ESE's works engine tuner

[breezy]

The cylinder pressure at exhaust opening can be as high as 7 bar, so if you put your transfer reeds even higher up, they must be able to cope with more than 7 bar.
This means strong, heavy reeds that will be very reluctant to open at the very limited scavenging pressure differential that the exhaust suction can generate.
And how would you start the beast? No running = no pipe suction = no starting...

We'll have to wait for Flettners sleeve valve uniflow engine to give us a partly answer. Flowing top-down or bottom-up won't make much difference in itself.
It will still breathe through the crankcase though. It would be easy enough for Flettner to open the transfers direct to the atmosphere, but then he would have to fit a fistful of carburettors (like I once did with a Rotax-124 cylinder) and make a provision for crankshaft and piston lubrication. And again: how would you start it?

wow" 7 bar."... if that environment could be controlled ..."
And how would you start the beast? No running = no pipe suction = no starting." a removable / suction device attached to the end of the exhaust for stimulating the reeds to open when starting up,
but perhaps reeds are not the answer maybe a more mechanically/electrically operating shutter would be more appropriate sat between the sleeve and transfer port in the cylinder casting for better control. do you know the pressure values which occur in the transfer ducts prior to opening on a typical 2 stroke? i can see now how the blow down period is essential to bring down the "7 bar" to stop all the the transfer flow screaming out the exhaust port on a typical 2 stroke. would you think being able to control both transfer port openings and exhaust port openings through the 2 stroke cycle would enable more power to be produced, over and above what is produced now, with the transfer ports set high or even in the cylinder head?

[lodgernz]

Thanks Dave and Wobbly. On to the next engine...

[Frits Overmars]

So this Ryger engine , which took a few years to develop, has about 40% MORE HORSEPOWER than the best ever 125cc engine ever produced, the RSA125 by Jan Thiel. It is difficult to belive. Is there going to be a technology transfer sometime soon or a share float. I guess when real evidence is produced we will be stunned, until then I still have faith in Jan Thiel.

I know what you mean Yow Ling. I felt exactly the same until I got some hands-on experience with the Ryger.

[husaberg]

I know what you mean Yow Ling. I felt exactly the same until I got some hands-on experience with the Ryger.

How long is it before there is liberty to discuss the details.

[Frits Overmars]

How long is it before there is liberty to discuss the details.

This is the current state of affairs: http://www.kiwibiker.co.nz/forums/sh...post1130876195

[dark art]

Too long anyway...

[jonny quest]

Dimensionaly, how do we keep a 190 exhaust. .. but have a very tall cylinder above exhaust port?

[Lef16]

Hello guys,I have (again ) some questions.
First of all because i didn't get it and google translate does not help a lot...with one word what is better?Step between exhaust duct and exhaust pipe or not?And if the exhaust duct exit is round like a lot of production motorcycles should be a step also there?
And one more,i'm sure mr Jan Thiel have already try this but I have to ask .You said that Aprilia couldn't make max power with more than 13000rpm because of the insufficient blowdown angle-area.What would be the results if the ehxuast port was raised into 204* or the B&C tranfer ports were lowered into 130*?Loss of power maybe?
Cheers!!

[peewee]

lef16 im not sure any of us have seen the final version of the rsa regarding the manifold/exh duct exit. atleast i havent anyways. last photo i seen still has a step. wobbly says that no step is best so we can probly assume he is correct. this would require welding inside the manifold so it goes from oval to round

i think somebody already asked ftrits what would happen if the rsa exh was raised beyond 202*. i dont remember his exact answer but it seemed like it had something to do with unfavorable torq conditions ?

[peewee]

Dimensionaly, how do we keep a 190 exhaust. .. but have a very tall cylinder above exhaust port?

simple. make a FOS

[F5 Dave]

What if they skimmed the head and really polished the ports?

Hey I bet that's the Ryger secret. We weren't super polishing.

[wobbly]

So here it is as simple as can it be made - NO STEP IS BEST - but this does NOT mean grind the duct to make it round OR bigger in any way.
If its a 3 port or a T port, then the duct exit should be around 75% of the total effective Ex area, then the spigot should transition to 100% round diameter.
If its a single port, the duct should be around 90% exit area, with no step and the header the same diameter if its round.
If you have a really dumb 3 port or T port with a round exit, THEN CHANGE IT.


Re the angle area of the RSA.
The answer is all to do with finely balancing all the variables to optimize the end result.
Do you REALLY think that if going to 204* was actually better then why the hell wouldnt Jan do exactly that.
We have had the same question on here about the pipe dimensions,why not simply make it shorter and fatter, well if that was better
do you really think that it would not have been done.
I have been running thru pipe designs for a 250 KTM for a road racing kart, and discovered in the sim that going over 132mm belly diameter makes
NO MORE power.
Aprilia under Jan would have actually thought about this and built the pipe - I dont need to waste my time, its called diminishing returns, proven easily now
by a major step forward in computing ability.

[husaberg]

wow" 7 bar."... if that environment could be controlled ..."
And how would you start the beast? No running = no pipe suction = no starting." a removable / suction device attached to the end of the exhaust for stimulating the reeds to open when starting up,
but perhaps reeds are not the answer maybe a more mechanically/electrically operating shutter would be more appropriate sat between the sleeve and transfer port in the cylinder casting for better control. do you know the pressure values which occur in the transfer ducts prior to opening on a typical 2 stroke? i can see now how the blow down period is essential to bring down the "7 bar" to stop all the the transfer flow screaming out the exhaust port on a typical 2 stroke. would you think being able to control both transfer port openings and exhaust port openings through the 2 stroke cycle would enable more power to be produced, over and above what is produced now, with the transfer ports set high or even in the cylinder head?

A reed if it was to be mounted against the cylinder wall (screws at the bottom) opening up of a high mounted transfer passage (likey easiest a c port) would open with flow pushing out into the cylinder(once the cylinder had been vented by the exhaust port lowering the pressure) yet be able to be shut quite gently by a rising piston. The skirt of the piston would then not allow it to open until the top of the piston again descending down towards BDC.
This would direct flow away from the exhaust as it would flow upwards it would allow airflow direct towards the cylinder head and should allow greater cylinder filling.

Neil whip one up this arvo.

[Flettner]

We'll have to wait for Flettners sleeve valve uniflow engine to give us a partly answer. Flowing top-down or bottom-up won't make much difference in itself.
It will still breathe through the crankcase though. It would be easy enough for Flettner to open the transfers direct to the atmosphere, but then he would have to fit a fistful of carburettors (like I once did with a Rotax-124 cylinder) and make a provision for crankshaft and piston lubrication. And again: how would you start it?

I've kind of run out of puff, (not a drug) 70HP has kind of run me up against the wall. Not that I ever thought I might even get close to 54HP but this Ryger thing has knocked the wind out of my sails, as it were.
I still have some ideas cooking in the back ground but 70HP, wow.

[Frits Overmars]

70HP has kind of run me up against the wall. Not that I ever thought I might even get close to 54HP but this Ryger thing has knocked the wind out of my sails, as it were.

I know the feeling Neil. I'm very glad to be involved with the Ryger engine, but it has also made me very reluctant about everything I thought I knew about two-strokes.