How much audible flutter/surge is normal.
 

Ok guys, I finally got everything sorted and running the other day and took her out to start tuning/playing. Its running stupidly rich in boost so it almost chokes itself out until about 5k...but thats a different problem >.<.

But when driving, right around the vac/boost threshold (or in vac when I let off the throttle lightly, not a full lift) I get a very audible compressor surge sound and sometimes under light throttle/boost I get a turkey call sound under slightly lift.

Here is the weird thing, even when I am boosting 7-10lbs and let off the throttle and the BOV pops, I can still hear like a turkey call coming from the turbo/intake-ish area. It is loud.

My roommate was driving behind me and said when I blow off, there is a noticeable amount of smoke/shit exiting the exhaust at the same time as the noise...I figure it could just be running rich as shit and dumping fuel off throttle, but he said it was white-ish. :O




WTF? is this normal?


Here is a picture of the engine bay...I have a big filter on a stick coming out of the turbo now.
Attachment 208846

when I was riding with Slos13 in his car and he was driving he didn't have any flutter, however because my driving style was different, it fluttered EVERY time I lifted off the gas. Not sure about the smoke, but you may need to add a helper spring to your BOV if it is too stiff

dont you mean put in a weaker spring?

you know what I mean :hustler:

you could put in a weaker spring or I've heard of guys clipping some of the stock spring off

Yea, sounds like the BOV needs adjustment.

Vash-

Yeah, weaker spring would be the best option. I have the same problem, and haven't tried to fix it yet. I probably should though.

just giving you a hard time:)

and yes: weaker or cut spring will help fix the flutter if its indeed from bov being too tight. just make sure you dont over do it, cause then it will suck at idle and cruise

What does compressor surge sound like? Is it just something you will get if without a BOV or if your BOV setting is too tight?

I'm also curious what the white smoke at liftoff might be and if it's due to BOV setting/compressor surge.

stock PCV? :dunno:

Turkey like.

Vash-

the crazy thing is some people think its cool and drive that way

^^^ Agreed, crazy. Even though I did not 'need' it with low boost, I put a BOV on my old 7 psi BEGI-S setup just to get rid of the annoying gobble-gobble sound.

Back to the OP. I Agree with the posts above; try lowering the preload if you have an adjuster, or use a lighter spring.

That was the other video I found under "compressor surge" on youtube. You mean you don't think turkey noise is cool? :bowrofl:

I had the HKS SSQV, but now I'm looking for something different, I just cant decide. I like loud BOVs. Its not like I'm always driving around making it pop off like a loud bitch. But I like having that option. :)

Vash-

Mine sounds like the vid. 18 PSI posted, but not that loud (from in the car anyway). Guess I need to get a softer spring for my BOV soon.

I mean how horrible is it for the turbo? My bov opens up at anything over 5psi, only at light throttle do I get any comp surge.

I'd like to know this too. I've heard it's bad, terrible, and destroys the compressor. And then I've heard it's harmless below 7ish PSI.

If I drive like a normal person, it doesn't do this. If I drive like I always do, which is sorta aggressive, it flutters/gobles/w/e when I shift till my BOV wakes up and opens. And does it whenever I boost too.

Thanks! I knew about the turkey gobble, but I wasn't sure if that was actual compressor surge or if there was another sound that the actuall compressor doing something to show you it's surging.

I have my Forge on the lowest spring supplied with my BOV, but I still get some turkey gobble. I also get another sound that's barely audible and a bit higher frequency when I let off the accelerator at 1-2 psi of boost. It sounds more like a muffled click.

I ordered the lowest setting spring for the Forge and I'm hoping that will take care of it.

you should look into the turbo smart valves like the 50/50. it has two ports that are staged or timed(which ever you wanna call it). it also has horns that are removeable and replaceable.
The horns make 'em super loud. I run the first stage port with a flange that is for recirculating(quietish at low boost) and the second stage with a horn so I can be ignorantly loud if I wanna. you can also adjust the sring preload with out any tools. they have basicaly a hand grip and you just turn it to adjust. and there is a large range of adjustment too.

for you guys that are still running an afm you can use one of these to recirculate and have a nice vta at the same time. it doesn't totaly keep your afm from going nuts, but it makes it a million times better.


TURBOSMART: BLOW-OFF and BYPASS VALVES (universal fit)

check out the one at the bottom of the page. I have this one, but in the all black sleeper series

Thanks guys. It sounds exactly like it does in that first video, little more pronounced sometimes than others. Weird thing is it only really does this in vacuum or low boost....when there shouldn't be much pressure.


I've got a TurboXS RFL...I need to see if they make a lighter spring/clean mine/do whatever if its going to be a problem. Like Pat I've heard mixed opinions on how bad it might be.

I've got the same problem. Mine is a cheap knock-off that came with two springs. With either one spring, it's wide open at idle, but with both I get a little bit of surge at low boost. Maybe I should cut one of the springs.