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    Default Water Injection Info. Read up.

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    Quote Originally Posted by luni
    This was posted by a guy on the MR2 board who works with Aquamist Water Injection. Good info

    In brief: Water injection cools the intake charge through the latent heat absorption of water in the evaporation process. Same principal as patio misters. The water vapor absorbs the heat in the intake charge and cools it down. I have seen 30-40 degree Celsius drops on my Power FC monitoring intake temps after the huge air/air intercooler has already done its job.

    Since we know the engine is a giant air pump, and the amount of power it is capable of producing is direction proportional to he volume of cool dense air it is able to ingest, the technology behind water injection makes perfect sense. Think of it this way -- everyone is concerned about air volume:

    "How big of a turbo should I run for my power goals?”
    "How about my intake, can that be bigger? ”
    "Can I run a bigger throttle body”
    "Is the AFM restrictive? ”
    "Is the TVIS restrictive? ”
    "Will a brand X free flowing exhaust or downpipe help me move more air? ”
    "What about a custom exhaust manifold? ”
    "What about higher lift/duration cam profiles? ”

    These concerns each address the volume of air an engine can take in and how efficiently it can push it out again. They all, of course, come to play in determining an engine's power potential.

    Equally important, and often overlooked, however is how cool and dense that intake charge is.

    Its simple physics, really -- engines like a lot of air [volume], but they like a lot of cool, dense, air even better [volume + temperature].

    Water injection systems like Aquamist displace a small amount of air volume from the combustion process by replacing it with water vapor. So wait, it is actually reducing air volume, right?

    Yes. But that tiny reduction in air volume is made up for in the second half of the equation dealing with the temperature. A cool dense intake charge provides for better combustion than a hot one.

    Want to address detonation? Look no further than the source of the heat that is brining it on.

    OK, we all know our cars can make a whole lot of power with little more than a manual boost controller [“MBC”], fuel cut defenser [“FCD”], and a bigger turbo [“Big Ass Turbo”]. Small investment = big power. For a while.

    What happens, however, is that as you crank up the boost, the turbo is now compressing and heating the air at a much greater rate as it reaches its efficiency limits. This doesn't necessarily happen at 20+ psi. It happens at as little as 16-17 psi.

    Suddenly, the timing maps that Toyota designed into our cars anticipating stock boost levels (plus a certain margin of safety for people living at higher altitudes, those who fail to keep their ignition components in good shape, and/or those running lower than the required fuel octane) are out the window. Likewise, the intercooler, which was designed to cool the intake charge within certain parameters, can no longer effectively cool the much hotter charge coming out of the turbo.

    That's right. A little turn on the boost controller knob, or switching to a bigger turbo, and Toyota's ECU tuning for ignition (and to a lesser extent, fuel) becomes far too aggressive. The little stock IC struggles to keep up and, before you know it, bye-bye engine.

    And this is not just happening to the crazy monster horsepower guys -- this is happening to guys making less than 300 hp at the flywheel.

    OK, so the obvious solution is bigger turbo (compresses air less = more efficient, even of the trade off is more lag), bigger injectors to fuel the bigger turbo, and ITC/AFC [ignition timing controller and air/fuel controller] piggybacks or a standalone ECU to remap the ignition and fuel curves, and finally a bigger IC to cool it all down. Lots of $$$$ spent, and then, on hot day, after sitting in bumper to bumper traffic or a after couple of hard boost runs against that Mustang in the next lane and...

    the IC heatsoaks...

    and Houston, we have a problem...

    So does this mean that those guys running 116 octane race gas need to start jumping up and down exclaiming that this is all a bunch of BS and that water injection is not needed if you're running the "good stuff"?

    Of course not.

    But for those of us unable to afford $5 a gallon for race gas, water is free.

    Plus, even on the "good stuff" take the same car on a road course, and run it on sustained boost for a few hours (yes, hours) on end and report back with whether the good stuff was good enough.

    Water injection is not just used to run more boost. In fact, most of the extra power I found on my car (40 rwhp) was
    attributable to being able to get away with running more aggressive timing and fueling curves than I ever could have otherwise. I never touched the boost controller. Oh, and this power difference was made going one octane point down from 92 octane to 91 -- thanks California oil refineries!

    At a recent track day at Thunderhill Raceway (local road course), my IC pipe to the throttle body was cool enough to hold with my bare hand, (nice parlor trick to make jaws drop) even after driving the car at 18.8 psi for 10 consecutive laps at 3 miles each. In fact, my poor overworked turbo seems to have suffered some heat related stress on the shaft from working so hard, yet my stock engine was doing just fine.

    How many MR2 owners do you know that are able to cook their turbos before they cook their motors?
     ...to the topTop

  2. #2
    Ultimo Miembro Fantástico Gigantesco ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD has much to be proud of ChrisD's Avatar
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    ...

    Quote Originally Posted by luni
    go to www.aquamist.co/uk to find out more info and availability.

    Or send an email to info@boostedgroup.com and DavidV from the MR2 board will help you out.
    Quote Originally Posted by conrad_turbo
    aquamist is a good add on device to a completed car, not to be used as a bandaid. i am a fan of aquamist (might be a distributor in a few months) but it shouldn't ever be used to fix problems that are occuring.

    but a long story short. when water evaporates the water vapor increases a little but the air temperature decreases a lot. this is due to the enthalpy of water.
    Quote Originally Posted by luni
    It depends Conrad. You alltrac guys heatsoak too. Instead of spending a shitload of money on a new intercooler, get an aquamist system. Install it after the intercooler. Make the intercooler more effective by in essence upgrading its effectiveness. Id rather spend 500 bux on water injection than spend 1000 on a Greddy Intercooler for my MR2 and only gain a couple percent thermal effeciency. Whereas the aquamist will make a night and day difference. I would love to be able to stick my hand on my intake pipe after a track run. That shit speaks for itself.
    Quote Originally Posted by conrad_turbo
    i plan on getting a semi intercooler, they can flow A LOT of air at a VERY low pressure drop. thats what i plan on doing when i do my fmic setup. for your setup it'd be best for a water/air setup. but ya its nice to have water injection handy but not something to rely on. b/c if you run out of water and your car has a hard time running b/c of heat soak then thoes problems should have been fixed before the water injection was put on. so basically have everything well sorted out so the car runs awsome, then add the water ijection to sweeten the deal.

    but getting water injection instead of a fmic is the same thing as nitrous vs a turbo. turbo kits sell and so does nitrous. i'd rather go with the turbo kit even though it costs more. but it'd always be nice to have a bit of nitrous when you need it. haha.
    Quote Originally Posted by luni
    Yeah but if your competant, you should never run out of water. A water cell full of water should last every 2 tanks of gas or so. If youre too lazy to refill your water, then youre a moron.
    Quote Originally Posted by NuclearHappineS
    water injection is possible for NA cars too ...

    as with boosted applications, the water cools the charge making for a denser mixture. Although the water does replace some of the air coming in, the advantage -cooling effect- in a well tuned setup will cancel out the disadvantage -replacing some of your air with water. This now leaves you at 0 gains but has potential for more power. Now that the air is cooler you are less likely to knock the engine to death and have room for more agressive compression and more agressive timing maps, as well as a leaner A/F ratio since you can use the water for cooling instead of running the car extra rich...

    works on NA race cars (think 13:1 CR and the likes) but not good for an all motor daily driver... i think you'd run out of water too quick since your static compression ratio is so high ...

    Nuke
    Quote Originally Posted by Conrad_turbo
    also to add, not all the water evaporates in the intake tract. some of the vapor will go into the combustion chamber, this water vapor slows the combustion process, thus mimicking high octane fuel. so this enables a higher knock point which means an engine can have more aggressive timing and make a bit more power that way along with the cooler denser air.
     ...to the topTop

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