ESE's works engine tuner

[husaberg]

jbiplane, thankyou.

I've been using the NZ made Link ECU. Used it on my Kawasaki crankcase/transfer port injected twostroke (shown in the picture, 2008) and also on the first B port TPI twostroke, YZ250 (2012)
This next development requires twin throttle control, detonation control and input sampling. The Link suits my needs for the moment.

Here you go Flet

KTM’s Transfer Port Fuel Injection
In this side view we see that as in any simple crankcase-charged two-stroke engine, the KTM's charge air first enters the crankcase through a one-way reed valve, and is slightly compressed there as the piston descends. When the moving piston's top edge uncovers the transfer ports that join crankcase and cylinder, the slightly compressed air in the crankcase jets into the cylinder on a looping path which offers minimum mixing of fresh charge and exhaust gas. Fuel injectors in the tops of the transfer ducts add fuel to the entering air streams
KTM’s Transfer Port Fuel Injection
In this side view we see that as in any simple crankcase-charged two-stroke engine, the KTM's charge air first enters the crankcase through a one-way reed valve, and is slightly compressed there as the piston descends. When the moving piston's top edge uncovers the transfer ports that join crankcase and cylinder, the slightly compressed air in the crankcase jets into the cylinder on a looping path which offers minimum mixing of fresh charge and exhaust gas. Fuel injectors in the tops of the transfer ducts add fuel to the entering air streams

Here we see the engine from behind and can see two of its transfer ducts in section. They conduct compressed air up from the crankcase and into the cylinder. A fuel injector, mounted in the top of each of these transfer ducts, sprays fuel against the moving air, thereby achieving a high speed difference between fuel droplets and airflow. This breaks up the fuel droplets, increasing their total surface area so that they rapidly evaporate to result in an easily ignited mixture of air and fuel vapor in the cylinder. The injection of fuel is timed such that none of it can reach the cylinder's exhaust port before it closes.


Illustration by Jim Hatch

[Juho_]

Hello.

No further progress has been done since the 35.2hp dyno run.

It is an Minarelli AM6 engine with a 'Roost Havoc 98' cylinder.
Bore stroke is 52/46mm

Keihin carb copy, 34mm
Vforce 3
Homebuilt pipe.
E85 fuel(at this time, will be methanol later on)

I've heard about that cylinder and seen some videos on youtube (zip stunter), seems like it has even more potential than I had thought.
Atleast there is a lot of blowdown and transfer area.

Have you done any more modifications for the crankcases than just ported to fit the cylinder and the reed valve (ktm sx 65 / tpr or stage6 version fits without modifications..but do not have quite enough reed area for that large carburetor)?
Not really sure if there would be any benefit modifying the reed valve angle (in stock condition the reed valve is aimed towards crankshaft)...but crankcase volume is something there must have been changed since it'll be quite small for 98cc cylinder capacity.

[Flettner]

2012, YZ250. Took KTM a while but they eventually caught up

[husaberg]

2012, YZ250. Took KTM a while but they eventually caught up

Well they did have to translate it into sausage speak, and then figure out how you did it without wearing lederhosen.
Due to KTM not coming forward with the patents I would suggest it is Rotax that holds it and KTM is using it under licence.
Rotax do have a similar looking patent as I pointed out ages ago.
https://patents.google.com/patent/US20020011223

[Flettner]

Close but no cigar, injectors are angling into the cylinder with this patent. where as with the product they now sell the injectors clearly fire back down the B transfer ports toward the incoming air, just like our YZ.
I don't think they show a patent because they can't, the technology has been 'free to air' (prier knowledge) since early 2013, on the bloody internet for all to see. The firing down the transfer port toward the incoming air from the crankcase is the key. Somewhere to store the extra fuel when transfer port open/flow time is not as long as injector on time. This also helps furnish the A port with fuel higher up in the revs, on the pipe. The key is the injector position and the fact it fires back down the port. KTM know that now.

[philou]

It is an Minarelli AM6 engine with a 'Roost Havoc 98' cylinder.
Bore stroke is 52/46mm

Keihin carb copy, 34mm
Vforce 3

Minarelli sheet6 hase a ridiculous crankcase volume and little material to enlarge.

how did you do to install vforce reed valve ?

32Hp gearbox 6 speed and 6 false neutral

[Muhr]

Hello.

No further progress has been done since the 35.2hp dyno run.

It is an Minarelli AM6 engine with a 'Roost Havoc 98' cylinder.
Bore stroke is 52/46mm

Keihin carb copy, 34mm
Vforce 3
Homebuilt pipe.
E85 fuel(at this time, will be methanol later on)

Hats off to V Force for 34hp at 16400rpm obviously no reed floting

[Frits Overmars]

Hats off to V Force for 34hp at 16400rpm obviously no reed floting

Maybe the reeds can't be bothered to close at 273 Hz. With the right combination {crankcase volume + inlet duct diameter + inlet duct length} they won't need to .

[SwePatrick]

I've heard about that cylinder and seen some videos on youtube (zip stunter), seems like it has even more potential than I had thought.
Atleast there is a lot of blowdown and transfer area.

Have you done any more modifications for the crankcases than just ported to fit the cylinder and the reed valve (ktm sx 65 / tpr or stage6 version fits without modifications..but do not have quite enough reed area for that large carburetor)?
Not really sure if there would be any benefit modifying the reed valve angle (in stock condition the reed valve is aimed towards crankshaft)...but crankcase volume is something there must have been changed since it'll be quite small for 98cc cylinder capacity.

We run 1.28 in compressionratio in crankhouse, so yes it has been ported quite some.
The reedvalve suprisingly is made for AM6, so it is quite small.
We have plans of taking a CR85 V-force and and use that, i also think that the reed as used in the 35.2hp dyno is stretched to its limit, and then some
They had to run without the stuffer, with the stuffer mounted it was a huge powerloss.

[SwePatrick]

how did you do to install vforce reed valve ?

Just bolted it on
But it needed a spacer also to enlarge crankhouse.

[SwePatrick]

Hats off to V Force for 34hp at 16400rpm obviously no reed floting

When stumbeling into a certain combo, reed is actually better then disc to let it rev high and still having some chance of jetting carb correctly for low speeds.
Frits mentioned some parameters.
I often calls it 'standing wave'.
When reaching this the engine just becomes a combustion chamber for the pipe, that is acting like a pulsejet

btw, 35.2hp not 34.

Some Dutch guy has dynoed above 36hp(can´t remember exact number, but is was above 36hp) with a Roost98, this with a boyesen KX85 reed.
The later Roost 100 flangemount cylinder is close to 40hp unported, HK tuning in Germany says he has dynoed above 41hp, but i´m not trusting that fully.

[Muhr]

When stumbeling into a certain combo, reed is actually better then disc to let it rev high and still having some chance of jetting carb correctly for low speeds.
Frits mentioned some parameters.
I often calls it 'standing wave'.
When reaching this the engine just becomes a combustion chamber for the pipe, that is acting like a pulsejet

btw, 35.2hp not 34.

Some Dutch guy has dynoed above 36hp(can´t remember exact number, but is was above 36hp) with a Roost98, this with a boyesen KX85 reed.
The later Roost 100 flangemount cylinder is close to 40hp unported, HK tuning in Germany says he has dynoed above 41hp, but i´m not trusting that fully.

I your case then deliver between 266-274HZ should speak against any standing waves teori?
In the case with 41hp, in the old good times, Vortex RVA delivered 38hp out of box with 3 transfer ducts and 177 ° exhaust, so why not.

[Juho_]

We run 1.28 in compressionratio in crankhouse, so yes it has been ported quite some.
The reedvalve suprisingly is made for AM6, so it is quite small.
We have plans of taking a CR85 V-force and and use that, i also think that the reed as used in the 35.2hp dyno is stretched to its limit, and then some
They had to run without the stuffer, with the stuffer mounted it was a huge powerloss.

The CR85 v-force reed valve might require quite a lot grinding, because it's wider than your current reed valve.
I'm using a stock CR85 reed valve on my Minarelli AM6 motor (55cc). Previously used TPR v-force reed valve, slight increase in power above 11,000rpm.
Not sure if the reeds thickness is even close to what they should be...should try and test some day.

If the v-force reed valve is even wider, the crankcase might require some welding to have enough material.
CR85 reed valves do fit to Derbi (EBS050) crankcase quite easily, with only minor modifications.

Also, I would suggest a Mikuni TM or TMX series carburetor.
I got my motor work a lot better everywhere, and more power compared to PWK copy carburetor (modified).

[SwePatrick]

The CR85 v-force reed valve might require quite a lot grinding, because it's wider than your current reed valve.
I'm using a stock CR85 reed valve on my Minarelli AM6 motor (55cc). Previously used TPR v-force reed valve, slight increase in power above 11,000rpm.
Not sure if the reeds thickness is even close to what they should be...should try and test some day.

If the v-force reed valve is even wider, the crankcase might require some welding to have enough material.
CR85 reed valves do fit to Derbi (EBS050) crankcase quite easily, with only minor modifications.

Also, I would suggest a Mikuni TM or TMX series carburetor.
I got my motor work a lot better everywhere, and more power compared to PWK copy carburetor (modified).

It isn´t sadly enough my engine, so i cannot force him to use Mikuni, but i can ask him to.
He doesn´t like them, and later on as it will be running methanol, the carb almost doesn´t make any differences(my own experiances)
Just enough airflow, then fuel is secondary to that, as almost all carbs doesn´t do the job very good, with that much fuel in the air.

The engine is 'welded' so one can grind out material if needed for bigger reed.

But i want to try the boyesen KX85 reed as it might do the trick without having to grind.

[SwePatrick]

I your case then deliver between 266-274HZ should speak against any standing waves teori?
In the case with 41hp, in the old good times, Vortex RVA delivered 38hp out of box with 3 transfer ducts and 177 ° exhaust, so why not.

Crank or rear wheel?

Standing wave can occur at almost any frequenzy, just study 4th order bassbox
Not to say that the engine has that frequenz, but as a statement that this is very dynamic, and as i said, 'stumbeling'.
Nothing is calculated in the reed.
One almost cannot calculate a reedvalve as the speeding air acts as a spring also, and by that disturbs all calculations.
Calculate a reed at stationary air inside/outside the cage, fine! i can recognize that.

One just has to rape the laws of theory sometimes to get an 'aha' moment.