Would Water Injection be of any benefit running 10psi boost

[macka'sxr6t]

Hi guys I'm new to this forum and have already found some useful info.
I live in Australia and have bought a my first turbo car. its a Ford Xr6turbo. 4.0lt DOHC VCT The Turbo used on this car is good for 600hp.

Standard from manufacture it produces 240kw at the flywheel. I have since made some modifications that have brough this figure up to 300 Kw approx 240 rwkw.
running 10psi boost. on 95ROn Octane Australian

My question is would water injection be of any benefit to me running this amount of boost or would it be better to go for a bigger IC. Factory IC is at it's or very close to flow limit.

I would eventually like to run 17 psi or higher.

[hotrod]

My personal opinion is that a WI system is probably much more cost effective than an upgraded intercooler. Not that familiar with your car, (ie compression ratio etc) but WI systems start in the $300 USD range for home built or simple manufactured systems, the expensive mapable systems cost about what I'd expect a new intercooler would run.

It also depends a bit on your tolerance for the continuing maint issue of keeping the WI reservoir full, how you use the car, and what sort of performance driving you like. If you want to spend a good amount of time on a track then the upgraded IC makes some sense. If your only making occasional sprints on the street, and want the option to run a cheaper lower octane fuel on occasion, I would lean toward the WI systems.

Given your climate in that part of the world is generally much hotter than it is here in the states, I would think you'd get great benefit from WI as its effeciency goes up with higher operating temperatures. WI really shines in high temp, low humidity environments.

The other unknown of course is how easy / difficult it will be for you to get clean mineral free water (preferably distilled). If your in a rural, near desert area, and drawing well water, You may have no easy access to a way to remove any mineral content. That changes the equation slightly as you would have more of an issue keeping your nozzles from plugging with mineral deposits. If you live in a metro area then clean water is easy to find. I know here in the U.S. desert south west, there are some small communities that demineralized water is a pretty scarce resource.

my 2 c
Larry

[macka'sxr6t]

Thanks Larry,

My car runs a 9:1 compression ratio. The reason why I am interested in WI is because the IC is to small for the capabilities of the engine. It will cost about $1800 Aus to buy and fit a larger one. I would like to run a higher boost setting but the IC is at it's max. Would WI give me power by using the same boost but more aggressive timing and leaner A/F mixture using the same or higher Octane fuel.

Water quality: Rain water from Tanks and reticulated town water, both suitable for human consumption

Neil

[hotrod]

Thats about what I figured on the probable compression ratio.

I would expect the WI to improve your performance for a couple of reasons.

1. It should improve your engines VE because of the cooling that takes place as the spray partially evaporates in the intake manifold.

2. It would increase your effective fuel octane so yes you should be able to use a more agressive tune.

3. WI improves the thermodynamics of the compression and power stroke.
During the compression stroke a portion of the still liquid WI dropplets are evaportated (or at least cool) the air as it is compressed. This reduces the "negative work" the engine has to perform to accomplish the compression stroke -- that is free power that gets passed to the crank shaft.

During the power stroke the presence of the water injectant gives higher average cylinder pressure even though it lowers the peak pressure and EGT.


Your water sounds like its okay, (especially the rain water) if it's collected in a clean container. One measure of water quality, is if you have very little if any mineral build up in cooking pans or water spotting on glass ware, then the water has a relatively low mineral content. If you want to get anal about it, you could set up a small solar still to re-distill your water also.

If you have concerns about mineral blockage of your spray jets, two suggestions. Set up a regular maint. schedule, buy a couple spare jets, and plan to pull the jets and clean them periodically, some vinegar is supposed to do a good job. The other thing you might do is set up the system with two smaller jets instead of a single jet. This way you have more safety as it is relatively unlikely that both jets would block at the same time. If you get a blocked jet you would still have some water flow.

Larry

[macka'sxr6t]

Thanks Larry,

I have made some inquiries about the availability of the aquamist system in Australia.
Which system is the best?

Would I be best to use straight water or a mixture of alcohol and water at current boost levels.

Macka

[janis]

Is boiling tap-water an option? Or doesn't that kill enough minerals?

[hotrod]

I have no first person experience with the aqua mist systems so will leave that recommendation to one of the others that can give you feed back based on their experience.

Water has the most heat absorbing potential on a pound for pound basis, but water alcohol mixes are capable of reaching lower intake air temps due to the very rapid evaporation of the alcohols. Many start with 50/50 water alcohol mixes and then go from there to see what the engine prefers.

With the aquamist you will want to avoid [edit -- error here, corrected I got the two alcohols reversed] --- ethanol and stick with methanol if you can find it easily. Here in this country many of the Buick Grand National owners use mixes of isopropal (rubbing alcohol) with success, but it requires different fuel air mix tuning than the methanol and ethanol for best effect .

Lots of discussion on these two issues already in many of the threads here so digging through some of the other threads will likely answer a lot of your questions.


Boiling in and of itself, will not remove any of the minerals unless you set up a means to condense the steam off in a seperate container.

Larry

[macka'sxr6t]

Larry,

I've only seen the aquamist system advertised on this forum. I have only been a member for 1 day.

Could you advise of other brands that are available.

Thanks Neil

[hotrod]

There are a lot of other vendors a quick "google search" will find them.

Due to forum policies I don't think it is proper for me to list links to other vendors.

Larry

[janis]

Originally Posted by hotrod

With the aquamist you will want to avoid methanol and stick with ethanol if you can find it easily. Here in this country many of the Buick Grand National owners use mixes of isopropal (rubbing alcohol) with success, but it requires different fuel air mix tuning than the methanol and ethanol for best effect .
Larry

Aquamist can NOT cope with more than 5% Ethanol, stick to methanol.

From the aquamist FAQ:

8. ....... Methanol is better than other forms of alcohol and is totally compatible with Aquamist products. Avoid using Ethanol based additives such as De-natured alcohol or Methylated spirit