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]

9000 Bulletin Board
1985-1998 [Subscribe to Daily Digest]
(Search Author's Posts: e.g. Keyword:username)*Members Only


[Main 9000 Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: Loss in Performance of 9000T
Like This Post: - Subscribe to Daily Digest for this Bulletin Board
Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Thu, 19 Apr 2001 14:08:22 Share Post by Email
In Reply to: Loss in Performance of 9000T, 879KT, Wed, 18 Apr 2001 16:52:01
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup

The warmer the air, the less dense. That's both because warm air has fewer air molecules per cubic inch, and because warm air can hold more water than cold air (higher dew point). Water doesn't burn well.

The engine control measures the MASS of the air coming in, and supplies the correct amount of fuel. The less dense the air, the less mass, so you get less fuel.

A turbocharger helps, because its job is to pressurize the air. But pressurizing air adds heat, and that heat is added on to the outside (ambient) temperature.

So a turbocharged engine has more power, and feels more responsive, at cooler temperatures. A car will feel (and be) a lot faster on a 35 degree dry day than a 85 degree humid day.

The intercooler helps to cool the incoming charge, but it uses outside air to cool - if it's a warm day, you're using warm air to cool off the incoming charge.

So in a word, yes, the car will feel slower when it gets warmer. In general, you'll notice a dropoff around 50-60 degrees, but it shouldn't be really noticeable until you get up into the 80+ range, or very high humidity. That's because the turbo has the capability to pack a lot of air in.

However, if you're noticing a major performance drop-off with reasonable temperatures, this could be due to problems in the system. For example, any air leak will degrade turbo performance, so the temperature differences will be more noticable. Also, as temperatures increase, the engine is more prone to knock. On the fuel your using the engine may not knock at cool temps, but will trip over into knock when it's warmer, and if the APC kicks in, you'll notice a big performance drop. See if the boost gauge is running lower. Try a tank or two of higher grade (higher octane) fuel and see if that helps.

Routing your A/C around will not help. There are a few laws of thermodynamics that tell you it won't work. Two really big reasons: First, the A/C can't provide enough air flow to make much of a difference, and second, the drag of an A/C compressor is MUCH higher than any extra power gained.


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!