Meth / water injection - revisited
 

Quoting MM from another thread . This is worthy of more discussion as many people here are taking it for granted that it is 'the answer' to our FI engine blowing blues .

I'll go ahead and quote RP here for posterity:

Here is the rest of the qoute from MM:

I'll also reiterate my question:
Very interesting stuff. So how much power loss on average do you see with using a 50/50 mix (on the same tune as running without)? In your opinion are there any situations where the charge cooling and octane boost would outweigh the potential damage to the engine from high EGTs and power loss like tracking or sustained high load driving in high temperatures?

On the last turbo car that I did a before/after comparison, the car went from 320 HP to 290 or so when the smallest jet was used with a turn-on point of 10 PSI or so.
IIRC, on one of the ~280 HP cali cars, the power only dropped about 7 to 10 with a 7 PSI turn-on and small jet.

My own car wont stop misfiring until the meth is essentially turned off. I removed it from the car today.

Sustained load is exactly where the meth is at its worst. I think its only useful application would be to have it turn on when you are exceeding your tune in some way. Maybe over-boost or something.
BTW - meth is NOT an "octane boost" in the strictest sense. Though it has a higher octane, it has a significantly lower fuel value and higher mix ratio.

Very interesting.....
Good information, thanks everyone

This kinda leads on to another debate ...
MM - I have noticed your recent remarks about what AFRs you are running and tuning for . These targets seem to have gotten lower than what we used to regard as "safe" .

If one were to streach the envelope with a small turbo (cough) producing very hot air - would going to say 11.0 AFRs be a better bet than using water meth ?

Yes.

I think that measuring of octane rating of fuels, which have high latent heat of vaporization is meaningless, cooling effect will skew the measuring.

Have you tried straight water? Or higher ratios of water vs. methanol?

I believe Juan did some dyno runs with a variaty of jet sizes?
If I remember correctly he did have some demonstated power loss with the bigger sized jets.
But with a total of 150cc ( 2 jets, one pre blower and one post) he did not?
I do know if you spray during closed loop (boost or not) it mess's with your ltft's!
I am curious as to to why some are seeing increased egt's with w/m use?
I have not used an egt sensor, but when I track I do notice that the exhaust system seems to be not as hot. I relaize that is subjective only.

People will try to selectively edit their way to get you to use water injection by stating "One can basically double the power output of an engine using water/methanol" and "It was used effectively in Formula 1 before being banned for adding too much power". This is pure bunk. Water or water/alcohol/methanol does not make power...superchargers and turbochargers make power. The cooling effect of the water injection only allows you to run higher boost pressures and leaner mixtures without engine damage. The increased density or higher pressure ratio is what makes the power, not the water. The last time we checked water wasn't a very good fuel.

Aren't EGT's supposed to peak at around 13.2 afr?

Besides to the best of my knowledge water injection is not for reducing EGT's, it is not about increasing octane, it is primarily used for reducing the chances of detonation from engine hot spots. All the other "side affects" are just observations used for marketing?

Following with interest.
OD

Yes. At anything less than 30% methanol, the power loss increases significantly (as does the misfire).

Misfire.

No. EGTs will peak just after LBT, wherever that might be on a particular car.
However, they will go up and down depending on ignition timing and can spike significantly if the AFR is very rich.

What i am getting from this is that on the same car at the same PSI more power can be had by tuning to a safer AFR rather then by running a leaner AFR with meth.

However turning up the boost on the same car and running more boost with the meth injection will produce more power. (Untill the meth injection fails and the motor detonates and destructs itself.)

So using meth ONLY as a security measure, is not worth it. You would get more power and have a "safer" tune by jsut lowering the AFR's.

Using meth as a tool to run more boost is effective but one still runs the risk of the meth failing and the motor detonating.

Am i understanding this correct?

Wait wait wait

..so um...what kind of charge cooling did MM use to push his turbo beyond its effeciency range and make uba powa?

Attachment 251800

That would be considered using the meth as a tool instead of using it ONLY as insurace. He never disputed the fact that you could adjust the tune to use the meth to allow for more boost. He only stated that when using the meth for ONLY insurace that it would be more effective to just tune to a "safer" AFR.

Big power was through the use of fuel.

nitrous?

No.
116 octane, 12.2:1 AFR, 14° of timing, 17 PSI on the GT3082r.

quoted for posterity :D:

btw..that seemed way too easy. I expected an epic game of mouse and cat. :lol:

So was water/meth the only means of charge cooling you've used? I always had this suspicion you used something more exotic.

Whp = ?

you mean you couldn't feel the earth move from where you were ?

Not at all... Must not have been as big as Mawnee is makin it out to be

'Twas a bunch. Not really relevant since I can't profit from it and you can't learn from it for a multitude of physical reasons.

For those pulls, it was straight methanol in a very small quantity.

a little birdie told me 430 ....

Cool, Thanks for sharing MM :)

Phish its an old subject, but I never really got the answer I was after in 'that' thread. It was semi on topic here so I thought I might have more success :)


MM is your assesment of water/meth renesis-centric or do you feel it applies to piston engines as well. What I mean is, is it a result of the renesis spark delivery inadequacies or the rotory compression method?

Just read Richard's post. It pretty well explains my stance, though I do believe that the losses on the Renesis are greater than on a piston motor because of the charge inertia issue.

I will give up my w/m when you pry its button out of my cold dead fingers.

Juan, per dyno did not lose power with the total of 160 cc/hr nozzles?

Wouldnt adding more fuel also mean that carbon build up would be more likely?

Good discussion--- but i have always thought that w/m was to help insure my octane level was ok? When you are pumping your gas (lol) you really dont know what octane you are getting. Then you add ethenol..... now if you just run straight ethernol:)
How do the egt's rise, but the power goes down? That seems contradictory?
OD