water injection

[Slaabish]

What is the purpose of water injection?

[Keith]

Have a read of this:

http://www.aquamist.co.uk/dc/dc.html

[eric_b]

Trust me, it helps. I recently did a dual-stage aquamist hybrid on my 84 900 turbo. I did not notice much of a power increase, but the boost is much stronger now. In fact, the needle now goes up to the red (with a little apc tweaking) and stays there, no matter how long I keep the boost on. Water injection would certainly be very helpful when running higher boost (I'm only running 1 bar (about 14 psi), I could maybe get more, but my car is 18 next month, so I don't want to push it.

-eric

[MBZ-BMW-SAAB]

Water injection is BIG help and more life for the engine. Since the air that the turbo boosts into the combustion chamber, is so hot, heat spots are sometimes formed, depending on how much boost you are pushing. To eliminate the heat spots, water injection works perfect. Especially if you are modifying boost pressure, and live in this hot climate, like Phoenix, AZ. Aquamist is a manufacturer who has water injection kits. Personally I believe their kits are expensive, and you can build the same thing yourself for a lot less greens.

[Matthew]

IMHO it's not worth doing water injection on the cheap. If you're running high boost, the water kit becomes a critical safety component. If it fails at high boost and engine speeds, engine damage can occur. Just my humble 2p.

[MBZ-BMW-SAAB]

"CHEAP" not necessarily meaning inexpensive. What I meant, is that the AQUAMIST kit, is not worth the money. Their pump is quiet small, and rather fragile. Then also, all depending on how HOT your hot spots are getting, and how much boost is being inducted. Most of the supplies that come in the Aquamist kit, can be bought at a local hardware store, for a lot less greens.

[tandino]

Afaic the Aquamist kit is built specifically for the job and as for the pump being fragile - what a load of rubbish :! - ive been using my Aquamist for 8 months now (as many others on this site who got theirs at the same time have too) and it hasnt missed a beat.
The reason why the pumps can burn out is if the supply water runs out - the water lubricates the pump,
A simple float level switch in the water tank will cut power to the water injection system and prevent failure.
As for it being expensive - i dont believe it is - i paid around $300 for my kit - i suppose it depends on wether you want a proven kit for your car or wether you want to cobble together a system using other parts and save $100 - i know what i want - a kit thats designed specifically for the job and a pump that is designed to provide a decent amount of presssure to atomise the water effectively.
I guess as always its your choice but please dont call the Aqaumist kits inferior...............

Pete.

[MBZ-BMW-SAAB]

Cobble together a systemI don`t see much difference, in a 5 mm hose through which water will flow, regardless if aquamist sells it, or if it`s from your local hardware store. There are better pumps out there that for less money.

[tandino]

Well as you seem to know alot about a better system for less money perhaps you'd like to advise us where we can get a better pump and what youve personally used to integrate this into a more effective system than the Aquamist kit - of course thats proven to out perform and thats cheaper than the Aquamist kit too.......
Over to you..............

Pete.

[aeroman]

Just bought my aquamist water injection, I should receive this week. Personally I bought the first basic system. have a look at this link : this man did a home made a water injection:
http://hometown.aol.com/taylorafdmb/water.html

you can notice that a major part of the components are from aquamist, price according to the owner is 220$

[Eric van Spelde]

I don`t see much difference, in a 5 mm hose through which water will flow, regardless if aquamist sells it
Now there's your first problem - correct atomization of the water into tiny droplets is vital for efficient and safe water injection operation. It requires a water injection nozzle that was designed for the purpose, and a correct water pressure level for the design of said nozzle. About the first point - don't kid yourself into thinking you can come up with something better than the Aquamist water jet for the twelve quid it costs. I certainly would not want to risk hydrolocking my engine to save a single digit amount of £.
On the second point - now there's some scope for discussion. Personally, I am using a set up corresponding with the Escort Cossie system (Ford was the single biggest customer for Aquamist water injection jets, but they weren't prepared to pay more than £15 for the pump...): two high pressure windshield/headlamp washer pumps in series. Eventually they'll burn out as did a fair number of Escort Cossie pump, but given my limited mileage with this car and the fact that the water injection only comes up close to max boost getting the £300ish Aquamist pump would only start to make economic sense after 100 years or so. I wouldn't bother with my set up if I were relying more heavily on my water injection system, tho'. The Shurflo pump is a big, heavy mutha (2 kgs) - frankly it's too big for my application IMO. For big displacement engines it might be the only way to go.

Swirches solenoids - yes, there is other stuff out there (I'm using a Dawes Devices pressure switch which is well-priced an user friendly) but you're not likely to save a lot over the corresponding Aquamist products here.

[tandino]

Amen Eric and well said :! .....
In my mind the Aquamist kit is the best kit for the job - it may be expensive but the pump and the rest of the system is the designed for the job in hand and the cost of the system has to offset the development costs that Aquamist sink into producing/designing/testing each component of the system,
Small doesnt neccesarily mean in-effective either - as Eric has mentioned lots of people have used the Shurflo pump but personally i dont particularly like the look of a huge pump bolted up in the engine compartment, - the aquamist pump's size makes it easy to tuck it away somewhere (under the headlight in my application) out of sight so as to not look intrusive and away from prying eyes.
And as for cost i dont think $300 is much more than the $220 that someone quoted after making there own system up.......

Pete.

[Alex]

The Aquamist pump might be small but it is well constructed and designed for its purpose. It can provide pressure of up to 12bar with virtually zero flow, and doesn't over heat. (Most pumps use the flow through them to aid cooling).

The piping that Aquamist supply is also capable of being used with Methanol, which is capable of rotting a lot of the hose materials available.

Whilst the Saab engine bay may be able to take a large alternative pump there are a lot of cars out there which have much more cramped spaces. A small pump is a must for this.

[MBZ-BMW-SAAB]

Now there's your first problem (apart from the shouting) - correct atomization of the water into tiny droplets is vital for efficient and safe water injection operation.
You guys are so smart. Just because you are *** to make something FUNCTIONAL yourself, you go out there and think you are the big baller, because you just bought yourself and Aquamist kit...

I bought a SHURflo RV automatic demand pump 45psi set, adjustable to 50psi cut out.

Aquamist injector
Aquamist 2 way valve
NAPA Pressure Switch
Bosch Fuel Filter with screen filter element
Bosch Relay
Indicator Lamps - Red & Green
Toggle Switch
Other pressure fittings, and hoses

I secured the water pump with zip ties. This is a heavy duty pump and it can take lots of beating not like expensive *** aquamist pump.
Before the pump I placed bosch filter, removed stock windshield pump and fitted the water line into water filter. I never use windshield washer so I removed it. :P THE BEST PART IS THIS :D I installed two lamps. One to show the system is activated and other when pumps operates. This way I can diagnose the system if any of the jets are pluged or if one of the lines poped off. When water is being injected lamp flashes of on allways the same flashing duration. If in any case light flashed in different speed than I know something is wrong. So far the system did not fail me after two months of driving.
TOTAL COST OF MY PROJECT WAS AROUND $150.00 :-) :-) :-)

[Eric van Spelde]

'Heavy duty'your pump may be - it's still the wrong pump for the job, since 45 psi is ever so slightly more than 3 bar, and the water jet needs a minimum of 3 bar differential pressure in order to operate correctly. Just because it's big doesn't neccesarily mean it's clever... ;)

As for being dumb, I built my water injection system based on the Aquamist jet back in 1997, and my IQ has been confirmed to be in the 95th percentile range on several occasions so I'm doing rather fine on that front thanks very much. ;)

[tandino]

MBZ-BMW-SAAB - if youve designed a system that your happy with then thats fine but dont criticise those who choose Aquamist which supplies enough pressure to overcome the differential - your just making yourself look foolish...
As for your system i would be very sceptical that its atomising correctly at that pressure that the pumps producing(45psi) especially if you run high boost pressure.........
I think we'll agree to disagree there and get back to the topic in hand.
P.S feel free to post pictures of this fantastic set up.

Pete.

[Alex]

Low Pressure Water Injection

Advantages:

Very cheap pumps and nozzles can be used
Good chargecooling effect

Disadvantages:

Erosion damage to compressor
Further damage if compressor looses its balance
Will start to fill the intercooler with water (if fitted)
Pump system needs to be reliable if significant cooling effect is utilised

High Pressure Water injection

Advantages:

Nozzle can be positioned to give either chargecooling, or det supression or combination
No damage to compressor
Nozzle can be positioned after the intercooler
Can be used with an accumulator and allow mapped water injection control
With sufficient water pressure excellent atomisation of the water can be achieved

Disadvantages:

Pumps can be expensive
Pump needs to be reliable (especially if engine is relying on it for det suspression)

[Eric van Spelde]

That sums it up well enough. Thanks Alex for getting this discussion back on track (hopefully). :)

[MBZ-BMW-SAAB]

Very Good.

We all have different opinions, based upon our own experiences. The main thing that all should remember, we are all here at saabcentral, because we all love SAAB.

[Marrk]

Looks like it derailed again.. :roll: :roll:

[kie]

Hi guys not been on for a while and when i do everyones *****ing like summers too hot. :lol:

As we know I smashed my saab right up, No tandino and Daveb the insurers won't give me the car arrrgh, but they did pay out with out trying to rip me off for the mods. Gutted as loads of goodies on there.

Is there another company offering water injection ?

I had my aquyamist pump fail twice once it cause a hole to form in piston one, the second time Mr APC took care of it.

I wasn't happy with Aquamist and don't want to fork out any more money to them.

stay cool
k

[tandino]

Kie,

Iirc - when you fitted the first pump and subsequently ran into problems when your engine (which was running high boost with Aquamist as its only safety factor) you did mnetion that you didnt install it correctly which led to premature failure due to the pump running without water and hence lubrication ( the pumps will run for 3 mins continuous before burning out - quite a long time really at high boost).
Tbh i dont think you can really blame the pump for this first failure can you??,
What happened to the second pump??

Pete.

[MBZ-BMW-SAAB]

Guys I GOT KILLED by a CIVIC and then later on by a CRX. Even though I`m running around 12 pounds of boost.

[Johann F]

MBZ-BMW-SAAB - 12lbs of boost does not require water injection - putting water in at this boost will probably be counter productive.

[87SPGIN]

So in all reality what is a good or ideal boost to be running for the water injection, and doesn't the water injection lower combustion temps to allow for more boost so in that you couldn't run more boost till you install water inj?