what is that fluttering noise???

[smooth87]

hey fellas. im new here. i have an 87 gn. everytime i spool up some boost, when i let off it makes this fluttering noise. it has some add ons like a k&n, 3"MAF tube, large intercooler(mounted infront of the radiator), headers, 3"downpipe, flowmaster stailess muff. and tailpipes, uhhh.. hks turbo saver. . thats the engine related stuff i guess.. i have a boost gauge on the A-pillar.. you can see the pressure flutter with the noise.. on occasion it makes this noise while spooling up. or sometimes it surges up to approx. 18#'s then settles back to the usual 15#'s. the waste gate has been replaced by the previous owner, and i suspect this may be the culprit. i dont have any money yet.. but im planning on upgrading to an adjustable WG. something was mentioned about the exhaust port(?) was too small... if i really mess with it and let off really slow it wont flutter. i would really appreciate your help. BUICKS RULE!

 

[blackbuick87]

Actually its probably the pressurized intake charge slamming into the throttle buterfly when you let off the gas. It comes back into the compressor wheel on the turbo.

It is not the best thing for the turbo, but once in a while will not have too much of an effect on the longevity

 

[striker_29]

Does it sound like a horse ? Its commonly refered to as turbo sneeze, and some people run a blow off vavle to help prevent it. Like blackbuick87 said its not the best thing in the world for the turbo, but perfectly normal for most cars.

 

[scottyb]

Your spike to 18 lbs may be normal depending on the chip you have. Some have a fast spool feature and this is a side effect. As long as you aren't in 3rd gear when this happens, and it settles back to 15 lbs, you are generally ok.

Some have also complained about compressor surge at part throttle. This can happen to bigger turbo's, but generally a stock turbo doesn't do it. So a search on compressor surge.

 

[smooth87]

actually its sounds just like a horse. but i have never heard another gn do it this loud. i mean.. its pretty loud. my turbo has "garret" printed on the side of it. this is the stock turbo i presume? but it does it all the time.. the part throttle thing is what pisses me off. like up to about 8 psi, it acts normal. but from there all the way to wide open throttle i have that surging. do you think the spring on the release valve is weak. part throttle performance sucks. but i guess that just means i'll have to romp on it all the time then

 

[smooth87]

i also have no clue what kind of chip it has. or if it is stock...call me stupid.. but uhh.... where do i find the chip? is it behind the glove box? i have no experience with computer controlled cars. but i would love some info! i looked behind the glovebox and i found a bunch of wires going into and out of a "plug". but it is wrapped in an adhesive foam tape, and i didnt want to tear it off just yet. please... enlighten the ignorant

 

[Swt_86]

Don't feel ignorant, we all had to learn this from someone or someplace. The chip is located in the ECM and the ECM is hidden in the kick panel on the passenger side of the car. Just take it off and everythng from there will be pretty obvious. There are two chips in the ECM under the plate on the side. The smaller one is the "limp home" chip.

 

[smooth87]

THANK YOU!

 

[menace848]

just let off of the gas more slowly while under boost, problem solved. I myself kinda like the sound, my friend has a turbo car and envies the noise .

 

[scottyb]

Here are the usual questions for you:
Do you have a scantool?
How is the fuel delivery system (pump/sock/filter/FPR)?

Don't play without them.

 

[smooth87]

all my friends seem to dig the "whinny" as well. sadly no i dont have a scantool.. and i dont have a place to work on the car, or tools for that matter. i just moved out of the house. im living in the campus apartments with my sister(im 17) i am trying to save up some money so i can purchase some of these doodads. but money is really tight.. i did just go check out my ECM and my chip though. everything seems to have DELCO all over it. man i wish i had a couple hundred bucks to spare!

 

[blackbuick87]

Just make sure you always run premium and keep the boost around 15# or less until you can do the basic things like fuel pump, scanmaster, etc. Once you get those you can get a 160t-stat and a Thrasher chip and you will be happy.

Have fun and take care of that car and keep asking questions