ESE's works engine tuner

[Muhr]

Think that the problem here is that the flow speed is so high that you get flow separation even though the shape is optimized

just wanted to add that blue is low pressure and red high

[RomeuPT]

Some pictures from seel cylinder.

Any idea why studs place is so high? Does it not look to have high porosity?

[jbiplane]

Recently we made new version of 2-cylinder boxer using Yamaha RD-350 reed valves. Using carburetor without filter we saw fuel spraying out in atmosphere...

Then we make simplest experiment: install inside short tube, see red colored and problem completely disappear.

Anyone had similar experience? If no could be useful for community.





In any case we are publishing articles in academic press and applied for invention.

[Tim Ey]

I'd put a stuffer into the RD350 reed (the cross sectional area on the bog standart reed block at its flange is ridicolously big compared to the reed opening area). And would make the connecting tubes smaller with less bend. Probably angle the reeds a bit so that they point more underneath the piston?

At the moment you got very big volume between carb and reed. And also the flow will seperate from the outside wall, hence the change in direction is too harsh.

If you change the diameter of the connecting tubes your eigenfrequency will rise --> higher "spit back" rpm.

I like your tube diode - a totaly KISS approach.

[JanBros]

Any idea why studs place is so high?

the creator probably has experience with cylinders cracking arround low stud-holes.

[wobbly]

The stud pads are up high so that big pockets are not needed low down in the casing to enable a ring spanner onto the hex nuts.
These pockets would likely restrict the transfer duct wall positions.

Here is the interim dyno result of my cylinder testing.
The 3 port Exhaust duct exit area is reduced to my recommended 75% and the Aux duct ears are enlarged right down to the end of the spigot.
No other changes to the tune at all.
Next step is a 1.5mm radius on the IAME piston shape , and to find the correct cylinder height to use with that radius , maybe get 50 Hp for the first time.

[RomeuPT]

The stud pads are up high so that big pockets are not needed low down in the casing to enable a ring spanner onto the hex nuts.
These pockets would likely restrict the transfer duct wall positions.

Here is the interim dyno result of my cylinder testing.
The 3 port Exhaust duct exit area is reduced to my recommended 75% and the Aux duct ears are enlarged right down to the end of the spigot.
No other changes to the tune at all.
Next step is a 1.5mm radius on the IAME piston shape , and to find the correct cylinder height to use with that radius , maybe get 50 Hp for the first time.

Just that change and more then 2 hp gain, you do miracles
How you think that happens, the ears allow for much bigger exit speed of the gases on blowdown?

[Matt@TYGA]

The stud pads are up high so that big pockets are not needed low down in the casing to enable a ring spanner onto the hex nuts.
These pockets would likely restrict the transfer duct wall positions.

Here is the interim dyno result of my cylinder testing.
The 3 port Exhaust duct exit area is reduced to my recommended 75% and the Aux duct ears are enlarged right down to the end of the spigot.
No other changes to the tune at all.
Next step is a 1.5mm radius on the IAME piston shape , and to find the correct cylinder height to use with that radius , maybe get 50 Hp for the first time.

That's a pretty huge result there Wobbly. Anyway that you can cool some of the spigot to see what happens? You're probably not allowed due to silly regulations, but just in the interests of science :-)

[jonny quest]

I didn't realize how bad those kart motors are down low, 7ish hp at 8k? They must really hit hard coming on the pipe

[1948rod]

Hi in Jan 2016 nick gill posted that he was making a ex. Spigot for a parilla tag engine. Was this as successful as I imagine it would be as the original header leaves a lot to be desired. Thanks for any info.

[wobbly]

I do cool the back of the spigot Mat, with slots thru the casting into the water.
The pic is an old version done by hand as a test - also shows the smaller exit now being used in red line.
The extended Aux ducts have a huge effect on the Blowdown Cd, Jan said he saw this extra flow pattern right up the diffuser on an Aprilia pipe when it was cut open.
Cant wait to test the bigger radius piston on the new cylinder ,the insert wont match exactly at the bore as it should ,but if the power is good then I will CAD up a new one.

[katinas]

Yesterday friend tested KTM SX 65 rounded piston with sharp edge at C.
On dyno 0,4 hp more than with full roundness. Same matched head like on full rounded piston, just modified to match piston shape at C.
They even had no time to test on track , just packing all and rush to this weekend race in Poland

[F5 Dave]

I think I'm going to vomit. The amount of dyno runs I've done trying shit that didn't work and was supposed to.

[TZ350]

I think I'm going to vomit. The amount of dyno runs I've done trying shit that didn't work and was supposed to.

I hear you, sounds familiar .....

[TZ350]

Recently we made new version of 2-cylinder boxer using Yamaha RD-350 reed valves. Using carburetor without filter we saw fuel spraying out in atmosphere... Then we make simplest experiment: install inside short tube, see red colored and problem completely disappear.



Anyone had similar experience?

Maybe similar.....

Changing the rotary valve timing did not have a beneficial affect on a blow back problem. But I got rid of the Blarrs by lengthening the inlet tract.

When I first made the plenum I made it with a very short inlet. I had brought into the, shorter the better inlet idea. But this proved wrong and to be a problem. It was the source of the Blarrrs thing at 4-5,000 rpm. and I wrongly thought the inlet duration needed shortening but that had only marginal effect. Lengthening the inlet was the answer.



Lengthening the inlet tract was what cured the blarrrs.

And another successful experiment was putting a divider in the inlet so one half could be closed off effectively changing the inertia and resonance to get rid of a pesky resonance hole.

Video of the V Tec in action http://www.youtube.com/watch?v=FeB9O6rtLXQ