924Board.org

crazyporsche · Posted: Tue Mar 04, 2003 1:35 am Post subject: Water or water alcohol injection

I have searched but have not found anything in past listings.

Has anyone considered using a water or water/alcohol injection system on a 931 for cooling and horespower gain. It seem to be a cost effective alternative to intercooling, especially if you build your own system.

I am lookng to increase power output without destroying my engine.

I am new to this game, so any help would be appreciated.

Thanks

Dave

AznDrgn · Posted: Tue Mar 04, 2003 2:25 am Post subject:

I believe smoothie has done it, if you flip through the album on this page there should be some pics of it.

http://photos.msn.com/viewing/album.aspx?m7A!X9U3q6bynoZEhFj0U*w9oI3gIv7Tm9a1IOuoiC61N*n2nImicgyFBfQTSKjLgfRZ7iLfiCV*DlbHox2jfC0*luXwqTUQwT*6rg7Vvo0PEga3m!zGSw$$
_________________
-'87 Jeep Cherokee 4.0L 6" of lift 33" Super Swampers

-'83 Callaway 944 2.5L turbo, 300HP, 1 of 42 ever made

Lizard · Posted: Tue Mar 04, 2003 2:29 am Post subject:

If I remember correctly BHO had alcohol injection, but I haven't seen him around for awhile
_________________
3 928s,

crazyporsche · Posted: Tue Mar 04, 2003 5:03 am Post subject:

Hey guys

Not sure who smoothie is, but his site is cool. Seems to be a tinkerer, low cost, do-it-your-self-er, and with this car that is the way to be. However, the system I am thinking of is a bit f more sofisticated.

Water injection prior to the turbo seems to be risky, doing damage to the turbo. The system I am considering is 2 stage, after the turbo. 1st stage injects W/A at 4-6 psi boost and then again at 10-12 psi boost. Pressure is somewhat high, 75-100 psi for good atomiztion, and has pressure valves, qualtity pump, and shut of solenoids.

My bigest concerns are damange to the engine.

My research shows cooling equal to intercooler, with easier and less costly installation ($200-300).

I will most likely install a manual boost controller (simple yet effective). Not sure if I will purchase or build my self. The combination seems to have potential.

Comments from anyone appreciated.

Thanks (and this is a cool site(.

Dave Paskarnis
dave.pasakarnis@zelana.com

81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

A water injection vs. Intercooler is not really an apples to apples comparison. The water injection is nowhere near as efficient. Also it limits the amount of usable air/fuel in the engine because the water vapors (non compressible) take up that space meaning less air/fuel, which equals less power. A water injection is not a replacement for an intercooler. It is meant to suppress detonation not cool the charge temperature.

AznDrgn · Posted: Tue Mar 04, 2003 11:31 am Post subject:

so idealy you'd want to intercool and then add water injection if your still detonating? is there a formula or rule of thumb to use so you know when to inject water or alcohol and how much to inject? how would you work this in if you had an adjustable ignition where you could retard timing with respect to boost pressure?
_________________
-'87 Jeep Cherokee 4.0L 6" of lift 33" Super Swampers

-'83 Callaway 944 2.5L turbo, 300HP, 1 of 42 ever made

Richard · Joined: 04 Nov 2002 Posts: 617 Location: Pacific N.W.

My first question is how do you plan to increase power. If it's by boost alone, then in part you problem is solved by automatic ignition retard with boost. You may not need water injection. If you had or could buy an ignition with knock sensing you would be on easy street. Water injection is really only used when other options have been used up and you still need more hp and have to much boost, or compression ratio, or lousy gas. My approach is to define a horsepower number you want to achieve and then design to that goal. Don't go trying to grab as much power as you can and decide what's enough after something breaks. Also remember that advancing the timing to get power is just a band-aid for an inefficient combustion process.

AznDrgn · Posted: Wed Mar 05, 2003 2:31 pm Post subject:

I personally am going to go with an NA engine and add a turbo and EFI. The ideal system I'm trying to build will have ~200HP, don't know what the realistic number would be though. EFI, 8.5:1 compression, and 15 psi boost. oh and I intend to achieve EFI through the use of a haltech engine management system or some other similar product.
_________________
-'87 Jeep Cherokee 4.0L 6" of lift 33" Super Swampers

-'83 Callaway 944 2.5L turbo, 300HP, 1 of 42 ever made

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

Water injection alwsy sounded good to me until I saw a bloke run his water out and blow his very expensive new engine to bits!

It is great technology but it is also a risk and unless your car is used only on the strip or perhaps the odd track day then I wouldn't say it was a good idea to set the car up needing water or alc injection.

Cheers
Simon
_________________
Blown is always best!