Performance test: E10 vs Ethanol Free vs Trufuel

I could agree with that. I'm not arguing how the mrtonic works, but your idea of an SD system.
Except...if that were the case all it would need is rpm..
Blindly turning a screw is crazy. Wouldn't it run really lean? Unsafe lean? I guess it would drop rpm going to lean?
Doesnt it have a temp sensor though? A pressure sensor?
I know nothing comparatively about mtronic, so just spit wading.
I could only imagine playing with rpm and fuel on a dyno.

The crank position is curious...good info.
It's funny you mention the wideband, I was thinking about pulling one and trying it. Placement would be Paramount. You would need a pipe to keep reversion from messing with it. Maybe a fancy oscilloscope to plot afr and rpm would be cool.

 

Same story here. We've been running e10 for over 20 years. In everything. No issues. But yes, no winter time freeze ups on snowmobiles after the e10 switch. Before e10, I know at least one of my 2 sled engine burndowns were from carb icing.

 

Haven't had a chance to really play. But bogging it (poor clutch) runs lean. The hotter it gets the harder you work it the richer it runs.

 

Now that right there is dedicated research! Never, ever figured I'd see a saw with an O2 sensor!!

 

what in tarnation is going on with that lol !

 

We don’t have E10 here. It’s rumored that the E10 don’t like the negative degree temp. Supposed to separate when the temp gets below-30*. Personally would not know.

 

No, that's a non issue, the low temp supposed issues.

You probably don't have e10 in Alaska due to lack of corn, and no ethanol plants close, due to the lack of corn. You can make ethanol out of many things, but corn is the easiest and least expensive right now.

 

Awesome! How rich is it running?

 

Keeping in mind that not all sensors are created equal, and I have not yet calibrated it... And I have not run it enough to reset the mtronic?....the actual afr numbers may be off(probably within .3), but the % change is what we are looking for.

With the factory sized opening or the pipe cap on it's running mid 12.50s under load.... 13 flat in a light cut...taking the cap off bumps it up to mid-high 13s......where it should be for a two stroke......

I've been running it muffler modded with a much bigger opening, so maybe it's slow to adjust.
Again just initial play time observations.
Running my snowmobile oil at 50:1 with 87 e10.

 

AFR of 12-12.6 to 1 may be the rainbows end ... proven way is a small engine dyno ... or you can do what I do ... squish ; muffler mod ; timing advance and a sharp Razer chain ... usually good for up to 40% gains depending on saw ... if u NEED more .... PORT IT !

 

How long does it take for the mtronic to relearn? If you had a big round you could stop mid cut and remove the cap to see how it reacts.

 

I haven't messed with it. I'm limited to a marine battery and six foot 02 cable lead. With the guage flopping around.
But taking the muffler restriction off(the cap) it changes immediately. (Noodle half way stop unscrew and keep cutting.) Showing it's not instantaneous fueling. It also loads up with fuel after running without the cap and putting it on.
I was noodling to give it constant long load. I don't know what or how it would respond cutting extensively.
It definitely uses temp to fuel, and probably time.

I think the temp sensor acts as a crude knock sensors or egt. And adjust fuel for running too hot or under hard load or even too lean.

 

the mtronic uses rpm to determine whether to add fuel (richen the mixture ) or give less fuel (lean the mixture) ...it’s a canned-ham from Stihl ... the timing can be advanced but the newer models are using a casting instead of an easily modified key .... there is a way to “trick” or hack the mtronic but I’ll leave that explanation to the genius on Ope forum lol !

 

You need a back pack to keep the battery in so you are more mobile
That is very interesting it does not change instant. Could there be a "delay" for a drastic change? Like if the saw needs more than 7% more or less fuel it runs that way for X amount of time then changes.

 

I don't visit that site I guess I'll have to check it out. Is there a certain post I should look at?

In a very crude comparison (you described what fuels trims do)its probably like a fuel trim on a car, slowly adding or pulling fuel.
I originally thought the temps sensor might be for starting.
The two crank magnets are again very curious. It signifies that it isn't just rpm but crank orientation. Again just a guess it could be used for knock detection.

 

That’s what powers the mtronic ... there’s no “battery” at all ... it’s a very simple yet ingenious system that alters fuel flow according to rpm ... no temp or o2 sensors ... now the husqvarna auto tune is a different animal !

 

There's a temp sensor in the coil.

 

Right, maybe the short term trims can only do so much.

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no sir ... there is No temp sensor - I will show pics if need be