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Methanol Plug Reading

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Re: Methanol Plug Reading

Postby jaded13640 » Sun Sep 09, 2012 3:19 pm

RednGold,
Thanks for the great info.
I really appreciate you piping up on this for me.
I don't recall exactly what the issue was with the O2 sensor setup, maybe it was just cost.
Could you direct me to some resources for components?
I priced the EGT system as a "kit" and it was pretty pricey.
What I ended up doing was I bought a monitor, the probes and some pipe couplers that worked just fine for bungs.
I probably saved 65 or 70% by doing it that way.
I don't have collected headers so this might not work for me at all unless I was willing to put a bung and probe in each of the zoomies.
I used to have an Omega catalog that has a lot of that sort of thing.

I don't understand the part about:
RednGold86Z wrote:
2) Methanol has a pre-ignition sensitivity of LESS THAN 0! This means it doesn't take much of a hot spot to nearly instantly destroy your plugs/pistons/exhaust valves.


I thought methanol less sensitivity to pre-ignition and this is why you can run methanol on motors with a compression ratio of up to around 19:1.
A gas engine usually needs octane greater than that of pump gas much above about 10:1.
I'm not for a second suggesting you're wrong, I'm just not following.

As far as ignition timing I've found what you said to be spot on.
I don't seem to run any more timing on methanol than I ran on gas.
I can but it doesn't make any more power.

This motor seems to be "happiest" with EGT numbers around 1200F.
Does that sound about right?
I've heard people say it shouldn't be above 1100F

All in all, very good stuff.
Thank you.



Tom,
Did you get that info from a website?
If so I'd love to see it.
My cylinder heads have room for the 3/4" reach plugs but has the hole for 14mm.
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Re: Methanol Plug Reading

Postby RednGold86Z » Sun Sep 09, 2012 9:49 pm

Pre-ignition is ignition from a hot spot, which causes it to burn before the spark, not from hot compression and approaching flame front started by ignition (knock). It's printed in the Automotive Fuels Reference book, as well, and I've lost several bi-fuel engines during development (at least 8! - difficult to convince Chinese car companies to believe it's the spark plug's fault) because of it - happy as can be on gasoline, as lean as you want, but put it on methanol, and it'll go nuclear on anything leaner than quite rich with the original plugs (WOT testing steady state for long periods). Cold plugs let you run max power lambda settings, and keep lambda 1 longest for better fuel economy.

Methanol does have high "octane" rating, which allows you to run crazy high compression or boost if you want, just don't let a hot spot form in the chamber.

For EGT reading at a reasonable cost, I use a Pico TC08 system, and get thermocouples in China. I've heard of people finding things cheaper than a Pico system, so do some shopping around. I also have some Innovate tc04 or whatever they're called. 2 of those would be needed for a V8.

Use the thermocouples to adjust fueling to each cylinder if they're far from the average, and to monitor if things have gone awry between rounds. Without a collector, you're not going to be able to get decent AFR readings with a lambda sensor, as far as I'd guess. I'm not sure what EGT you'll be looking for.
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Re: Methanol Plug Reading

Postby jaded13640 » Mon Sep 10, 2012 11:57 pm

RednGold,
I'd be curious to learn more about this "hot spot". I've never had a detonation issue but I'd still be intersted in learning more on the subject.
If you a link to any information or discussions on the topic that'd be great.

When I asked about a line on components I was refering to the O2 sensors, AFR monitor and other necessary components.
Like I said in my last comment I found the EGT kits pretty price so I bought all the pieces and built an EGT monitoring system myself with considerable saving.

It would appear the "issue" I was talking about with using an O2 sensor was because I have zoomies and not collected headers.
"Collecting" my headers is not an option so I guess AFR monitoring is a definate "no go" at this point.

Thanks,

Wayne
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Re: Methanol Plug Reading

Postby RednGold86Z » Tue Sep 11, 2012 12:23 am

jaded13640 wrote:RednGold,
I'd be curious to learn more about this "hot spot". I've never had a detonation issue but I'd still be intersted in learning more on the subject.
If you a link to any information or discussions on the topic that'd be great.

When I asked about a line on components I was refering to the O2 sensors, AFR monitor and other necessary components.
Like I said in my last comment I found the EGT kits pretty price so I bought all the pieces and built an EGT monitoring system myself with considerable saving.

It would appear the "issue" I was talking about with using an O2 sensor was because I have zoomies and not collected headers.
"Collecting" my headers is not an option so I guess AFR monitoring is a definate "no go" at this point.

Thanks,

Wayne


By hot spot- I mean anything that'll glow - like a spark plug, exhaust valve, carbon deposit, sharp edge on a piston valve notch. Hot spark plugs are the typical first place to get hot enough to start methanol on fire. Page 141 of the "Automotive Fuels Reference Book" Second Edtion - "Methyl alchohol (<0) is poor but isopropyl alcohol (62) is good." when referring to preignition resistance. They measure it with a filament in a test engine. Toluene was pretty good stuff, and lead improves the resistance of most poor fuels. The high flame speed of methanol also can heat the deposits or electrodes much more easily and to higher temperatures. There's a fairly good relationship between flame speed and temperature of hot spots in an engine.

Yep, no-go for AFR, I'd say - so tune using a G-Tech Pro! It'll show you a power curve, and is surprisingly repeatable, so changes throughout the curve can be seen - say if you adjust the thing overall richer, it may increase the torque at lower speeds, while decreasing it at higher speeds, but this might be hard to see with just a time slip.
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