Kpro & Part Throttle Efficiency

[Corey872]

I have been doing some part throttle tuning work to boost cruising efficiency while still maintaining WOT power. The way I understand the ECU / Kpro interface ? When Kpro is set to closed loop, the ECU controls the AFR to 14.7:1 and there is basically nothing that can be done with this? Is this correct? I also understand that Kpro can be set to open loop, the fuel can be controlled to a leaner mixture, but there will be no O2 sensor feedback to correct the mixture?

This leads to a couple of questions:

First, looking at the nitrous control functions, I can choose an RPM / Load / Throttle ?window? then choose to remove fuel and add timing. This would define an efficient ?lean burn window? for very light throttle cruising, but does the fuel command in the nitrous control have any effect if the ECU is in closed loop?

My second thought is that it would be possible to use the nitrous control to engage a relay during the ?lean burn window? ? The relay would effectively engage an electronic circuit that would fool the O2 sensor into thinking the mixture was richer than it is. The computer would respond by leaning the fuel, but would still be in ?closed loop?. The O2 signals would still pass through, just at an offset to get a leaner burn.

Third question ? is it possible to include something like this in Kpro? Something similar to the nitrous control using the same RPM/Throttle/Load layout, but have function for ?offset O2 sensor voltage by XX? or ?offset lambda by XX?

Last (sorry for the long post!) is anyone else actively working on part throttle efficiency as well as WOT power? Just curious if anyone else is around to bounce ideas off of.

Thanks

[Spunkster]

There is no way to get WOT power durring part throttle.

What you are talking about doing will not work. If all you want to do is not run 14.7 in closed loop, then you should just put the ecu in Open loop and just hope that you do not run too rich or to lean durring part throttle. This will all depend on you properly tuning the part throttle areas.

[Corey872]

Thanks for the input. I know there is no way to have WOT power during part throttle. What I was referring to is having a small "window" of tuning - say 1750 rpm, 29kPa to 3500 rpm, 75kPa which represents a light throttle, lean burning region of the map. Say cruising 60MPH on flat level road.

Ideally, what I am looking for would be to have the ECU in closed loop, but controling the AFR to 15 to 15.5:1 (for starters) I know the nitrous control can define the window and take fuel out, but don't know if this overrides the closed loop? - I guess experimentation may be in order.

The other option would be to use the nitrous control to kick in a relay and power up an electronic circuit which would intercept the O2 signal, offset it slightly, then present it to the ECU. The ECU would then correct back to what it thinks is 14.7:1 but the actual AFR would be higher. Again, I guess experimentation is in order.

However, under WOT, the ECU is at totally different locations on the maps, so it is still easily possible to tune those areas for max (safe) power.

I'm not hard to please - I'd only like to see ~ 35-37mpg cruising and maybe 260-280 WHP on the top end. :lol:

[locash]

Have you considered altering the target air/fuel tables in the settings menu?

Or am I wrong on this one?