sly fox

Calling all scooby owners with aquamist fitted!!

I was at elvington this weekend and there was an mr2 turbo the with a aquamist kit fitted. I was talking to the owner and his mechanic and they thought very highly of it.

Has anybody got experiance of this system on a my00 scooby.

Car info, it is just under 300bhp with a mappable ecu and i do trackday/qtr miles very often.

Please can anyone give me any info as to if it is worth while investing in and who can fit the system??

sly

TBMeech

IMO most definetely, I had it on my MY99 STI V for about 6 months, had no problems, it reduces det (not that I had much anyway lol!) but it's also good piece of mind, its relatively easy to install, you can run more ignition timing / advance from adding it as it cools the charge which is another good thing.

I'd deffo have it again this time round.

RRE

What is the price of a system, and which ones to go for?

P20SPD

iTrader: (1)

I have just purchased the system2d from Mark at Lateral Performance, and i will be installing shortly.

The main reason i went for it is the cooling/safety side of things, and to possibly get a bit power out of the car

Forgot to say that this one is the self mapping version that works off injector pulses etc, IIRC.

[Edited by P20SPD - 4/29/2003 10:09:58 AM]

sly fox

can you keep me posted with how you go on with it?

Have you got mark @ laterals number?

sly

TBMeech

RRE,

I believe they start at approx £325ish for the System 1a which isnt mappable but is still a very good starter system.

P20SPD

iTrader: (1)

sly fox, i will do

email m@rk-a.com

sparkster

Does the mist kick in automatically or do you have to fiddle with a switch?

P20SPD

iTrader: (1)

Switch for on and off i believ, then once on, it sprays automatically once boost reaches your preset pressure level.

BruceWarne

What happens if it runs out of water?
Would the car knock itself to pieces?
Or does it give you adequate warning?

P20SPD

iTrader: (1)

You can get a low level sensor that indicates when the tank is running low, thus ensuring you dont run out.

StickyMicky

that mr2 just passed me near the very end of the 1/4 mile, was the only time i was beaten

up at higher speeds that car could kick sum ***

P20SPD

iTrader: (1)

CR4p off the line though

Adam M

if you dont change the map to compensate for the fact that you have water in it, then there is no reason why it shoudl det when the water runs out any more than it would have done before you installed the system.

the cheapest system is just pressure switch activated and is a 1s system.

the new system as staed is the 2d where the water volume is proportional to fuelling, and is combned with a pressure switch so it only activates above a specific boost.

But as stated you can have a low water level light also.

water injection achieves it goal of reducing propensity to det by reducing temperature of cylinder after combustion, not by reducing charge temperature. If this is your goal, it is an inefficient way of doing it and you would be far better off concentrating on intercooler design and using water spray.

By by lowering peak temps by boiling the water droplets, a greater amount of the energy of combustion is used up in converting the water in to steam. this removes energy from the charge without raising the temp of the gases. if the average cylinder temp is lower, then the det threshold should also be lower.

remember, that every molecule of water that goes into the engine takes away space from fuel and oxygen, and so water injection without mapping will cost you power but increase safety.

If you map to compensate, you can gain more power than you lose, but once the water runs out in that situation, you do standa good chance of detting.

Pavlo

So by injecting as close to the inlet as possible these effects will be reduced. Even better is direct injection at very high pressure after or near inlet valve close, no lost inlet charge then.

I think a good compromise would be a nozzle for each cylinder similar to the injector, or even tapped in the head itself, or onto any manifold spacers.

Ultimate aim is to reduce temps just prior to actual ignition, and during ignition for the unburnt charge (ie before the flame front raches it).

Paul

Paul

Adam M

Paul, it is so nice to finally hear someone attempting the same goals from water injection.

I must admit, I thought the cylinder temp was reduced because the water prevent it from getting as hot so that it is cooler for the next combustion event, rather than erlying on the water to remove the heat just before combustion.

Not sure what kind of pressures you are talking about injecting at.

do you mean at tdc? if so maybe some kind of diesel injector would suffice? sicne the pressure is so much higher, I presume it can guarantee that the water will not evaporate until it is injected. By injecting directly into the cylinder you could have finite timing control of exactly when you want to reduce the temp.

Do you thik it would be possible to have a feedback system with a real time accurate temp sensor inside the cylinder, so that you could inject when necessary?

of course you wouldnt be able to map around it though.

David_Wallis

oh dear..

Pavlo

You want ideally for the inlet charge to be cool on the compression cycle, then get as hot as possible during combustion, but not so hot it spontaneously ignites away from the spark or flame front.

You don't want to take heat out of the combustion itself, that's where the power comes from.

Paul

BugEyed

Hmmm

Pardon me for being a touch dense, but does water injection reduce the amount of air available for combustion?

I can understand that if you have the gas at the same temperature and pressure, and part of the gas is water vapour, then it stands to reason that there is less air. But, surely the water injection also cools the gas going into the cylinders, meaning that the resultant gas is at a higher density for a given pressure - the same process as a very efficient intercooler. Or am I just being hopefull?

Duncan

PS Adding water injection to a MY01+ allows the ECU to run some more advance on hot days at full boost.

Pavlo

Yes the water can reduce the amount of air in the charge.

But it is slight, providing it remains as liquid until the inlet cycle is complete (quite likely if close to inlet).

If you inject further upstream, then the reduction in available volume is probably offset by increased density. I did work out one time but can't remeber the difference, so probably veyr slight.


But like I say, if you injected direct into cylinder, you would have the bset of both worldfs

Paul

Adam M

paul your typing is up the spout, are you taking the pss out of me?

I always found that strange. Water injection actually reduces engine efficiency. By removing heat from the charge after combustion it will be costing you power, yet its does suceed in reducing egts.

Pavlo

my typing *was* up the spout, I was talking to someone and hurrying to go make a tea.

Reduced temp at the end of combustion is okay provided you have reduced start temp. If the temp difference is seriously reduced, you will have lost out.

Realistically, you will vapourise all the water during combustion, this takes energy to do.

Paul

5 Type R

I run a dual pump WI system that a mate designed.
Have it controlled and mapped with the Unichip.
Very happy with it. Provided slightly more power when mapped but ultimately their as a safety mod

http://www.imoc.co.uk/users/upload/Water-Injection-Manual.pdf

Nearlythere

Sorry, i have edited this post to remove what appears to be blatant advertising. Should your friend wish to advertise on Scoobynet, then either visit shop.scoobynet.co.uk or contact webmaster@scoobynet.co.uk for more information

Regards

Steven

[Edited by P20SPD - 4/30/2003 7:46:01 PM]

Delboy2

Had Aquamist ERL water injection on my MR2 Turbo. On the rollers changing from a 0.5mm jet to a 0.7mm jet the BHP mildly increased but the torque increased from 293lbft to 323lbft. The car was heavily modified but when sold I removed the water injection kit and may fit to MY96 when I have time. I had it set to cut in at about 7psig on the pressure switch. Overall a good system!!

Deep Singh

I know the question was about AM but should'nt fmic also be discussed.For anything less than mega tuning(where you would need both perhaps) is'nt a fmic a much better way to go? It will provide more consistent and lower charge temps than the WI.It c'ant run out so the car can be mapped for the lower temps(ie more advance) and also it does'nt 'rob' the car of power under some circumstances.
Does cost more though.

Adam M

deep,

you have missed the point.

fmics and WI do different jobs.

A fmic lowers inlet charge temps (pre combustion), to increase density and allow more power by allowing in more oxygen, it will also mean you can run more advance of course, but even if you dont you will get more power if you fuel accordingly.

WI reduces cylinder temps (post combustion) and hence egt to reduce likelihood of det. It can enable you to get more power (but doesnt allow you to add fuel) by allowing more advance before getting to the point of det.

in essence, if you map to compensate for a fmic, you add fuel and retard timing. If you map after WI you add timing and remove some fuel (tiny amount I guess).

john banks

With my FMIC I leaned it out and advanced the ignition slightly for a given airflow. At a guess I think I ended up with the same absolute amount of fuel because there was a denser charge. I think we are saying the same thing but expressing it as absolute vs ratio.

Adam M

john?

I am not a mapper so bear with me, but denser charge = more oxygen molecules per unit volume of air.

more oxygen density would surely require more fuel to maintain lambda voltage.

please explain more clearly why you wouldnt need to add fuel.

RT

Adam, I don't understand the arguement of WI reducing post-combustion temps. Apprec if you can elaborate?

My impression was - Having a water mist in the combustion chamber while the cylinder is on its compression stroke would lead to a smaller rise in charge temperature at the end of the combustion stroke, since much of the heat energy would have been used to vapourise the water mist.

This smaller amout of heat present would hence postpone the onset of det. Plse correct me.

Cheers.