rithsleeper

Just thinking of ways to cut down on heat and push some limits safely. Does anyone use a meth injection on their NA motors? It seems like super cheap insurance. And from what I've read people use about .5 gal for every 20 gal of fuel? So like $4 of meth every fill up? To me that just seems like a no brainer.

Then getting the fluid looks pretty easy either heet or windshield washer fluid? The whole system is only like $300 and I'm betting the tune would be basically the same.

Why doesn't everyone use this system? Wouldn't the temps be considerably reduced also? You could run some serious compression and timing also safely. Say instead of a 12.5:1 ratio you could run a 13:1....

Anyone run them?

Joshboody

Too complicated and dangerous if tuning around it. For example meth boils around 150deg and if this happens the flow stops leaning afr and lowering octane.

If you have e85 this is the way to go... I run a 50/50 mix (about e43) sometimes which is great. The only downside is running low on fuel during a track day and having to bring 5gal reserve.

Edit: been thinking to try an open loop e85 tune leaning out cruise and WOT to see how much I can limit the 30% vol difference with gasoline.

jbsblownc5

I run Meth on both my vettes...

I've had it on my SCed C5 for 10 years, and I've also been running it on my NA built 12.1 comp C6. Works GREAT, just need a good tuner, and a properly setup system.

I use Alky Control, Maf based for the C6 and boost referenced on the C5.

Joshboody

Oh yeah, I was going to comment on water injection. The problem here is that water adv is only when it vaporizes taking heat from surroundings so ultimately you want this to happen in the cyl, but instead it will vaporize on the way there reducing the effects.

Even with meth you are mainly utilizing the autoiginite resistance and not so much of the cooling benefits. E85 will effectively have higher octane since injected closer to cyl.

Anyway I thing meth injection is great... did a bunch of testing with it on my last FI platform. Just a lot of things involved, especially on the track.

rithsleeper

Hmm. That does seem odd. I guess that is why I never see people mounting the resiviors in the engine bay. So a 50/50 water meth would boil at 150 or would it be higher? What about keeping a little pressure on the tank? I would think the vaporizing would happen even on a street car let alone a road race car.

The e85 what is involved in a conversion to that? I would assume a powerful fuel pump, bigger injectors but would the injectors need special valving? Fuel mapping shouldn't be too hard.

Guess what it comes to is the meth system is $400 would a conversion to e85 be around same price?

BrianCunningham

Running water instead of meth because the SCCA rules state you cannot run both gas & meth

Joshboody

There's prob a bunch of threads with LSx running e85. The tuning is easy. Depends on your mods for injectors and pump, but basically at same AFR you need 30% more vol of e85 over gas. I saw about 10% increase in IDC with 50/50 tuned about .50:1 leaner.

If I was to get more aggressive with it I'd install a fuel pressure sensor to watch it.

I'm not sure how people setup meth for LSx, but when I did it on a BMW we'd have a piggyback controller to monitor meth flow which would either adjust tuning or trigger a fail safe map if flow stopped.

Boiling point is higher with h2o, but still low. I'm live in AZ so it's damn hot and meth tank underhood would NOT work due to boiling... even with 50/50 mix. In the trunk I had no issues.

rithsleeper

I have 40lb injectors right now but at my power numbers I'm seeing that I would need min of 45lb injectors. Pure water would be cheaper it seems and pretty easy to keep full. I wouldn't be looking to really use water to push the limit, more like use it as a safety measure. Say have a 12.5 tune and 36* of advance at max HP. With a 11:1 compression if the water fails I would still be OK with my knock sensor but with water could keep it well within the safe zone.

Does water injection decrease the power if used with the exact same tune? Or does it only become effective by being able to push the limits?

hungryhippo

I removed the methanol kit as my car became more track oriented. I would run through about 1 gallon every 20 minutes. Methanol pumps are more reliable than they used to be, but there's still a chance for failure. It is also extra weight.
Now I run a few gallons of 100 octane mixed in my tank instead.

chuntington101

So are you wanting to trust a $300 fuelling system for a several $,000 high comp engine? Sounds very band aid to me! If you want to run high comp. and high power then Run it on the right fuel to start with. You can get E85 in a barrel if it's not available at the pumps.

Might also be worth looking at GMs flex fuel system so you can automatically adjust timing based on the alky content within the fuel. This uses the normal fuel system to deliver but you can adjust your tune based on the alky content of the fuel. This gives you the 'get home if no E85 available' option and the added power from E85 when's it's available.

rithsleeper

I know the thread has had a couple of post so I'll summarize. I do not want to build a race compression engine. I have a 11:1 ratio engine that just leaned out and blew because of a failing pump. I'm trying to figure out safety features that will increase reliability and consistency. I'm not saying a meth/water inj system would have solved my problem, I just don't want any more problems.

For $400 it seems like a pretty easy way to fight detonation (which is a huge problem running the engine in 100* weather with track temps at 120*....). I in no way want to rely on it. The engine will function correctly without any help. I'm looking at the meth injection in the same way as a knock sensor. Not necessary but couldn't hurt.

Moving to e85 looks like it would cost me a lot more and the engine is still used on the street. It doesn't look to be as cost effective and I don't have e85 readily available. Maybe somewhere but not just cruising around. Meth on the other hand wouldn't be so hard and I could shut the system off if not at the track since I wouldn't have a huge heat problem.

Chance are I'll do nothing. It was just a thought since I'm dealing with this blown engine (that was a combination of me and bad luck). I would like to one day have a car I can just tow to the track and have fun and drive. Not worry about reliability, it breaking down, etc. I know it is a wild and crazy dream but I still have it.

acroy

‘Cheap insurance’! why not. Run off the windshield washer reservoir, and only come on at say 90% throttle or more

I see no reason not to install a simple WI system on a moderate to high compression NA motor used for tracking. Do not tune to it; just spray a little water to cool the intake charge.

It seems there’s modest upside, and no downside if done right.

Joshboody

I agree water injection is fine and don't have to worry about tuning.

When you are moving IATs are fairly close to ambient and if the tuner adjusted ECT corrections conservatively, you should be fine.

Any extra injection won't help if you loose fuel pressure though. Install a gauge so you can watch it and would be good to link to a scanner so you can closely monitor in datalogs occasionally.

Apocolipse

I run low quantities of methanol and mainly all distilled water. You can run the blue washer fluid to make it easier but that's close to 35-40% meth. I hover around the 5-10% range to decrease the surface tension of the water and increase the fineness of the mist. I just buy a small jug of meth and pour some in when it's empty and then fill with water.

I had it under hood without any issues. It will increase the octane rating of your fuel and allow you to run leaner as it really cools the combustion chamber.

I use it as a safety system to keep my engines clean and knock free. I don't really add more power to it in case something happens to the system. But...in all reality...anything has the potential to fail regardless of costs.

acroy

Awesome feedback Apocolipse, thanks

OP: not a bad idea to run a AFR gauge; they are cheap these days. It'll let you know if engine runs lean for any reason.

Apocolipse

Thanks!

Another thing to consider is that lambda for meth is different than gasoline so it will affect your AFR gauge "accuracy" (I'll call it that for simplicity).

I've run it on N/A engines and I have run it on high boost (30+) engines as well so I understand how they work and how to utilize their potential.

When looking in the big picture, water/meth combo injection is not really for IAT reduction, especially when running something like 10/90 mix like I usually do. It is more for the effects inside of the combustion chamber, lowering temps, decreasing flame front speed (octane increase), cleaning valves and pistons, and also smoothing out the pressure spike in the chamber during combustion.

Food for thought here: "technically" pure water is infinite octane which is why it has these effects when added into the chamber with fuel.