Intercooler misting vs water injection - SaabCentral Forums
*
Home Saab Pictures Saab Classifieds Saab Dealer Listings Saab Forum Saab Forum


Go Back   SaabCentral Forums > Saab C900, 1979-1993 & '94 Convertible (C=classic) > C900 Performance, Mods & Tuning

C900 Performance, Mods & Tuning Covers Tuning & Performance modifications for the Classic 900 (C900)

SaabCentral.com is the premier Saab All Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools Display Modes
  #1  
Old 2nd August 2005
Si's Avatar
Si Si is offline
Saab on the Brain!
 
Join Date: Jan 2003                                                
Location: 5225′34″N 00152′19″W
My Saabs: Sensonic NG900T, a gagle of rusty c900's
Posts: 5,975
Default Intercooler misting vs water injection

As Mr PDA is in the process of sorting out his misting kit I thought rather than diverting his post I'd start a new one.

So what are the pro's and cons of Water Injection/Intercooler misting?

Is one a better option than the other?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 2nd August 2005
DrSquirley's Avatar
DrSquirley DrSquirley is offline
Saab Crazy
 
Join Date: Dec 2003                                                
Location: Gorham,Maine, US/potsdam,ny
My Saabs: '89 900S 3dr | '90 900S 4dr
Posts: 528
Default

Intercooler misting is a less efficent means to cool the charge, but it also comes with less risk as you dont have to worry about flooding the engine with too much water.

-Alex

Rally cars use water inj, and generally not intercooler misting.
Reply With Quote Quick reply to this message
  #3  
Old 2nd August 2005
shaverjeff shaverjeff is offline
Saab Crazy
 
Join Date: Apr 2005                                                
Location: florida
My Saabs: 1994 saab 900 turbo vert
Posts: 948
Default

i am familiar with how the misting works but can you tell me in detail how the water injection works? where is it injected?
Reply With Quote Quick reply to this message
 
  #4  
Old 3rd August 2005
Si's Avatar
Si Si is offline
Saab on the Brain!
 
Join Date: Jan 2003                                                
Location: 5225′34″N 00152′19″W
My Saabs: Sensonic NG900T, a gagle of rusty c900's
Posts: 5,975
Default water injection

Water injectors inject misted/atomized water into the inlet, the water then absorbes some of the latent heat in the charged air and allows it to compress more therefore you get more O2 to burn. Also presence of the water vapour helps the fuel mix more evenly and also reduces pinking or knock as it stabilizes the combustion process.

I think the earlier turbo cars used water injection to sustain higher levels of boost without reducing the compression ratio or risking damaging the engine, the Auz 900 Enduro ran at 17psi with permenant water injection(the system was always active, injecting under boost).
Reply With Quote Quick reply to this message
  #5  
Old 3rd August 2005
pda's Avatar
pda pda is offline
Saab Lunatic
 
Join Date: May 2003                                                
Location: ipswich suffolk england
My Saabs: T8, FMIC,173bhp & 228ft lb
Posts: 1,782
Default

IIRC the early 99T/900T rally cars ran W.I. but they ran crazy boost.. BHP & ft/lb figures

I have read somewhere their W.I. tanks were "BIGGER" than their petrol tanks

HTH Paul

____________________________________________
Sleeper baby, no show & all GO.............................
__________________
Paul
Reply With Quote Quick reply to this message
  #6  
Old 3rd August 2005
Tomarse's Avatar
Tomarse Tomarse is offline
Saab on the Brain!
 
Join Date: Sep 2003                                                
Location: crewe UK
My Saabs: LPG '80 99GL, '80 99T 2dr, LPG '93 ng900
Posts: 5,677
Default

This is how the saab water injection works

You may have to just look at the pictures in places as its not all in english! (the main diagram and the testing section are though)
Reply With Quote Quick reply to this message
  #7  
Old 3rd August 2005
Si's Avatar
Si Si is offline
Saab on the Brain!
 
Join Date: Jan 2003                                                
Location: 5225′34″N 00152′19″W
My Saabs: Sensonic NG900T, a gagle of rusty c900's
Posts: 5,975
Default water injector

Will this work?

Use a fuel pump to supply the water & a 8v injector, then the overpressure switch to switch on & off.

As the injectors only open @ 4 bar it will only run with water in the system, the fuel pump should be able to get the pressure up.

Will i knacker the fuel pump running water through it? I was going to take the one off my parts car.
Reply With Quote Quick reply to this message
  #8  
Old 3rd August 2005
Tomarse's Avatar
Tomarse Tomarse is offline
Saab on the Brain!
 
Join Date: Sep 2003                                                
Location: crewe UK
My Saabs: LPG '80 99GL, '80 99T 2dr, LPG '93 ng900
Posts: 5,677
Default

I think you might have trouble running water through the fuel pump. They have enough trouble with fuel! (Took me 4 tries to get one running on the 99T!). I'd keep the one you have as a spare if i were you!

You really dont need to work with that much pressure for water injection. The saab system in that PDF is really simple - its basically just a glorified window squirter that it injects with! (it is just a washer pump and reservoir too!).

I would be tempted to invest in some of the aquamist stuff (basically a pump and an injector), and rig up all the triggering stuff myself. Or find an existing water pump out of another car that can do the required pressures and flows and then use a proper nozzle.

On yours you would need to inject as close to the throttle houseing as possible, and getting a good mist would be important. Mine goes in pre-turbo and the turbo mists the water up nicely.

Last edited by Tomarse; 3rd August 2005 at 05:53 AM.
Reply With Quote Quick reply to this message
  #9  
Old 3rd August 2005
DrSquirley's Avatar
DrSquirley DrSquirley is offline
Saab Crazy
 
Join Date: Dec 2003                                                
Location: Gorham,Maine, US/potsdam,ny
My Saabs: '89 900S 3dr | '90 900S 4dr
Posts: 528
Default

Water injection is partially what allows the rally prepared wrx's run 4 bar of boost with a 10:1 or higher compression ratio. Interestingly the way everything is tuned, they have a problem with detonation very low in the rpms as i understand it.

-Alex
Reply With Quote Quick reply to this message
  #10  
Old 3rd August 2005
Basre Basre is offline
Banned
 
Join Date: Nov 2004                                                
Location: canada
Posts: 637
Default

Aquamist sells a V good Water injection system.. it works as advertised :-)
go to their site and read for yourselves.
Reply With Quote Quick reply to this message
  #11  
Old 4th August 2005
Si's Avatar
Si Si is offline
Saab on the Brain!
 
Join Date: Jan 2003                                                
Location: 5225′34″N 00152′19″W
My Saabs: Sensonic NG900T, a gagle of rusty c900's
Posts: 5,975
Default Aquamist

I've seen there products before, just a bit expensive for me at the moment, probably not completely nessesary for my requirements, would be overkill.

It's more interesting to figure out how to do it yourself, if it was just about how much you've got to spend half of the postings on this site would'nt excist.

I've also modified my APC unit so that it runs on 2 settings, normal and modded, i'm going to add the water injector circuit into that so i can either run normal boost/rise rate or high boost and water injection.

Last edited by Si; 4th August 2005 at 06:34 AM.
Reply With Quote Quick reply to this message
  #12  
Old 7th August 2005
uberfast's Avatar
uberfast uberfast is offline
Saab Crazy
 
Join Date: Sep 2003                                                
Location: Salt Lake City, Utah, USA
My Saabs: 1986 Saab 900 16v Turbo
Posts: 510
Default

Quote:
Originally Posted by pda
I have read somewhere their W.I. tanks were "BIGGER" than their petrol tanks
well water is a lot heavier than gas, so wouldn't the extra weight hinder a "race car?"
Reply With Quote Quick reply to this message
  #13  
Old 7th August 2005
Si's Avatar
Si Si is offline
Saab on the Brain!
 
Join Date: Jan 2003                                                
Location: 5225′34″N 00152′19″W
My Saabs: Sensonic NG900T, a gagle of rusty c900's
Posts: 5,975
Default weight vs performance

I think being able to run at 17psi of boost or higher with permenant water injection would make up for the extra kilo per litre of water your carrying
Reply With Quote Quick reply to this message
  #14  
Old 24th January 2011
Casey Casey is offline
Junior Member
 
Join Date: Jan 2011                                                
Location: Seattle, WA
My Saabs: 1990 Saab 900 Turbo
Posts: 15
Default

I would love to know where some of you c900 guys mounted your injectors. It seems like as close to the intercooler as possible on that metal intake pipe would be a logical place?
Reply With Quote Quick reply to this message
  #15  
Old 25th January 2011
Squaab99t's Avatar
Squaab99t Squaab99t is offline
Saab Lunatic
 
Join Date: Jul 2005                                                
Location: Shoreline Wa USA
My Saabs: '89 900t 4dr'78 99t'78EMS'11 9-3 Turbo4
Posts: 1,237
Default

Quote:
Originally Posted by Casey View Post
I would love to know where some of you c900 guys mounted your injectors. It seems like as close to the intercooler as possible on that metal intake pipe would be a logical place?
I have a FMIC and Water/ Meth injection. I placed my nozzles just after the intercooler exit. This allows the intercooler the greatest delta T (temperature) between the force induction air and the ambient air, making the best use of the intercooler. Atomizing the water/meth in the tubing allows the media to absorb the most latent heat with the runner length (longest time possible).
http://www.saabcentral.com/forums/sh...=ecu+injection.

I have seen nozzles placed in each runner of an intake manifold. Although sexy, I believe it does not make the best use of the heat absorption. It also creates a siphoning due to the engine vacuum depleting the fluid in the tubes from the nozzle to the pump or check valve.
Reply With Quote Quick reply to this message
  #16  
Old 25th January 2011
Casey Casey is offline
Junior Member
 
Join Date: Jan 2011                                                
Location: Seattle, WA
My Saabs: 1990 Saab 900 Turbo
Posts: 15
Default

Your build is amazing! I would love to know what capacity you found the windshield wiper reservoir to be. I can't seem to find the info anywhere.

Also, I was planning on adding water injection without replacing the stock intercooler. Will the stock one be alright to use for small to medium gains (~1bar total, I am mostly looking to have a super reliable build and try not to kill the tranny)? Because of this, the farthest back I could mount the nozzle would be the metal intake pipe directly upstream of throttle body. I figure this gives me between 8-12 in of room for the mixture to vaporize but what do you think? Another option I suppose would be to mount in the plastic literally on the intercooler but i feel that the rubber elbow connection could cause me problems.

Your downpipe looks great, and I was wondering, what kind of battery you are using? I will be using this car for a daily driver sometimes in cold conditions. I have heard really mixed things about lightweight battery's under these circumstances.

(I'm really sorry if this is somebody's pic, no intention of copy write or anything)

Sorry for all the questions but you seem to know a lot about what your doing. This was my first car but was taken from me at a young age (mom stole it when I went to college). I should be getting it back this summer though and I couldn't be happier!

Last edited by Casey; 25th January 2011 at 02:17 AM.
Reply With Quote Quick reply to this message
  #17  
Old 25th January 2011
Squaab99t's Avatar
Squaab99t Squaab99t is offline
Saab Lunatic
 
Join Date: Jul 2005                                                
Location: Shoreline Wa USA
My Saabs: '89 900t 4dr'78 99t'78EMS'11 9-3 Turbo4
Posts: 1,237
Default

Quote:
Originally Posted by Casey View Post
Your build is amazing! I would love to know what capacity you found the windshield wiper reservoir to be. I can't seem to find the info anywhere.

Also, I was planning on adding water injection without replacing the stock intercooler. Will the stock one be alright to use for small to medium gains (~1bar total, I am mostly looking to have a super reliable build and try not to kill the tranny)? Because of this, the farthest back I could mount the nozzle would be the metal intake pipe directly upstream of throttle body. I figure this gives me between 8-12 in of room for the mixture to vaporize but what do you think? Another option I suppose would be to mount in the plastic literally on the intercooler but i feel that the rubber elbow connection could cause me problems.

Your downpipe looks great, and I was wondering, what kind of battery you are using? I will be using this car for a daily driver sometimes in cold conditions. I have heard really mixed things about lightweight battery's under these circumstances.

(I'm really sorry if this is somebody's pic, no intention of copy write or anything)

Sorry for all the questions but you seem to know a lot about what your doing. This was my first car but was taken from me at a young age (mom stole it when I went to college). I should be getting it back this summer though and I couldn't be happier!
Thanks, it is my project car, so usually doing something to it to keep my mind busy and out of the bars.
Capacity of the reservoir: I have a 2 stage manual boost controller .75 and 1 bar, and the pump only kicks on when the manifold pressure is above .80 bar, and it is flow is metered relative to the fuel flow, so the end result the water meth mixture last a pretty long time unless I'm really on it at a track day or dyno tuning. I run a 50-50 mixture by mass of water and Meth. I bought a 5 gal can of Methanol 2 years ago and it is about 1/2 gone.

There are mixed reviews of Water/Meth injection but in my opinion go for it. Adds a bit of safety margin and power because methanol is a fuel. We proved that on the dyno.

Your location looks good. I think anywhere along that pipe is fine. My first water/meth injection was on a 1978 99t and I placed the nozzle just in front of the second rubber coupling. It was the cast pipe, so all you did was tap the wall. if you have the newer mandrel thin wall you will have to add a bung. You don't want to put a jam nut on the inside and risk it coming loose.




Battery: I tried an experiment with a Braile style battery. 15 lbs 275 cca nice and small. Used it for about 2 years. Depleated charge if you did not start it weekly. It turned over fine in normal weather, but did not really trust it in cold weather.
Recently switch to an Odyssey 925. a bit heavier 26 lbs, but still compact. Plenty of power 925 cca for the first 5 seconds. 600 something after...


Your mom is smart for "stealing" a 900c from you. She has great taste in cars.
Reply With Quote Quick reply to this message
  #18  
Old 27th January 2011
lancer lancer is offline
SaabNut!
 
Join Date: Jan 2009                                                
Location: Kansas, USA
My Saabs: 1988 900T convertible
Posts: 317
Default

Water injection does not need to be complicated or costly. I built mine for under $200. You can get most everything you need at a farm supply store. Your pump needs to run around 100psi. Much above that and the water goes in at too fine of a mist. I also found out that if you install the water injector nozzle as close to the throttle valve as possible you will get a little better result. I mix my own fluid with a 50-50 mix of distilled water and alcohol.
Not only does the water cool the incoming air charge but it also adds mass to the airflow making it more dense. The alcohol adds a few points to the octane rating.
Basicly water injection makes it winter all year around.
You need to make sure you tune the system to your car. If you add too much water the car will bog down. Also make sure that you have your fuel ratios correct. Water will take care of a lot of problems but it is not a substitue for correct fuel ratios.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the SaabCentral Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:18 AM.



Powered by vBulletin® Copyright ©2000 - 2017, vBulletin Solutions, Inc.

top of page | sitemap | email us



copyright © 2003 - 2011 saabcentral.com, All rights reserved http://www.whiter.co.uk - valid xhtml - valid css
SaabCentral is an independently run website and is not affiliated in any way to Saab Automobile AB.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
 

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.