Turblown

Here is an old dyno of JamaalSmith's car before we worked out some bugs on the vehicle. The bugs were running too rich past 6k rpms, and not having the aux ports open. Anyhow it had an AEM water injection with the smallest jet( I believe 200cc? )

Dyno is labled, as you can see it loses roughly 10rwhp almost everywhere...

We will do some more tests in the future...

Mawnee

Did you add timing on the water runs? If not thats kinda to be expected isnt it?

Turblown

Tune was unchanged.

I did an evo 9 a while ago and we picked up 20awd without retuning @ 430rwhp or so. Rx-7s generally pickup power too. Only thing I can think of on his car is since we are using a Garrett core the intake temps are low enough where there isn't any intake temp drop, just displacing air which will reduce power.

Brettus

iTrader: (2)

could also be due to the fact that boost pressure is so low - leading to low intake temps as you suggest .

Thanks for posting - very interesting .

NgoRX8

iTrader: (1)

In certain cars, like the evo, and more broadly certain ems/ecus, ignition timing will be altered with the presense of w/m due to the reduced intake temps.

For our car with most of us running the MAF (which houses the IAT sensor) pre-turbo, our ecu does not detect the colder IATs (which happen post turbo/pre throttle body), and thus does not account for it as others do by advancing timing. our ecu also does not modify ignition timing directly based on IATs but rather indirectly based on Calc Load.

Also, the reason for the power loss is as you said, water replacing air, but also due to octane. Since water acts as a detonation suppressant, you are effectively increasing the fuel value. Running higher octane without tuning for it will result in less power.

The higher the octane, the lower the energy content, but the more timing can be advanced before detonation.

Turblown

The timing did not change on the other vehicles I tested, we were running standalone ecus. Power increase is due to lower intake temps.

rxat2012

iTrader: (1)

since we are on the subject has anyone tried precompressor injection..... on the garrett units probly not that usefull, but on one of the td06's like the stock greddy or some of the upgrades you might get some good numbers...

halimsteven

did you guys run 50/50? at what PSi did it start spraying if you don't mind i ask...

i have been using it for 3 years, at 5 psi start spraying....but we didn't get a chance to dyno it...
may be my new set up which will be finished in 2 weeks....
steven

FazdaRX_8

iTrader: (1)

very interesting indeed, do you have ambient environment specs?

Jamaalsmith

So here's my question...when increase the boost pressure (and subsequently the IAT), we should see an increase in hp due to the w/m...?
At what level of boost will we see this benifit?

FazdaRX_8

iTrader: (1)

I think a better question is at what intake temperatures does the W/M start working the best?

Mawnee

My understanding is that W/M doesnt give HP in itself unless you are running high IATs and the cooling effect gets your engine back to a reasonable operating temp. The real advantage is that the added octane(knock reduction) gives you a level of safety allowing you to run safer with your normal timing, or give it more timing to pull out extra horses. Obviously the the gains from a degree or two of timing will be greater the higher the power level you are running. So I can understand why the guys pushing the envolope do it to max out a particular setup.

Myself, I've never bothered to run W/M on my boosted cars. I simply run power adders within their effeciency and keep the tune conservative. I'd rather buy a bigger snail in the first place than run a little one and have to fill up another tank to keep it safe at my desired power level.

Jamaalsmith

I just realized how horribly jumbled my question was...sorry guys...
To my understanding the more you compress air, the hotter it gets. Dont know exactly how this corresponds to boost pressure exactly, but ill take a gander that as the pressure increases, the temperature increases as well in a somewhat linear fashion.

some dudes's gas law or somethin like that...

Im pretty sure temperature, pressure...all that good stuff plays into how much air (volume) gets into the engine which i think is the ultimate concern, but i think boost pressure can help us dicern slightly more about the overall air flow than temperature can. After all, we dont compress air simply to reach a certain temperature, we compress it to get cram as much as possible into the engine...an increase in temperature is a side effect of the process.

Mawnee, your rational is completely in line with my train of thought..at least on my car. It was/is in place to provide an increased factor of safety. (det supressant) Im ok with losing 10hp if my engine doesnt explode.

olddragger

iTrader: (3)

the one thing i like about 50/50 w/m is its a little insurance. IMHO insurance is a good thing because the gas you get at the pumps is anyones guess now a days.
local drag racers are sample testing local top tier gas stations and finding 7-18% ethanol content.
yes you do loose a little power--but is the extra 10-20 hp worth the risk?
I really dont know---but it does rest my mind a little. Plus I do like the cleaning affects it offers.

999miki

Were there any indications of misfire? Change in AFR or EGTs?

Rote8

LOL,

S/C'd and tuned for 87 octane crappy gas.... lower compression.

Rote8

My observation is that getting a colder engine when hitting the switch requires a mix closer to 100% methanol or a nitromethane / methanol mix. The straight alky will drop your engine temp gauge fast.


//you can freeze the outside of the blower and intake with a straight methanol spray.....

olddragger

iTrader: (3)

until it catches on fire
OD

halimsteven

i thought that some people in the forum have discussed about the purpose of W/M a long time ago. what i remember was that it will not give us WHP, but it gives us safety reasons....correct me if i am wrong..

steven

HiFlite999

iTrader: (2)

If I'm reading this right, the dyno curves show 100% water injection, no methanol. (?)

Turblown

During those runs with and without the water on( car was running 100 percent water) there was misfires above 6k rpms. Ambient temps were pretty low 65ish F. We started the alchy at 5psi I think, which is 3.5k rpms and above. No change in AFR, and egts gauge is too slow to catch such a small change in EGT.

On the Rx-7s I have done EGTs generally don't change with water, they drop slighty with achly. I have also done a lot of pre-compressor injection, including running no intercooler in my time.( see attached photo ).

6 year or so ago we slapped pre compressor only alchy injection on a to4B rx-7 and picked up 30 ft lbs of torque across the entire rev range in boost.

Turblown

Every turbo vehicle I have worked on makes more rwhp with water injection. These cars however are running 15+psi and intake temps are generally above 90F. Water injection will slightly lower it and make more power.

As soon as we are done with a new motor for JammalSmith's car I will do some more testing...

Phish806

iTrader: (4)

Why was he/you only running water and not water/meth? Wouldnt the Meth go even a little further in the safety aspect of things?

Jamaalsmith

Yes,
but meth is also a fuel...E and Jeff were also trying to nail down the tune, and adding additional fuel to the mix would have complicated the process.

olddragger

iTrader: (3)

very true.
You may want to PM Juan from The Pettit SC thread as he has dynoed some with w/m on and off with different jets on a twin screw set up. He did not loose any power--with a total of 175cc jets. @ nozzle set up one pre blower (and a/w intercooler) and one post blower.
Folks may not realize that all methanol sources may not equally be as good.
OD