ESE's works engine tuner

[husaberg]

the result

Some more details Lozza

[Muhr]

Water cool inside the transfer inner walls.

Something like that?!

We'll see what the caster says...

[Muhr]

Something like that?!

We'll see what the caster says...

one more view.

[Haufen]

Do you have any thoughts on ideal inlet tract length? (the problem with the V-twin engine is the cylinder offset of 21mm)

I'd propose the following approach:
Use whatever value the sim tells you as a baseline. (you're a "user of the product", are you?)
From that baseline, allow for 15-20mm of length change in both directions.

This will allow you to validate the sim on the dyno and make adjustments if you choose to change the peak performance rpm in the future, for example. I am using laser cut spacers between the cases and the carb rubber on one of my engines for example.

[Frits Overmars]

I have no idea why its splitting up wobs quotes but it will not edit it out.

While you're investigating the problem, could you also do something about the white text on an almost-white background in your quotes, Husa?
I'm having this problem with your posts only, and I'd rather not switch to the 'The Dark Zone', but I don't want to miss part of your contributions either .

[SwePatrick]

The flow conditions are not the same - on the V8 inter-cylinder air stealing is a major issue and one of the reasons for the small radius.

But still, the divider between A-port and B-port on RSA/RSW cylinders also have quite small radius.

[SwePatrick]

Then maybe they don't have a bigger radius because this would move the effective resonance point out of ideal tune. And getting ideal distance and big bellmouthes is not possible because of space / design limitations etc. (or maybe just because nobody has tried yet). There are several papers out there describing the ideal bellmouth shape. And a small radius is not what one would look out for in this occasion.

these are fully grown bellmouthes for example
n/a F1 engine on dyno

(they really should make such videos for two-stroke people, too)

I like your idea about the V8 2S engine, although you'd probably have to throw in a couple more cylinders without supercharging to achieve these 3500 hp.

I think Muhr could increase the radius from the entry to the bore face. Seems to be quite small at the moment - if there is one. And as he is designing the cases by himself, he might be able to place the discvalve accordingly to allow for an ideal inlet tract length.

At the lip of the velocitystacks the radius is quite small.

[SwePatrick]

You are right there is no radios at the moment (was a bitch to lay something with the geometry the program can't work out)
Do you have any thoughts on ideal inlet tract length? (the problem with the V-twin engine is the cylinder offset of 21mm)

Make the discs and the 'lids' the same offset.
Then you should have the same length on them both.

[Muhr]

Make the discs and the 'lids' the same offset.
Then you should have the same length on them both.

Im doing a singel crank engine.

[SwePatrick]

Ohh,, forgot about that.
but still make two length´s on the 'lid' to compensate for the offset.
Then try to shorten everything, in my pic i posted one can place the disc even more close to the crank.
You don´t need any rubberbot for the carb for an example.
Just machine a o-ring groove, then push in the carb, it locks in place on carb´s groove.
Shorten the velocitystack on the carbs.

I actually thinking if too long inlettracts you might stumble into problems at lower rpms and hardcore timings on the disc.
Problems as: very difficult to start as it can become a low frequent helmholzresonator that only spits outwards.
You might have seen that problem before

[Muhr]

Ohh,, forgot about that.
but still make two length´s on the 'lid' to compensate for the offset.
Then try to shorten everything, in my pic i posted one can place the disc even more close to the crank.
You don´t need any rubberbot for the carb for an example.
Just machine a o-ring groove, then push in the carb, it locks in place on carb´s groove.
Shorten the velocitystack on the carbs.

I actually thinking if too long inlettracts you might stumble into problems at lower rpms and hardcore timings on the disc.
Problems as: very difficult to start as it can become a low frequent helmholzresonator that only spits outwards.
You might have seen that problem before

Of course, I will try to have the same intake length unless the sacrifices are too big.
As far as carburettors are concerned, I have spent too many hours on foaming to have the energy getting that to work.

Yes we have had som problems! in that case it was a unfortunate placement of the intake which made opening and closing times very long(inafficient) and restrictions in possible size and of course hardcore timing

It's too bad that rotary valves do not care about piston speed.

[Muhr]

I'd propose the following approach:
Use whatever value the sim tells you as a baseline. (you're a "user of the product", are you?)
From that baseline, allow for 15-20mm of length change in both directions.

This will allow you to validate the sim on the dyno and make adjustments if you choose to change the peak performance rpm in the future, for example. I am using laser cut spacers between the cases and the carb rubber on one of my engines for example.

Thanks Haufen

Yes i am!(I realist that you most have done your one engine before you die. And my first son is 4 so a better hurry)
I had a thought of making rubber distances and see how long you can get away with.

[jonny quest]

The later year CR125 came with no PJ TMX Mikuni. They do have TPS. So many bag on that TMX. I really like them.

[2T Institute]

Some more details Lozza

Hopefully next round of improvements well see over 50hp, lifts the front in 2nd with no clutch, can win races outright against GP250's.

Main thing is it is tuned to the point of deto each time it hits the track.

[F5 Dave]

Pah!. My 50 has won races against a GP250 with a small gurl riding it.

I have the picture. He must have felt (and been) a complete wally.