Base boost increase? - The Saab Link Forums

Go Back   The Saab Link Forums > Saab Classic 900 Forum '78-'93 > Performance Modifications for the Classic 900

Performance Modifications for the Classic 900 This forum contains PERFORMANCE related Q&A's for the Classic 900. 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 03-13-2007, 09:49 PM   #1
Deez Nutz
Site ModeratorElder
 
Palmer's Avatar
 
Join Date: Oct 2005
Location: Cheese Country
Posts: 15,679
Send a message via AIM to Palmer
Base boost increase?

Should I?


It's at 6psi now.


I have: Bigger injectors, FMIC, apc mod, and an intake.

What would happen if I turned it up to say, 10psi?
__________________
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
Sponsored Links
Advertisement
 
Old 03-13-2007, 09:55 PM   #2
Moderator
Elder
 
DeLorean's Avatar
 
Join Date: Nov 2003
Location: In a compound on a hill
Posts: 7,595
Send a message via AIM to DeLorean
run away boost. once the rod is too short, the wastegate CAN'T open enough to vent enough exhaust gas to maintain "base boost". you may have 10 PSI at 3000 RPM's but by 4500, it will be more like 25 "base boost". The better the engine flows, the more wastegate opening you need at high RPM’s

with my base boost set properly (5.5 PSI), I have this happen on my car... only climbs up to 15 or so though, which is just slightly dangerous...
DeLorean 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 03-13-2007, 09:56 PM   #3
Deez Nutz
Site ModeratorElder
 
Palmer's Avatar
 
Join Date: Oct 2005
Location: Cheese Country
Posts: 15,679
Send a message via AIM to Palmer
Hmm.

So what if I split the difference, and go to 8 PSI?



Still the same issues I assume?
__________________
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 03-13-2007, 10:02 PM   #4
Moderator
Elder
 
DeLorean's Avatar
 
Join Date: Nov 2003
Location: In a compound on a hill
Posts: 7,595
Send a message via AIM to DeLorean
eeh give it a shot. I actually don't think you can even make the rod short enough to get that much base boost out of it, but prove me wrong. I don't really know what will happen, but my guess is that the boost starts getting away from you at high RPM's. be real careful when you are testing this, the boost may really start to kick around 4500-6000 with very little warning.
DeLorean 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 03-13-2007, 10:03 PM   #5
Elder
 
PaulH's Avatar
 
Join Date: May 2004
Location: Reading, PA
Posts: 5,805
Send a message via AIM to PaulH
you should be fine with 8psi, Deloreans car is just exaggerated since he has the header and all. base boost typically should be around half your max boost. basically as long as you dont get knock ever at your base boost you should be fine, because you have to keep in mind that thats as low as the APC is gonna be able to bring the boost if it sees trouble.

Paul
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
PaulH 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 03-13-2007, 10:06 PM   #6
Deez Nutz
Site ModeratorElder
 
Palmer's Avatar
 
Join Date: Oct 2005
Location: Cheese Country
Posts: 15,679
Send a message via AIM to Palmer
Well, the 1/2 of peak makes sense.

I hold 15-16 pretty good now, all the way up to the redline, so I'll try for 8. It went to 6 pretty easy.

I'll have to see what I can get out of it.


Thanks for the input guys!
__________________
S55/LC100/KL

Last edited by Palmer; 03-13-2007 at 10:08 PM.
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 03-14-2007, 05:19 AM   #7
Live, eat, and sleep by TSL
 
900AERO's Avatar
 
Join Date: Mar 2007
Posts: 1,590
I was told by Gary from swedish dynamics that you can run up to 10 psi base with no harm. so i did about an approx 8.5 and so far so good .
instead of shortining the wastegate rod. I put an additional spring but I was told to shorten the rod. also remeber G9 would used to sell a 9psi actuator.
__________________
WHATEVER.....SAAB'S ARE FASTER THAN WHAT YOU THINK.
900AERO 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 03-14-2007, 05:52 AM   #8
Live, eat, and sleep by TSL
 
SAABOOST's Avatar
 
Join Date: Aug 2006
Location: Albany NY
Posts: 1,478
Quote:
Originally Posted by PaulH View Post
Base boost typically should be around half your max boost.
Paul
X2
Finally someone that agrees with me. I can't tell you how many customers of mine give me attitude about raising base boost. Some how they think that from 5-8 base is going to give them in the mid-twenty range.
SAABOOST 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 03-14-2007, 05:59 AM   #9
Live, eat, and sleep by TSL
 
ohlins8990's Avatar
 
Join Date: Sep 2005
Location: Peoria
Posts: 1,543
Send a message via AIM to ohlins8990 Send a message via Yahoo to ohlins8990
I want to say mine is at 6.5 right now. Mine will hit the redline on the boost gauge by 3k rpm, continue going uptil it hits just above 1/2 way in the red, pop back to about 1/3 into the red, and then start coming back at around 4.5 to redline. At least thats how it works until the IC heat soaks and it goes down it to the yellow

I don't have as much done as you though. Just K&N drop in, APC mod, and 3 bar FPR.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ohlins8990 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 03-14-2007, 06:34 AM   #10
Live, eat, and sleep by TSL
 
900AERO's Avatar
 
Join Date: Mar 2007
Posts: 1,590
Andrew , what upgrades have you done to the car?
__________________
WHATEVER.....SAAB'S ARE FASTER THAN WHAT YOU THINK.
900AERO 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 03-14-2007, 07:15 AM   #11
Live, eat, and sleep by TSL
 
ohlins8990's Avatar
 
Join Date: Sep 2005
Location: Peoria
Posts: 1,543
Send a message via AIM to ohlins8990 Send a message via Yahoo to ohlins8990
Just the K&N drop in, 3 bar, and 900aero apc mod. I have F pot turned all the way up and P up a tad. I havent hit fuel cut yet which kinda surprised me. Probably cause its too hot and humid in houston, don't know, but it does 70-100 pretty damn fast in 5th.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ohlins8990 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 03-14-2007, 11:38 AM   #12
Live, eat, and sleep by TSL
 
900AERO's Avatar
 
Join Date: Mar 2007
Posts: 1,590
for what you have i would keep it this way, unless you get a fuel chip and some 30lb injectors. then you can run more boost and get more power.
Your box is ok but from what i have tried and what i have read on the web from other users " Vince, saabator" he said he had both G9 box and SD box . He said that the SD box was more agressive. but i would say forget the apc box for now. just increase fuel and make sure your ignition is A+ and go from their.
if you do not get the results you want then you might need to invest in a SD apc BOX.
__________________
WHATEVER.....SAAB'S ARE FASTER THAN WHAT YOU THINK.
900AERO 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 03-14-2007, 12:53 PM   #13
Live, eat, and sleep by TSL
 
ohlins8990's Avatar
 
Join Date: Sep 2005
Location: Peoria
Posts: 1,543
Send a message via AIM to ohlins8990 Send a message via Yahoo to ohlins8990
i think my dad has 6 temp sparkplugs in there too instead of the stock 7's, the ignigtion timing could probably be tuned up a little, i dont no the last time it was looked at.

Also, teh car is still on the orginal tranny, and @ 270k, I dont think I want to do much more to it.
__________________

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

Last edited by ohlins8990; 03-14-2007 at 01:58 PM.
ohlins8990 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 03-14-2007, 03:40 PM   #14
Elder
 
saabsbreakdown's Avatar
 
Join Date: Nov 2005
Location: Gig Harbor, Washington
Posts: 2,624
Send a message via AIM to saabsbreakdown
270,000, that means you have 730,000 left?
__________________

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

Car 178 - 1975 Saab 99 EMS

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
saabsbreakdown 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 03-14-2007, 04:00 PM   #15
Live, eat, and sleep by TSL
 
ohlins8990's Avatar
 
Join Date: Sep 2005
Location: Peoria
Posts: 1,543
Send a message via AIM to ohlins8990 Send a message via Yahoo to ohlins8990
unfortunatly we werent the original owners.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ohlins8990 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 03-14-2007, 05:46 PM   #16
Elder
 
Green9kAERO's Avatar
 
Join Date: Jul 2006
Location: Central Maine
Posts: 4,187
i was always told that shortening the wastegate rod (toomuch, as in shortest position) is like nuetering the APC and that i should just tweak the pots on the aPC.... idk though...

my 91 9k is running about 10-12 psi base boost, but its ONLY running base boost so i dont really see any issues... i was trying to install a MBC between the wastegate actuator and the pressure side of the turbo, but idk what happend i CANNOT get any more then 10 PSI.... course this car now has a T3 turbo with a T25 wastegate actuator that has been modified to clear teh balence shafts..
JP
__________________
Quote:
I heard Tom Had a 2 pump dump on his injector duty cycle....

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Green9kAERO 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 03-14-2007, 06:10 PM   #17
Live, eat, and sleep by TSL
 
ohlins8990's Avatar
 
Join Date: Sep 2005
Location: Peoria
Posts: 1,543
Send a message via AIM to ohlins8990 Send a message via Yahoo to ohlins8990
IDk, I'd be concerned if I had no way for the ECU to knock boost back.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ohlins8990 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 03-14-2007, 06:17 PM   #18
Elder
 
90SPG's Avatar
 
Join Date: Oct 2005
Location: Lancaster, PA
Posts: 3,148
Send a message via AIM to 90SPG
the engine is the last thing you need to worry about on these cars. as long as you have reasonable fueling and good hardware, which he does, I think you can get away with a fair amount of boost. these may be famous last words but I think you should be fine.
__________________
'90 900 SPG (RIP rust)
'86 900 SPG (DD)
'86 900S
"A car with an image so immaculate it can hold confession and communion."
90SPG 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 03-14-2007, 06:30 PM   #19
Elder
 
PaulH's Avatar
 
Join Date: May 2004
Location: Reading, PA
Posts: 5,805
Send a message via AIM to PaulH
well you have to keep in mind the way the APC works, let me try and explain this simply.

you have the APC solenoid, wich has the ability to basically "hide" boost from the wastegate actuator. base boost is what the wastegate will open at without the APC solenoid hiding boost. so when the APC sees trouble (knock) it opens up the solenoid, and "shows" the WG actuator the boost (usually lots more than base boost) and it swings the wastegate open. so basically you want to make sure that if theres knock, APC can pull the boost back to a reasonable level to stop it.

Paul
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
PaulH 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 03-14-2007, 07:22 PM   #20
Live, eat, and sleep by TSL
 
900AERO's Avatar
 
Join Date: Mar 2007
Posts: 1,590
you do not need the 6temp plugs, i was told that the 7es gaped @ .25 is the best way to go. i was also told that the 6 will need regaping almost with every oil change. you will need to worry about hotter plugs selection after the fuel issue is taken care of. then you might need a hotther spark to ignight all the extra air and fuel you will be pushing into the cylinders.
and also when timing set the timing to 15, that should allow for safer higher boost ans should give you better top end power.
__________________
WHATEVER.....SAAB'S ARE FASTER THAN WHAT YOU THINK.
900AERO 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 01:30 AM.


Powered by vBulletin® Copyright ©2000 - 2020, 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 © 2020 DragonByte Technologies Ltd.
All content is copyright The Saab Link and it's original authors.


 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.