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]

Performance Bulletin Board
[Subscribe to Daily Digest]
(Search Author's Posts: e.g. Keyword:username)*Members Only

[Main Performance Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: mbc theory...
Like This Post: - Subscribe to Daily Digest for this Bulletin Board
Posted by Dean (more from Dean) on Wed, 24 Oct 2001 12:48:48 Share Post by Email
In Reply to: mbc theory..., kooch, Wed, 24 Oct 2001 11:51:05
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup

It replaces the solenoid.

The MBC goes between the pressure source and the wastegate actuator. Most often the pressure source is the hose barb on the compressor housing.

The APC will be disabled, as the descrete APC job is to reduce boost to control knocking.

In the NG900's, the ECU executes the APC function in code and controls the boost. It can reduce the boost to control knocking. However, the T5 ECU also controls knocking with timing and mixture. Boost is reduced as a last resort. If your timing is fixed on your vehicle, then using an MBC could be dangerous. The NG900s work very well with MBC and no knocking related issues have been reported. However one should always use good fuel and plugs. Keep flow resistances down to avoid higher temperatures.

Perhaps an MBC can be hooked up WITH the boost solenoid to achieve the same or slightly higher boost levels. This would provide for faster turbo spool up. The APC function would then be preserved. This would require some experimental effort.

Note that this ball-spring behaviour is characteristic of advanced MBC's. A basic MBC 'bleeder valve' has the characteristic of boost onset delay caused by the wastegate cracking open too soon. Note that this is in common with the BPC solenoid valve. The BPC is a solenoid modulated 'bleeder valve'. So, much of the 'torque shaping' of the Saab turbo charged systems is basic bleeder valve induced boost onset delay.

So try a MBC between the solenoid and the wastegate actuator. I think someone did something of this nature one on a NG900. A $35 experiment.

It you have an aftermarket ECU, perhaps it will be timing and mixture adaptive to the signal from the knock sensor. If so, a normal MBC configuration might work well.


posted by 207.43.19...
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!