ESE's works engine tuner

[Frits Overmars]

hey frits and wobbly i was trying to think what the purpose of boyesen ports is. to add inlet area but it seems like they should have a downward angle somewhere about 45*, which wouldnt be to sharp as to cause the air to hit a brick wall and go straight down . the reason i think this is because they would be responsible for filling the lowest portion of the case and the main inlet would mostly go straight in and fill up the cylinder middle section. does any of this sound like what actually happens ?

You want to feed the transfers directly from the inlet, so those Boyesen ports should aim straight at the transfer ducts. But as your picture shows, there is insufficient material and the studs are in the way. Hence the switch from cylinder reeds to case reeds.

[Flettner]

So Frits, you say the Ryger uses standard exhaust (and muffler?). If we are putting a lot more gas through this system then there must be a significant pressure (and temp?) increase. This must change the pipes wave length somewhat, yes. Is this how we are able to spread the power band over such a wide range? And does this pressure and temp increase the energy at which the pipe operates ie works (pumps) harder. Is this a fair question?

[MotleyCrue]

So Frits, you say the Ryger uses standard exhaust (and muffler?). If we are putting a lot more gas through this system then there must be a significant pressure (and temp?) increase. This must change the pipes wave length somewhat, yes. Is this how we are able to spread the power band over such a wide range? And does this pressure and temp increase the energy at which the pipe operates ie works (pumps) harder. Is this a fair question?

Maybe just to add to the question.

If the Ryger pipe was install on a normal top level 125 engine, would the Ryger pipe then be too short for the regular 125 to run properly (13500 peak)? I think we all know the answer to this question, but maybe not. Maybe the Ryger pipe is longer than expected for a 17000 rpm peak.

If we looked in the Ryger pipe with a flashlight would we see anything out of the ordinary as far as 2 stroke exhausts go?

[Frits Overmars]

So Frits, you say the Ryger uses standard exhaust (and muffler?).

Yes, muffler too.

If we are putting a lot more gas through this system then there must be a significant pressure (and temp?) increase. This must change the pipes wave length somewhat, yes.
Is this how we are able to spread the power band over such a wide range?

Let's do some math. A regular kart engine produces its maximum torque at about 12000 rpm with an exhaust gas temperature in the pipe of about 600°C ; that's 873 K.
The Ryger's max.torque rpm is 1,4 times as high. And as the Ryger uses a regular pipe (more about it further on) the waves in the pipe must travel 1,4 times as fast.
As those waves travel with the speed of sound (yes Vannik, I know, but I am talking to normal people now) the speed of sound in the Ryger pipe should be 1,4 times the speed of sound in the regular engine's pipe.
How do we accomplish that? The speed of sound is proportional to the square root of the absolute temperature but is independent of pressure or density.
So the temperature in the Ryger pipe must be 1,4 x 1,4 x 873 = 1711 K. That's 1438°C. Steel melts at 1430°C....
And if we want to rev on to 30.000 rpm, the exhaust gas temperature should be 5183°C. Steel boils at 2900°C; titanium melts at 1670°C and boils at 3287°C.
No Neil, this is not how the Ryger spreads its power band over such a wide range.

The pipe: I promised to say something about that too.
The Ryger engine is based on a regular VM kart engine and the Ryger parts are for the most part standard VM parts, including the pipe. You'll find the pipe dimensions here:

[tjbw]

Yes, muffler too.

Let's do some math. A regular kart engine produces its maximum torque at about 12000 rpm with an exhaust gas temperature in the pipe of about 600°C ; that's 873 K.
The Ryger's max.torque rpm is 1,4 times as high. And as the Ryger uses a regular pipe (more about it further on) the waves in the pipe must travel 1,4 times as fast.
As those waves travel with the speed of sound (yes Vannik, I know, but I am talking to normal people now) the speed of sound in the Ryger pipe should be 1,4 times the speed of sound in the regular engine's pipe.
How do we accomplish that? The speed of sound is proportional to the square root of the absolute temperature but is independent of pressure or density.
So the temperature in the Ryger pipe must be 1,4 x 1,4 x 873 = 1711 K. That's 1438°C. Steel melts at 1430°C....
And if we want to rev on to 30.000 rpm, the exhaust gas temperature should be 5183°C. Steel boils at 2900°C; titanium melts at 1670°C and boils at 3287°C.
No Neil, this is not how the Ryger spreads its power band over such a wide range.

The pipe: I promised to say something about that too.
The Ryger engine is based on a regular VM kart engine and the Ryger parts are for the most part standard VM parts, including the pipe. You'll find the pipe dimensions here:

Don't laugh, but I was thinking a pipe designed for a 180cc engine would work for a 70hp 125.

I suspect some of us would be no wiser even if we saw the full homologation pdf.

[MotleyCrue]

The Ryger is full of riddles at every turn. I think somebody found Aladdins lamp and showed Aladdin their ultimate wish list.


Is the exhaust pipe an ornament or is it's regular pulsing function still needed?

Likely the pulsing function is still needed, but I wonder if it is needed all the way to 17000 (30000) rpm or if it is mainly there just for the lower revs like it would be on a regular 125 such as < 14000 rpm.

Has it ever been mentioned what rev range would be considered the actual "powerband" for the Ryger? If it peaks at 17000 then would the top of the powerband be 18-19000 rpm or does the power just hang on to a lot more rpm than that?

[Flettner]

Yes, muffler too.

Let's do some math. A regular kart engine produces its maximum torque at about 12000 rpm with an exhaust gas temperature in the pipe of about 600°C ; that's 873 K.
The Ryger's max.torque rpm is 1,4 times as high. And as the Ryger uses a regular pipe (more about it further on) the waves in the pipe must travel 1,4 times as fast.
As those waves travel with the speed of sound (yes Vannik, I know, but I am talking to normal people now) the speed of sound in the Ryger pipe should be 1,4 times the speed of sound in the regular engine's pipe.
How do we accomplish that? The speed of sound is proportional to the square root of the absolute temperature but is independent of pressure or density.
So the temperature in the Ryger pipe must be 1,4 x 1,4 x 873 = 1711 K. That's 1438°C. Steel melts at 1430°C....
And if we want to rev on to 30.000 rpm, the exhaust gas temperature should be 5183°C. Steel boils at 2900°C; titanium melts at 1670°C and boils at 3287°C.
No Neil, this is not how the Ryger spreads its power band over such a wide range.

The pipe: I promised to say something about that too.
The Ryger engine is based on a regular VM kart engine and the Ryger parts are for the most part standard VM parts, including the pipe. You'll find the pipe dimensions here:

Ok, thank you, way off base.

[yesyes]

Yes, muffler too.

Let's do some math. A regular kart engine produces its maximum torque at about 12000 rpm with an exhaust gas temperature in the pipe of about 600°C ; that's 873 K.
The Ryger's max.torque rpm is 1,4 times as high. And as the Ryger uses a regular pipe (more about it further on) the waves in the pipe must travel 1,4 times as fast.
As those waves travel with the speed of sound (yes Vannik, I know, but I am talking to normal people now) the speed of sound in the Ryger pipe should be 1,4 times the speed of sound in the regular engine's pipe.
How do we accomplish that? The speed of sound is proportional to the square root of the absolute temperature but is independent of pressure or density.
So the temperature in the Ryger pipe must be 1,4 x 1,4 x 873 = 1711 K. That's 1438°C. Steel melts at 1430°C....
And if we want to rev on to 30.000 rpm, the exhaust gas temperature should be 5183°C. Steel boils at 2900°C; titanium melts at 1670°C and boils at 3287°C.
No Neil, this is not how the Ryger spreads its power band over such a wide range.

The pipe: I promised to say something about that too.
The Ryger engine is based on a regular VM kart engine and the Ryger parts are for the most part standard VM parts, including the pipe. You'll find the pipe dimensions here:

What a headache

[tjbw]

What a headache

Yes, but what could be simpler, it seems that the VM engine to Ryger conversion kit just includes:
stepped piston, cylinder, connecting rod, spacer with valves, and perhaps ignition timing changed. Did I miss anything?

I can comprehend that the Ryger primary compression may be much more positive, with much higher primary compression ratio. This might be great for starting the engine. But to get more power than the VM engine I think you need more fresh mixture in the cylinder, and I can't imagine how the same VM exhaust can do this.

If it gets 70HP with wide powerband using VM exhaust, then wouldn't it be possible to optimise the Ryger exhaust design for even more power?

I recall that a disc valve is good for 10HP over a reed valve, based on RSA V Derbi comparison, so might we see an 80HP 125cc Ryger with disc valve?

Frits, any idea when the Ryger engine will make it's debut?

Hope we get some more Ryger details real soon, or I'll have no hair left

[Yow Ling]

Maybe when the rights are sold the truth will be told ?

[F5 Dave]

Yes, but what could be simpler, it seems that the VM engine to Ryger conversion kit just includes:
stepped piston, cylinder, connecting rod, spacer with valves, and perhaps ignition timing changed. Did I miss anything?

I can comprehend that the Ryger primary compression may be much more positive, with much higher primary compression ratio. This might be great for starting the engine. But to get more power than the VM engine I think you need more fresh mixture in the cylinder, and I can't imagine how the same VM exhaust can do this.

If it gets 70HP with wide powerband using VM exhaust, then wouldn't it be possible to optimise the Ryger exhaust design for even more power?

I recall that a disc valve is good for 10HP over a reed valve, based on RSA V Derbi comparison, so might we see an 80HP 125cc Ryger with disc valve?

Frits, any idea when the Ryger engine will make it's debut?

Hope we get some more Ryger details real soon, or I'll have no hair left

Try compare factory Honda and it wont be 10hp.
But there is the question of stinger diameter that increases with an increase of output. Surely the ryger would need another 3mm to not melt if a conventional engine. So can it break the rules here too?

[Lightbulb]

I think that the view of needing more fresh mixture to make more power, may not actually be the answer. I think the answer is the other way around.
You need better combustion to get less CO in the residual exhaust. Then you automatically get more effective charge from the same amount of air fuel.
It has to be that way or else it would be using more fuel and not less. For the air to mix better , it needs the most amount of time possible to mix best with the air and heating the air will help in a better dispersion. So I doubt that it uses any direct flow to any of the cylinder or ports. Neil

[trevor amos]

It might be more realistic to suggest that the disc valve arrangement offers a potential 10% advantage over the reed valve and not a blanket 10hp!

Trevor

[cotswold]

[QUOTE=Frits Overmars;1130916123]Yes, muffler too.

Let's do some math.

as you are a lot better at maths than myself and Husa, if you feel inclined, would you take a peek at my 50 page as I have some of your drawings I am assuming were for the RSA(w) 125 ? and my question is sat waiting for you

[Frits Overmars]

there is the question of stinger diameter that increases with an increase of output. Surely the ryger would need another 3mm to not melt if a conventional engine. So can it break the rules here too?

Yes it can, Dave.

It might be more realistic to suggest that the disc valve arrangement offers a potential 10% advantage over the reed valve and not a blanket 10hp!

Right, Trevor, as long as we're talking conventional engines. I don't think the Ryger would benefit from a disc valve.

as you are a lot better at maths than myself and Husa, if you feel inclined, would you take a peek at my 50 page ....

What is 'my 50 page' ?