robl45

Just wondering if anyone has tried water injection? Being in Florida, I'd like to be able to cool the air a bit to avoid losing power.

Paul2x

Water injection, is only useful on turbo charged applications, so get a turbo, and an intercooler and then you can use water injection,
Did you possible mean, alcohol injection? You can do that on NA motors which is basically like boosting your octaine.

robl45

The water should still cool the incoming air right? I know its mostly used for turbo and supercharged applications, but cooling the air would seem beneficial.

ares

iTrader: (2)

I believe the application your talking about is misting the intercooler which is there to cool the air of a turbo charged car since the turbo can get very hot.

spraying water into your intake you blow up your engine from hydro lock, you get the most power from dry air. Ive never heard of anyone humidifying their air to cool it.

robl45

People spray water into their intakes all the time with turbo cars. All I want to do is try it with a naturally aspirated car to achieve the effects of driving the car on a cold winter day instead of losing half the power in a 90 degree heat wave.

Zaphod 350z

You will see a benefit with water injection even in natural aspiration. You see more gains with FI. There's no risk of hydro lock with a decent system. The spray is a fine mist, not a jet of water. You will see gains because the water cools the air and makes it denser. Also, if you make a mixture of 70% water and 30% methanol, the alcohol will add extra oxygen in the intake for better combustion. Water injection is used widely in race applications in NA vehicles for the purpose of cooling cylinder walls.

robl45

So now that that has been settled, has anyone done it in the 350z yet?

ares

iTrader: (2)

no, no one on this site. or they havent shared. I think Ive read pretty much every post, never heard this discussed before.

McDan

Water injection/alcohol injection is useful as a knock supressant only, period. An N/A or turbocharged engine straight from the factory would not see any performance gains. They are already designed to run on 91 octane. I used alcohol injection on my Supra once I increased the boost up from 11psi to 18psi, and saw substantial gains. This was only because on pump gas the knock sensors would pick up knock, and the computer would pull timing. With either race gas or alcohol injection the engine would not knock at high boost levels.

So, conclusion: water/alcohol injection would not be beneficial until to start to push the limits of your fuel system with either forced induction of possibly nitrous.

Dan

tim_n/a

I disagree with that. I tried a mist system on and there was gain on a NA engine. The gain is mainly from cool dense air. However, I don't think the gain is worth the trouble on a NA, unless you run out of every trick already.

robl45

Its not about a gain, its about keeping the horsepower that you should have to begin with, surely you all agree that cold air works better than hot air. So someone driving in 30 degree weather is getting more power than someone driving in 90 degree weather. Considering the Z isn't all that impressive in 30 degree weather, I can only imagine what it would be like in 90 degree weather without some type of water injection to cool the air a bit.

robl45

so what your saying is, when you drive your car in the dead of winter and the hottest time during summer, you feel no performance difference?

LPEdave

I think your point would be that in the summer, there's less oxygen per square foot of "air" that your intake pulls in, than in the winter, right?

The problem with the water injection, or even using an intercooler to cool down this hot summer air is that you're not compressing the air coming through your air filter. You're still sucking in the same volume of air, and normal atmospheric pressure. All you're doing is cooling the existing air you have. That's great if the engine is knocking due to the heat, but just cooling it down isn't going to create more oxygen, to mix with more fuel, to create horsepower.

Hope that helps...

Dave

robl45

okay, when I drive my turbo car, there is night and day difference between summer and winter, you are saying the effects are because it is turbocharged a normally aspirated car wouldn't have the same effects?

LPEdave

No, I'm agreeing that even in a normally aspirated motor you have a significant difference in power between summer and winter. But to get this same effect in the summer, starting with hot air, you'd have to cool the air outside of your intake so it would compress (getting you that extra oxygen which is what's making the power) *then* feed it into the air filter (and speficially the MAF sensor, if that's what it's called on the 350Z). To accomplish that, you essentially need a supercharger.

Dave

ares

iTrader: (2)

the difference between hot and cold air is small if you were curious. also CAI can help with that. alot of the heat difference comes from the engine bay heating up to extreme temps in the hot summer sun.

I still fail to totally agree, cause if you mist water in, even atomized water, you are simply displacing air for water. only way this could be cooled is if it evaporated. this is why people mist intercoolers, a wet surface will cool faster as heat is absorbed to evaporate.

I think the thing everyone here has said tho is that it will not make enough of a difference to be worth it. turbochargers only get gains by increasing the possible boost, not because the actual mist raises hp, but the extra boost faciliatated by the mist does so.