Like the title says dose any one make a kit for this the reson i posted this hear is due to the boost guys seem to know there stuf when it comes to H20 alky injection. i am looking for some thing like the old edeljunk setup.

 

Here you go! Snow performance

 

cool any one know how well this model works

 

isn't water injection kinda a bandaid though.
it just seems that water in the combustion would hurt the combustion properties. kinda like dome pistons. not saying it can't help just like dome pistons might make more power but there are better ways to make for more compression them doming the pistons.

I would think you should be able to run more boost or higher compression also then using water injection.

 

you know, someone always says that and for the life of me I never understand it… bandaid for what? It actually does something different in the chamber then fuel does controlling detonation. You can replace the fuel that you would normally add under load to control detonation with water, and get improvements in power output, detonation control and combustion efficiency up to 1.5x the amount of the fuel in weight.

In general, I would agree that adding alcohol to the mixture is a bit of a bandaid, since you’re using a second system to deliver more fuel then what your fuel system is supplying, and in general, with tuning you should be able to deliver all the fuel that you need with your fuel system and get the detonation control properties from the water, but in some cases (when it’s cold) the alcohol is necessary to prevent the water from freezing.

 

how much do domed pistons realy hert performance

 

vs a smaller head and using a flat top or slight dish piston I wouldn't be surprised if a decent enough amount.

 

I won't deny it seems to help. two of the people around here with rx7's are using it on their boosted cars. but I would think there should be a better way to do it then having to rely upon water or alchy injection.

kinda like I said with the domed pistons. sure they work and they improve compression ratio and boost power vs the stock compression ratio but there is a better more efficient way of doing it.

it just seems that with adding water it will take heat away from the combustion proccess which means less pressure. I don't really see it cooling the intake charge that much to make an increase in power to offset the colder combustion. also I would think with the water misting it might slightly disrupt the combustion process as well.
works yes I won't deny it. it does let you push the boundry more. is it the most optimum way I wouldn't think so though. that is why I called it a bandaid of sort.

that and if your getting detonation try addressing the reason why your getting detonation rather then cover it up with water/alky injection if at all possible

 

Without some kind of flame path cut into the dome of the piston it could hurt quite a bit… essentially anything that slows the flame front travel across the cylinder will promote detonation and decrease power output, and putting a big lump in the middle of the combustion chamber is a perfect way to accomplish just that

 

Such as?

Not a correct analogy, I don’t know what water injection is taking away from the process, I do know what domed pistons are taking away

Water injection adds to the BMEP, when the water hits the chamber it vaporizes… ever hear of a steam engine? The heat that the water absorbs is mostly from the actual chamber itself, which would be dissipated to the cooling system, the heat taken from the combustion process is marginal, and even if it wasn’t, it is still used to move the piston down.

look up the latent heat of vaporization and do the math, it’s much more significant as your percentage water goes up, and even at small amounts it’s fairly significant, but the reason to do it is not to cool the intake charge (well, unless you’re using it in the place of an intercooler on compound system).

The problem is that you’re really not understanding what the water is doing. In this case, it’s actually being used to better break up the mixture in the chamber resulting in faster combustion. In most cases the water concentration does not get high enough to risk putting out the flame front until you get to concentrations of 1-1.6x the weight of the fuel used.

so what would you say if you made more power with water injection then by decreasing timing, boost or compression enough to run without it? What about if you made more power on pump gas then even the same combination (timing boost and compression) on race gas?

 

with what you said I might be mistaken

but if you have some more information to give I would be welcome to take it as I'm always willing to learn man.


but you can at least see my point of logic even if it is incorrect at least I hope?


but to at least answer a few of the questions if I can
better way I would think is try to work with the combustion chamber/piston shape to develop a better flame travel that is less prone to detonation and should be more efficient. I know can only go so far though. well ok so that was the only question I Was able to answer only thing I have no is questions of my own cause I'm curious and don't fully understand.

as far as the water creating higher bmep wouldn't that possibly lead to more detonation though because of the higher pressure?

how does the water break up the combustion proccess?


and would water alky injection really add more power then using the same combo on race gas?


most the people I know who are using aren't using it to get more power. they are the guys who have blown their motor too many times (one guy 4 times in a year) or have hung around said guy who has blown his motor too many times and want to play things safe for those times when things happen or when they want to up the boost a little more.

thank you though for the time

 

My car runs on propane and want to build a motor to take addvantage of the high octane of lpg. I have my eye on these pistons http://kb-silvolite.com/claimer.php?...etails&P_id=18 , they do have a flame path. New heads are not in the cards

any comments

 

yea, I see where you’re coming from… ignoring the facts you’re making perfect sense…


shape is one way, but why limit yourself to one way?

Part of what you’re probably getting hung up on seems to be the basic issue that detonation is usually when a second, compeating flame front starts and collides with the main one, usually from the pressure spike after the initial ignition and delay in the chamber. Just about anything that promotes a faster burn will result in better detonation control.

the pressure increase from the water is more of an average increase in pressure, which is relatively marginal compared to the pressure spike after combustion. It’s somewhat similar why under boost you’re able to run higher dynamic compressions and higher cylinder pressures without detonation then you would NA, because the pressure increase does not happen at the same time as the traditional NA spike.

Fuel droplets don’t burn all at once (vapor is nice from an efficiency standpoint at part throttle, but limits ultimate fuel delivery at WOT, so you’re hoping for atomization, not vapor), they only burn on the surface of the droplet. The smaller the droplets the more surface area and the faster the burn. Adding water to the process breaks up the fuel into smaller droplets in the chamber in a few different ways, primarily by breaking up the droplets as the water hits the hot metal in the chamber and vaporizes and some give a reasonable argument as a catalyst to the process.

when setup correctly on an engine that needs it… yes. Add in that it lets you use cheaper gas and less of it you’ve got a win, win win situation. The only real loss is that you now have a more complicated system feeding the engine

 

My $.02: I’d avoid a set of domed pistons at all costs.

What compression are you shooting for? What is the engine you’re messing with?

Heads are out of the question? Not knowing details, snapping up a set of early/mid 80s 305 heads and cleaning them up will be much cheaper then swapping pistons, and get you a point to 2 points compression over a set of stock 350 heads. Milling/angle milling those heads (starting with a 55-58cc 305 chamber) can get you another point or so and you can get more compression and better quench by zero decking the block (assuming it’s out, should be if you’re swapping pistons) or by running a thin headgasket (like the felpro .015” thick, rubber faced steel shim gasket, which should get your quench distance in that same happy place with a stock deck height). The whole deal should be possible for about the same cost as the pistons and raise our compression about the same ammount if not slightly more and do it with a flat top piston.

Another thing to look for would be a set of used, small chamber iron eagles or similar head used. I’ve seen some 48cc chambered heads go for very cheap probably mostly because most people don’t have a good use for something that small.

 

your a smart feller. but it does make sense to me just my brain doesn't want to wrap around it right now. I really need to get some sleep since I'm always up a little too late most the time
once again thank you

 

still looks as though it would disrupt the flame front fairly well.



though I do have a question with flame fronts and domed pistons.
how much of an effect would it have with a through the top spark plug like whats on a lot of DOHC motors?

 

Sorry i should have told you what i had to work with

Anywho i have...
-ported TFS heads that have been milled about .020 to .030 (can't recall) around 62cc i figger
-a corr 4 bolt standered bore 350 (will completly rebuild)
-edelbrock C-26 dual quad intake
-2 impco 425 mixers/carbs
-1-5/8 lt headers/full mandral 3" exhaust
-cam, don't have but most likely go hydro flat tap

i want around 13.5 to 14 to1 cr and have a shift point about 6000 to 6200rpm.

 

You know, I’m stumped on what to tell you

Honestly, the problem is that I’ve never been excited about the TFS 23* heads… quality is OK but the heads are nothing special. I was always really disappointed when they got rid of the twisted wedge heads which flowed much better.

What kind of power are you hoping to make with this thing? I’m still sorta leaning towards what I’ve already said, I’d even be tempted to sell of the TFS heads to finance the rest of it. Iron heads will also keep more heat in the chamber helping that whole issue with your combination…

 

thanks for trying to help out. I value your input... anywho

I want to run 12.0s on plane radials and stock converter at what ever mph. Power wize, what ever it takes to acheve my goals. I've gone 12.3s@113.5+mph n/a on gas with....

-650dp
-rpm intake, 1/2" of devider cut out (like airgap) lite clean up porting
-TFS heas with lite clean up porting (by a hak, aka me)
-16rr
-comp xe268h cam
-.039" thick hg
-stock deck
-30 over flat top pistons (355) (had 160 cranking compression)
--1-5/8 l/t headers/full mandral 3" exhaust dynomax superturbo muffs
-stock converter
-th350
-3.50 gear
-235-60-14 radial t/a tires
Car weighed about 3380-3400

I found i got beast et and mph shifting at 6000rpm. I tryed a vic.jr. intake but the best i could do was a .15sec and 2mph slower and had to shift at 6200 to even get that.

What ever i do i want to stay with aluminum heads. I do agree a flat top piston and a small chamber head would be a better way to go.