compressor surge with stage 3 - The Saab Link Forums

Go Back   The Saab Link Forums > Saab NG900 '94-'98 and 9-3 '99-'02 Forum > Performance Modifications for the NG900 / Old 9-3

Performance Modifications for the NG900 / Old 9-3 This forum contains PERFORMANCE related Q&A's for the NG900 and 9-3. This may also include suspension.

SaabLink.net is the premier Saab Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools
Old 05-29-2008, 03:59 PM   #1
SAABeginner
 
Join Date: May 2008
Posts: 8
compressor surge with stage 3

I have a 95 900se with a Jak Stoll Stage 3 setup including 3" turboback with cat , viggen i/c and tuned ecu. After ruining a couple turbo's due to a cheap blowoff valve (got the bosch one back in), I am experiencing compressor surge when I get above 15 psi or so and the rpm's are below about 3k. It's the same sound i would get between shifts when my old blowoff wasn't venting all the boost, but this time at peak boost levels, and I can hear it coming from the intake side. The aftermarket boost gauge I have also goes crazy when this happens. It will happen with the vacuum disconnected form the WG, but if i unplug the bpc and crank the WG actuator to make like 15lbs of base boost, it will creep to 20lbs with no flutter. I'm just noticing this phenomenon now since I reinstalled the turbo, but it may or may not have been happening all along before i replaced it. Any ideas?
wkndracr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 05-29-2008, 05:33 PM   #2
Elder
 
Legit's Avatar
 
Join Date: Jun 2007
Location: St. Paul, MN
Posts: 2,983
Did you hook up the vacuum line to it? Also check your wastegate arm
__________________
2002 Viggen Convertible
Legit is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-29-2008, 07:49 PM   #3
JZW
Elder
 
Join Date: Oct 2006
Location: Boulder Colorado
Posts: 3,153
Quote:
Originally Posted by wkndracr View Post
I have a 95 900se with a Jak Stoll Stage 3 setup including 3" turboback with cat , viggen i/c and tuned ecu. After ruining a couple turbo's due to a cheap blowoff valve (got the bosch one back in), I am experiencing compressor surge when I get above 15 psi or so and the rpm's are below about 3k. It's the same sound i would get between shifts when my old blowoff wasn't venting all the boost, but this time at peak boost levels, and I can hear it coming from the intake side. The aftermarket boost gauge I have also goes crazy when this happens. It will happen with the vacuum disconnected form the WG, but if i unplug the bpc and crank the WG actuator to make like 15lbs of base boost, it will creep to 20lbs with no flutter. I'm just noticing this phenomenon now since I reinstalled the turbo, but it may or may not have been happening all along before i replaced it. Any ideas?
I would have to hear it to be sure, but what I think you are hearing is the typical boost chatter or the pst, pst, pst of the ecu controlling boost! That is why you don't hear it if you leave the turbo unlimited with the waste-gate hose not attached.

That is fairly normal, you don't want it to run full boost all the time, that is letting you know knock is being detected and the ecu is dumping a little boost. This is normal ecu controlling the bpc and controlling boost...

I get the same thing, you are pumping more air than the head can handle at the lower rpm levels, try rolling into the throttle a little bit and go wot after 3k and the head will be able to handle the boost much better... I p/p my head for that reason and it all but went away after that, but my aero does exactly what you're car does at stage 3 level.

You will get varying amounts of the boost chatter depending on weather and the fuel you run...

If you don't want the tuned ecu to control boost, but a mbc on it and put the hammer down...

John
__________________
b234r ng900, E-85 Holset Super [email protected] mph a mile high 645whp/650wtrq Sae Denver
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
JZW is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
 
Old 05-29-2008, 07:51 PM   #4
Elder
 
codesplice's Avatar
 
Join Date: Aug 2005
Location: Huntsville, AL
Posts: 4,388
^^ That was going to be my suggestion, except I didn't know how to describe it as nicely as John did
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2001 9-3 - Nordic Stage 3
2007 9-5 2.3T Wagon

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
codesplice is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-30-2008, 04:11 AM   #5
SAABeginner
 
Join Date: May 2008
Posts: 8
Thanks for the replies. I was thinking it may be the ecu controlling the boost, but it will happen with the hose to the wastgate actuator disconnected. the only time it doesn't happen is when i have the wg arm cranked so tight as to get like 15lbs of base boost, with the hoses to the bpc connected, but the electrical connector unplugged. I will try putting my old mbc back in temporarily and do a couple of runs to see if anything changes. It could be a warm weather thing i suppose, but i want to try everything before i write it off as normal.
wkndracr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-30-2008, 06:54 AM   #6
JZW
Elder
 
Join Date: Oct 2006
Location: Boulder Colorado
Posts: 3,153
Yea, that is normal, you are pumping more air at low rpm than the head can handle.... ONce you get higher in the rpm its not a problem.

Putting base boost at 15psi is a very bad thing and can cause detonation and there is no way for the ecu to reduce or dump boost to save the engine.

I played around with base boost with my stage 3 and about 8psi was the max I could run without pinging. 9psi had some ping and detonation on the dyno...

John
__________________
b234r ng900, E-85 Holset Super [email protected] mph a mile high 645whp/650wtrq Sae Denver
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
JZW is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-30-2008, 03:52 PM   #7
SAABeginner
 
Join Date: May 2008
Posts: 8
yeah, i just cranked up the base boost temporarily to see if that had any affect on it. It is reset to the recommended 10 psi. So is it more of a cylinder head thing, or would an upgraded intercooler and maybe 2.5" delivery pipe help the situation any?
wkndracr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-30-2008, 04:49 PM   #8
Flirting With TSL Addiction
 
jonny72888's Avatar
 
Join Date: Sep 2006
Location: Taunton, Mass
Posts: 896
quick question, to bring base boost up should you make arm longer or shorter?
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2001 Grand Cherokee Limited 60th ed.
jonny72888 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-30-2008, 09:33 PM   #9
SAAB Road Master
 
Join Date: Sep 2007
Location: Germany
Posts: 305
Quote:
Originally Posted by jonny72888 View Post
quick question, to bring base boost up should you make arm longer or shorter?
longer (sorry, I meant shorter) hangs head in shame
__________________
curly fries or skinless chicken?

Last edited by 93nut; 05-31-2008 at 12:32 PM.
93nut is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 01:37 AM   #10
Live, eat, and sleep by TSL
 
Join Date: May 2004
Posts: 1,122
Quote:
Originally Posted by 93nut View Post
longer
shorter. If you increase the length of the rod you decrease the pretension = lower baseboost
Vigge is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 05:23 AM   #11
lms
Live, eat, and sleep by TSL
 
Join Date: Jan 2006
Posts: 1,337
Quote:
Originally Posted by wkndracr View Post
yeah, i just cranked up the base boost temporarily to see if that had any affect on it. It is reset to the recommended 10 psi. So is it more of a cylinder head thing, or would an upgraded intercooler and maybe 2.5" delivery pipe help the situation any?
Why are you running bb of 10psi and who recommends that?
lms is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 05:58 AM   #12
Elder
 
Legit's Avatar
 
Join Date: Jun 2007
Location: St. Paul, MN
Posts: 2,983
Quote:
Originally Posted by lms View Post
Why are you running bb of 10psi and who recommends that?
x2 just bring it down to 6.5
__________________
2002 Viggen Convertible
Legit is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 10:59 AM   #13
JZW
Elder
 
Join Date: Oct 2006
Location: Boulder Colorado
Posts: 3,153
Quote:
Originally Posted by lms View Post
Why are you running bb of 10psi and who recommends that?

I think 10psi is too high for you're set-up, the ecu cannot dump all the boost if the ecu detects knock. I had bad pinging at 9psi, had to lower to 7-8psi.

I would not run over 7-8psi!!!!

John
__________________
b234r ng900, E-85 Holset Super [email protected] mph a mile high 645whp/650wtrq Sae Denver
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
JZW is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 02:05 PM   #14
SAABeginner
 
Join Date: May 2008
Posts: 8
10lbs was what Jak recommended, unless I'm remembering incorrectly.

Today I tried an mbc set to 15lbs for a couple of quick runs, and I get the same thing, although not as bad, as I get close to 15lbs. I'm wondering now if there's something up with the turbo.
wkndracr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 02:07 PM   #15
Elder
 
Legit's Avatar
 
Join Date: Jun 2007
Location: St. Paul, MN
Posts: 2,983
Its not the turbo, it has to do with how the air is recirculated / vented either back into the system or the atmosphere.
__________________
2002 Viggen Convertible
Legit is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 11:15 PM   #16
JZW
Elder
 
Join Date: Oct 2006
Location: Boulder Colorado
Posts: 3,153
Quote:
Originally Posted by wkndracr View Post
10lbs was what Jak recommended, unless I'm remembering incorrectly.

Today I tried an mbc set to 15lbs for a couple of quick runs, and I get the same thing, although not as bad, as I get close to 15lbs. I'm wondering now if there's something up with the turbo.
Like I said, this is normal!!! every one I have driven in does it a little to a lot depending on weather and how low in the rpm you get on it... The head cannot handle the extra boost down low in the rpm... Once you reach the point where no more air can be pumped through the head, it backs up and pst, pst, pst out the bpc or bov and if it was really, really bad, it could back up and pass through the turbo compressor blades, true compressor surge...

I am sure Jak said try 10psi, but that does not mean 10psi is perfect for every car and 10psi is just a good ball-park. I had issues trying to run 10psi and 9psi, so just be carefull. Most run around 7psi....

All the stage 3's I have ridden in and driven here in Colorado have the same boost chatter that you speak of and its nothing to worry about in my opinion.

If you get a bigger turbo, it will no longer push as much air as low in the rpm and that boost chatter will be a thing of the past... Or P/P the head and that helps a good bit or just don't worry about it...

John
__________________
b234r ng900, E-85 Holset Super [email protected] mph a mile high 645whp/650wtrq Sae Denver
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
JZW is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 05-31-2008, 11:19 PM   #17
Deez Nutz
Site ModeratorElder
 
Palmer's Avatar
 
Join Date: Oct 2005
Location: Cheese Country
Posts: 15,679
Send a message via AIM to Palmer
Yep.


I pretty much figured out that this was my "issue" in my 9-3 with the GT30.


I heard some odd stuff under light boost at low RPM's and it freaked me out at first, but then I did some reading, and it made sense.
__________________
S55/LC100/KL
Palmer is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 06-01-2008, 08:16 AM   #18
SAABeginner
 
Join Date: May 2008
Posts: 8
Ok, so i guess it is normal after all. I was thinking it had something to do with the motor not being able to take the extra air at lower rpm's and it's good to hear the same thing from others. I just figured there was some way to correct it. It does seem bad enough that the air comes back out the turbo, tho. I can hear it coming from the passenger side even with the bpv vented to atmosphere. I suppose with the warm weather now, it would be more prominent. I guess i just have to change my driving style to minimize it, or dig into the pockets to improve airflow When you say bigger turbo, do you mean just a TD04, or something even bigger?
wkndracr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 06-04-2008, 01:33 PM   #19
JZW
Elder
 
Join Date: Oct 2006
Location: Boulder Colorado
Posts: 3,153
The td04 would not be big enough. My 9k aero that I get the same thing you are describing is a tdo4 6cm2. I don't get any with my gt3076

I did get some with my gt3071 .64ar and my buddy had the gt2871 .64ar and he had it worse than me, but my head has been p/p.

My thoughts were that since my car was the best out of 3, Jak's, Co-saab's and mine, the p/p head was the reason. The lower in the rpm band you can make a lot of boost, the worse it will be on surge.

The hotter it gets, the worse the bpc boost chatter will be since its being controlled by pulses from the ecu controlling boost and the hotter it is, the more it will regulate boost.

The bpc is on the passenger side and that might be what you are hearing and not true compressor surge, which is louder and more pronounced...

John
__________________
b234r ng900, E-85 Holset Super [email protected] mph a mile high 645whp/650wtrq Sae Denver
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
JZW is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Old 06-06-2008, 10:11 AM   #20
SAABeginner
 
Join Date: May 2008
Posts: 8
I would definitely say it's not the bpc because i get the same noise even when it is disconnected. it sounds just like when my old bov wasn't venting all the boost. I'm getting used to driving it so it doesn't happen, but it's a little annoying that i can't boost fully in 5th to pass someone unless i'm doing 80.
wkndracr is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the The Saab Link Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Vehicle Info.
Enter your vehicle information (year, model, mods)
Insurance
Please select your insurance company (Optional)

Log-in


Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 10:39 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.