ESE's works engine tuner

[wobbly]

The dyno inertia has a big effect on the run time accelerating thru the pull.
If its too low, then no matter what you do the pipe wall temp,and egt will never stabilize at the correct level - reducing overev power,simply due to lack of heat soak..
The crank in the RS125 Honda was quite low in inertia, and removing the flywheel tipped it too far in favor of low inertia and faster acceleration capability.
The Aprilia by comparison has a huge amount of added Mallory around the outside of the wheels, making it a high inertia assembly by default.
Adding more would tip that too far the other way and slow down the acceleration capability.
I have used an old KZ9 crank with alot of mass removed with alloy plugs, and re-balanced it with Mallory, and that made better top end power than the
latest so called high mass KZ10C factory crank.

[TZ350]

I received a reply from Ecotrons lastnight. The advanced calibration file needs some changes to be able to monitor and record results from the wide band oxygen sensor. Hopefully I will get to try it out this afternoon.

I used to think that it was easier for the local 2T Kawasaki 350 and Yam 250 that are successfully running EFI because they did not rev much past 9,000 and so only needed one logical injector and that the bigger capacity helped mask fueling miss steps.

I started to have doubts about that when I saw that some small 2T drone aero engines 25cc or less were successfully running the Ecotrons EFI system. But these engines basically run at a constant speed.

The issue for me is drivability, i.e. throttling off for a corner and then on again exiting. After Nath88 pointed out that you can have two different air flows through the engine due to pipe action/non action for the same Throttle/Rpm position on the Alpha-N EFI fueling map. And remembering Frits's explanation of how the wave action in a pipe collapses when throttling off and how it takes some time to re establish after throttling on again.

I now think that one of the big differences is how aggressive the pipe is. On a small capacity high performance race engine the pipe action in drawing air through the engine would be much more variable than the pipe action on a larger capacity MX or Trail bike engine setup more for power range and usability than outright power hit.

So in getting 2T EFI to work, it turns out the pipe makes a huge difference, who would have thought ......

[Flettner]

I received a reply from Ecotrons lastnight. The advanced calibration file needs some changes to be able to monitor and record results from the wide band oxygen sensor. Hopefully I will get to try it out this afternoon.

I used to think that it was easier for the local 2T Kawasaki 350 and Yam 250 that are successfully running EFI because they did not rev much past 9,000 and so only needed one logical injector and that the bigger capacity helped mask fueling miss steps.

I started to have doubts about that when I saw that some small 2T drone aero engines 25cc or less were successfully running the Ecotrons EFI system. But these engines basically run at a constant speed.

The issue for me is drivability, i.e. throttling off for a corner and then on again exiting. After Nath88 pointed out that you can have two different air flows through the engine due to pipe action/non action for the same Throttle/Rpm position on the Alpha-N EFI fueling map. And remembering Frits's explanation of how the wave action in a pipe collapses when throttling off and how it takes some time to re establish after throttling on again.

I now think that one of the big differences is how aggressive the pipe is. On a small capacity high performance race engine the pipe action in drawing air through the engine would be much more variable than the pipe action on a larger capacity MX or Trail bike engine setup more for power range and usability than outright power hit.

So in getting 2T EFI to work, it turns out the pipe makes a huge difference, who would have thought ......

Who??? Crank angle enabled exhaust pressure sensing perhaps. The exhaust chamber, and the piston / cylinder / crankcase are two separate engines, not exclusively working together.

[TZ350]

Crank angle enabled exhaust pressure sensing perhaps.

Definitely.

The exhaust chamber, and the piston / cylinder / crankcase are two separate engines, not exclusively working together.

Yes, nothing simple about the simple two stroke.

[diesel62]

Can I ask where you have the O2 sensor mounted? In stinger?

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[TZ350]

Can I ask where you have the O2 sensor mounted? In stinger?

The wide band O2 sensor is mounted in the convergent cone near the start of the stinger.

[RomeuPT]

The permanent magnets in the flywheel simply pass their field thru the coil - this magnetic field passing thru the wire creates voltage.
It makes no difference if that created voltage is used or not.
The on/off " resistance " you feel when turning the rotor ( especially with Neo magnets ) is the fields passing over the steel stator elements,and that is a constant.
Many tuners thought they were being clever dumping the magnetic rotor in favour of total loss, only to find the thing then simply would not rev out.
Honda and VHM had to make heavy cranks, that in effect simply recreated the original rotational inertia of the stock crank - and this brought back the overev power.

Thank you.

Ok, Then is worth to cut some if not needed.

Do you have any ideia of ignitech and other cdi's power consuption?

Cheers

[Frits Overmars]

Crank angle enabled exhaust pressure sensing perhaps.

Very definitely. If you monitor the exhaust return pulse, you can see whether it arrives at the exhaust port too soon, too late or just in time, and then you can adjust the ignition timing accordingly. No need for rpm-throttle-advance tables anymore; not even a need for exhaust gas temperature measurement anymore.

[dutchpower]

What Frits if you have new exh. and make other cdi curve's all not respons better then OEM part ( cdi )

[jamathi]

The dyno inertia has a big effect on the run time accelerating thru the pull.
If its too low, then no matter what you do the pipe wall temp,and egt will never stabilize at the correct level - reducing overev power,simply due to lack of heat soak..
The crank in the RS125 Honda was quite low in inertia, and removing the flywheel tipped it too far in favor of low inertia and faster acceleration capability.
The Aprilia by comparison has a huge amount of added Mallory around the outside of the wheels, making it a high inertia assembly by default.
Adding more would tip that too far the other way and slow down the acceleration capability.
I have used an old KZ9 crank with alot of mass removed with alloy plugs, and re-balanced it with Mallory, and that made better top end power than the
latest so called high mass KZ10C factory crank.

At Aprilia we did not have an inertia dyno, as I would have liked.
Crank inertia tests were done on-track.
Exchanging dyno information with 'track-people' was forbidden....
You know by whom I think!
But we still won....
I still think we could have done a lot better than we did!

[lohring]

Can I ask where you have the O2 sensor mounted? In stinger?

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Below are some pictures of a stinger slide on O2 sensor for small engines.

Lohring Miller

[jasonu]

At Aprilia we did not have an inertia dyno, as I would have liked.
!

You seamed to do OK without one...

[diesel62]

What is the red material. Nylon seal?

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[RomeuPT]

Hi.

This is the Gearbox from NSR/CRM 125:

from 1st to 6th

11/34
15/30
17/25
19/23
(23)/24
(24)/22

This gear box is ok for a road bike, but 5th to 6th is a huge jump of 13.74%, for a top end engine, that is far too much, and the engine gets out of the real power band.
Other better gear boxes are about 9%.
So I took a backup engine gearbox to see what can be done, and the 23 tooth sproket from tht 5th can fit in the 24 of the 6th gear the tooths are only 1mm wider, this would put me right at 9% jump.

But of course they have different diameters (around 2,5mm) and the tooths are a bit further apart. Can this cause any trouble or bigger loss of power?

Cheers

[RomeuPT]

At Aprilia we did not have an inertia dyno, as I would have liked.
Crank inertia tests were done on-track.
Exchanging dyno information with 'track-people' was forbidden....
You know by whom I think!
But we still won....
I still think we could have done a lot better than we did!

It's wonderfull how it still achieved so much.
It looks like the Aprilia team had considerable restricitions and disagreement between yourselfs and the "boss".
Always had a thought that this dellorto used in the Aprilia would be better then keihin and read at pit lane that it wasn't exacly that way.

Was any component from the Aprilia made in Japan or other place besides Europe?

What would had happen in your opinion if the 125 2t was still at GP, do you think it would have achieved 60cv by now after more 6 years of R&D?