ESE's works engine tuner

[Carel H]

=My idea is to find the difference between maximum and minimum crankcase pressure each cycle and output this in a modified form to the EFI CPU as an indication of real airflow through the two stroke's motor.

The on/off/on toggle switch simulates the ignition trigger pulse for timing the start/end of each cycle by allowing a digital input pin to go high briefly. The trigger is connected to a digital pin configured as an interrupt. The MCP4725 feeds directly to the meter and it is also read by the Arduino on another Analog input pin so all inputs, outputs and internal processing variables can be serial line printed in real time to the PC's screen for de bugging purposes.

It has taken a while to learn about Arduinos and programming them and of course, at the moment it is just a concept and I have no idea if this is going to improve my 2T's EFI system or not until I try it.

First, there is a magic pin on the ATMEGA, the arduino processor. It's called ICP1. It can capture the time of an event, so you can calculate RPM and set a switchpoint for Plan A---Plan B. This also enables you to set something like: So an engine revolution takes X clockcycles, I want to do something at 60 degrees after the triggerpoint, which is thus X / 6 after that. With this, your measurements match the crankshaft position.

Why not use the MCP4725? At 100 kilohertz I2C speed you have a transmission time of 0.0003 second and it's 5 volt tolerant.

Embedded real time programming is a sport of it's own. For example: if you design your program for an engine that does 15000 rpm, your total program should execute within 1 / 250 second, which is the absolute maximum. So scope your software and parts of it, just by setting a pin on entry and clear it on exit. You will see the wonders of a processor and that miracles don't exist.

[TZ350]

First, there is a magic pin on the ATMEGA, the arduino processor. It's called ICP1. It can capture the time of an event, so you can calculate RPM and set a switchpoint for Plan A---Plan B.

Great, very interesting. Thanks.

[philou]

What are you going to do with that cylinder? Interested in selling it?

I'm sorry, currently I do not want to sell it

[TZ350]

Hopefully that MAP signal will be an indication for the inhaled air mass.

Yes, hopefully I am onto something useful ..... fingers crossed for luck.

But if you rev the engine beyond the rpm allowed by its blowdown time.area, spent exhaust gases may cause a pressure rise in the crankcase that will easily exceed the highest useful reading, although it has nothing to do with the air breathing...

True, but in this case, so long as it does not exceed 3.5 bar the worst that happens is that it over-fuels and quenches the fire.

[Pursang]

Alpha-N maps are RPM/Throttle position = Fuel required. Simple and work well with predictable air flow.

My idea is to find the difference between maximum and minimum crankcase pressure each cycle and output this in a modified form to the EFI CPU as an indication of real airflow through the two stroke's motor.

If I can find a good way to indicate changes in air flow (charging efficiency) then I may be able to also use a Volumetric efficiency map below 25%, just like 4T's do.

When the engine is on the pipe, Alpha-N works well but when the motor is swapping between on the pipe and off Alpha-N is either correct or to rich for the motor to run. So we need a way to adjust the fueling to match the changeable air flow.

Rather than trying to accurately measure the airflow, perhaps d(RPM)/dt and/or Gforce could be more easily measured and integrated with the throttle position & RPM in the Alpha-N map.

Cheers, Daryl.

[SwePatrick]

Earlier i hinted about a project that is going on in my garage.

It´s a twin Piaggio engine with malossi case.
We have done some machining this weekend to beeing able to start fitting crankshafts etc etc.

I milled out the crankhousings to fit the new crankshafts from Roost.(47mm stroke)
Also chopped the two crankshafts so we can mate them together with a coupling.

A teaserpicture:


It is still some porting to do to fit the banshee reeds, but it´s a five minute job.
As we speak i´m milling a keyway in the crankshafts to keep them 180 degree apart when mounting the engine.

[DaisyB]

Having circuit raced a Malossi C-one cased 77cc Piaggio Zip, I'd imagine that's going to be a bit of an animal!

[peewee]

What thread is needed Peewee, I will measure the Dellorto ones I have here.

https://www.dellorto.co.uk/shop/dell...-needle-valve/

hey mate its m10x1.0, see what you've got that might be other options. but to be honest , it seems ive got this modified 3.5 mikuni working perfectly, atleast in the bench tests. ill try it next week on the running engine to make sure I haven't over looked something. two things I found to be very critical. once you get close to 4.5mm ( I bored from 3.5 to 4.48 in about five or six step increments), be very carefull to bore the hole perfectly round. at the end I used a 4.48mm drill bit by hand so not to bugger it. if its ovaled then your valve will be good only for the scrap heap because it likely wont seal again. other thing is, I used a 15/64" drill bit, turning only by hand , to put the ramp back into the hole so the needle tip can seal. so far it seals perfect

[jonny quest]

Looking for a set of RG400/500 oem carbs. Also electrical parts

[gamma500]

Hi Wobbly and Frits, I have a question about cylinder head water flow.

I have been searching for Yamaha gytr kit parts for 125, and I noticed that gytr head water flow is a bit different from standard Yamaha.

As you can see on the gytr head most of the water flows from the back of the cylinder and then back to the front of cylinder head.

In the std Yamaha the water outlet is at the rear of the head.

Is this gytr flow path any better than the original yamaha design?

[husaberg]

Hi Wobbly and Frits, I have a question about cylinder head water flow.

I have been searching for Yamaha gytr kit parts for 125, and I noticed that gytr head water flow is a bit different from standard Yamaha.

If i remember right the "KIT" long rod was just the std rod from an older model.

[Frits Overmars]

I used a 15/64" drill bit, turning only by hand, to put the ramp back into the hole so the needle tip can seal. so far it seals perfect

Inserting a suitable-diameter bearing ball and giving it a hammer tap can create a perfect seat for the float needle.

I have been searching for Yamaha gytr kit parts for 125, and I noticed that gytr head water flow is a bit different from standard Yamaha. As you can see on the gytr head most of the water flows from the back of the cylinder and then back to the front of cylinder head. In the std Yamaha the water outlet is at the rear of the head. Is this gytr flow path any better than the original yamaha design?

I like the GYTR flow path, but did you notice the air bleed bolt? Because of the low-placed hose pillar, an air bubble will form in the upper part of the head, and bleeding it once in a while may not be sufficient. I'd replace the air bleed bolt with a small hose pillar and connect it to a high point in the cooling circuit, like in the RSA pictures.

[peewee]

Earlier i hinted about a project that is going on in my garage.

It´s a twin Piaggio engine with malossi case.
We have done some machining this weekend to beeing able to start fitting crankshafts etc etc.

I milled out the crankhousings to fit the new crankshafts from Roost.(47mm stroke)
Also chopped the two crankshafts so we can mate them together with a coupling.

A teaserpicture:


It is still some porting to do to fit the banshee reeds, but it´s a five minute job.
As we speak i´m milling a keyway in the crankshafts to keep them 180 degree apart when mounting the engine.

nice project there. is it for drag racing and where is the gear box ? some how i would like to make a twin with two ktm 250cc cylinders

[Muhr]

Does anyone have any experience with titanium conrods?

[peewee]

i dont have experience with titanium conrods but i thought they had to much elasticity for high piston speeds ?