ESE's works engine tuner

[2T Institute]

Not on our kart tracks. A Suzuki RG with std parts will fail if shown much over 13000. But clearly better parts will extend things considerably.

17? Heck that's well out of my experience but I built way too conservative. Blowdown for those revs would be hard to get close to ideal.

Most are turning those sort of rpm in the 50cc race in Europe. Fit a larger rear sprocket

[husaberg]

If it doesn't lead me anywhere I'll put it on ice for a while and get that replacement valve.
.

Skill saw blade........

maybe fit a rotating disk with a cut-out between the carb and that big hole ?
I guess that would stall the outgoing charge

You could drive it off the end of the crankshaft & experiment with the cut out timing to gain peak performance!!!

Seems a little bit boring..........

[SwePatrick]

heres a oil question. i had been using 6% oil in methanol and decided to try 9%. i didnt notice the engine run any better or worse so i thought of trying 12% next time. if nothing else maybe the bearing and cylinder bore might last a bit longer. what do you guys think of this idea ?

Why?
I run 3% and all is fine.

I run Shell Advance Racing M, no need to mix up with a blending agent.
Just mix methanol and racing m to desired percentage and you´re fine.

I tried 4% first when engine was new,, and it all became a fat oily mess everywhere.

[Grumph]

klotz benol 100% castor and klotz super techniplate which is 80% synthetic-20% castor. they are intended for petrol, methanol, nitro methane. they can be mixed to atleast 18% oil content when used in methanol or nitro. im pretty sure the super techniplate is what some rc fuel manufacturers like VP are using, although the msds sheet doesnt say specific name brands. it dissolves just fine but beyond 18% i think it gets to viscous and some kind of thinner oil is used, thats my understanding anyway. i just figured with the corrosiveness of methanol and nitro why not use more oil if the internal components last longer.

I have no experience with those oils so can't comment. But the "corrosiveness" of methanol is simply because it's hygroscopic - and the water it captures condenses and promotes corrosion. I have painful memories of several seasons of washing banks of carbs in petrol after every days racing. And the speedway car guys would give me their carbs which by then were pretty much a solid block of white corrosion...
I'd probably try spraying something like WD40 into a wide open carb while turning the motor over - best while it's still warm.
The carb of course should be washed every time...

[teriks]

Why?
I run 3% and all is fine.

I run Shell Advance Racing M, no need to mix up with a blending agent.
Just mix methanol and racing m to desired percentage and you´re fine.

I tried 4% first when engine was new,, and it all became a fat oily mess everywhere.

While anicient, I like to think there's still some merit in the tests of Jennings from way back in time.

http://www.bridgestonemotorcycle.com...oilpremix6.pdf

All in all, more oil - more power.

Now, the physics haven't changed, but for sure cooling, manufacturing tolerances, materials and oils so those results might be completely irrelevant for the racing two strokes of today.

Personally I have no need to experiment with oil since we are required to run a standard fuel, 80%methanol, 20%(!) castor oil. Also the application is quite different from anything used in motorcycles given the ring-less pistons etc. Still interested in some modern take on the subject.

[Lightbulb]

I think Frits mentioned these way back in this thread. But for Adegnes engine, maybe a form of Tesla valve may help to reduce the negative pulse, and along with it, increase the induction length.
Neil

[SwePatrick]

Tesla valves is crap!

To get enough area for flow to make power, it doesn´t restrict any good any more.
And, on lower rpms, with small throttleopenings the air density is so low in crankhouse that it doesn´t restrict at all.

Forget that mumbo jumbo.

[Pursang]

Valveless pumps are not unusual in other applications.

I thought I posted this earlier....but ???

Flow will take the less restricting option..... Bernoulli told lies!!!

cheers, Daryl

[Haufen]

Tesla valves is crap!

To get enough area for flow to make power, it doesn´t restrict any good any more.
And, on lower rpms, with small throttleopenings the air density is so low in crankhouse that it doesn´t restrict at all.

Forget that mumbo jumbo.

Is that an assumption of yours, or is it based on hard facts like testing and / or simulations?

[oldjohnno]

It's amusing that the devices being considered to replace a disc valve that's simple, compact, positive and non-disruptive to flow have few if any of those attributes...

[136kg136ps]

I recall I had an older engine I had with no RV or reed.They called it a piston port.

There may be some "magic" AKA law of physics which necessitates a valve of some kind at specific frequencies to initiate or control a resonance in the inlet tract beneficial at those frequencies.
In any case, it seems there is more power to be made or lost on the exhaust side of the equations, it has got my attention until I figure I have it optimized.
That exhaust control valve looks a great start for an ATAC.

[SwePatrick]

Is that an assumption of yours, or is it based on hard facts like testing and / or simulations?

A blend of both worlds.
Been tuning engines for 33years now, that gives me a good solid common sense
A couple of friends have simulated and tested it on a twostroke, result?
It ran crap!

[Frits Overmars]

Frits, I assume you've done more research than most on the subject. In theory could no valve be better than a properly tuned rotary valve for peak power and overrev?

The advantages of a 24/7 inlet are an unrestricted mixture flow with better symmetry than a sidemounted rotary valve and minus the friction of that rotary valve.
A 24/7 inlet is no use at all below the power band, as you have already found out. But in the power band it can give good cylinder filling, and power in the overrev tends to be better than in the case of a rotary valve, unless you do a Flettner with variable rotary valve timing on the fly, but controlling that will definitely be more complicated than controlling a 24/7 valve. By the way, starting a 24/7 engine without any starting valve at all may be a pain; you've found that out as well.
That is why I designed it with a simple reed that swings out of the way, once the engines runs in the power band.
Experimenting with different inlet tract lengths is the way to go. In theory you could also experiment with different carb diameters and different crankcase volumes,
but changing a length piece is a lot simpler.

[peewee]

I have no experience with those oils so can't comment. But the "corrosiveness" of methanol is simply because it's hygroscopic - and the water it captures condenses and promotes corrosion. I have painful memories of several seasons of washing banks of carbs in petrol after every days racing. And the speedway car guys would give me their carbs which by then were pretty much a solid block of white corrosion...
I'd probably try spraying something like WD40 into a wide open carb while turning the motor over - best while it's still warm.
The carb of course should be washed every time...

i flush the engine and carb with petrol premix at the days end. no problems so far. i bet the reason some rc fuel uses 18% - 23% oil content is to maybe reduce the nitric acid accumulation inside the engine. thats the only thing i could think of

[breezy]

While anicient, I like to think there's still some merit in the tests of Jennings from way back in time.

http://www.bridgestonemotorcycle.com...oilpremix6.pdf

All in all, more oil - more power.

Now, the physics haven't changed, but for sure cooling, manufacturing tolerances, materials and oils so those results might be completely irrelevant for the racing two strokes of today.

Personally I have no need to experiment with oil since we are required to run a standard fuel, 80%methanol, 20%(!) castor oil. Also the application is quite different from anything used in motorcycles given the ring-less pistons etc. Still interested in some modern take on the subject.

i would think that if the lubrication of the cylinder/piston was applied in another way and not have to deal with being contained in the fuel mixture and subjected to the heat caused by the combustion process, that the engine power would increase. more oil, less friction, less stress on the oil to lubricate without oiling up the plug.