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]
[Main C900 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: Pumps
Posted by Sjer (more from Sjer) on Sun, 3 Feb 2002 13:25:00
In Reply to: May be too fanatic?, Cedar White, Sat, 2 Feb 2002 22:17:37
Members do not see ads below this line. - Help Keep This Site Online - Signup
I spec pumps used in industrial process applications as part of my job. Higher viscosities reduce the pump flow because of higher pressure drop in the coolant passages. (If you look at a centrifugal pump curve, you will see the flowrate drops as the backpressure on the pump increases.) As you point out, not really a concern at start-up, except that it makes the engine harder to start. The components of the pump (impeller, shaft, bearings, etc.) can handle any reasonable viscosity that may be seen w/ coolant. The pump life is more influenced by overly high operating temperature.
One of the reasons for keeping the ethylene glycol down to 50% is viscosity, but not for the reason you might think. Heat transfer rate goes way down as ethylene glycol fraction is increased, because of the higher viscosity and lower thermal conductivity of ethylene glycol vs water. Also the water pump delivers higher flow when a higher percent of water is present as I mentioned earlier. So for all these reasons a 50/50 mixture provides better cooling than 70/30 mixture. Also, higher amounts of ethylene glycol make coolant mixtures more prone to leaking through seals.
Viscosity is critical in lubricants because the pumped oil provides the lubrication. Viscosities outside the desired range result in poor lubrication, especially on the high side.
Hope this is of interest, I did not mean to be overly critical.
posted by 208.58.24...
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.
StateOfNine.com
![](/tsn/xyz/stateofninebutton.gif) |
SaabClub.com
![](/tsn/xyz/scnabutton.gif) |
Jak Stoll Performance
![](/tsn/xyz/jakstollbutton.gif) |
M Car Covers
![](/tsn/xyz/mcarcoversbutton.gif) |
Ad Available
![](/tsn/xyz/buttonavailable.gif) |
![](/tsn/images/tsnmap.gif)
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!