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Offline Uniflow

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Cycle World Two Stroke article
« Reply #45 on: September 18, 2012, 12:13:57 AM »
You can try but it's so secret even Wobbly don't know what he's doing!
I'm sure Lozza, he will spill the beans. He's just making sure I don't do my "usual" and just estimate port time area's. His simulator is way more accurate than me.


 
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Davo

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Cycle World Two Stroke article
« Reply #46 on: September 21, 2012, 12:03:28 AM »
Really good work Uniflow!

Did you consider using Ignitech's combined ignition and EFI ECU... the Ignijet? How hard/easy was it to nail down the fuel maps to give good running across a range of temps and conditions?


Hey Jeram, this is where youve been hiding... found your name all over this forum, forum whore! he he (dmcca here)
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Jeram

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Cycle World Two Stroke article
« Reply #47 on: September 21, 2012, 05:26:12 AM »
haha hey dave!

In not a forum whore, I dont get paid for it...

-Im a forum slut haha
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Cycle World Two Stroke article
« Reply #48 on: September 21, 2012, 11:44:50 PM »
Yes I did think of using wobbly's ignitech unit. Cost a little more than the Link. I've used quite a few link units in the past on the Subaru powered gyro copters we build and have a good working relationship with the guys at link. But I was a little disappointed that the Atom unit I was sold did not have the suitable soft wear activated even though I was told that it was when I bought it. No problem, as it will be available in the next soft wear release. At the moment I'm "tricking" the computer into doing what I want. To be fair not a lot of after market computer makers have had a lot to do with transfer port injection where timing is so important. It is interesting to note that the default setup for injector timing is batch fire every 180 crank degrees ( fourstroke car engine ), this timing is random every time the engine is started. Once started it stays constant, but next time you start it will locate somewhere else. You can imagine the issues this caused, trying to tune this type of setup was impossible and it took a while to sort it out. I ended up making a device to strobe the injectors on and off points. Link's experience with twostroke injection has only been with snowmobile engines injecting into the intake ( an electronic carburetor ) where injection timing seems to be less important. You can appreciate I've put a lot of time and thought into this project.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Cycle World Two Stroke article
« Reply #49 on: September 21, 2012, 11:56:31 PM »
How hard was it nail down tuning? Well it's still happening, some of the problem has been the computer setup as stated above and some the ethanol fuel I'm running ( too many new things at once ). Ethanol has the odd requirement for more fuel above 70 / 80 degrees C ( engine temp ). Water cooled engine you would never notice. Air cooled, at 120 degrees it becomes very lean so more fuel is needed. This is were the computer is soo good as it can easily be setup for this. This was always the problem with the MFI system I had previous. Very rich cold and early in the race only to come right at about two laps in, very frustrating! Now we can fuel it so the engine never sees 120 C.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »