ESE's works engine tuner

[Nath88]

I took a look at a Piezo switch and thought that I might be able to use the exhaust pulse instead of a finger press to activate it.

Attachment 333136

There is a 100Meg resistor across the piezo sensor which acts as the load, piezos need high impedance on the output to measure low frequencies, so that's fine. However the next 100Meg resistor and 100pF capacitor form a low pass filter of 15hz. This acts to smooth and slow the input, probably so it works decently as a switch instead of flicking on and off with any variation of pressure applied to the piezo. It may work, I would expect a delay between the pressure input and when the mosfet has enough voltage at it's input (gate) to 'switch'. The switch threshold would be set by the gate voltage of the mosfet combined with the filter.

My pulse sensor gives clear indication at high rpm light throttle, which was the problem area with the pressure sensor used earlier. At 7700rpm the exhaust pulses are the strongest, so that's probably the peak resonance of the pipe. However at around 4600rpm the indication is poor, not a big difference between full throttle and closed throttle. The exhaust pulse from the port is probably being cancelled by the existing wave, why at 4600? It's giving me a headache so I've made the maps the same below 5000rpm, low rpm response was never an issue.

[Frits Overmars]

Frits, if you are still wondering where you once saw the reference to 83.3 as Lodgernz calculated, it can also be seen in Gordon Blair`s books shown his pipe calculation formulas.

Thanks Trevor and Lodgernz. It was in my own notes from when I developed the 'simple exhaust concept'. I knew it looked familiar .

[Greg85]

In the paper the two hook positions were part of the experiment matrix.
The two positions gave different results, but in some older RS125 cylinders the pin is offset,and grinding the boost port septum's symmetrical gives
more power when used with the later pistons that have the pin at 6 o'clock.

The PJ and SPJ jet quite differently due to the length difference,if you are running a race 125 then the stock Honda jets in the SPJ are a good start point.

hello wobbly, do you also work with flowbench when you work your cylinder? according to the document yamaha jaros it says that 0.325 RFC is the maximum after the admission and exhaust systems are more suitable, I think that there is a lot of parameters that are taken into account to operate a good high RFC cylinder cranckase compression, inlet, carb, Time area, sta, what do you think about wobbly? thank you sorry google translation

[katinas]

In the paper the two hook positions were part of the experiment matrix.
The two positions gave different results, but in some older RS125 cylinders the pin is offset,and grinding the boost port septum's symmetrical gives
more power when used with the later pistons that have the pin at 6 o'clock.

Cylinder from 1987 Honda RS-250, last model without power valve.

[katinas]

In the paper the two hook positions were part of the experiment matrix.
The two positions gave different results, but in some older RS125 cylinders the pin is offset,and grinding the boost port septum's symmetrical gives
more power when used with the later pistons that have the pin at 6 o'clock.

The PJ and SPJ jet quite differently due to the length difference,if you are running a race 125 then the stock Honda jets in the SPJ are a good start point.

Cylinder from 1987 Honda RS-250, last model without power valve. Thicker wall between right B and C. Right B transfer have deeper pocket near wall with C than left B transfer.

[wobbly]

I have given up trying to interpret the results from flow bench tests,as I believe its only a small part of the overall scavenging regime.
Same with using CNC Jaros type scavenging machine results - this gives the opposite effect, in that is it shows the velocity and vector directions
but takes no account of bulk flow.
The best setup is that used by DEA, a pulsed flow visualizer, but im not that rich.
Here is the best example I can give re the flow bench result.
A reed cage with a nice smooth aerofoil type splitter in front of the reed tips flows way more air than the modified cage I have developed with a thin splitter
and a flat wall,perpendicular to the flow directly under the reed tips.
Guess which setup makes way more power.
VHM show big gains in flow with a flat top piston and a timing edge radius, but the dyno result though near on 1 Hp in near on 50 is nowhere near as significant a result as you would expect.

[RomeuPT]

Cylinder from 1987 Honda RS-250, last model without power valve. Thicker wall between right B and C. Right B transfer have deeper pocket near wall with C than left B transfer.

They come all that way.

I have 3 std client factory RS125 cylinders 91, 97 and 01.

It would be plausible that the 01 cylinder (dif case bolt pattern) might had came with dif transfer port angles etc after the SAE 1999... I have spent some time looking and the only dif I can be sure is that the 01 has more 0.5mm height, which puts all ports lower and thus helps keep the transfer not has high has the 97 cylinder, more blowdown?!

I even putted some water flush to see if I can see dif flow patterns, transfer ports angles, areas, exhaust port look very the same.

[RomeuPT]

I have given up trying to interpret the results from flow bench tests,as I believe its only a small part of the overall scavenging regime.
Same with using CNC Jaros type scavenging machine results - this gives the opposite effect, in that is it shows the velocity and vector directions
but takes no account of bulk flow.
The best setup is that used by DEA, a pulsed flow visualizer, but im not that rich.
Here is the best example I can give re the flow bench result.
A reed cage with a nice smooth aerofoil type splitter in front of the reed tips flows way more air than the modified cage I have developed with a thin splitter
and a flat wall,perpendicular to the flow directly under the reed tips.
Guess which setup makes way more power.
VHM show big gains in flow with a flat top piston and a timing edge radius, but the dyno result though near on 1 Hp in near on 50 is nowhere near as significant a result as you would expect.

If the reed port flows less how can it make more power?

[wobbly]

Simple answer, the flow bench measures constant bulk air flow by looking at the pressure drop ( say 28" ).
A two stroke reed valve opens and closes the petals every revolution, so is nothing like a constant depression value.
My take on the power increase is that the flow "dissrupter " face is turning the flow just as it exits the cage, and this opens the reed petals quicker.
Thus more area at initial opening of the reed curtain exit.
Exactly the same power increase as you see from a 4T with better low valve lift flow.
This is exactly the point I was making - just looking at flow bench numbers is very misleading.

[Greg85]

I have given up trying to interpret the results from flow bench tests,as I believe its only a small part of the overall scavenging regime.
Same with using CNC Jaros type scavenging machine results - this gives the opposite effect, in that is it shows the velocity and vector directions
but takes no account of bulk flow.
The best setup is that used by DEA, a pulsed flow visualizer, but im not that rich.
Here is the best example I can give re the flow bench result.
A reed cage with a nice smooth aerofoil type splitter in front of the reed tips flows way more air than the modified cage I have developed with a thin splitter
and a flat wall,perpendicular to the flow directly under the reed tips.
Guess which setup makes way more power.
VHM show big gains in flow with a flat top piston and a timing edge radius, but the dyno result though near on 1 Hp in near on 50 is nowhere near as significant a result as you would expect.

thank you wobbly for the answer, yes the bench jaros is nothing significant jan me had already said also in a previous post, a professional near me has a jaros I tested several cylinder TM by comparing the RFC 1 was good and the other worse by testing the cylinders in the dyno with the same time area I had almost the same hp 0.3hp here are some pictures of the tests, vhm yes already tested the flat piston then gain 0.5hp crest nothing of significant seen the price nothing better than tm 4 degres.good your reed box you are in full test reed box also there are gains to make a pretty sensitive point as I could see it on modena mkzAttachment 333167Attachment 333168Attachment 333169

[Greg85]

thank you wobbly for the answer, yes the bench jaros is nothing significant jan me had already said also in a previous post, a professional near me has a jaros I tested several cylinder TM by comparing the RFC 1 was good and the other worse by testing the cylinders in the dyno with the same time area I had almost the same hp 0.3hp here are some pictures of the tests, vhm yes already tested the flat piston then gain 0.5hp crest nothing of significant seen the price nothing better than tm 4 degres.good your reed box you are in full test reed box also there are gains to make a pretty sensitive point as I could see it on modena mkzAttachment 333167Attachment 333168Attachment 333169

[wobbly]

I suggest you look at the IAME piston,that has a 5* angled edge for around 7mm that then becomes a flat top.
This setup in a TM with a new insert ( with the plug alot closer to the piston and a very flat bathtub ) makes better power than the 4* TM setup ( same cc ).

[TZ350]

Got a Piezo switch today, 24V 200mA max.



Tried it out on my trusty PLC test bed. Piezo switch works great, pulse output non latching. Will check later how it goes with 12V and how square the wave form looks on a scope.

[Greg85]

I suggest you look at the IAME piston,that has a 5* angled edge for around 7mm that then becomes a flat top.
This setup in a TM with a new insert ( with the plug alot closer to the piston and a very flat bathtub ) makes better power than the 4* TM setup ( same cc ).

thank you wobbly for the information, I tested the new housing modena mkz it is more power on the whole curve I controlled the changes brought then more volume of low crankcase we arrive at 520cc atdc before 490cc inclination of the angle for the reed box 2 degrees down and another shape inside what do you think wobbly changes made? thank you

[wobbly]

Remove around 3mm of material in the side of the duct outside of the reed cage - this helps flow from the petals that exits sideways from the cage ( not directly out the tips).