chopping air sound


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Jun 23, 2003
when i had my PTE44 on my car it would make a weird sputter/ chopping of the air sound. this was with very light throttle and letting the boost only get up a few pounds from zero while cruising. i wasnt sure what it was. the turbo spooled great, no shaft play, etc.

i put on a PT63E yesterday and it does not have that weird sound at all. i will be putting the TE44 on my fathers TTA and would like to make sure im not installing a turbo that is about to go south :confused: . what could cause the weird sound from the te44?
Normal . Both my te-44 and my te-60 did the same thing. My gt42 is much quieter than both.
Its a mild case of compressor surge. Very typical. We have this happen on our diesels. If you mat it , the chopping of the air goes away ;)
chopper (free Huey under your hood)

Could the wastegate not be bleeding off enough exhaust at the given throttle position? Maybe throttle plate isn't open enough for that boost level? Turbo could be spooling to good.

Otherwise the is the noise when you get into boost (pretty much anything 1psi +), then let out, (close throttle body by letting off gas pedal).
The boost that was just built has to go somewhere, so out the compressor wheel it goes. The noise is the backpressure rapidly slowing the compressor wheel and exiting out the air filter. If this is not the case can you send a sound byte? Good luck.
Everyone has seen/heard the little turbo imports with their "Sneeze" valves. That is to eliminate what we [Buicks] are hearing on deceleration. Remember, the turbine and compressor wheels are connected; what one does, so must the other. When you lift off the throttle (after load) the intake opening closes and the compressed (intake) air has nowhere to go. This results in a pressure spike at the throttlebody. This pressure becomes greater that the exhaust pressure driving the turbine wheel. This results in the intake air reversing direction and "chopping" through the turbo and exiting out the MAF sensor and air filter.
This causes two (2) problems. 1) The turbo shaft and bearings take a beating. Most common failure for our turbos is thrust bearing failure. 2) The air rushing through the MAF sensor causes the ECM to think air is rushing in (when it is really rushing out). This results in the fuel injectors matching that air (that isn't there) and causing the infamous Buick stall or bog when coming off the throttle.

Hope this help.
get a bov; i posted once and still stick to it that i have a tial bov with a TA-60 turbo. A buddy of mine has the same turbo i do with no BOV, and his car is louder then my car when u let of the gas. Its definitly the compressor surge from left over psi in your pipes. Just my personal experience.