Like I said, I'll have quarter mile times before / after.

And just what have you accomplished in the realm of NA performance? An engine test stand?

 

I never said I had. I'm not naive enough to think that I can walk fresh onto the automotive engineering scene, with very little professional training or extensive race experience and be able to do a one-up on what took factory engineers months or years to come up with, with their large backing.

Sure, there are simple upgrades that can improve on the stock setup...mainly where compromises were made by the engineers in the realm of creature comforts, reliability, or emissions compliance. OUtside that, most people who tinker with things only wind up vastly reducing driveability, reliability, or just plain screwing something up. Not saying that you're one of these people, but let's be realistic here. You can't honestly sit here and tell me that you, a guy in his back yard, can do what those guys at mazda couldn't do with all their backing, equipment, time, and research, do you?

Don't you think that since water is free, gas is a commodity recently, and manufacturers are constantly searching for any edge they can get, if they thought water injection on any or every NA engine on the market would be a feasible improvement, they;d be DOING it? IF water injection allowed you to run cheap gas and make 50 extra hp in NA form, every friggen car on the road today would have a gas tank and a water tank. Trust me, they know some things we don't. Most likely, those things are

1) it isn't worthwhile for the effort required. For a very few instances it can be worthwhile, but a nonturbo street car isnt one of them.
2) water injection actually reduces power overall. IF you think that the cooling effect of water on the intake tract and intake charge outweighs the amount of fresh air/fuel displaced by that volume of water, you're probably mistaken. By the same token, we could route air from our air conditioners into the intake tract, and we'd wind up with a net hp increase, even with the a/c on. It doesnt work that way.
3) it isn't as reliable as other cooling methods or plain good tuning. Read some in depth articles (hell, even the threads in the FD section are good reads) about this from teh turbo guys...WI can be used in leiu of an IC, but is far less reliable...one malfunction or one time running out of water and the engine is toast...with a permanent IC setup, it pretty much works all the time without fail.
4) who the hell is going to fill up a water tank every time they fill up a gas tank? This is the same reason mazda went with the rotary's stock OMP system...not many people can be expected to reliably top off an auxiliary system on a regular basis...most people do well to top off gas and oil and check coolant twice a year.
5) a competent water injection system will add at least a few hundred dollars to the cost of any car's setup, and most people wouldn't see enough benefit to justify this.

 

i agree with you in many cases, kevin, but not in the "they'd do it if it were better." in reality, they're after profit. maybe not all in the "get rich by any means necessary," but they have to keep profit at a definite rate. the economy and business is a funny structure. there's no doubt they like seeing gas powered vehicles on the road. the oil business is big.
someone before made a statement that was something like "if there was a better way, they would do it." sorry, but i dont believe that's true. the example i used was a type of brake fluid/system that is superior in all aspects, but is only available in certain cars. i forget the acronym, but i want to say it was a type of mineral oil. i remember it was 4 letters. if i remember correctly, there is no reason that most all production vehicles shouldn't be running this type of brake fluid/system.
also, not everything is hand built. the casting of the irons is not perfect, but can be cleaned up by a guy in his garage with a dremel. what's the difference? mainly time.
and do i think they'd be using water if it made an improvement? no. what about the big rave over running premix? do you think any car company is going to ask you to do anything extra that no other car does? thats called risk. business is a funny category. you have to find the balance between being like everyone else and taking risks. you can only be so different.
and as far as the rotary techs who know the r&d, i would love to see what some of them could do.

 

I'm with casio on this one. Mazda is not gonna sell many cars if you tell the buyer unlike other cars similar to this one you have to fill up on water when you get gas, its too much hassle for your average joe. There are about a million things mazda could do better or any car company, but you aren't gonna see it cause anything new to a car from the traditional is a risk of failure/lawsuit/recall or any number of chances. If the profits they could gain doesn't beat out the risk it doesn't happen.

if you do the water injection, you could tie it into the windshield wiper fluid system for a warning if you are running low on water. But as pointed out before, for a boosted car this shouldn't be your only system. For those who are gonna run a SC with no intercooling at all at relatively low boost it sounds like a good option cause you won't blow up if it fails and you can get the gains from denser air.

 

Yeah... mazda cut out a lot of things just to make it easier on the drivers, atleast the lazy ones.

Another example is premix with 2 stroke oil. So now we're at filling up on water and a specific type of oil while at the pump.

 

Well, why don't some of you with "modded" na's go out and hook up a line to a jug of water and a dc motor and flip the switch while accelerating at WOT...tell us what happens. Your car will stumble and misfire, and lose power. So you say, that you need a proper injection setup huh? Fine then, go spend a couple hundred bucks or more and make it right, the way you want it. Now go dyno for us...one run without water injection as a base line, and to heat soak those manifolds really well ( ). The next run with water injection...get back to us with how much power you LOSE. Oh, but be sure to have an intake air temp gauge hooked up the whole time to monitor the gains you get from all the "cool intake charge".

Then, account for your time and your cost involved, and tell us what *proven* mod you could have done for the same amount of money.

 

i hope that wasn't aimed at me. i was simply making the point that, though something might work better, it will not necessarily be adopted by a mainstream engine/car manufacturer. i'm with you on the water thing. if anything, i'd rather have an intake manifold constructed out of something that doesn't absorb so much heat. as for water injection, if there were a way to direct-inject it into the combustion chamber, that might help as an anti-detonation system, though i really don't plan to ever need such a system.

moreso, i'm not sure why they use this on turbocharged cars. is there a performance gain over running the correct amount of fuel in the first place? if i had an awesome knock sensor/ecu system, ideally it could spray water when needed, i suppose.

i guess my question is this: why should a car ever need water injection??

 

See, with an NA engine, you only suck in what air the engine wants. Depending on your intake, this air temp can be anywhere from ambient, to engine bay temp, and factor in a little bit for heat soak of the intake manifolds. So, your average intake air temp on a hot day at WOT (after you've been moving a while) might be 100*.

With a turbo engine, you must keep in mind that intake air temps soar. All of your intake air is routed through the turbo, which is directly connected to the exhaust, so even the compressor side is hot, even hotter than the intake manifolds of a nonturbo. Secondly, from the time that the turbo starts to compress the air (slightly below atmospheric) it heats it. Anytime you compress air, you heat it (this is the principle air conditioning/refrigeration is based upon, as well...compress, push through a heat exchanger, decompress, the air gets very cold). So, you're compounding the high intake temps with a turbo...intake air temps can easily exceed 200*.

Detonation is caused by several contributing factors. What detonation is, also called preignition, is when the combustion chamber surfaces get too hot, almost red-hot all the time. The injected fuel/air charge gets ignited by the hot chamber, before the plugs even have a chance to do their job. Since this ignition event isn't controlled by the engine's plugs, it happens at the wrong time, and is uncontrollable, so instead of the combustion helping push the engine in the right direction, it just spikes all at once and puts un needed stress on parts as a whole.

As you can see, high intake air temps contribute to detonation, and a large reason turbo/sc engines are so much more sensitive and prone to detonation. This is where wate rinjection is most helpful...the water cools the combustion chamber, keeping detonation away. Yes, you still lose some of your power (because of water dilution in the intake charge) but its a worthwhile trade off, and on a turbo setup, you just raise boost a bit more to make up the difference.

ON a nonturbo rotary, you're usually nowhere near the threshold of detonation. And, you can't just up the boost to make up for the power loss of water injection.

IN the light of this evidence, someone explain to me the benefits of water injection on an NA again?

 

I'll agree with the statements of "Just because it can be done better, doesn't mean it will be." I think most of you are too young to remember the whole Pinto fiasco (I am too, but did a bunch of research on it for a project). Basically, if a Ford Pinto got rear ended, there was a really high chance of the gas tank rupturing and catching the whole car on fire.

Through an investigation, it was determine that Ford *knew* of the problem, and had determined that the costs of lawsuits & such would be less than the $20/car or so it would cost to fix the problem.

Same thing with the oil injection. It's hard to argue that the stock system is the best option available. However, it's the one Mazda went with for non-technical reasons.

It would be interesting to see what kind of stuff Mazda has laying around their rotary R&D labs. I bet there's some really cool things that will never make it onto any production vehicle.

-=Russ=-

 

i know about heat, pre ignition, hot spots and hot air temps, but i guess what's confusing to me is *when* to run water injection. is this best for drag racing since drag is only so many seconds and nearly constant WOT? i mean, if a motor isn't on the absolute verge of running lean, are the chamber's walls really that big of a concern for developing hot spots? the whole use of water injection is just iffy to me right now (and usless, in my opinion, as i have an n/a).

yea, i read about the pinto's with their unsafely placed gastanks. remember someodd months back when it was on the news that a few cop cars were doing that? i want to say it was the ford crown vics, but i could be wrong. i think they were slightly prone to catching on fire.

 

Oh god, I'm chomping at the bit so hard after reading that. Where do I start with U!

Aaaaaaah!! I can't believe I read that coming from someone so accomplished and respected in this field of sports cars. I am seriously shocked in you Kevin. I don't even know where to begin with that post.

The reason water injection was not experimented with by manufactures is probably the same reason a two stroke oil tank wasn't a part of the OMP system on FC's. American consumers wouldn't buy a car that required them to do more top ups of fluids (especially oil that was *burned* by the engine ), and water injection would be beyong joe consumer's understanding just like TCW3 premix oil. Just look at everyone ******* WI in thiis thread.

Regarding the engineers knowing best . . . yes , yes they do know best. However, the engine was designed to pass smog in a time when EPA was imposing strict constraints on car emissions relative to past allowances. Everyone knows the 10A's of many years ago produced more horsepower than the 12A's of FB time because the designers could spec a more agressive port, because emission controls weren't as restrictive. It's not a drivability issue! U need to drive my little experimental street ported FC and then drive a stock one to see the true reality about drivability and intelligent NA engine mods. I don't port like other NA builders, and neither did Mazda when they spec'ed the ports for the 10A.

Oh god I can't take this any more. This board has a wealth of technical information for stock FC's and modded TII's, but when it comes to the really challenging stuff like making an NA scream without wild ports, the knee jerk rejection some ideas get from experienced members just slaps me in the face. :shrug: I can't understand why everyone thinks engineers design for performance first . . THEY DON'T . . ask any engineer working for pay and they will tell u that they must design for a set of parameters that the marketing department gives them . .

Anyway, no ill intent meant by my attitude here, I'm just so shocked at how everyone thinks engineers made the optimum design when they designed to pass emissions and not give consumers too much power (to keep the generic mpg ratings higher). Speaking of MPG, I get 20/26 in my streetported FC. That's better than stock.

Peace.

 

Well I guess this is the place for this question. And I'm a noob way out of his league. Has anybody ever heard of a sonic emulsifier? It seems that most water injectors only inject misted water. That is, droplets of water, huge gobs on the moleculer scale. The sonic emulsifier through the use of piezo-electric injectors completely vaporize the water upon injection. Supposedly vaporized water can freely mix with the AF mix and do pretty much the same thing that higher octane does and provide some measure of cooling. I heard about this technique many years ago but can't find anything about it anymore. Hmmmmmm?

 

Yey, data!

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

James