ESE's works engine tuner

[Flettner]

Thanks Frits, I might just do that.

[F5 Dave]

Air cooled engines are fuel cooled as well. A well placed injector would be fair sport and good for LE Brg lube.

[Drew]

Air cooled engines are fuel cooled as well. A well placed injector would be fair sport and good for LE Brg lube.

Even more so given that it's under pressure with EFI. So an injector pointing straight at the bottom of the piston could be an idea to trial. Fuel would vapourise real nice on contact too.

[peewee]

Peewee, I like the look of that Japanese handpiece. What looks good is the small size and design of the head that will allow the working end of the rotary file to sit a lot closer to the centerline of the handle, which should reduce chattering. Will it run off the Foredom flex-shaft like the other handpieces in the second photo, all of which I assume are from CC Specialty because that's where I got mine (in the early '70s)? What are the extra goodies in the kit?
One thing that's good to have is a reversible drive-motor, because sometimes where you get into areas that cause uncontrollable chatter you can use reverse-twist rotary files and run the motor in reverse, and solve the chatter problem. I was very happy when somebody told me about that, back in the day. Peewee, I hope the bevel gears have a bit less lash than those in the CC Specialty unit (you want to disassemble the head and lube those occasionally).
.

all my handpieces (even the new one) use a foredom flexshaft sr series motor with foot pedal speed control. its very powerful and has forward/reverse. i use reverse nearly as much as forward and for that reason i wouldnt even consider owning a motor without reverse. also i have a few reverse spiral carbide bits which i use frequently.

i havent bought much from cc, just the new 90 handpiece and 3 or 4 of the bits. everything else was bought at other places. the two straight handpieces are foredom, the larger 90 is from germany and fully servicable as it can be taken apart and bearings oiled and bevel gears greased. the new 90 is supposed to be a sealed unit with no further lubrication needed but obviously it can be taken apart if you wanted. when its worn out i suppose you send it back to nakanishi for a replacement of the bevel gears and bearings. since this stuff is just a hobby for me its unlikely ill wear out any of these tools anytime soon. some of them ive had for several years and they still work like new. if you go with high qaulity stuff it will last many years

while im thinking of it, whats everyones preference for texture on the walls ? ive heard alot of various opinion on this subject, mostly from noobs that dont know much, so i figured i would ask the experts here. ive always just used the carbides and pretty much left that texture on the walls but maybe theres something better ?

[TZ350]

Air cooled engines are fuel cooled as well. A well placed injector would be fair sport and good for LE Brg lube.

Even more so given that it's under pressure with EFI. So an injector pointing straight at the bottom of the piston could be an idea to trial. Fuel would vapourise real nice on contact too.

That is pretty much what I have been trying to achieve with the upwards directed injection stream from the central injector.



The central injector is aimed at the underside of the piston crown through a slot in the piston. If I have to replace the main outside transfer injectors because of time considerations with a larger single one in the inlet port I will still try and retain this smaller center injector in the rear transfer port.

[Flettner]

It won't be any different from what we are used to, Breezy. On the flow bench the central scavenging column created by the six incoming transfer streams has proven to be very stable; even if I blocked one of the transfer ducts completely, that column remained intact, albeit off-centre. And the exhaust characteristics depend on the gas dynamics in the pipe. The gas will be the same, the pipe proportions will be the same, so the pipe behaviour and the engine characteristics will be the same.

Here:
http://www.pit-lane.biz/t117p318-gp1...-part-1-locked
http://www.pit-lane.biz/t117p333-gp1...-part-1-locked
(it took me over an hour to find those links; I think I should cut back on my forum activities. Which one should I drop first? )

Like any other pipe resonance-dependent two-stroke.

Sure, also like on any other pipe resonance-dependent two-stroke: programmable ignition, power jet, power valves, trombone pipe.
But since I am under the impression that you can build anything you can think of: how about shrouds in the transfer roofs? If you lower them, you will lower the transfer timing, so wrongly-timed exhaust pulses will have less chance of shoving fresh cylinder charge back into the transfer ducts. Moreover, lowering the transfer timing while leaving the exhaust ports alone will increase the blowdown angle.area. That will put an end to the dreaded part-throttle detonation that plagued all Aprilia racing engines.
Taking this thought a little further, you could even use the movable transfer ceiling instead of a throttle.

.

You would need fuel injection BUT constant flow type NOT pulsed. I think an electronicly controled constant flow in the inlet might be the way, if using the transfer ports to throttle.
Or maybe six pulsed transfer port injectors? With a power jet type thingy in the inlet at full throttle?

[TZ350]

A Piezo injector may be the answer to the problem of only having a very limited time window available for the injection cycle at 14,000rpm on a 2T because ""a piezo actuator acts up to 5 times faster than a standard injector solenoid "" http://www.dieselhub.com/tech/piezo-injectors.html and are currently used on diesels so they can have several injection events in quick sucesion. Increasingly common on diesels but I have not been able to find any petrol ones I could buy yet.

http://www.germanautocenter.com/blog...n-german-cars/ "With the advent of piezo injectors, engine developers can now inject fuel into a cylinder’s combustion chamber in just 0.2 milliseconds." at 0.2ms they are a whole lot faster than the 2ms minimum on time injectors I have now.

[husaberg]

husaberg-with-a-small-h, pay attention, it's Smitty, s-m-I-T-T-y, American-style with two t's, not "Smithy." Anyway, I never heard that project called the "King Konig," but Dieter Konig (with umlaut) showed up with it at a big race in Texas some time in the early '70s. It was a one-off, which he made from one of his class D (about 700cc) flat-four motors and half of another, for something close to 1000cc or 1100cc (there was a rule change about that time) which was what we called F class I those days. FWIW, I was one of a few guys around the US who wanted to drop the old M/A/B/C/D/E/F designations (the M was for "Midget": 125cc), and change to the cubic centimeter designations which the Japanese motorcycle invasion had made common parlance; I like to think that an essay I wrote had some influence on the matter, and that another essay influenced the authorities' decision to drop the requirement to run engines they approved, thus opening the opportunity to adapt engines from bikes, sleds, etc., to outboard racing.

Anyway, I only saw a few photos of that F Konig flat-six, which IIRC ran well but went back to Berlin and wasn't run again. Pretty sure it had a single big rotary valve with three holes, three carbs. There were other home-brew projects of a similar nature, with two class C (500cc) powerheads stacked up, or set side-by-side on a gearbox. They sometimes made tons of power, had many teething problems, and generally were abandoned fairly soon, usually because they were very hard on lower units. Also heavy. I'll see if I can link you to some pix.

Dieter Konig was a talented man who supplied racing outboards that gave a lot of people including me a lot of good times. Some of the workmanship was not quite the best, and Konig fell well behind the state of the art in 2-stroke design by the mid-seventies, but his engines were affordable. As you guys know, he was involved with motorcycle racing for a couple of years, and with side-car racing for longer and with more success. Helmut Fath built his own GP engines that ran well as I understand, and it looks like they were modeled on Konig's flat-fours, which had first appeared (as outboards) in about 1965. Konig also built some little motors for ultralights, but unfortunately was killed flying one.

Smitty without an h this is all I could find.
http://quincylooperracing.us/subpage112.html
6
4

Fath

[Flettner]

Look at those nice drum valve throttles.

[TZ350]

American tether car racing http://www.amrca.com/

Jennings 2T tuners Handbook. http://www.amrca.com/tech/tuners.pdf

Lots of interesting little 2T & 4T handmade motors http://www.onthewire.co.uk/epitbx3.htm

[Frits Overmars]

If I can get the EFI thing working then we will be re visiting the plenum idea on the new 30+hp engine as the plenum with EFI will allow a very big, very short inlet tract.

As long as that tract is not as short as it could be, I will call it long.
and don't tell you won't be able to get to that top disk cover bolt .

this time the 24mm orifice will be on the plenum inlet.

Where else? Imagine that you are in a test cabin and the total air entrance to the cabin is a 24 mm orifice. You can be sure that the air flow through that orifice will be 24/7, not just 220° out of every 360 crankshaft-degrees. That's 60% better...

Previous experience with the plenum has suggested that the plenums resonance can be adjusted

It can be, but this will inevitably mean that there will be circumstances where the resonance works against the engine rather than with it.
With EFI you don't need to worry about fuel dropping out of the mixture due to too low a flow velocity, so make that plenum a big as you can; think Samsonite.

[Frits Overmars]

A carburettor mixes fuel with all the air that passes through it. So with the inlet injector what I don't want to end up with is patches of air that have no fuel in it.

If a carburettor has one advantage over fuel injection, this is it.
When the quantity of fuel is controlled via the open/shut time of an injector, it is practically impossible to create a homogeneous mixture at the injector. And I'm not even talking about vaporized fuel here; I'm just talking about every part of air getting the same number of fuel droplets.
Fortunately for us much of the necessary homogenisation takes place in a two-stroke's crankcase, with the con rod stirring things up and transferring its heat to the yet-unvaporized fuel droplets. But with direct fuel injection you loose this advantage, and the con rod bearing looses most of its cooling.

You would need fuel injection BUT constant flow type NOT pulsed. I think an electronicly controled constant flow in the inlet might be the way, if using the transfer ports to throttle. Or maybe six pulsed transfer port injectors? With a power jet type thingy in the inlet at full throttle?

Keep it simple, Neil. Spraying a constant flow of fuel in the inlet will do fine. I've been doing some work on 6,5 cc engines (google F3D and MB40) and since those little bastards rev to 36.000 there was no chance in hell that I would find injectors small enough and fast enough, so I designed a constant-flow injection; really simple, with an electric motor driving a gear pump and a spring-loaded conical-seat injector that would open according to the pump yield.
The pump is no problem: they are readily available for people building there own miniature jet engines. Controlling the pump rpm was less easy because the motor that comes with the pump, simply won't run slowly enough. Those litte jet engines are real guzzlers, even compared to a two-stroke, and the motor's stall rpm would still drown our piston engine while we were trying to start it.
Stepper motors were out because their bearings could not handle the gyroscopic forces in an F3D-airplane cornering at over 40g, and because stepper motors can miss steps without giving any feedback other than the engine running too lean. So I had to pulse-width-modulate the original pump motor in order to keep it running at a low, but to all intents and purposes regular rpm. I tried to measure its rpm by having a Hall sensor look at the teeth of the pump gears, but the teeth were so fine that the sensor couldn't distinguish them. The solution was to drill a small number (say 4) holes in the gear flank and have a Hall sensor look at those.
This is where the project came to a halt because of other, more pressing activities. But it may give you something to go by.

[peewee]

hey wobbly i been changing up the numbers alittle on engmod for a bit more power and rpm on this yami engine. first order of business is sorting out the intake area which needs to be bigger. the 2 main windows are fairly tall now but could be made taller still if need be. however i was thinking it would be better to try and gain as much of the extra area from enlarging the boyesens, then if the total intake area is still a bit small i can raise the main windows further as needed. what do you think ?

reason for my thinking is because it will put more of the intake area down lower near bdc, rather than sky jacking the main windows. plus the larger boyesens would help fill up the transfers faster. maybe im wrong here but this seems to make the most sense to me

[TZ350]

I will still use Flettners ball valve throttle but this time the 24mm orifice will be on the plenum inlet.

Where else? Imagine that you are in a test cabin and the total air entrance to the cabin is a 24 mm orifice. You can be sure that the air flow through that orifice will be 24/7, not just 220° out of every 360 crankshaft-degrees. That's 60% better...

LOL ... English is a funny thing ... I meant that the 24mm restriction that can currently be seen in the inlet tract of the Flettner ball valve will be re located to the plenum inlet. In the plenum configuration the 24mm restriction has always been in the plenum inlet. 24/7 flow through the regulation 24mm restriction was the whole point of the plenum concept.

EngMod2T suggests 3L is a good size for the plenum, 2L is minimum. Currently its 1L and when I tried it, it gave a significant boost to the lower part of the torque curve but the higher rpm part of the curve was suppressed. That gave me the idea that a variable plenum volume could be very useful too and with the Suzuki GP cases that would be reasonably easy to do.

[wobbly]

Yes, its way better to enlarge the Boyesens as they dont have any flow disruption from the piston.
There is plenty of room to cut away the floor and angle the flow down into the transfer duct feed area in the case.
Example of Cheetah cylinder, the Boyesens are 25 high by 14 wide.