The Saab Link Forums

The Saab Link Forums (https://www.saablink.net/forum/index.php)
-   Performance Modifications for the 9-5 (https://www.saablink.net/forum/forumdisplay.php?f=46)
-   -   Fluttering? (https://www.saablink.net/forum/showthread.php?t=112978)

Jameson 07-27-2016 06:42 PM

Fluttering?
 
With all my new mods, I have developed a fluttering sound at WOT.

I am thinking my Forge came with a 15psi max spring and that is the fluttering sound, that I am exceeding that boost and the flutter is the BPV. By ear, the location is high drivers side front which is the right location.

Only other thing I can think of is the wastegate. Anyone else experience this?

I figure throwing a beefier spring in the Forge is a cheap way of diagnosing.

turbojohnny 07-28-2016 03:45 AM

I think your diagnosis is most likely correct. The BPV is going to be the first thing to let go at higher boost levels.

g96nt 07-28-2016 06:25 AM

How did you install the valve?
The stock way, or the right way?

srp 07-28-2016 06:56 AM

Have a look at this: https://www.saablink.net/forum/perfor...-9-3/65634.htm

g96nt 07-28-2016 07:39 AM

hah... such strong opinions in that thread.

Jameson 07-28-2016 07:55 AM

Quote:

Originally Posted by g96nt (Post 2148906)
hah... such strong opinions in that thread.

Yeah.

All I know is, with some links that SRP sent of Turbo Cobalt owners running Forge BPVs, they all describe the exact sound and sensation I am getting. They all point to shims as the cure or uprated springs and or shims. So I will try a shim or two first.

Jameson 07-28-2016 03:03 PM

Turns out I have the green spring which is rated 5-15psi. Cobalt people seem to great results with shimmed green springs holding 22psi with no issues. So off to Home Depot I go!

turbojohnny 07-29-2016 03:53 AM

well?? how'd it go?

g96nt 07-29-2016 07:12 AM

You're fighting an up-hill battle if you have it installed incorrectly.
do you have it so the pressure from the vacuum hose is pushing the piston against the pressure of the charge-pipe?

(also, you won't need a heavy spring)

Jameson 07-29-2016 08:03 AM

Quote:

Originally Posted by turbojohnny (Post 2149010)
well?? how'd it go?

I found kind of thin fender washers, put in two, it made the car laggy and I still had flutter.

I went and bought a gold 15-23 psi spring and will give that a try.

I did some boost logs and make a healthy 17.2psi in 2-3rd and 17.8 psi in 4th. It tapers a bit as expected at 6k, its more like 15ish.

Quote:

Originally Posted by g96nt (Post 2149066)
You're fighting an up-hill battle if you have it installed incorrectly.
do you have it so the pressure from the vacuum hose is pushing the piston against the pressure of the charge-pipe?

(also, you won't need a heavy spring)

It's installed correctly. Again, I have had 0-issues, this flutter popped up after the added boost of the 18T install.

g96nt 07-29-2016 11:30 AM

What's your boost source for the valve?
You're not using the solenoid, are you?

Going straight from the manifold to bpv, I hope!

Jameson 07-29-2016 01:03 PM

Quote:

Originally Posted by g96nt (Post 2149106)
What's your boost source for the valve?
You're not using the solenoid, are you?

Going straight from the manifold to bpv, I hope!

Correct, did the BPV mod a long time ago. I did put a proper cap on the line from the TB yesterday though, it was a bit ghetto rigged previously.

scenturion 07-30-2016 09:07 AM

Quote:

Originally Posted by g96nt (Post 2149106)
What's your boost source for the valve?
You're not using the solenoid, are you?

Going straight from the manifold to bpv, I hope!

For those of us new to this, can you explain what the correct way to mount the BPV is, as well as where the vacuum line should go?

Jameson 08-12-2016 07:19 AM

New tune is in, 18-19psi, figured the green 15psi spring was not ideal. I put in the yellow 23psi spring.

I still get the flutter. However, I noticed it does not do it at WOT/100%, 50-90% I get the flutter. Wouldn't that point to a small vacuum leak causing the noise?

The only other thing I can thing of, there seems to be a bend/kink in the wastegate rod.

g96nt 08-12-2016 08:52 AM

It means that the pressure on the top of the valve is not as high as in the pipe.

Jameson 08-12-2016 10:05 AM

Quote:

Originally Posted by g96nt (Post 2150114)
It means that the pressure on the top of the valve is not as high as in the pipe.

And?

That's fine?

Should I try and solve it, and how?

g96nt 08-12-2016 01:21 PM

I don't know, Jameson.

I have the base spring in my valve, and it's set up the way I said.

I have the recirc valve pressure line coming off the nipple with the fpr and the line that would come back from the solenoid capped on the throttlebody.

It works flawlessly.

Cark 08-13-2016 06:25 AM

Quote:

Originally Posted by Jameson (Post 2150106)
there seems to be a bend/kink in the wastegate rod.

This was done when Dave Kennedy built the turbo, it needs to be bent to work with the 6cm housing. A lot of waste gates utilize "bent" rods.

http://www.forgemotorsport.com/userf...e-Actuator.jpg

Never had any issues with fluttering. But also never ran at 18-19psi and very rarely even hit WOT.

Jameson 08-13-2016 07:38 AM

Quote:

Originally Posted by Cark (Post 2150290)
This was done when Dave Kennedy built the turbo, it needs to be bent to work with the 6cm housing. A lot of waste gates utilize "bent" rods.

http://www.forgemotorsport.com/userf...e-Actuator.jpg

Never had any issues with fluttering. But also never ran at 18-19psi and very rarely even hit WOT.

Good to know about the rod otherwise I could have replaced it thinking it was no good lol.

Cark 08-13-2016 07:45 AM

I know Jak Stoll used to talk a lot about waste gates being blown open under too much boost. The c900 guys were using helper springs and such to cure the problem... not sure that would be the issue at only 18-19 PSI?


All times are GMT -8. The time now is 12:11 AM.

Powered by vBulletin® Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.5.2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
All content is copyright The Saab Link and it's original authors.


Garage Plus vBulletin Plugins by Drive Thru Online, Inc.