For anything related to the 'official' Speeduino boards (Eg v0.3, v0.4 etc)
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By PSIG
#69382
Yes, altering a cylinder's fuel and timing is due to engine flaws. All engines have flaws, some more, some less. You can look at the cylinder head flow data of two or four ports and find some rather wide variation. Add to that differences in each intake runner, each exhaust port and tube or runner, etc, and pretty soon it can be shocking.

Yet more issues are due to heat or cooling, such as the famous Mopar I4 turbo engines (2.0, 2.2, 2.5, etc) that have poor coolant circulation for the last cylinder. It is a design flaw, and it's not common to 'fix' it. So, they de-tune the engine enough to avoid knock in #4 on pump gas. Or, buy higher octane. But the alternative is to alter the tune to allow all the cylinders to run at their capacity, not held back by that hot one. That's ICFT for flows, and ICIT for heat.

I would say integer timing increments are fine. Most that need this kind of attention are requiring perhaps 2 or 3°, or more, and less than that is a minor issue and not worth the time. I see this when reading plugs and checking knock, and it may show some varied but similar signs of knock onset. But, if one cylinder sticks-out with heavy signs, or no signs, that's when it's worth looking closer for some special treatment.

IMO - while we can assume that race teams and competitors would find quick performance use of these features; getting a hot cylinder to not knock on a hot day in commuter traffic can be just as useful for engine safety and longevity on that last fill-up from that 'other' fuel station. Here's hoping you have that capability and do not need it. :lol:
By Domenico.mezzacapo
#69385
Since it is a V-Twin engine, the rear cylinder receives less air and, as a result, is hotter. Below you will find the timing tables loaded onto the original ECU:
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By Pim205gti
#69409
digmorepaka wrote: Fri Aug 30, 2024 3:32 pm
Domenico.mezzacapo wrote: Thu Aug 29, 2024 8:49 pm Should I use the MAP algorithm considering the presence of the turbo?
Absolutely, TPS only fueling is a good way to blow a hole into your piston when running a turbo. You will most likely want to run a hybrid setup where in low throttle you will use TPS, and when the manifold pressure signal becomes usable use the MAP sensor.
That's funny because the Honda Engineers in 1980 did exactly the opposite on the CX500 Turbo

http://speeduino.com/forum/download/fil ... 28a2fa37d1
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CX500 Turbo Switch over Point.png
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By digmorepaka
#69416
Pim205gti wrote: Fri Sep 06, 2024 8:04 am
digmorepaka wrote: Fri Aug 30, 2024 3:32 pm
Domenico.mezzacapo wrote: Thu Aug 29, 2024 8:49 pm Should I use the MAP algorithm considering the presence of the turbo?
Absolutely, TPS only fueling is a good way to blow a hole into your piston when running a turbo. You will most likely want to run a hybrid setup where in low throttle you will use TPS, and when the manifold pressure signal becomes usable use the MAP sensor.
That's funny because the Honda Engineers in 1980 did exactly the opposite on the CX500 Turbo

http://speeduino.com/forum/download/fil ... 28a2fa37d1
The 80s were wild with what engineers would come up with for EFI control methods.
As demonstrated by honda it can be made to work however you're significantly limited in terms of efficiency, and performance outside of the ideal zone in the name of not blowing it up.
Alpha-N fueling is an estimation of load, not a measurement like Speed Density.

With Alpha-N and a turbo you need to assume that you have the most amount of air possible at any given time at that load/rpm bin that can be there. This then also needs to be correlated against Baro and IAT. IAT needs to be especially accurate with how much it swings around with air speed and intercooler effectiveness.

If you look at the plenum design of the CX500 Turbo you can see that it has a large chamber before the runners with a single throttle, more like a car than a motorcycle. This allows it to have a usable MAP signal at low loads.

Unlike OP who's running ITBs with a tiny volume between the throttle plate and valves - meaning most likely a completely useless MAP signal below a certain rpm/load.

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