Water vs Methanol : Ultimate Tuning

[parmas]

Finally I got a map tuned with the right ignition timing and fuel mixture.

Now I would like some advice to have a good tune with a 50/50 mixture.

Question 1 :

Would water only or a 50/50 mixture need more ignition timing ?

Question 2 :

Methanol is fuel, so the map needs to be leaned out. By how much? is there a formula for this ?

Question 3 :

Water cools combustion more than methanol but if both injected there is a note that water nor methanol do not "see" each other thus mix more with air.

So what about Air Temps? Would using a 50/50 mixture gain cooler air temperatures but increased cylinder temperatures due to methanol burning?

[Flr Power]

That's why 50/50 by weight is the best mix.

[parmas]

Originally Posted by Flr Power

That's why 50/50 by weight is the best mix.

If you have a clear answer for the above question I would appreciate your feedback

[parmas]

During the time researching about water injection during the past 3 years I never came across into a definitive thread on "How to tune correctly water injection". Let's try to define this here.

Presently I have a basemap tuned by myself on 100% water injection. During this time I came across that eventually the practice of water injection does infact change the theory of fuel & ignition timing needed by far.
Right now I am boosting a 1.5L engine with a GT2560R turbo @ 18psi. The engine is happy with a 13.5 AFR on high load. Insanely this is a ratio a normally aspirated engine should run.

I am using an AEM progressive injection system start injection at 6psi and give it full at 10psi (due to no intercooler). Injecting about 350cc PRE-Throttle body and 150cc PRE-Turbo = Total of 500cc

Pre-turbo comes 4psi later than Pre-throttle body by using a variable check valve.

At this stage I am seeing about 50DegC during high-load/rpm @ 18psi @ 500cc water injection. Ambient is 26DegC and injecting below 10psi temps stay within 30DegC.

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Water to fuel injection Ratio :


A hard pull on 4th gear up to 7000rpm :

Start of water injection @ 6psi = 250cc of water

End of water injection @ 18psi = 500cc of water

Fuel according datalog :

@ 6psi Boost / 564cc x 4 injectors = 2256cc @ 20% Duty = 451cc

250cc water vs 451cc fuel = 55% Water to Fuel

@ 18psi Boost / 614cc x 4 injectors = 2456cc @ 46% Duty = 1130cc

500cc water vs 1130cc fuel = 44% Water to Fuel


According to the theory of water injection, not more than 15% water to fuel should not be injected as it could cause damage to the engine. Apparantly this is all falks as I am running this setup for more than a year without damage !

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What are the differences in the burn when injecting 100% Water vs 50/50 Water/Methanol ?

I am not going into chemistry and molecules, all we want to know is "What are the overall effects when injecting Water Only or 50/50" ?

We all know this! Water does not burn so injecting 100% water does it's "100%" to cool the Flame down.

But what happens to the Flame Burn when using a 50/50 mixture?

Methanol burns slowly than Pump fuel so still it does a % to cool the Flame down. So roughly now we have 60% is there to cool down the flame while 40% is there ready to burn.

So if we take a 100% water burn vs a 50/50 Water/Meth burn, the 50/50 is going to burn hotter.
Heat increases pressure - More pressure = More Power. So logically a 50/50 if tuned right! it should produce more power overall.

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What Happens to the AirTemp when using 100% water or 50/50?

Air is cooled by the evaporation of the liquids during a rush of Air or more boost. The hotter the Air the more the evaporation effect takes place. That's why many find water injection in forced induction applications and many tell not to inject below 20DegC.

There is a theory saying that when two different liquids like methanol and water are evaporated at the same time, evaporation can be increased above the theoretical 100% relative humidity thus cooling more air. (100% R/Humidity means altough there is a rush of air, there is so much water in the air that the air rush is not enough for evaporation to take place thus no more cooling can be obtained)

I still do not have a practical data to confirm this but I am working on it.

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Tuning on 100% Water then 50/50. Why?

From experience in tuning, I confirm that 100% Water does not change AFR altough if injected more than it should boost could not reach it's maximum since the turbine needs heat/speed of the flame to run. Water slows this process down eventually.

The best is to tune on 100% Water and find maximum power/torque with the least possible AFRs. Mine is about 13.5AFR.

Once tuned right on 100% Water, put a mix of 50/50 and leave all as it is. Make a run and AFRs should go below the 100% water values since now methanol is burning aswell. Put the engine on dyno and check power/torque accordingly. If W/M injection is right you should leave the ignition timing as it is as the extra timing was already put during the 100% water tune.

[Richard L]

What is your goal with your experiment? I believe improving the BSFC (Brake specific fuel consumption) has to be the aim.

I have not heard any reports on engine damage running 50% of water to fuel, it just looses power. More probably due to lack of capacity of the ignition system.

M50/W50 puts less stress on ignition system. For most, it is easier than upgrading up the ignition system. Alcohol engines normally requires multispark ignition system.

I love to see your tests/result involving on monitoring AFR, MBT, EGT and power output. If those figures, you can see estimate BSFC and compare the merits of water and methanol.

Fortunately you have find those experiments on dozens of research papers published.

[parmas]

Richard,

Thank you for your reply.

Yes, the aim is to obtain an overall maximum power across all the rev range with the least possible fuel.

Due to that I tune on street all I can monitor is AFR / EGT / AIR TEMP. Next I will datalog a run with 100% water vs another run with a 50/50 mixture and post results.

[GOFAST]

Originally Posted by parmas

Pre-turbo comes 4psi later than Pre-throttle body by using a variable check valve.

why does the pre turbo come in later ?

I also inject pre turbo and I want to learn as much about it as I can ?
how do you determine when to inject pre turbo and when to inject post I.C ?

gr maurice

[parmas]

Originally Posted by GOFAST

why does the pre turbo come in later ?

I also inject pre turbo and I want to learn as much about it as I can ?
how do you determine when to inject pre turbo and when to inject post I.C ?

gr maurice

Hi maurice

During the time reading on pre-turbo injection, many state to inject as late as possible due to the fact that injecting at "low boost" would eventually result in a possible damage to the compressor blades.

Also you have to understand why are you injecting pre-turbo eventually?

To increase compressor efficiency.
Mainly compressor efficiency is lost on high boost due to the compressor efficiency map and due to heat generated by high boost.

So when would one inject pre-turbo?

One should set pre-turbo to start just before the compressor start to loose it's boost efficiency.

Example : I own a Garret Gt2560r turbo. Comparing this turbo to my engine airflow, it start to loose efficiency past 14psi. Infact between 1 to 12psi the amount of heat generated is low while past 14psi till 20psi it almost doubles.

So in this case injecting @ 12psi progressively increasing till max boost

Check out the attached compressor map

[parmas]

Water vs 50/50 (By weight) Water/Methanol

Today I made a street run testing with 100% water injection and 50/50 mixture.

All Injection settings and Boost was kept the same . Starting @ 6psi giving full 300cc Post turbo + 150cc Pre Turbo @ 12psi.

The Results:

- It was noticed that with the 50/50 Mix the Air Temperature was seen colder by an average of 5DegC with some moments giving a 10DegC better efficiency. Since I am probably injecting at 100% Dew point of water, the theory of two liquids mixing better with air gave positive results. Thus the theory actually is true.

- AFR dropped by 1 point when using 50/50 Mixture giving from 13.5AFR on water to 12.5AFR on 50/50.

- EGTs were dropped by 50DegC. Strangely the excess fuel from methanol seems a better coolant than giving the engine 100% water. Presently I am below 700DegC.


Next is a trial run on the drag strip and see what we get on friday.

Cheers

A good luck would be appreciated

[Richard L]

Good luck and look forward to the results.