REM and snow performance

**Paul@Rem** · 03-05-2009, 06:03 PM

I wanted to take a moment to post some results from our install and tuning of a Snow performance stage 3 water\meth injection kit. Keep in mind that for years we worked hand in hand with Snow developing tunes for Fords and consider ourselves knowledgeable and competant tuners.

To help understand the benefits of Water\meth I'll offer the following explanations.
It’s easier to think of Water\meth as having two key points to it's function, the first being chemical intercooling and the second being detonation suppresion. They are inter-related, but it is easier to separate them. By accurately injecting a super fine mist of water methanol into the intake charge, evaporation begins to take place immediately creating a much cooler and denser charge. As an example think of putting your hand in water that is room temperature, then blow air across your hand, the resulting evaporation pulls heat from your hand making it feel much cooler. With accurate water-methanol injection, we can exploit that trait to a great degree.
Once in the combustion chamber the affect is a much slower and more controlled burn - much like that of race fuel. Many tuners and installers choose to run straight Methanol as it is easier to tune and allows a much larger margin for error ie: by injecting too much you will not quench or misfire as will happen when there is water in the mixture. The addition of water is vital to making power in a few respects, one vital aspect is that in the combustion chamber the water turns to steam acting like a steam engine expanding to a large degree and putting downward force on the piston. The other reason straight methanol isn’t as good is because you can greatly over-inject fluid with no misfire, you can start to get to the point of cylinder wash (which never happens with 50/50 water-methanol) and the potential for damaging backfires, etc.

The other important factor is Latent heat of vaporization. Gasoline absorbs approximately 135btu per pound of fluid, methanol absorbs about 450btu per pound of fluid and water absorbs 1,000btu per pound of fluid. You can see from these numbers how important the addition of water is to cooling in the intake and combustion chamber.

Now, once you get past what water-methanol injection does, you can exploit it even furter especially with very accurate injection. Snow Performance’s new Stage 3 injection system can read and inject according to Fuel Injector pulse-width, and/or boost (if forced induction). By using the fuel injector pulse width as a reference point for injection (they aren’t simply mimicking it), the stage 3 benefits from the ECU’s functioning and the data it gathers from the IAT sensor, MAP sensor, TPS, coolant temp sensor, etc etc. Additionally, if you are forced induction, you can inject according to both boost and IPW, and quickly and easily change the importance of those input signals to tweek the whole 3D map, with just a few quick button presses (you don’t have to change hundreds of data set points because the software does it for you).

The end result is, we can get as close as possible to injecting the correct amount of fluid for all different circumstances. That means we not only get the correct amount for high rpm WOT but all the mid-load and roll on states as well. Just like going from an over-simplified carburetor design to the newest fuel injection, with more accurate delivery, you get better results over the whole delivery range and conditions.
The attached test was done on our Mustang MD250 eddy current dyne using a SRT-8 charger with the vehicle weight set at 4500 and the vehicle 50@14. The base run and all subsequant runs were started with the coolant temp at 180 degrees. The base run was with a REM carbon cold air intake and a U7135 predator tune, the final run was the same setup with the addition of the snow Stage 3 kit with a 50\50 mix of water-meth.

Our gains so far are a max of 32hp and 37lb\ft torque and a minimum gain of 28hp and 17lb\ft....This was done with an A\F in the high 11's.. The car will back on the dyne in the next few days and we feel if we get leaned out to the 13's we'll find another 20hp or so

**dudeiwin86** · 03-06-2009, 02:28 AM

am i correct when i assume that the final tune involved CMR tuning to dial in the water meth? as in.. much more advanced timing?

was the first run stock with no tune? a canned tune? a CMR tune?
was the final run after retune with CMR, or just bolt on the meth and you have this?
just curious about exactly what changed between graphs

**Paul@Rem** · 03-06-2009, 08:05 AM

am i correct when i assume that the final tune involved CMR tuning to dial in the water meth? as in.. much more advanced timing?
Yes you are correct, the final tune involved tuning however it was done with just modifying the 93octane \cai can tune.

was the first run stock with no tune? a canned tune? a CMR tune?
[COLOR="blue"]The first run was with the canned predator tune[COLOR="blue"]

was the final run after retune with CMR, or just bolt on the meth and you have this?
The final run was with the stage 3 meth kit installed with a 375 jet and the pump pressure raised. We now need to put the car back on the dyne and custom tune it using CMR as we cannot get the fuel curve leaned out enough.

**PaCharger** · 03-06-2009, 08:21 AM

Was this a stock SRT8? - well at least without major power adders?
It would be very interesting to see a pull with the tuning complete - before/after water meth injection.

I've always been skeptical to the real benefit of water/meth for NA stockish type cars. I fully expect you can advance some timing or run a tad leader to net out a 5-10hp gain - not doubting that. Simply - I think the benefit for NA cars is not even in the same ballpark as the relative gain for power adder cars.

Thoughts?

**Paul@Rem** · 03-06-2009, 10:32 AM

PaCharger
If you re-read my post you'll see where I stated the car has just a Razors Edge CAI and a predator tune, no power adder except for the water meth. The base pull was with the CAI and the tune, the second ( the last of many) was with tuning and the stage 3 kit.
I follow your train of thought however these are real gains on an N\A car. I can get into writing a long disertation on the tuning if the interest is there.