will not hold any kind of boost when pressurized from the inlet of the turbo....air coming from where the cover meets the the turbo right by where the drain is...feels like air is coming from between the oil return gasket as well....only time it smokes is when idling for a good while and revving or driving after....my question is how does this affect everything....is the area behind the compressor wheel in vacuum when the turbo is compressing? Would this be drawing un-metered air in under boost or blowing out? What about not in boost?

Looking for nice technical answer...maybe Patrick can chime in on this or someone with some real solid info....all my boost leak experience on my ricecar would lead me to believe this is causing me to run way off the compressor map even at stock boost and this should be throwing my part throttle fueling waaayyy off but it doesnt seem to be....

No shaftplay whatsoever and never blows anything under boost....

 

[bison]

Car will not hold any kind of boost when pressurized from the inlet of the turbo....air coming from where the cover meets the the turbo right by where the drain is...feels like air is coming from between the oil return gasket as well....only time it smokes is when idling for a good while and revving or driving after....my question is how does this affect everything....is the area behind the compressor wheel in vacuum when the turbo is compressing? Would this be drawing un-metered air in under boost or blowing out? What about not in boost?

Looking for nice technical answer...maybe Patrick can chime in on this or someone with some real solid info....all my boost leak experience on my ricecar would lead me to believe this is causing me to run way off the compressor map even at stock boost and this should be throwing my part throttle fueling waaayyy off but it doesnt seem to be....

No shaftplay whatsoever and never blows anything under boost....

What turbo? What makes you think the compressor seal is leaking? Is it a carbon type seal or a dynamic seal? A dynamic seal is not a very positive seal. It uses a piston ring type seal. Unless youre running the turbo really hard i doubt your anywhere near the overspeed limit for the compressor. It woudl have very little effect on metering also.

 

[gtfrede]

It is the stock turbo...I usually run 15 psi or so on the street and with good gas I set it to peak 20psi on initial hit and fall to 18 or so using a ball/spring/bleeder boost controller....

This is the only type of leak Im assuming wouldnt let any pressure build in the charge piping when using a boost leak tester at the inlet bell..I can hear and feel air coming from under the turbo right where the compressor cover meets the center section (also coming out of turbo oil return where it meets the center section)..as well as a tiny bit of oil is usually always in the inlet of the turbo right under the compressor wheel when I take the maf pipe off...

 

[RUQWKNF]

If this is a stock turbo, my bet is the factory O-ring that seals the compressor cover to the backing plate, is torn or broken. That would be the first thing I would check out. Can't blame it for being 25 years old right? If it's torn, it's possible it could be letting some pressurized air into the bearing system.
Just a thought.

Patrick

 

[gtfrede]

Not really a big deal to me other than maybe it pressurizing things that shouldnt be....so it is an easy fix? Maybe on the car? Where can I find the o-ring? I would like to fix it if I could...could you hook a brother up patrick?

 

[gtfrede]

Anybody?? gpopshop have these? anyone with part number for that oring type gasket under the compressor cver?