ESE's works engine tuner

[wobbly]

The intake in the example is the wrong length for 12000, the intake wave crosses zero pressure ratio, going positive, way too soon.
This appears to be tuned to the second harmonic, with only one pulse in the intake.
Also look at the RZ400 trace, it has twice the frequency of pulses and crosses zero at the same time as the case goes negative.
Fine tuning makes a big difference.
The pic shows a TM125MX kart motor with a standard Honda RS125 intake rubber, then a 15mm shorter one from an early model RS125.
2 Hp, just by shortening the intake length, real numbers off my dyno.

[TZ350]

Someone was asking about an Aprillia 125 crank.

Attachment 251080Attachment 251081

These are photos taken by Chambers looking inside an Aprillia125 at Phillip Island during the last Moto GP. Chambers took them to show me that Aprillia don't bother to champer the inlet side flywheel edge, in this engine anyway and they use a fairly solid I beam conrod.

[TZ350]

Simulation Time ....

Attachment 251102

The simulator tells me that those nifty little side exhaust ports I made before are not going to do much for me. I suspect the 24mm carb is starting to choke the engine and the effort of tripple exhaust ports for more blowdown is not worth the trouble unless I can find a way to induct more air into the engine.

Attachment 251101

A comparison of the 24mm carb vis a 30mm one confirms for me that I am getting close to whats easily possible with the 24mm carb at 12.000 rpm and its becoming the bottle neck. I now have to start looking for any further gains to come from fine tuning the rest of the engine and pipe, thank goodness for a good simulator.

Attachment 251103

Wobbly I would be interested to know what are good numbers for TexAv, average exhaust temperature and TUMax, maximum temp of the end gases in the squish area.

Dratio delivery ratio, what sort of numbers do you expect to see here on a mildly well tuned engine and PurCyl purity of the fresh charge, 97.7% has got to be good, hasint it?

I am particuarly interested in how to blowdown the cylinder quicker so that I can get rid of that pressure hump in the transfer port (left side of graph).

Any pointers here would be very helpfull.

[speedpro]

That's really interesting. To get rid of the transfer port pressure hump it "looks" like you need more blowdown. Also looking at the reduction rate of pressure in the transfer I wonder what effect a change in crankcase volume would have.

[teriks]

Increased blowdown time*area is my take on it as well.
Have you compared this curve for your different exhaust ports?
-You mention some nifty side exhaust ports, those could be the key.

PS: You do know that you can plot both results in a single chart this using Post2T, right?

[kel]

Work faster guys, the premier Auckland F4 meeting was run over the weekend and there were no 2 strokes in the top ten

[TZ350]

Work faster guys, the premier Auckland F4 meeting was run over the weekend and there were no 2 strokes in the top ten

will be ....... and congrats I hear you managed a third against some realy stiff compitition ......

[TZ350]

That's really interesting. To get rid of the transfer port pressure hump it "looks" like you need more blowdown.

Increased blowdown time*area is my take on it as well.

Attachment 251116

STA numbers for the graph, looks like plenty of Blow Down Time Area, I think it must be something to do with the exhaust tract/pipe.

The inlet port (rotary valve port) is good for 39hp but it requires a 34mm carb, the 24 is holding it back.

Have you compared this curve for your different exhaust ports?
-You mention some nifty side exhaust ports, those could be the key. PS: You do know that you can plot both results in a single chart this using Post2T, right?

No ... just learning, thanks for the tip.

[TZ350]

I wanted to see what could be done with a dash of DihydrogenMonoxide.Unfortunatly I did the runs with the 30mm carb so max power is overstated.

This is a 30mm carb and tripple exhaust port (blue line) with DihydrogenMonoxide.

Attachment 251117

Look at the predicted improvement to the torque curve, those FXR's could be in trouble yet ...

With a slightly better airflow through the carb, triple exhaust ports and a touch of DihydrogenMonoxide (Hydric Acid) and I could get to here.

As DihydrogenMonoxide has a much higher latent heat of evaporation than Methanol I would not need to induct much with the fuel to get the Methanol effect. Read more here about DihydrogenMonoxide:- http://www.dhmo.org/facts.html

Attachment 251118

This looks promising and I won't have to use much to get the same latent heat effect as Methanol.

[koba]

When I was a kid I almost died because of that Dihydrogen Monoxide. Dangerous stuff.

[husaberg]

I wanted to see what could be done with a dash of DihydrogenMonoxide.Unfortunatly I did the runs with the 30mm carb. So this is a 30mm carb with (blue line) DihydrogenMonoxide.

Attachment 251117

Look at the predicted improvement to the torque curve.

With a slightly better airflow through the carb, triple exhaust ports and a touch of DihydrogenMonoxide (Hydric Acid) and I could get to here as DihydrogenMonoxide has a much higher latent heat of evaporation than Methanol I would not need to induct much with the fuel to get the Methanol effect. Read more here about DihydrogenMonoxide:- http://www.dhmo.org/facts.html

Attachment 251118

This looks promising and I won't have to use much to get the same latent heat effect as Methanol.

ban it i say. It already killed heaps of people. Its use is on the rise according to stats. It has already done untold damage to my bikes.

[koba]

'snot a fuel in most forms but it is arguably illegal for a 125. Not to mention irresponsible and dangerous.

[Frits Overmars]

Someone was asking about an Aprillia 125 crank.

Attachment 251080Attachment 251081

These are photos taken by Chambers looking inside an Aprillia125 at Phillip Island during the last Moto GP. Chambers took them to show me that Aprillia don't bother to champer the inlet side flywheel edge, in this engine anyway and they use a fairly solid I beam conrod.

Here are some other pics, from an RS250 and an RSW125. As you can see, inlet flow is not hindered too much by the flywheels.
By the way, the RSA125 does not have chamfered flywheels because its inlet is at the rear, not the side.

[cotswold]

[QUOTE=TZ350;1130199606]Attachment 251116

STA numbers for the graph, looks like plenty of Blow Down Time Area, I think it must be something to do with the exhaust tract/pipe.

The inlet port (rotary valve port) is good for 39hp but it requires a 34mm carb, the 24 is holding it back.


Would the GP100 offer more as it has no restriction on the carb ?

[dinamik2t]

To Wobbly:
I am probably asking something you take as a given. By "3rd harmonic" we mean the third oscillation from EPO? I get confused with the physics terminology we use at college.
In the RZ400 example in the other topic, the 'tuning spot' it at approximatelly 120 degrees or after ~1.5 period of oscillation after EPO. According to what we use to say in physics, that would be ~ one harmonic (oscillation) and a half.

The snaps of the traces I presented were from a 61X54.7 engine actually. I can't even get to 12nbars of BMEP


To TZ350:
Aren't the time areas you show a little too much?? Especially those tfr numbers are huge! For an 125cc engine, with 50mm stroke. Except if I am not using correct input in all my calculations..
Good requests by the way! It would be very interesting to know a fine setup numbers. Not to copy it, but to have a point of comparison.
In these sim there are so many interdependant variables, that you can sim and sim and sim for months!

After Wobbly gave us some info on how to interprate these graphs, I tried to study the results from the two GP engines coming along the sim, an RS125 and a TZ250G. But I got even more confused. Especially the inlet traces are a lot different at max-power-rpm, than what the ideal situation described above.
Another strange point is that RZ400 example, at EPO the inlet pressure is atmospheric and descends, while in all my graphs it's atmospheric and ascends.

I would like to summarize a couple of the info until this far:

Inlet traces:
> Inlet pressure should rise above 1, at the same point where case pressure falls below 1. That's best to be at the "3rd harmonic".
> Transfer pressure shouldn't rise too abruptly after TPO. That would mean a need for more blowdown.
> (on a question mark - that's a personal observation) Reeddisp shouldn't rise to be too close to the crank/inlet pressure.

Exhaust traces:
> (on a question mark also) Cylinder pressure should start falling from peak at TPO and reach peak again at EPC.