gunzo

iTrader: (2)

Some updates ..

with more methanol, I can run about 2-3 degrees more timing ..

I start spraying at 7psi with about 150cc/min with timing around 18-20 degrees
full boost is 26psi with close to 500cc/min, timing at 9-10 degrees (previously 7-8 degrees)
at 7500rpms boost tapers to 24psi 450cc/min with timing at 25 degrees

This is with 93 Octane fuel (R+M/2)

How does it compares with you guys ??

Ted B

iTrader: (6)

With more methanol, you'll be able to run a bit more timing, and make more power. With 100% methanol and appropriate tuning, you will make more power still.


WRC rules prohibit the injection of methanol or any other supplemental fuel. Some teams (not all) use water injection to cool the ACT, which is beneficial (especially in hotter climates). The article in question features comments such as . . .

"Water injection has been introduced since we looked at the engine in 1995, and has assisted in the exploitation of a higher compression ratio, although Lapworth says that its use is not critical in this respect" (due to use of a larger IC).

"In practice (says Lapworth), the effect is marginal, and is only effective at lower engine speeds."

Mr. Lapworth notes that a ban on water injection and water IC spray will result in a "slight decrease in engine power".


The point here is not to diminish the benefit of water injection at lowering ACT, but to squarely disagree with Richard L's assertion that water injection provides a greater power benefit than 100% methanol.

With 100% methanol injection, I've witnessed common increases in power along the lines of 15% with little effort. For a 300whp car, that amounts to an additional 45whp from methanol injection alone. If water injection provided that degree of power potential increase, ALL the WRC teams would be using it. The fact is it doesn't, and they don't. Again, not because it isn't effective at suppressing detonation and cooling the ACT, but because it does not give an advantage so great that it makes it a 'must have'.

I do agree with Richard L on the point that methanol injection requires retuning and should be used with a fail-safe system. Likewise, 100% methanol can be hard on pump parts (e.g. santoprene).

C6C6CH3vo

iTrader: (9)

So your running 9 - 10 degrees peak? I'm running a little less (8 - 9*) with good results but have recieved criticism with reports that 8* is too much for bottom end.

Anyhow, 2 psi start spraying with a (boost, MAF) ramp up to about 10 psi, and then it's full spray (375 mL/min @ 100psi rated equivalent) up to 24 - 25 psi. Timing at redline only 22. Oh yeah, 80% methanol

Richard L

iTrader: (5)

I would like to add more deatil on the quotes in Green...

Richard

Ted B

iTrader: (6)

FWIW, Lapworth quotes 700nm in the article, which as per my math works out to ~515 ftlb. I don't mean to be picky, but there is a substantial difference between those two figures.


I don't think we would be investing our time in discussing it if we weren't interested in said details. Consider this a formal request.


Neither have I, but that doesn't mean it can't be done, nor does it indicate that it's any more practical for street driven vehicles than is anti-lag methodology.

Richard L

iTrader: (5)

You are absolutely correct on the article. In real life... it is a different thing.


This is only my view and some practical experiences gathered over time, so please discuss this further, I need more inputs...

Power producing potentials:
In theory, more power will be produced if more charge is jammed into the combustion chamber, resulting in higher cylinder pressure and temperature. In practice, the associated components such as pistons, turbo turbine, etc has a finite operating temperature constraint. This is normally reflected by the EGT. The general accepted EGT figure is about 900C.
Power is basically a force exerted onto the piston per unit of time. Force (pressure) is generated with heated air in a confined space. If cylinder pressure can continue to increase without temperature rise, we have the ultimate power plant. Water injection and alcohol injection will be a good tool to perform this work, lets examine this in more details how each concept can help achieving this.

POWER TUNING:
(Assuming we have a powerful ignition system, a strong engine and unlimited supply of air and fuel).

For water: the task is relatively simple. First generate as much heat as possible by adding more boost and fuel. Water is then injected to absorb the excess heat until EGT is within a permitted safe level. Overall BMEP (Brake Mean Effective Pressure) is now increased due to the vaporized water. The amount of BMEP increase will depend on the mechanical strength of the engine structure. Water’s ability to push the power capability is almost unlimited.

For methanol: First consider using methanol as a fuel instead of Gasoline. Methanol’s ability to increase power is confined to the knock threshold, and available heat to increase the BMEP of an engine. Methanol has only about half of the energy content of gasoline, so twice as much methanol has to be injected to produce the same power. As twice the amount of liquid has to be injected, the cooling effect is huge, resulting in over-cooled combustion chamber, limiting the BMEP. A 100% methanol engine has to use multi-spark ignition system to ensure the mixture is constantly being re-ignited due to the cold combustion chamber. Within those constraints, there is still huge potential of power increase.


It will take a brave soul to do that, I am sure it will happen one day, sooner the better, showing the true potential of alcohol injection.

gunzo

iTrader: (2)

Here's a comparison of the 2 runs .. the dull color is the one with lower timing .. note the lost in torque with a corresponding lower timing at 6-7* versus the 9-10* timing .. it's enough to be felt!! .. each line is 10ft lbs difference
My flowrate is measured courtesy of DDS3

If I understand what you (RICHARD L) wrote correctly, if I go 100% water injection, I can correspondingly run higher boost and leaner fuelling. I would guess that timing advance determines when BMEP occurs so if I lower timing to allow pressure to build as much as possible I'd make more power??

But increased boost also increases power correct??
what I want to know is .. with WI, do you recommend to run higher boost?? or higher timing ?? or both??

Can I break it down to layman terms ??( not that I do not want to learn !! )

Methanol = run more advance timing closer to knock threshold
Water = run higher boost with lower timing to generate higher pressure safely

Ted B

iTrader: (6)

But unfortunately, the engine's ability to accept the addition of an external, non-combustible liquid is not. Of equal importance, some point exists whereby further increasing the 'contamination' of water in the combustion charge is of no further benefit (due to reasons of physical chemistry).

With respect to the WRC cars, what is the WI rate with respect to manifold pressure vs. rpm? With regard to the detonation threshold, how close is it run to the ragged edge of destruction, and how large/small is that margin? What are the AFRs and the EGT? You mentioned 900C, but that figure will take its toll on a street driven vehicle in relatively short time (but is of little consequence to a WRC car).

C6C6CH3vo

iTrader: (9)

Pig rich, moddest boost, and bold timing just feels good to drive to me

SlowCar

iTrader: (4)

hope you change your engine oil often........

Richard L

iTrader: (5)

You will surprised how much water the engine can accept before misfiring. A 50% water to fuel is only accounted for a mere 6.25% of total mass. (A14.5/F1/W0.5). As water and fuel does not mix, it acts as a cooling agent between fuel/air molecules. If you stand them inline, it is only one in every 16 molecules.

Extra fuel however, used as a cooling agent will impede burn due to the production of CO. CO will interfere with the combustion process much more than water. If you are running pig rich, the CO will take prescious oxgen molecules ouit of the combustion chamber happly, resulting in power loss. There is only 20% of oxygen in air, transporting the oxgen out of your enigne in the form of CO robs 60% of energy compared to CO2.

If given the choice between injecting more fuel or water as a coolant, water is your only sensible chioce. Given the fact that you only need to inject 1/6th to have the same effect with no CO contamination.

I think we are slowly moving away form alcohol but worth digging deeper into the subject.




WRC car are not that special except it pushes the limit a bit further than a street car. It is mappped with the same tools. 900C EGT is good for street car with cast pistons and 950C-1050C for forged piston. Providing the piston ring clearance is accounted for at 1050C.

The WRC engine don't run the car in the rugged edge of destruction. In fact it is far safer than most of the car on this forum as it has good failsafe mechanism to monitor every eventuality. I am shocked to see prople tuning their car with alcohol with little or no failsafe implanted.

Monitoring the a/f ratio is one way to avioid problem but in the absence of alcohol, the knock is a big issue, retarding the timing only produces more heat, merely delay the next knock event, not curing it.

What failsafe would your recommend for street cars?

Richard L

iTrader: (5)

What about adding some water, less rich. A gallon of gasoline will take you further and faster.

Richard L

iTrader: (5)

I have seen people runs pig rich seeing their oil level goes up in the sump!

Those people also boosted their engine never uses a drop of oil Check your oil by sniffing the dip stick gives a better indication.

dustin03

iTrader: (54)

So I have been running 100% denat. alc and my tunner said he want to tune me on Meth do you think it will benifit me?

Richard L

iTrader: (5)

If you want to go 100% WI, you really need to put your engine into an engine dyno and map it there. In order to take greater advange of WI properly, you need to run the EGT/coolant temperture beyond its safe limit and use however much water to bring it back to a safe level. It is a long and boring task, not recommend for those who charge their customers by the hour.

There is a recent example of such application on an diesel engine, employing this method to make more power. http://www.aquamist.co.uk/dieselmax