SUGO CDI for Borut... (ignition curves)

[41juergen]

So here it is... Attached the data included now the -80 CDI.

[maccas]

Well that ignition curve is a big surprise!

Almost looks like an unleaded curve. Nowhere near as much advance as i expected. The pv fully opens a lot later than i expected too. I thought it would be fully open nearer 10k.

Brilliant info thanks to all involved!

Dan

[41juergen]

But isn't it that AV gas likes much comp and lean mixture, but less advance (and unleaded opposite around) like Wob and Frits say? The -80 was designed for AV gas as shown in the manual.

And in the sim it looks like a clever idea to fully open the PV later to use max of the power stroke as possible until you need the ex timing for the high / overrevs.

Juergen

[Toop]

This is a great step forward for knowledge

[Neal]

But isn't it that AV gas likes much comp and lean mixture, but less advance (and unleaded opposite around) like Wob and Frits say? The -80 was designed for AV gas as shown in the
Juergen

This is the way I was taught many years before I heard of Frits and Wob , with avgas you can run high compression to help your mid range pull out of the corner but then you back off the timing to get the over rev back

I'll have my 75 cdi available after the season ends 

[maccas]

I was always under the impression that as avgas is a slower burning fuel it needs more advance to get it to burn optimally.

Dan

[Yuri]

Now we only need the 70 and Neel's 75
Then all the sugo secrets are out 

[Yuri]

I was always under the impression that as avgas is a slower burning fuel it needs more advance to get it to burn optimally.

Dan

I was under the exact same impression 

[Paul]

I was always under the impression that as avgas is a slower burning fuel it needs more advance to get it to burn optimally.

Dan

you're right, else it pours out your exhaust port unburnt

[ybk]

All of them together:



Just a general question, so the advance changes based on rpm and throttle position, why would there be more advance at 0 throttle and lower revs (i assume that's when you're braking for a corner) :

[Paul]

thanks for that yan, my eyes were bulging out my head trying to compare them in xls
i wasnt aware that the TPS was connected on SUGO bikes, nor Airjets
but i am not a SUGO expert
this is all so facinating
thanks jurgen
my guess on the 3D mapping being higher at 0 was that when rolling on power your advance tapered off depending how wide you open the throttle.

[maccas]

The advance is higher at lower throttle positions to compensate for poor cylinder filling when the throttle is part closed. Basically the less efficient the engine the more advance is required to compensate.

Also more advance puts less heat in the pipe, meaning it works better at lower rpm's.

Dan

[41juergen]

Yeep Dan, that's also my understanding... I tried that TPS ignition mapping first time 2 years ago with my RZ350 with success and a nice feeling on the throttle when opening the gas.

[Warwick]

More great data. Excellent work, Jeurgen .

I'd expect the -70 to be very similar to the -80 really, but as mentioned earlier, if you haven't managed to get hold of one by late October, I'll be happy to send my -70 over to you for reading. It'd be nice to have the full set .

The main interest to me was confirmation that the -80 operates the solenoids for a while through the midrange as well as right at the top. I'd heard that that was the case, but it's good to see the confirmation in data form.

Do you think something closer to the Sugo curve might help you win some over-rev, Dan?   

[EEKNOWS]

I was always under the impression that as avgas is a slower burning fuel it needs more advance to get it to burn optimally.

Dan

Yes I had someone explained it to me like this. Fuels have a volatile and a high energy components, leaded have more high energy and unleaded more volatile components. So in essence it was a bit like the difference between gunpowder and gelignite. To ignite, gunpowder only needs a spark and is highly volatile while TNT needs a detonator and is stable. With ULP the volatile component can easy ignite the high energy component, with leaded a bit of extra time is needed for the volatile to ignite the high energy component