turbo sputtering

[Mikemill]

I just installed a new te-44 and am having a problem, if i slowly build boost it will start to sputter at about 12lbs. of boost.
If i stand on it the boost will climb just like it's supposed to.(9 out of 10 times)
The engine is running good no vac. leaks. blm's,iac counts and tps reading are good.
It's sounds like it is directing air back out the air cleaner.


Thanks
Mike M.

 

[TurboToy]

what is max boost set at? you are probley bouncing off the waste gate. normal noise if thats what it is doin. easy way to check set the waste gate where it will slip on and that should be about 13lbs and see if it makes the same noise when you go WOT


turbotoy

 

[Mikemill]

Maximum boost is set at about 22lbs. (i have alky inj.) I don't understand what you mean by bouncing off the wastegate.

Thanks

Mike M.

 

[TurboToy]

if you are not all the way in the boost and there is not enough vac built up in the system the act cannot completly close and thats when you hear the flutter thats the boost reliving past the puck if that makes sense. turbotoy

 

[BoostKillsStres]

What your probably feeling is some turbo surge. I had a similar feel w/ my TE44, just as I would get into boost in the about 9-13 psi range the boost gauge needle would vibrate a bit and you could hear a kind of slight turbo whooshing sound from the air cleaner area but if I pushed thru to about 15psi or higher the sound and feel would clear up and the car would pull hard.

Your basically right at the lower surge range of the turbo at that point and it also has a lot to do with the IC tube volume and IC setup. Some people have a terrible time with this and other don't have it at all.

HTH

 

[TurboDave]

Boostkillstres I think hit the nail on the head.
You're experiencing compressor surge because of various design criteria in your intake tract, such as tubing size into and out of the intercooler etc. the turbo is coming up on boost right near the surge line.

 

[Mikemill]

I spoke with a turbo vendor and he say's the same thing, it is probably turbo surge.
The fact that i have a stock intercooler probably isn't helping things.

Thanks for the help guys!

Mike Miller

 

[87GNcospg]

i also recently installed a Precisoin TE44 on my 87 GN. i have a shorty style K&N intake and big neck on my stock intercooler. my problem is that i hear this sputtering/fluttering/air being chopped/intermittent whoosing sound when i ease into the throttle from 2psi to about 10psi. this is with slight pressure on the gas pedal. the sound seems to be coming back out the filter. when i go WOT i wont hear this sound at all.
everyone else seems to hear this at much higher boost levels. why would mine occur at such a low boost level?
not hijacking your thread but trying to get help on the same problem.
what exactly is surging from the turbo?

 

[TurboDave]

Originally posted by 87GNcospg
i also recently installed a Precisoin TE44 on my 87 GN. i have a shorty style K&N intake and big neck on my stock intercooler. my problem is that i hear this sputtering/fluttering/air being chopped/intermittent whoosing sound when i ease into the throttle from 2psi to about 10psi. this is with slight pressure on the gas pedal. the sound seems to be coming back out the filter. when i go WOT i wont hear this sound at all.
everyone else seems to hear this at much higher boost levels. why would mine occur at such a low boost level?
not hijacking your thread but trying to get help on the same problem.
what exactly is surging from the turbo?

Same problem. Turbo is going into surge. It just happens at different levels for different turbos and intake tract designs.

 

[87GNcospg]

what exactly is surging from the turbo?
is it the "bouncing off the wastegate" as stated above?

 

[TurboDave]

Originally posted by 87GNcospg
what exactly is surging from the turbo?
is it the "bouncing off the wastegate" as stated above?

No. I've been in the turbo world for just over 20 years now, and I don't have a clue what "bouncing off the wastegate" even means (knowing what I know about wastegate operation).

It's very complex, but turbo surge can occur if it's starting to operate near or over the surge line. Under various conditions of air mass, velocity, and boost, this can occur. A lot of it has to do with the volume of the plumbing between the turbo and intake.

 

[BoostKillsStres]

It might help to think of surge as a kind of cavitation of air in the system in that boost range, not a good explaination I know since I don't even think air can cavitate but might help.

If you do a search for compressor maps you can see how different turbos are designed to work in different pressure ranges and there is a surge range like a pressure area on a weather map where surge will occur as the turbo moves from just starting to work then thru the surge range and finally into its effiecency range.

Might check the gnttype.org site and look thru the turbo section to see if there's an explaination of compressor surge.