The banner above is an advertisment - if it asks you to download software, please ignore.
Site News - 7/1: Members: Log In to See Fewer Ads! | 5/28: SAAB Evolutions/TSN T-Shirts $14
[General | Members | C900 | 9000 | NG900 & OG93 | 93 | 95 | NG95 | 99 | Sonett | Vintage Models | Clubs | Other Cars | FAQs | Gifts | Member Photo Galleries | Member Directory | Classifieds | Manuals | *Buddy Registry | *Mileage Registry | Polls | What's New | Raffle | Photo of the Month | Sponsors]

NG900 & OG93 Bulletin Board
1994-2002 [Subscribe to Daily Digest]
(Search Author's Posts: e.g. Keyword:username)*Members Only

[Main NG900 & OG93 Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
theory and a possible solution
Like This Post: - Subscribe to Daily Digest for this Bulletin Board
Posted by Dean (more from Dean) on Fri, 12 Sep 2003 07:58:25 Share Post by Email
In Reply to: Ben....still positive on Joe P's MBC?, Thom, Fri, 12 Sep 2003 07:25:46
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup

The ball-spring MBC opens the wastegate at the last moment as you get on boost. When the MBC starts to flow, it has to pressurize the WGA to the point where the pressure just balances the spring pressure and the WG valve is zero pressure on its seat. So that takes time and the WG has not started to open. Then it takes more time to increase the pressure and move the WG to a stable control point. When boost comes on fast in cool or cold weather, there will be pressure overshoots because the MBC just cannot stroke the WGA fast enough. No variations on the basic design will help and expensive units with adjustable bleed ports don't help either. So you quest for a MBC that works better than another as far as fuel cuts goes, will be of no avail.

When the air flows to the WGA it has to compress the air already in the WGA's spring chamber. So the flows are greater than the change in WGA volume as the WGA diaphragm moves. I hope that the design is such that the air volume in the WGA is near aero when closed. If not, that parasitic volumne needs to be compressed and and that would introduce more delay.

I solved the problem with a pop-off valve, but that was difficult, and expensive. And not a bolt on solution!

I have an idea for solving the problem which should work, and will be cheap and relatively simple. Search the performance BB for drs<underscore>anticipator and read that and the whole thread. We will have some experience soon, so sit tight. I don't own a T5 anymore, so I can't do the work myself.

posted by 208.24.179...

Posts in this Thread:
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup
Post a Followup

No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.

Name: Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
E-Mail: (Optional)
Re-Enter E-Mail: (Confidential & Secure - Not revealed to other users!)
Note: Please check your spam folder for BB responses.

Subject:

Posting rules are simple - No for sale/wanted ads may be posted here - use the site classifieds.
You may not cross-post your message to multiple BBs.
Not permitted: political/religious topics and being disrespectful (personal attacks, insults, etc...).
 Site Members do not see any red text, inline ad links, bottom of page anchor ads, box ads, or anti-spam check.

Message: (please no for sale/wanted classifieds - post those in the Saabnet.com Classifieds)
Links are now automatically made active, no need for any special code (or use the Option Link field below) - don't put links in () or end with a '.'
To add inline images to your post, use [img]http://www.domain.com/img.jpg[endimg] (or use the Optional Image Link field below).

Links are now automatically made active, no need for any special code (or use the Option Link field below) - don't put links in () or end with a '.'
To add inline images to your post above, use [img]http://www.domain.com/img.jpg[endimg] (or use the Optional Image Link field below).
Optional Link: (e.g. http://www.saabnet.com/)
Link Title: (Optional)
Optional Photo/Image Link: (e.g. http://www.saabnet.com/img.jpg)
Photo/Image to Upload: (Please be patient while file uploads)



StateOfNine.com
SaabClub.com
Jak Stoll Performance
M Car Covers
Ad Available

The content on this site may not be republished without permission. Copyright © 1988-2024 - The Saab Network - saabnet.com.
For usage guidelines, see the Mission & Privacy Notice.
[Contact | Site Map | Saabnet.com on Facebook | Saabnet.com on Twitter | Shop Amazon via TSN | Site Donations]

Random Saabnet.com Member Gallery Photos (Click Image)
This is a moderated bulletin board - Posting is a privilege, not a right. Unsolicited commercial postings are not allowed (no spam). Please, no For Sale or Wanted postings, SERIOUSLY. Classifieds are to be listed in The Saab Network Classifieds pages. This is a problem solving forum for over 250,000 Saab owners, so expect to see problems discussed here even though our cars are generally very reliable. This is not an anything goes type of forum. Saabnet.com has been a moderated forum since 1988. For usage guidelines, see the Saabnet.com Mission and Purpose Page. Please remember that you are not anonymous. Site Contact | Site Donations | Other Sites by SP - Poverty2Prosperity.org | Run Club Menlo Park | ScreenBot


Site Members do not see red text instructions, bottom of the page anchor ads, or box ads.
Click here to see all the Site Membership Benefits!