Today I began my installation of the water injection kit on my 2004 rx-8. Its such a simple install, everything fits in the engine bay and is hidden. Even with the cover off you cant see the pump or even know water injection is on the car unless you look for it.

My 1994 rx-7 was alot more difficult to install the kit. I should be finished tomorrow with any luck.


I will track test the car at the local drag strip. I know my trap speed remains constant so this is a good indicator. I will run the following tests.


1) with water injection off.
2) with it on using water
3) with it on using methanol/icewater.


with my kit a 2004 SRT owner installed the water injection on his car without any tune and gained 15 HP and 18 lbs torque. His results are below. http://www.srtforums.com/forums/showthread.php?t=84131

with that said I strongly believe that water injection will be the best thing for the rx-8 owner who wants to run a turbo, run a supercharger or wants to run it n/a and advance the timing or run fuel mods that lean out the engine. It will also be great for those that run low octain or are having a problem pinging. I prefer this not get into a debate about the merits of water injection on a n/a car, lets let the results speak ... whatever those results may be.


I'll keep everyone updated with the installation and results of the tests. I'll even follow it up with a few dyno runs after I get the kit installed and tested at the track. Oh yea, one more thing. I am working on a custom piece that will fit in the stereo face plate where the tape deck plate is. This will be a control center to have LED's light up and have a arm/disarm switch.







SRT OWNER TESTS
Peak hp and tq with water injection fully activated;

254.2 hp @ 5300 rpm
260.6 ft lbs @ 4700 rpm

Peak hp and tq with only 1 of 2 stages of water injection activated;

254.3 hp @ 5400 rpm
263.8 ft lbs @ 4600 rpm

Peak hp and tq with water injection turned off;

249.7 hp @ 4950 rpm
265.9 ft lbs @ 4900 rpm



From these peak numbers, you'd think that water injection doesn't do a whole lot. But at the end of the power band is where BIG differances are!

At redline(6200 rpm) here are the power differances in hp and tq.

both stages of water injection activated;

240 hp
208 ft lbs

one stage of water injection activated;

235 hp
205 ft lbs

water injection turned off;

225 hp
190 ft lbs

 

Those results are on a foced induction car and are not a valid comparision with a nonforced induction car.

 

What are you gonna aim the water spray at, the radiator or the oil cooler (or both)?

Both have heaps of boost running through them, so it's necessary to cool the charge down before it hits the inlet manifold.

LOL

 

I knew you would say that, you are so predictable.

I'm dont anticipate any power gains, I'm just testing to see. The advantage of this will be for those that mod the car and want protection against detonation. This kit will provide that, regardless.

 

I don't think the intake velocity is going fast enough for it to be heated compared to forced induction. It's good to see that you are experimenting though. This information could prove useful once we get into high-boost applications.

 

stop trying to pretend like you know what you're talking about.

 

Uh, this is dumb.

Why don't you wait until you have forced induction?
An Aquamist system on an N/A car is worse than useless.

 

Coolingmist,

I have installed a water spray kit on my 8 solely for reducing temp of water n oil. Results were good, overall managed to bring down oil temp by 7-8 degrees C. Are u talking about the same thing?

The reason i did it was because the freakin 8 peaked at 142 when i tracked the baby. Then again, we have intense summer whole year round here (ambient temp when i was out there = 37 deg C) It was unbelievable n disappointing. My next project or wishlist is the HKS oil cooler kit which costs a whopping $1300SD.

Goin bankrupt soon.....

 

I want to say this is grounds for a seport; I covered this some time ago, and came to the conclusion water injection is not optimal for N/A apps.

 

Of course I'm predictable. I'm right! Predictability doesn't always have to apply to opinion. It can apply to fact too.

If you don't anticipate any power gains, why are you going to do any track testing or dyno testing? There's no point for no gain.

If you want protection against detonation you have 2 options. You can either buy a new ecu that you can tune to make more power and be less detonation prone. At least with this option you'd be spending your money wisely. The other option is to spend the extra few cents and use a higher octane fuel. It's so simple and not installation or testing is required.

I can see how water injection can be used for forced induction. But even then, it is ONLY practical for the drag strip as a supplement to the rest of the system. I'd sure hate to be under boost and have the water tank run dry.

 

Great to tell your uneducated mates you have water injection on your 8, but does it serve any other purpose?

Anyone else smell a "ricer-modification"?

 

yeah, kinda what i meant, but i don't want to make myself into too big of an *******.

 

Rotarygod,

My brother had one of these kits on his Srt-4, bought it from this same guy.. I was awsome on his, But he sold the car... I know that this doesn't apply because ours is missing that darn turbo...

But I think it might work for the ping issue that might show up once some of the bolt ons are on. And I agree with you on just use higher octane gas... but when the Super Unleaded is 90-91 octane (which I memory serves is equivalent to most peoples plus gas) then this might be an awsome option.

Cooling Mist, on the Srt-4 my brother said it came on at about 8 lbs of boost, what do you use to make it work on a N/A car? a window switch?

Later
Chris

 

It won't cure ping caused by advanced timing or lean mixture. All it does is cool the intake charge which will never be above under-hood ambient to begin with.

 

Yeeuup

 

Does the track allow water to be sprayed? I would think it would be a safety hazard...

 

i mist is np.. as long as you dont leave anything on the track your fine

 

I don't think we're all talking about the same thing here. There are people who use spraybars with water or nitrous on their oil cooilers, radiators, and intercoolers. I don't think that's what this thread about. Water injection systems actually send water (aqua mist?) into the combustion chamber, in the same manner that fuel or nitrous would be injected.

 

Read this thread everyone.

https://www.rx8club.com/series-i-tech-garage-22/water-injection-13b-msp-32449/

 

Water into the combustion chamber?!?

...I most definitely hope not!

 

Yep water in the combustion chamber, but not like puddles of water, more like a mist, think of it as a Swamp cooler for your engine.... Kinda crazy how a mist benefits an engine, but if you hook up a super soaker it ruins the engine...

 

well all the water does is just add a lot of heat capacity to the intake charge, lowering its tempurature, i don't think that the water is really "good" for the motor ('cause steel + water = bad)

 

I don't have any idea how the water spray would effect a rotary engine, but in a standard piston setup, it basically steam cleans the cylinder walls. Some people actually use water to "steam clean" their combustion chambers out of carbon deposits. It actually works quite well. Just gotta make sure your not at idle when you do it, and use only a "small amount" of spray. It also effectively cleans parts of the valvetrain, etc. There are actually how-to articles on using distilled water to clean an older engine .

Of course a better system (if you have a programmable pcm) is alcohol injection. Using a similar system, but spraying alcohol instead. The cooling effect is much more pronouced, and it momentarily raises the octane level as well. On my fathers twin turbo 91 dodge stealth (400 awhp or 550bhp), it can drop the intake charge as much as 30F when it sprays.

 

Keep in mind you dad's car is turbocharged. coolingmist happened to do an install on an N/A 13B-MSP.

 

Aye I'm not arguing for the alcohol injection on the renesis, just explaining how it works in response to wakeeh's statement.