mrrpm
Posts: 455
Joined: 1/6/2008
From: Denton NC
Status: online
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Have ya'll figured out how to adjust timing on the 800 can ams with the stock computer, or just talking about motors in general?
On the issue of timing being optimized when cyl head temps are the coolest, the only way to tell that is to hookup a dyno to the crank, as the engine rpms swing around faster than a thermocouple's temp can stabilize. This is done with an engine dyno, like is used on sleds. I have an engine dyno where the motor gets mounted to the dyno, ran, and adjusted on there. This allows you to do exactly what ya'll are talking about, and I think those sled dynos are just like my engine dyno, except the engine is left in the bike, clutch is removed, and the water brake is installed in the place of the clutch.
The way a engine dyno works, the motor held at wot, then a load is introduced to hold the motor at any rpm you want, or do a sweep, across a selected rpm range. On a car motor, I have found that a motor can run a little more timing at the track, than it can on the dyno, and run faster. IMO the reason is, the motor is loaded completely on the dyno, and allowed to accelerate at a controllled rate, whereas, in a car, the motor will accelerate faster in first gear, than it does in high, allowing the tuner to "get away" with more timing when it is accelerating faster (low gear), and less when accelerating slower (high gear)...............NOW in a cvt, we have the same basic load, at wot, throughout a run, whether it be at the first of a run, or the end, with the engine holding a constant, or nearly so, rpm. So IMO we need relatively minute timing changes at different rpm points, because the motor is seeing the same load, all the time, with no engine acceleratng speed changes.......NOW, for part throttle operation, since we aren't under hardly any load, the timing isn't really important from a power production standpoint, but from a throttle response standpoint, it makes a good bit of difference, however not a whole lot, on a na motor.
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Rotax Performance Master
'07 228hp Renegade 1004cc Turbo
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RE: wideband commander - 
. This process is easy in excel...Although I'm not sure if the Wideband Commander software has the ability. Worst case scenario, you copy over a number of datapoints into excel and use the "equivalent" line graph in temp vs time. The more points you add, the more accurate the experiment. I'd probably try 20 or so, depending on the variation of the temperature. Where the graph goes flat will be Tmax, which then becomes our reference Temperature, and is also the solution to our previous D.E.(gotta love computers!). 
omg my head hurts now
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