ESE's works engine tuner

[seattle smitty]

Seems to me you really can't offer a final verdict about any alternate fuel or blend if all you do is tweak the jetting and spark timing and plug heat-range; most of the alternatives mentioned over the last couple of pages would work better if combustion chamber volume were also modified to best suit THAT fuel. Add that alteration and I'll bet you start seeing your fuel in a much more positive light.

One hint if you haven't already discovered this, with nitro blends a lot of times the fuel inlet needle and seat are the first restriction you have to address.

[Flettner]

Seems to me you really can't offer a final verdict about any alternate fuel or blend if all you do is tweak the jetting and spark timing and plug heat-range; most of the alternatives mentioned over the last couple of pages would work better if combustion chamber volume were also modified to best suit THAT fuel.

True that, use it properly or not at all.
When they go back to the original rules and allow 100cc fourstroke "anything goes" like it was originaly, I'm in
I don't like fourstrokes but supercharged on ethanol / nitro blend does interest me somewhat. Parts are being aquired.
Unfortunatly I can't shake this "if some is good more must be better" mentality.

[TZ350]

We have tried and used RE85 somewhat a lot in Finland. Our booze moped is 79cm^3 air cooled lazy 2-stroke Suzuki. RE85 gives enormous (not sure if you can say that ) amounts of low end torque, or shall I say toughness.

Are those snow/ice tires on your bike. It is not something we see here in NZ but I have seen video clips of ice racing.

[TZ350]

When they go back to the original rules and allow 100cc fourstroke "anything goes" like it was originally, I'm in
I don't like fourstrokes but supercharged on ethanol / nitro blend does interest me somewhat

That would greatly interest me too.

[sitkuura]

Maybe i should introduce myself. I´m over aged (as my wife says) moped tuner from Finland. So far my best result is 11,75hp@rear wheel on Tunisti's dyno with 74cc aircooled suzuki engine.

Pic of my moped after race in last august.


And some videos...
https://www.youtube.com/watch?v=12ohDziUnvc last fall with e85 fuel
https://www.youtube.com/watch?v=nGaQgosY_qs and winter tire testing with 98octane gas

Are those snow/ice tires on your bike. It is not something we see here in NZ but I have seen video clips of ice racing.

That bike 3rd.person bike. I don´t know anything about it, but it has great power... Tires are self studed with car studs (road legal in Finland) and they have nothing to do with real winter racing tires I made similar for my moped too.

[TZ350]

Thanks, looks like fun.

[nasone32]

I am very interested in this as Team ESE have a CVT project in mind.

Then I'd be glad to help you.
Since i received so much from people in this forum, i'd like to explain a key fact in cvt engines, which most don't consider.

A good racing cvt puts a constant load on the engine, this is why it stays at a fixed rpm.
This presents a problem.
the maximum torque point is not a stable point of equilibrium for the cvt.
suppose you have a sudden increase in the load on the transmission. typical example would be when the transmission heats up, or you are on a sloping road.
The load increases, the engine revolutions go down and now it is working on a lower torque point in the torque curve of the engine. the engine will never catch up.

What you want to do is set the transmission to work a bit over the maximum torque, which often means over the maximum power, because a cvt engine can have a narrow power band and this means max torque and max power are near each other.
in this condition, if the load on the transmission increases suddenly, engine rpm will go down, but now you will be on a higher torque point on the curve.
this makes a stable equilibrium point.

this is why you want to develop the engine to have some usable range over the maximum power.

also a cvt usually benefits from power produced with more revolutions and less torque.

[seattle smitty]

Unfortunatly I can't shake this "if some is good more must be better" mentality.

Well, the developer of this rig (which I have shown here a while ago) found that as he started taking the nitro percentage over 20% the engine really woke up; I think they raced it with 40-45%.

http://www.outboardracing.com/images/Image1707.JPG

[TZ350]

Since i received so much from people in this forum, i'd like to explain a key fact in cvt engines, which most don't consider.

Thank you, that is very helpful.

[Tunisti]

Seems to me you really can't offer a final verdict about any alternate fuel or blend if all you do is tweak the jetting and spark timing and plug heat-range; most of the alternatives mentioned over the last couple of pages would work better if combustion chamber volume were also modified to best suit THAT fuel. Add that alteration and I'll bet you start seeing your fuel in a much more positive light.

One hint if you haven't already discovered this, with nitro blends a lot of times the fuel inlet needle and seat are the first restriction you have to address.

That's true that there are several parameters that need to be adjusted for different fuels. Our ugly little Suzuki is just a test bench for all the silly ideas. The combustion chamber of it is ridiculous for any fuel, and so is the pipe and porting too. But hey! It's the kind of machine, witch is perfect for quick, stupid and very experimental mods!

We once tried 50% nitromethane 50% methanol mix, witch also had on top some synthetic oil and acetone as mixing agent for the oil. It idled and started quite well, half throttle was okay but at full throttle the carburator dried up in about one second. It also knocked with high compression head, so we changed it to less compressive model. After that we added some more methanol, until the mix was 40/60. This gave a bit more time to run WOT until the carb dried up. So, we removed the fuel tap, float, fuel inlet needle and needle. We had main jet with 3,1 times more flow than petrol jet. After that it tolerated few seconds of WOT. Engine reved much higher, ran cooler and there was very significant improvement in torque at low rpm:s and low throttle openings. This compared to petrol/ethanol. The engine lasted about 3 litres of that stuff, until piston ring shattered. But it was fun!

With sitkuura's moped we dynoed different combustion chamber designs with RE85. It seemed that about 10% smaller chamber volume works well with RE85, compared to 98 octane petrol. Ofcourse that test was very coarse, but it gives some directions. If i remember correclty, the ignition advance was best when few degrees earlier compared to petrol.

Btw. This was the appearance of the spark plug, when the little Suzuki was tuned for RE85. The oil is castor based.


Btw, some calculations of required fuel flows:
http://i893.photobucket.com/albums/a...ti/virtaas.jpg
http://i893.photobucket.com/albums/a...sti/peeaa0.jpg
http://i893.photobucket.com/albums/a...sti/peeaa1.jpg

Picture of moped

That's not my bike. But to show the "poor man's winter spikes":



http://i893.photobucket.com/albums/a...ps7c24116d.jpg

Cheap self drilling sheet metal screws! Traction is awesome, and they seem to be pretty durable too. Stoppie on snowy/icy road isn't problem at all. I would install those to my car too, if they were not illegal to use...

[nasone32]

this is the reed valve
it's a 125cc kart reed valve, it is as wide as the transfer ducts
It's a bit of a strange concept, i hope it will work.

[Peiter]

Your engine casing looks good, that must have been a lot of work !

Currently the stuffer inside your reed valve has a concave shape, promoting flow to the center and preventing flow over to the sides of the valve.
However, in order to get a larger overall flow, a convex shape should be used such that mixture can leave the reed valve over the sides too.

I think Wobbly and Frits already wrote something about this subject in this thread and hopefully they will fill in my gaps / elaborate further on it .

[nasone32]

Thank you, i'll take a look using the search function!

[adegnes]

this is the reed valve
it's a 125cc kart reed valve, it is as wide as the transfer ducts
It's a bit of a strange concept, i hope it will work.

The same configuration was widely used in the old 50cc french gr3 single variated racing class.
Not much info around that I can find, at least not in englishl(and you know the French...)

[adegnes]

Alot of pictures here

http://galerie.competition50cc.info/index.php?cat=12

These guy's took it to the extreme.