Oh we've all seen this one before, and I've always been a supporter for meth injection, knowing that it does indeed cool the air charge more than any air to air intercooler can.

But today I was talking with a guy and he said that meth injection displaces air-meaning oxygen-and that alone it won't pick up any power. Where an intercooler will pick up power without adding any timing or boost.

I would like to see a test where they compare the two, at the SAME boost and timing levels.

What do you guys think? No a$$bag comments like snow's site says this or coolingmist says this....

 

I'd think that the increase in density from the the cooling of methanol would outweigh any displacement of oxygen.

Whatever though, I vote for both.

 

use both the cooler the air is before u inject the meth the cooler it will be when u inject it

 

Better yet, cool the charge with nitrous instead.

 

That's what I would think too, but I do recall magazines saying they didn't net much power without changing timing at least.

Both is definitely best, but I plan on running E85 in the near future which should handle any detonation problems. So the meth kit wouldn't do any good for me if it doesn't make any power in itself.

 

Lots of things on the engine don't make any more power themselves, but they help lose less.

 

Nitrous isn't a bad idea. It's not like it needs any more power on the street!

 

When I ran the intercooler (front mount) on my firebird I got soo much pressure drop the car went slower. Being able to run 'more advance' didn't make up for it.

Not to say an intercooler is bad, I imagine on a race car with less bends and maybe an intercooler that cost more than $400 it could work well.

I blew up a motor playing with meth injection. You can run more advance but your walking a fine line. 10 runs in the 1/4 all fine. 11th boom.

-- Joe

 

Check out this report:
http://www.not2fast.com/NACA/naca-wr-e-198.pdf

On page 6, there is a rather strong statement:

"In all cases, however, the engine power at normal spark advance with a given inlet-air pressure is increased by the use of internal coolants."

See charts on pages 22-25 to see the effects. The increase in power (expressed as imep) amounts to about 1-2%. An additional 2% can be gained with optimum timing.

If you study the chart on page 25 however, it would appear that the heavier internal coolant ratios could drop below the normal curves, if they were extended all the way back to normal timing of 28/34 degrees. Depending upon how much internal coolant is used, you could easily end up losing power.

It should be noted that the injection is upstream of the supercharger as was common at the time. I believe that this will result in more power as compared to injection after compression, due to the impact on compressor efficiency and impact on the mass air flow which should be increased for a given impeller rpm.

While it appears to be clear that there is some benefit, the actual benefit is rather limited. Injection after the supercharger is likely to be on the order of 0-1% gain, or 2-3% with optimum timing. Unless you're adding boost, it is kind of pointless from a power persective for a car that can run on pump gas.

 

So meth injection isn't going to give me much power if I only have 4* of timing to put back in, and the blower is already maxed out.

I was told by a respectable rep of an alcohol injection system that injecting meth into the impeller can increase boost by 2 or 3 psi on my blower. Thats about 40-75hp I figure. But, then I have to pull fuel out of the carb to maintain a good afr ratio, which would mean, I'd have to run the meth injection all the time. And if it were to fail, I could hurt my engine. This amount of power also might not be enough to get me where I want to go.

I think I might just shoot a 75 shot at it, maybe into the impeller, which should turn into at least a 100 shot. The motor can handle it, dunno about the head gaskets. I think E85 would surpass my A1000's output, so I'll just run race gas at the track to be safe.

I think I'm set on the nitrous, just need to decide whether I should spend the money for a good dry kit to spray into the impeller or just go with a standard cheap under the carb wet kit.

 

the biggest advantage of methanol is not the power increase due to the methanol, but the ability to run a certain boost level at a specific timing on pump gas that would not be attainable without the methanol. it is simply another tool to help increase power, by allowing more timing and more boost.

 

So you're saying my first question of my last post is correct?

One thing I forgot to think about is my top gap is only .024. I'm guessing thats going to be questionable.

 

I missed that. Yeah, you probably wouldn't see a whole lot of gain from meth, though spraying it through the blower like recommended would probably be pretty helpful. worth experimenting with anyway.

 

I think it would. I think what I'll do is get a wet kit and try that for a while, then get a dry shot and spray it through the blower.

I'm still a little questionable on the top ring gap though. I'm only running 8 psi and a 75 shot would be like another 3 psi. 11 lbs of boost seems like it should be fine with a .024 gap. I'm also running a non-blower cam with more overlap than optimal, so I'm cleaning some heat of the top of the piston.