ESE's works engine tuner

[philou]

No.

Not depending on the bore, but on the stroke/bore-ratio.
Attachment 330479

I do not understand the calculation

Example A-port stroke 54,5 bore 54

0,46 X 54,5 / 54 = 0,462

Editing : i'm crazy. I have forgot "atn"

[jamathi]

I'd rather say they had a water cooled head cover. Coolant in the cylinder was hardly moving; cooling below the exhaust was non-existent.
Not the best solution if you want reliable power.

Such a Maico engine gave 27HP

[husaberg]

I'd rather say they had a water cooled head cover. Coolant in the cylinder was hardly moving; cooling below the exhaust was non-existent.
Not the best solution if you want reliable power.

Progress aye, it was still more uniform i'd wager than the air cooling.
Out of interest Frits how common where the water cooled disc Maico 250 road bikes?

Seen this today neat
https://grabcad.com/library/aprilia-...nder-incompl-1
seeing one in 3d is pretty neat
Needs a little work on the AUX exhaust

I am surprised no one commented on this?
where te pic is click on the link where is says load in 3d viewer and play with your mouse

[Frits Overmars]

Out of interest Frits how common where the water cooled disc Maico 250 road bikes?

Hen's teeth. I've never seen one in the flesh. And can you imagine Maico not only built a 250 cc cylinder on their 125 cc cases; they also built a 50 on the same cases. Apparently aesthetics were not part of the company policy. Neither was survival, as we now know. I was invited to visit the Maico racing department in the 70s. They had electric light, which was more than could be said of the series production facilities. Workers had to make do with the scarce light entering through the roof windows.

I am surprised no one commented on this? where te pic is click on the link where is says load in 3d viewer and play with your mouse.
https://grabcad.com/library/aprilia-...nder-incompl-1

Nice job.
The cylinder is an APC, an elderly type, recognizable because the edges between the bore and the transfer duct entries at the cylinder base are still sharp, not radiused.

[shnaggs]

I am surprised no one commented on this?
where te pic is click on the link where is says load in 3d viewer and play with your mouse

Husa, I was intrigued earlier by this but was having difficulties loading it in my CAD software. Now that you bring to our attention that we can view the cylinder in their 3D workspace is great!

Anyone else notice that there are 2 extra A ports and B ports in the drawling laid on top of each other??? You can de-select the bodys on the left hand side to view them better. Is this a goof by the designer? Or was there a version that had bigger transfer ducts???

[Norman]

Progress aye, it was still more uniform i'd wager than the air cooling.
Out of interest Frits how common where the water cooled disc Maico 250 road bikes?



I am surprised no one commented on this?
where te pic is click on the link where is says load in 3d viewer and play with your mouse

I made a few cuts in the model and copy paste pictures on the inside of the RSW cylinder from GrabCad. Very interesting!

[husaberg]

Hen's teeth. I've never seen one in the flesh. And can you imagine Maico not only built a 250 cc cylinder on their 125 cc cases; they also built a 50 on the same cases. Apparently aesthetics were not part of the company policy. Neither was survival, as we now know. I was invited to visit the Maico racing department in the 70s. They had electric light, which was more than could be said of the series production facilities. Workers had to make do with the scarce light entering through the roof windows.

Nice job.
The cylinder is an APC, an elderly type, recognizable because the edges between the bore and the transfer duct entries at the cylinder base are still sharp, not radiused.

The 3d rendering is not mine i should point out.
Flet has my APC copy cylinder and patterns at the moment He is going to run of a few cylinders for some people.
The Maico story is an intersting one esp with the MX bikes.
They had at the time the best open class bike in the world ruined by silly cost cutting (some say internal conspiracy)that they never recovered from.

Husa, I was intrigued earlier by this but was having difficulties loading it in my CAD software. Now that you bring to our attention that we can view the cylinder in their 3D workspace is great!

Anyone else notice that there are 2 extra A ports and B ports in the drawling laid on top of each other??? You can de-select the bodys on the left hand side to view them better. Is this a goof by the designer? Or was there a version that had bigger transfer ducts???

I think its incomplete, there is a few little other errors i noticed arround the AUX entries to the main duct

I made a few cuts in the model and copy paste pictures on the inside of the RSW cylinder from GrabCad. Very interesting!

Nice

There are Nsr125, NSR250 and RS125 sectioned cylinders and 3d models to compare them to on the net.
http://thetrxproject.blogspot.co.nz/2013/04/

[lodgernz]

This is probably going to be the most valuable bit of I of I gain from this thread.

From those in the know, and you are about to make a new cylinder, would you use the same as below or is there something you may want to change?

The drawing shown by Jan in post #25655 showed an elder type RSW cylinder. Here are the RSA values.
A-ports timing 130°, roof angle 25°
B-ports timing 132°, roof angle 10°
C-port timing 132°, roof angle 50°

The next thing, if you have a non power valve exhaust, ie just a hole, would you change anything as above?

I thought I read domewhere on this thread, that a non-PV engine should have the A-transfers open before the Bs?

[wobbly]

Those transfer port numbers were used with a 3 port Exhaust that had a huge top radius timed at 79*EPO,so was at the absolute outer limit in every respect.
It also had a power valve that wasnt fully up till around 12,000,only 800rpm away from peak.
Deleting the powervalve would basically destroy all the mid power capability, thus the engine would need a major rethink regarding its STA distribution.
It would not be able to have anything like the STA's needed by the peak power generated by those timings for the Aprilia.
Thus reverting to non reverse stagger and much lower timings are needed, as this configuration naturally generates better powerband width,at the expense of outright peak and
overev - due to the natural effects of the scavenging regime.
At a guess I would opine at A 115.5, B 117, C 118.

[TZ350]

.

The old det sensor had been buzzing away during full power runs. Didn't matter how rich I made it or how advanced or retarded the ignition or how open the PV was. I suspected the piston might be hitting the head again and ringing the det sensor. So I popped the head off.



No signs of detonation or the piston hitting the head but curiously there was this small 3mm id washer???????

Without any marks on the piston/head its hard to believe the washer was the problem. Maybe it dropped in there when I took the plug out, but where could it come from? There is nothing immediately obvious missing....



The head cover has different sized water channels so the water flow is biased to flow across the back of the combustion chamber insert from one side to the other.



With the head off, it was a good time to see what mV servo feedback value corresponded to what PV open position.

For my setup the numbers came out at.

mV ATDC Duration
2.3 = 95 ... 170
2.4 = 93 ... 174
2.5 = 90 ... 180
2.6 = 86 ... 188
2.7 = 84 ... 192
2.8 = 82 ... 196
2.9 = 80 ... 200
3.0 = 78.5. 203



Now that I know what Exhaust duration corresponds to what mV servo position. Instead of opening the PV in a straight line I could try taking advantage of the symbiotic resonance between port and pipe that happens with an exhaust duration of 192 deg. And only opening it further as the exhaust STA runs out. That way I might be able to take advantage of the symbiotic resonance to plump up the lower part of the torque curve.



Another interesting feature of the Ignitec ignition is that the PV servo position can be mapped TPS vis RPM. I might be able to use this to improve the trapping efficiency at high RPM and low TPS by closing it, at say below 20% TPS for improved EFI throttle roll on after shutting off for a corner.

[breezy]

Jan / Frits do you think there would be an benefits from unmasking the smaller transfer port by the barrel spigot?

[jamathi]

Jan / Frits do you think there would be an benefits from unmasking the smaller transfer port by the barrel spigot?

Yes, I think so!

[136kg136ps]

Those transfer port numbers were used with a 3 port Exhaust that had a huge top radius timed at 79*EPO,so was at the absolute outer limit in every respect.
It also had a power valve that wasnt fully up till around 12,000,only 800rpm away from peak.
Deleting the powervalve would basically destroy all the mid power capability, thus the engine would need a major rethink regarding its STA distribution.
It would not be able to have anything like the STA's needed by the peak power generated by those timings for the Aprilia.
Thus reverting to non reverse stagger and much lower timings are needed, as this configuration naturally generates better powerband width,at the expense of outright peak and
overev - due to the natural effects of the scavenging regime.
At a guess I would opine at A 115.5, B 117, C 118.

Wob,would using an ATAC allow you to use the transfer numbers you quoted earlier if an PV was unavailable?

[Norman]

The 3d rendering is not mine i should point out.
Flet has my APC copy cylinder and patterns at the moment He is going to run of a few cylinders for some people.
The Maico story is an intersting one esp with the MX bikes.
They had at the time the best open class bike in the world ruined by silly cost cutting (some say internal conspiracy)that they never recovered from.



I think its incomplete, there is a few little other errors i noticed arround the AUX entries to the main duct

Nice

There are Nsr125, NSR250 and RS125 sectioned cylinders and 3d models to compare them to on the net.
http://thetrxproject.blogspot.co.nz/2013/04/

As I have a little bit of a problem visualizing the air flow through cylinder transfers I asked a CFD guy at work to show me his tools and if he at the same time could do a quick flow visualization of the RSW cylinder. With my limited 3D knowledge a made a bottom end (crankcase substitute, not perfect or anything like the original..) to connect to the cylinder and we put the piston at BDC. I asked him to send 0,04 kg/s into the bottom inlet channel to see how it looked like. I hope it is not that far from an air flow that could be seen. Changing the flow between 0,01 to 0,04 kg/s did not change the flow pattern so much, if I remember correctly.

I think we got close to 0,16 bar pressure difference from inlet to outlet at this flow.

Please note that it is a steady state flow right through the cylinder and without the actual very transient situation during operation. I guess it cannot be much more simplified than this. Can it possibly indicate how the flow would look like just before the return pulse stops the flow and pushes back into the cylinder? See pictures attached.

Please note that all pictures represents 0,04 kg/s even if otherwise stated.

Jan Thiels statement that the flow is attached to the bottom of the transfers, is clearly also observed in the simulations!

[Frits Overmars]

Now that I know what Exhaust duration corresponds to what mV servo position. Instead of opening the PV in a straight line I could try taking advantage of the symbiotic resonance between port and pipe that happens with an exhaust duration of 192 deg. And only opening it further as the exhaust STA runs out. That way I might be able to take advantage of the symbiotic resonance to plump up the lower part of the torque curve.

Good thinking. But remember that, even with 192° exhaust timing, at low revs the first return pulse will arrive at the cylinder too early.
You ought to combine it with a trombone pipe.

Another interesting feature of the Ignitec ignition is that the PV servo position can be mapped TPS vis RPM. I might be able to use this to improve the trapping efficiency at high RPM and low TPS by closing it, at say below 20% TPS for improved EFI throttle roll on after shutting off for a corner.

High rpm means diminishing blowdown time.area, so the pressure of the spent, hot gases in the cylinder at the end of the blowdown phase will increase.
If you close the throttle as well, the scavenging pressure is sure to drop below this cylinder pressure, the spent gases will enter the transfer ducts and you'll get detonation like you've never seen before.