flutter sound of turbo????

[fwdmoparman]

Hey, my shelby z makes a weird flutter noise(pretty sure something to do with turbo) when I let off of the gas. It doesn't make the sound when I push on the pedal to accelerate, but it does when I go to shift and let off the gas. Any idea of what this sound is? Is it a problem? THANKS alot, Adam

[89daytonaTII]

the sound you are hearing is called "compressor surge" and it is not a good thing. when you let off the gas the throttle plate is closing and giving the incoming air no where to go so it essentially "stacks up" all the way back to the turbo where it hits the compressor wheel. the only cure.. a BOV. when you let off the gas the BOV will open allowing the pressurized air in the intake pipes to vent and thus extending the life of your turbo.

all TD's 88+ have a plastic BOV from the factory except the t2's they do not have one.

[BuRn__]

yep, compressor surge. get a bov in there asap

[2Lebarons]

ive always wondered why the t2`s didnt have a bov?

[lametec]

Because the Garrett turbo's have a much bigger/beefier thrust bearing, and as such the engineers figured it could handle the abuse. That's a lot of money saved by not putting BOV's in all those cars.

Wait a minute... Couldnt it be the wastegate??? Because mine makes a fluttering noise to when shifting and so does my friends car.. And it seems to come from the Wastegate. And when I talked to a guy at the local turbo shop he agreed the sound was the wastegate.. Due to no BOV


Maybe im wrong.. And dawm if I am how bad is it because I have been driving for a month like that... What kind of damage is caused?

- Mike

[89daytonaTII]

the sound is not coming from the wastegate, it is from the compressor wheel. and yes due to lack of BOV. It's not the end of the world if you don't have a BOV and your turbo's probably not going to blow within the next week b/c of it. just think of all the intercooled cars from 86-89 that never came with a bov. many of them left in stock form, no BOV, can and do have their turbo's live long healthy lives. it is just better to have a BOV, cause with the higher the boost your running the harder that surge is on the compressor wheel.

your car came stock with a bov, did you take it out or was it removed when you got it?

i'd be wary of that turbo shop, seems he doesn't really understand

I have one but there is no vac line hooked to it... Previous owner un hooked it.. Just havent had the time to hook it up.. Will do now though

- Mike

[89daytonaTII]

you haven't had time to plug a vac. line on a nipple. that's a lame-o excuse if you ask me.

if it is the stock one it is probably leaking on you if you are running 14psi

Actully its not an excuse.. See I dont have any extra vac lines and well I havent had teh time to T off of one and run new lines...

[mahanse]

well i have been noticeing the same sound in my 86 glhs and thank *** i ordered a BOV today because me and my friend just upped the boost to 20psi....i will make sure not to boost untill that is installed.


Mike

[89daytonaTII]

yeah be nice to your turbo and don't run 20psi w/o a BOV. probably won't wreck it but it's just not helping anything.

[87OmniT2]

Go to "thedodgegarage.com" and look at the install procedure for a mitsubishi eclipse BOV. This is a decent valve, holding up to 18 psi, and can be bought on ebay for 30 bucks. This will relieve the compressor surge.

As for the "wastegate guy", find another technician. This should be common knowledge for a turbo guy.

[Subliminal]

I re-hooked up the stock BOV on my van, and running 10 psi it still makes the noise most of the time (immediate release of the gas pedal makes the noise, slower release makes a nice whooosh)

Now if i could only figure out why screwing my grainger valve tight only produces 13 psi...hmmmmm

[89daytonaTII]

Quote:

Now if i could only figure out why screwing my grainger valve tight only produces 13 psi...hmmmmm

i don't know whether the hmmmmm meant that you already know or something but... i'll bet it is your BOV leaking they are cheap plastic things that don't hold much boost.

As for the dsm BOV's do not get fooled into buying one from a 2nd gen car, they are just as ****ty as our oem bov's and a waste of money. You want a 1st gen bov, they are all metal and as said hold 18psi no problem and can be modified to hold 30psi. to buy one mounted on a usable pipe (not the stock dsm one) they usually run up to $75-80US and can be bought for around 50 not mounted on anything.