ESE's works engine tuner

[Niels Abildgaard]

Hello Wobbly

In dec 2020 You were engaged to do some 30.5ccm experiments.
Can You tell what You achieved?

[Flettner]

I assumed they did this as by refrigerating it they can have more fuel for the same volume until it warms up anyway.

Suzuki used to do this in the Castrol six hour races, at Manfield.

[Wos]

Wos , the unleaded FIM GP fuel brought into being in 1998 was nominally 100 octane , but was so dangerous to handle gloves and a respirator had to be used to fill the tanks.
Teams also refrigerated it prior to use.
Elf did a ton of research on the mix , ending up with what was called MITS 32 that would literally melt your nose.
So much for the virtue signaling clean green bullshit.

Thanks wob👍

If you look closer behind ...most green things are totally bullshit🤮

[wobbly]

Hello Niels , I had to sign an NDA for that project , but suffice to say I changed absolutely everything including all the port radial and axial directions , used a longer rod , and did a Titanium pipe.
I would have to go back and see what the NDA terms were , but its was the usual story of not enough funds nor enough fundamental knowledge of leading edge
2T technology by the guy I worked with.

The frozen fuel in GP racing was more about being faster for 5 laps , as the volume change due to the temp delta was minimal.

[husaberg]

Suzuki used to do this in the Castrol six hour races, at Manfield.

I had heard of aussies pre prepping the tank by freezing the tank whist full of fluid to increase the total capacity when the water expanded.....it was still stock just a bit mishappened...

[Niels Abildgaard]

Hello Niels , I had to sign an NDA for that project , but suffice to say I changed absolutely everything including all the port radial and axial directions , used a longer rod , and did a Titanium pipe.
I would have to go back and see what the NDA terms were , but its was the usual story of not enough funds

Thank You for answering.

It is just a game to see if someone can better the Aprilia RSA perfection.

Formula is

(30.5/125) ** 2/3 multiplied with the imortal 54 horsepower and that means 21.o8 horsepower for the 30.5 ccm as the choking limit of the optimum blow down time area.

[Frits Overmars]

It is just a game to see if someone can better the Aprilia RSA perfection.
Formula is
(30.5/125) ** 2/3 multiplied with the imortal 54 horsepower and that means 21.o8 horsepower for the 30.5 ccm as the choking limit of the optimum blow down time area.

Niels, predicting the achievable engine power via the cube root of (its cylinder capacity divided by the cylinder capacity of the RSA) is mathematically correct, but physically only applicable when those cylinder capacities are not too different from each other.
An elephant is never cold and a mouse is always shivering: relative heat losses increase strongly with small cylinder capacities because the surface/volume ratios increase sharply. And a second rescaling problem is that boundary layer thicknesses are not scalable.

[SwePatrick]

A 700cc four-cylinder two-stroke on methanol without any form of supercharging except for the contribution of the pipe, putting out in excess of 350 Hp?
That's over 0,5 Hp per cc. That would be damn good from a 50cc single. But from a 700-4?? 'If something sounds too good to be true....'

That what a well tuned methanol engine do..
i know of a similar engine in sweden, only 500cc thou, but it puts out 261hp
And remind yourself, they measure power differently.(not on the sprocket)
Normal powergain on methanol on a twostroke watercooled engine is in the area of 8-11%

[lohring]

We've been running very small engines on nitro/methanol fuels for a very long time. Inertial dyno tests on these engines have also been done for a long time and continue today. A sample of some early testing is in this paper. https://web.archive.org/web/20030205...om:80/dyno.htm It shows a BMEP of 92 (6.3 bar) and 4.44 hp at 20,000 rpm in an 11 cc engine. They were running 65% nitro and i bet around 20% oil. I doubt that any of these engines exceed a BMEP of 100 psi (6.9 bar).

We ran a lot of similar tests on 26 cc gasoline fueled engines and race boats. We also did some fuel testing on an engine setup for gasoline to see how fuel cheating would work. We decided that it wouldn't matter unless the engines and pipes were designed for the methanol fuels.

Lohring Miller

[Gradella23]

So I looked thru my files and found a TZ50 , this is 40 bore with 39.3 stroke.
With 16:1 the cc is 3.33 and squish is 0.42 and to get 38M/s MSV the width is 50% = 5.84mm
This uses a 10mm NGK race plug with Iridium fine wire electrode and a Platinum fine wire ground = R0373A - 10 the same nose configuration as the 14mm R 7376 that is the best
race plug in every other configuration.
As this isnt a flat top the chamber wall can be steeper to suit as the squish is also angled.

Thanks Wobbly, mine is 40x39,7 but i got the concept. It's almost impossibile to teach this configuration without an M10 plug, that was the main issue. I'll try boh solutions and see what happens. Have you experienced significant gain using a domed sqhish band with the same radius of the piston versus a tangent -best similar angle One? The difference in height would be only some hundreth of mm

[wobbly]

Never been able to back to back test a very close tangent squish against a radiused squish as I always use CNC for this where I can.
But I have taken on board Frits same as piston radius idea , even though 90% of the engines I do have a conical squish area.

[Wos]

CNC is best Equipment wob

To get same radius is not easy to do by hand.

I am using fine sandpaper and polish fluid for aluminium, to radius the plan/ straight squisharea done by lathe

For contol use "mechanics blue" ...kind of paint used for example in metal molding.. between the touching surface of piston and squish..to see footprints that have to be done better...

Hard to explain for me in english cause my last lesson is about 40 years ago😅



Wob? frits...all the others

Do you polish both surfaces too?

Thank you very much!

Grüße Wolfgang

[Frits Overmars]

For contol use "mechanics blue" ...kind of paint used for example in metal molding..

And in dentistry, as I discovered the last few weeks. I've got a bite like a vice grip now .

Wob? frits...all the others, Do you polish both surfaces too?

I do. The piston dome, the combustion chamber and the exhaust duct are the only surfaces I polish. But not for the sake of flow.
Polishing a surface slows down carbon deposition, but far more importantly, a shiny surface reflects heat radiation. The big difference with a heat-insulating layer is that the surface of such a layer becomes very hot because it does not transfer the absorbed heat to the underlying metal. And that hot surface promotes detonation; not something we are waiting for. A reflective surface also protects the underlying metal against heat radiation, but the surface itself does not heat up.

[lohring]

Speaking of dentistry, I keep thinking the zirconium ceramic alloy we use in crowns would make a good material for engines. It's strong, crack resistant, high temperature and easily machinable in the unfired state. The CNC machining program compensates for firing shrinkage and results in a very accurate final product. Grinding the fired material is straightforward. We use diamond burs and diamond polishing compound. If I still raced ringless piston, small (under 15 cc) engines, I would consider seeing if a dental lab could make some parts.

Lohring Miller
PS For those who didn't know, I've been a dentist for 45 years. Engines are my hobby these days.

[wobbly]

I use increasingly fine wet and dry on the combustion chamber and piston , then polish to a mirror with Mothers Mag Wheel Cleaner.
But never the squish area , my thinking was derived from experiments years ago using ceramics on both the piston and insert , it detonated like hell.
But just coat the chamber and the piston away from the squish and it made more power - simply due to retaining more heat in the combustion process and dumping less into the water , or into the bore via the ring.
Ceramics prevent migration of heat thru the coating to the substrate , but the actual surface is very hot , so by deduction I thought reflected heat from a polished surface into the trapped squish end gases would have the same effect
as a coating.