Site News - 7/11: No New News Today | 5/10: Members: Log In to See Fewer Ads!
[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
Dean/Adam: OK, so where's your new test?
Like This Post: - Subscribe to Daily Digest for this Bulletin Board
Posted by Greg Netzner (more from Greg Netzner) on Thu, 21 Nov 2002 15:36:37 Share Post by Email
In Reply to: That's exactly what I thought when I read it..., AdamB [Profile/Gallery] , Thu, 21 Nov 2002 05:34:35
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup

Look, I know how easy it is to find the flaws in other people's work (I've been hired to do it for several companies), but simply saying something's wrong without resolving it, or theorizing what might be right or wrong without testing, doesn't help anyone. I've dragged this poor guy's comparison over here as an example of tests he's run on a variety of valves. He might have some inconsistencies with his methods, but he does try to warn you multiple times about it.

No, he did not get to pressure test the Hyper; he says right up front that this test was added later on. If you combine this fact with his comment about not having the Hyper for a long-term test, isn't it possible that he was borrowing the valve? I don't know 'cuz I haven't asked the guy. Perhaps you should, as this would help to answer your questions/theories. The fact remains that this guy's actually tested all these valves, & that's why it's being referenced.

Adam, I'm glad you like your Hyper & I'm not trying to convince anyone to buy any particular brand; I'm only trying to pass along what I've uncovered. (The previous post you reference was a group buy offer only, not a marketing ploy.) Dean, it sounds like you're running your Turbo XS backwards & having success with it. It's good that we know the Turbo XS can be run this way! And I agree with your observation about positive boost pressure "helping" to open the valve & dumping boost quickly.

The idea is to get the spring just strong enough to keep boost pressure from moving it & not so strong that the vacuum can't. Of course, there are decisions to be made: do you want as light a spring as possible to allow the valve to open as quickly as possible to avoid any potential damage to the turbo, or do you want as stiff a spring as possible so that the turbo is on-line as long as possible? The downside to the first choice is less boost-time, while the second choice might allow the pressure wave to kick back to the impeller.

Yes, a longer spring chamber will use a coiled steel spring of a lower spring rate, but is this a good thing? If you want quick, on/off response, a shorter chamber using a coil spring of a higher spring rate will do this better than a long chamber/soft spring combo. Also, don't forget that air is a spring (which is why shortening the vacuum lines has a beneficial effect). As long as the chamber's volume doesn't change between any given valves, the amount of "air spring" will be the same. However, like a longer coil spring, a longer air spring will see more relative piston movement for any given compression rate. Why is this important? Because it allows the piston to be partially open a greater percentage of the time. Isn't that what you don't want?

As for presenting a smaller pressure face so as not to overrun the spring's rate, keep in mind that this is the orifice thru which your turbo-damaging pressure wave is travelling. Like modifying the lip of the TBTC, reducing restriction here is a good thing. A better way to balance this is by using the proper combination of coil spring rate & chamber configuration.

C'mon guys, let's not trash something unless we've done the research to refute it. What other valves have you guys tested? I'm always looking for more data to add to my collection, so post your results so we can have something tested relative to Saabs. Then I can drag your comparisons over to somebody else's board.

posted by 216.160.177...
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 © 1988-2025 - 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!