ESE's works engine tuner

[Flettner]

TZ, the EFI YZ is getting used at trail rides, three now, trouble free.
Why are there not more EFI twostrokes out there? This bike is a lot of fun to ride. We are experimenting with injection timing changes, interestingly this changes the way the power is delivered.
So far a 14% fuel saving over my carbed YZ 250. Same track, same times, same rider. This must go to show there is less fuel spillage out the exhaust.

I am keen to see that ball valve working on your 125. I like the boost bottle idea, best way to beat that restriction so far.

[TZ350]

... the EFI YZ is getting used at trail rides, three now, trouble free.

So far a 14% fuel saving over my carbed YZ 250. Same track, same times, same rider. This must go to show there is less fuel spillage out the exhaust.

It sounds good and very responsive on the throttle too.

I am keen to see that ball valve working on your 125. I like the boost bottle idea, best way to beat that restriction so far.

Its going back together now but next week I am away for work, so the week after I should be able to start wiring the EFI and maybe get to see if it starts. One of the issues will be the EFI and Ignitec electricaly sharing the same TPS. The problem being they have different source voltages and therefore different voltage ranges to represent 0-100% throttle position, hopefully I can figure a way around that.

[speedpro]

The Ecotrons system learns 0% throttle when you power it up so that shouldn't be a problem. As far as the max throttle goes, one system will detect 100% while the other may detect only 80%. The remaining 20% won't matter. It will just be a portion of the map that is not used. Effectively you will have lost some resolution. Or is it a bit more complex than that.

[TZ350]

Not everything goes our way....



Chambers and I have been tweaking his 50 and we have virtually tuned it to a standstill.....

Started with the red line and after much hard work got to the blue line, looks like someone left the barn door open and the ponies escaped.....

[F5 Dave]

That's a lot of revs if you're still running the std suzuki rod. they'll live all day long at 12k, but ticking if you're at 13.

[FastFred]

I think at one point they had it running to 15k with an even shorter power spread......

[RomeuPT]

Been reading and watching post's mostly waiting for news about the raised exhaust port floor.... could be a new kick in the a** for the 4 joke fans and industry.

Meanwhile bought a KTM 250 SX, 2002 model to ride with my buddies at the weekend. The exhaust has some dents and I am thinking about filling it with water and put in the frezzer watching the dents go out....

Of course already thinked about building a pipe for it. Wobbly, what should be a start for it? I am thinking about 1000mm total lenght (9000rpm peak power), 135 belly max diameter, long swallow baffle like the stock ones!?

Thanks

[F5 Dave]

Nah nah, he's already split the good oil back page 817.
11600. Rpm. If a stinkn $onda can do it can't let it beat a pumpkin huh?

[Frits Overmars]

... bought a KTM 250 SX, 2002 model to ride with my buddies at the weekend....Of course already thinked about building a pipe for it. Wobbly, what should be a start for it? I am thinking about 1000mm total lenght (9000rpm peak power), 135 belly max diameter, long swallow baffle like the stock ones!?

Let's pretend I am Wobbly: a 135 mm belly diameter sounds fine if you can accommodate it. But the angle.areas of the 250SX cylinder are insufficient for 9000 rpm.
If you force the engine to run at that rpm by means of the pipe, it won't deliver the power that can be had at lower revs.
You can enlarge the blowdown angle.area and gain a lot of peak power, but that will make the engine character too vicious for terrain riding and spoil all the fun.
Now I am eager to see what the real Wobbly has to say about it .

[Frits Overmars]

Chambers and I have been tweaking his 50 and we have virtually tuned it to a standstill.....

Detuning tends to be easier than tuning. If you can't improve engine power, then try to reduce it. You will probably succeed and it can be just as instructive .

[RomeuPT]

Let's pretend I am Wobbly: a 135 mm belly diameter sounds fine if you can accommodate it. But the angle.areas of the 250SX cylinder are insufficient for 9000 rpm.
If you force the engine to run at that rpm by means of the pipe, it won't deliver the power that can be had at lower revs.
You can enlarge the blowdown angle.area and gain a lot of peak power, but that will make the engine character too vicious for terrain riding and spoil all the fun.
Now I am eager to see what the real Wobbly has to say about it .

I know that Frits, saw this dyno, but not sure that's correct. I pretend to do a pipe for the same peak rpm as the stock pipe, the stock one has maybe a 120 belly diameter...

[Frits Overmars]

The above torque texts do not correspond to the graphs....

[RomeuPT]

The above torque texts do not correspond to the graphs....

Can you say why? I looked and didn't conclude anything.

I dont know why the riders say so good from the fmf pipe. The stock is better mostly.... at least taking this dyno in consideration.

[Muciek]

Look close , it says under the picture that factory pipe 49HP and fmf 45 but scale of graph ends at 45 and looking at it you can see that factory pipe is around 42HP and FMF 41 or sth close to it. IMO it lacks a second scale for torque on the other side too :P

[Frits Overmars]

Can you say why? I looked and didn't conclude anything.

Can't you see that the orange 40.6 Nm torque curve has a higher maximum than the red 47.6 Nm torque curve? And that the orange maximum torque is not produced at 8500 rpm as the text says, but at 7500 rpm? And that the red maximum torque is not produced at 8250 rpm but at 7000 rpm? And that the quoted rpms for maximum power do not correspond to the graphs either?