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
Re: a few more test runs.. some more info...
Like This Post: - Subscribe to Daily Digest for this Bulletin Board
Posted by Dean (more from Dean) on Wed, 18 Apr 2001 10:15:45 Share Post by Email
In Reply to: a few more test runs.. some more info..., cl, Tue, 17 Apr 2001 20:41:15
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup

You should not have to use spacers or stretch the spring.

The size of the bleeder orifice will affect rates of spool up and overshoot. But when connected to the comressor housing hose barb, the short hosse lengths are too short to cause overshoots as a result of time delays in pressure propogation.

Keep hose lengths short consistant with the installed location.

On cold days the boost will ramp up very fast and it is in 2nd gear where you will get the fastest boost rise and where you will find your fuel cuts. It sounds like you are very close to a final setting now.

Your drop off of prssure is caused be a few things. The controller is controlling pressure at the turbo, and your power and boost indicator are driven from the manifold. As rmp's go up, pressure losses in the pipes and IC beccome significant. You also need to do the transistion casting rework, as that is a significant resistance, as well as the discharge silencer. Air box too! These resitances all add up to pressure losses and heat. Both reduce the charge air density in the cylinders. So now that yo uhave the bug, you can get after those three other items.

If you pressurize the MBC from the manifold, then you will get better pressures at higher RPM's, but you will then get boost overshoots in 2nd gear in cool or cold weather.

I am currently dialing in pressure with a compressor housing hose barb connection, and I am seeing the same things as you, but to a much lesser degree. I have created a fitting that will allow me to get a pressure tap downstream of the IC, this might be the best tradeoff.

Please also note that pressure losses in the system make the turbo compressor run harder in flow regimes where its efficiency is lower. This translates into more heat for the undersized IC. And the added power required by the compressor makes the wastegate remain more closed to generate shaft HP in the turbine wheel. This translates into higher back pressures on the pistons which leads to less power. So there are multiple and compounding problems working against you. But if you eliminate the problem areas that I have described, then you will get synergistic improvements, where the sum is greater than the parts.

Fitting a viggen IC would be the next step after the other changes.

Use good fuel, highest octane pump gas that you can find. Keep plugs in good shape. Clean injectors with Techron Conentrate 3X's per year.

The engine ECU will not have any problems getting used to mapping at the higher pressures. Not an issue.
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!