Understanding Autotune

Rocket_Rider

Supercharged
Joined
Jan 26, 2019
Messages
238
Location
Sydney Australia
Ride
Rocket 3 Touring 2018
Dear all,

I had the bike dyno tuned finally. They said they wrote a tune in the PC V and when I look into it there are values in the fuel table.

here’s the bit I’m not clear on. They say it’s better to leave the autotune active. Thing is, they’ve set it with a target AFR of 13.1 and low swing of 5% so basically I now have a trim table where almost every box says -5% .... I don’t see the point in having it active? It’s just trying to trim and can only go 5% so is putting in minus 5% seems pointless? Appreciate any thoughts on this... I have discussed it with the tuner but they don’t explain it other than with bikes like this it’s good to adjust for variability in conditions... also doesn’t make sense to me looking at the tables? Am I missing something here?
 
According with the folks at Dynotune, leave it on so it continously adjusts to desired fuel values (your folks who tuned your bike are correct). Using a small limit to the trim (+/-5%) keeps the air/fuel ratio closer to where they want it and prevents large auto trim inputs for conditions like cold air inversion when off the throttle or accelerator pump input when quickly opening the throttle. Just remember to never accept and send trim values to the map or you'll dork up the map they made.
 
You got some significant gains with that tune, money well spent.
I added an air/fuel gauge and a wideband o2 to see where my bike is at in all conditions and I see the tune air/fuel holds as conditions change.
I'm not sure the reason for an autotune when you have a custom tune. I know people that use autotune instead of a custom tune.
 
Thedogsbollocks said:
so would I be right in saying - If you have arrived at a great map via Tune ecu - then you load a zero map into the PCV - input target AFR value as the same on the tune in the ECU map and then run AT restricted to 5%?
Click to expand...
That is how I tuned my Rocket except I initially set adjustment limit to +-20%. Let AT trim (and accept trims) until you achieved within +- 5%. Then set limit to +-5%, let AT continue to adjust, and never accept the trivia adjustments from that point. The easiest and fastest way to achieve accurate fuel trims for the PCV is to install an on/off switch that allows you to turn AT on or off. You want AT off when you are just riding around varying the throttle. You only flip the switch to activate AT when slowly advancing throttle and turning AT back off before reducing the throttle. You want to avoid AT making trims when decelerating or when opening throttle rapidly. I have mine within 2-3% on all gears with fuel values shown in the ECU (I monitor with a POD-300).
 
Thanks!
 
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