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View Full Version : MSnS-E Boost Control

kyle242gt
08-02-2005, 12:49 PM
Open loop control has been giving me fits, which I brought up in prior posts. Basically,I wasn't getting to max boost (15-17PSI:evil: ) at times.

I figured it out.

The duty table has a column for TPS%. Well, it's not the same TPS% as the TPSgauge/realtime display; that's what you set with "Calibrate TPS".

No, instead, it's using TPSADC/255 = %. IOW, My TPS goes from 20 to 200 on a full sweep. That means at closed throttle, I'm not at 0%, I'm at 20/255 = 8%. Similarly, at WOT, I'm only getting 200/255 = 78%.

It wasn't a big deal until I had my DC%=boost values worked out and tried to move max boost higher in the throttle %... then 15PSI at 85% is out of reach and I only got 12.

Just an FYI for anyone running open loop or planning to.
Matt Dupuis
08-02-2005, 04:13 PM
Maybe I knew that from farting around with it so much and exchanging emails with James Murray. I sort of forgot that was an issue to be rectified - you might want to email James to get it fixed up in the next revision.
The Aspirator
08-03-2005, 01:38 AM
Sweet! You're using an 850 valve right? (Man I should have nabbed that from Jordan's car last weekend, can't believe I forgot. Stole the seats though :twisted: ).

Poi was also telling me about an aftermarket valve for like $30 that can hold a ton more boost than the 850 one likes to deal with. But if the 850 one works......
coldfusion21
08-03-2005, 03:17 AM
dang, i knew we forgot something....
kyle242gt
08-03-2005, 12:12 PM
Hey John, that's right - Volvo 850 valve. They're mounted on the air cleaner housing under the intake piping.

It's doing fine at 17, which is really more than I have fuel or transmission to handle ;-)

But you might ask around and see if any other OEM or aftermarket valves will work properly in closed loop. I'm curious if that's a problem with the 850 valve or the software.

K
benflynn
08-03-2005, 03:04 PM
anyone use a saab apc valve? i still have one from when i wanted to go the apc route
Unregistered
08-03-2005, 03:29 PM
All Saab bypass valves have superceded to a 30 PSI valve, Saab number 4441895, Bosch number 0280142110.

30 PSI? Really? Really. Viggens made 20 PSI stock.

eEuroparts has them for $50, FCP Groton $55.
the poi
08-03-2005, 04:45 PM
anyone use a saab apc valve? i still have one from when i wanted to go the apc route
matt dupuis has. they won't work without a low pressure actuator. they only take like 3-5 psi.
Unregistered
08-03-2005, 06:05 PM
moderator, please delete the above post about the Viggen valve. i mis-read the original inquiry...