ESE's works engine tuner

[TZ350]

Fabricate a quick straight pipe 4 stroke style. That will tell you if it's the pipe causing havoc under 25%.

Good idea, might try that if I cant make any progress with the Arduino amd MAP sensor idea.

We made in 2015 injection in intake noise silencer for experimental 50cc 4-cylinder axial engine rotating 24000 rpm (12.5cc per cylinder). Intake silencer volume was about 1400cc and flow inside was practically luminaire. The only one nozzle were firing inside silencer according air volume flow with few times less frequency than rpm. May be similar approach will work in other cases?

Very clever idea, injector firing half or quarter time into the air silencer volume, and using the silencer volume like a plenum full of the correct air/fuel mixture.



I had tried the air/fuel mixture plenum idea when I was running a carburetor as a way to push past our racing class's 24mm carb restriction rule for 2T's > 104cc.

It ran Ok. https://youtu.be/YxiEo8cgopg .... https://youtu.be/p4ef-WUO1Qs

But gave it up when I realized there was a lot of fuel dropping out and pooling in the bottom of the plenum.



Ironically a plenum is what got me started on EFI as a way to avoid the fuel dropout and the ensuing poor air/fuel mixture control and doubtful engine lubrication.

Now 2T EFI has become an interest in itself.

[ken seeber]

Good & open fairly detailed coverage of the Suter @ Isle of Man...around 14 mins or so:

https://www.facebook.com/suter500/vi...6407281112852/

[husaberg]

Good & open fairly detailed coverage of the Suter @ Isle of Man...around 14 mins or so:

https://www.facebook.com/suter500/vi...6407281112852/

Nice find ken
Gee that airbox looks small esp compared to the NSR500.
twin

various 4's

[husaberg]

RGV

YZR
yeah i know
Cagiva
i swear the air filter on the first Cagive injected pic is a ram flow like the webber on my 1600 MK1 esky had.

[RomeuPT]

Romeu, the IAME piston I use in the TM engine,is in my opinion only, the best shape for a 2T piston.
It combines all the elements that have been used over the years with success, all for different reasons.
Yamaha have used a very narrow, angled edge that than becomes a flat top for many years in many designs.
The angled edge helps flow ( bulk, and cooling attachment ) at small port opening angles, and of course the flat top allows the use of a toroid to get the plug down very low
within the combustion space.
The IAME has an angled edge 7mm wide that matches a normal squish width in a 125 bore,but in the case of the KZ engines we cant go that wide.
But the next test,using a 1mm radius on the timing edge, combined with its 0.5mm higher deck height, makes what I consider a really good setup for the kart engine
where I cant use a toroid.
I have already proven the angle/flat top makes more power than the straight 4* conic that TM use,so if the radius added is better again, then that will be a real winner.
In a T port engine, the same logic would apply, but in your class of racing you can use the toroid as well - and get better power again than I can.

Thanks. I was not sure so I rather asked first before going on and try.

you mean 1mm radius on the piston edge like it seems on this ktm piston? I would like to hear if possible of the test conclusion, this radius may help flow at transfer and exhaust closing angles!?

[Frits Overmars]

All the best Jan!

[SwePatrick]

Yes, things happen different before and after this simulation.
What I tried with here was to study flow separation on the top of the inner radius. The color is velocity.
Based on what I've seen, Fritz is right that a larger constant radius is better for flow separation

Yes constant radius is good as air takes it 'shape' and you don´t 'alter it'.
But what i find might cause a problem is that the runner is tapered to hard.

And to use in calculations, the highest crankpressure is just before you open the transfers.
Some sort of a small blowdown(blow in?) period so to speak.
Thereby you would have the highest airspeed some degrees before btdc.

[TZ350]

All the best Jan!

Happy birthday Jan and many thanks for your contributions to this thread.

[TZ350]

I am still very interested in the plenum idea because when I was experimenting with it on the dyno I saw a very very large low end boost in power. At about the same point that I would usually see a large dip from the pipe being in anti phase and working against the engine. You don't forget things like that.

I put the power boost down to the plenum/inlet system being in happy resonance with the engine.

What a power spread boost it would be if we could keep a variable volume plenum in happy resonance with the engine over a wide rev range.



Another useful thing was being able to divide the inlet tract in half. Variable inlet kinetic energy I guess. This had the benefit of cleaning up the carburation considerably.

In my wildest dreams I dream of using a variable volume plenum and a variable inlet controlled by something like an Arduino because I think they could show great improvements in two stroke performance and power spread. Imagine a high performance 2T with a 6-7K power spread instead of the usual 3-4.



Include a variable pressure bleed in the exhaust and you could have true 2T magic.

I dream of combing all these concepts on one of the Team ESE engines along with the more conventional state of the art 2T tuning techniques.

[TZ350]

.
I have enjoyed a bit of success today.

Used EngMod2T to simulate a series of runs so I could look at the variations in crankcase pressure just to see if there is a consistent change that can be measured and reflect changes in air flow through the motor.

These are pressure ratios, absolute crankcase pressure divided by atmospheric pressure.



This series of runs were taken at 8,000 rpm and is where the engine is really starting to get on the pipe.

Looking at the graphs. It is obvious that I only need to know when the end of each cycle is and that I wont need to know where in the cycle the high and low occurs only that it does and its amplitude.

The objective today was to see if the Arduino could read the MAP sensor and output a sensible result.



MAP sensor plugged into a spare injection port in the crankcase and the laptop and volt meter setup to monitor the Arduinos (true) analog voltage output.

The Arduino program looks for the highest and lowest pressure and the average for each cycle.

Then it outputs the sum of the average plus the difference.



Flashed the bike up and gave it a couple of blips. The analog voltages coming out of the Arduino look to be in the ball park and changed in a way that reflected real pressure changes (read, air flow) in the crankcase.

Its looking good for tomorrow. When I will connect the Arduino to the EFI CPU's MAP input.

With the new simulated MAP sensor input I expect the fueling to get messy but as long as I can use ECOCAL to data log some of the EFI CPU's output including the MAP trace I will be happy, ecstatic if it looks like it is the answer to seeing the un predictable air flow through the motor at less than 25% throttle position.

It is looking hopeful, Fingers crossed.

[husaberg]

Happy Birthday Jan
Thanks for sharing the information.

[Juho_]

I am still very interested in the plenum idea because when I was experimenting with it on the dyno I saw a very very large low end boost in power. At about the same point that I would usually see a large dip from the pipe being in anti phase and working against the engine. You don't forget things like that

When your accelerating below pipe's "powerband" with full throttle and the engine reaches that large dip in the power curve; does the engine get past that dip if you use only half throttle ?

I had the same problem on my 55cc minarelli am6 with pwk carburetor.
Afr went very lean at that dip for some reason.

Then I replaced it with Mikuni TM28 and after some adjusting the engine worked a lot better, produced a bit more power and the dip got a lot smaller (didn't require half throttle to get past it).

Didn't really think a different carburetor could do any difference on that problem...but I was wrong.

[F5 Dave]

You should have tried a kiehin. They totally kick mikuni arse
Pwk 28 is ok for a fairly hot 50.

Yeah I know.

[Frits Overmars]

On the off chance that somebody here is interested in motorcycle racing:
live-stream of the Italian Grand Prix at Mugello
http://live.drakulawidget.com/stream...g-4669250.html

EDIT: here's another link in case the first link stopped working, as it did on me:
http://www.fixalen.tv/20180601/vv-19....87771154.html

[Juho_]

You should have tried a kiehin. They totally kick mikuni arse
Pwk 28 is ok for a fairly hot 50.

Yeah I know.

I had tried 2 different keihin pwk (24 and 26mm) copy carburetors.
Oko and ysn branded.

Didn't find any keihin pwk 28mm (used) that had a price tag less than 80€.
Used pwk copy carbs can be easily found for 30-50€ and I paid for the mikuni tm28 40€.

Cheap carburetors.
For testing purposes I don't like to pay a lot for some part that I'm not 100% sure if it actually has benefits (= help to produce more power).