The NB doesn't know the difference, but the math works. Like was mentioned before, if you tune for 14.7, then you can do the math to hit your target rpm. This is how I tune on the dyno too, and it works. To make it even easier, MLV and Autotune do the math for you! No, it won't be perfect, but you can get very acceptable results.

For instance, if you tune for 14.7, and you want to take a cell (or range) to 12.5 AFR, then you just need to calculate the multiplier:

14.7 / 12.5 = 1.176

Now multiply the cell(s) by 1.176, and you'll be at about 12.5 AFR.

I have to concur, I've tuned with a NB sensor, albeit on an n/a car.

It's a complete ball ache and takes way longer, but you can achieve a satisapfactory tune.

Mine too concurred once id installed a wideband. I think I did it the same method as yourself, with MLV.

Using brains suggestion of ncorporate AFR and tuning everything to stoich then adjust the targets to what you want is also sound advice as long as the engine is n/a IMO.

yep, it's simple math at that point.

Maybe I am on a wrong forum.

Do people on this forum actually tell others to do power runs aiming for 14.7 so that they can then do the math? And how do you verify that your tune is actually ok?

Is that you John Wayne? Is this me?

No, I don't tune for 14.7. But MLV or Autotune can see 14.7, and therefore determine what 12.5 (or whatever) is. Verify on a dyno... or with a wideband :-D

Initially, you'd tune the VE table, with incorporate AFR on, and your AFR targets pretty much set at stoich throughout. Then, adjust your AFR targets, once the VE table has been tuned and you will be hitting your targets as inputted in the AFR table. By doing it this way, you're making a true VE table, not a "PW" table.

Because if your VE table is able to hit stoich throughout, and since the AFR targets are part of the fuel equation, then changing the AFR targets will add/subtract fuel based on the equation.

where:

PW = ReqFuel * VE * MAP * stoich / targetAFR * GammaE

as opposed to:

PW = ReqFuel * VE * MAP * GammaE


tuning at stoich will mean stoich / targetAFR = 1

then if you want to target 12.0:1, 14.7 / 12 = 1.225, so you'll add 22.5% more fuel.

I dont really see how else you can tune a NB.

Brain pretty much explained how to tune on a refined ecu. IMO anything else that doesnt allow the use of a VE and target afr table like MS does with incorporate afr is a massive waste of time and shouldn't be bought because the people who made it are either lazy or idiots.

FWIW, I created a tune from complete scratch using a NB sensor. I sorta guessed on my initial map. Then I tuned idle... then added 500 rpms... then 500 more, and so on.

I had to do this because I was using Airflow Meter mode (no MAP sensor).

Here is my action plan:

I will first upgrade the firmware to 3.2.4 so I can use TS for tuning.

Then, I will install a wideband + gauge to get all values right. Keeping the WB setup, or reverting back to NB once it is tuned is something that is up in the air at this point.

My biggest fear is completely screwing it up with this method. This is because the system is modified to begin with, and I really do not know if they used standard I/O ports. In other words, I am not sure whether or not I will be able to use the existing wiring harness once I upgrade the firmware in the ECU.

What the hell... It will be a great learning experience. The scooter has tons more power already. Push comes to shove, I can always start from scratch and build a dedicated MS for it.

Right, Rev? ;)

with that being said, I still dont do it that way*. :)




* only cause I dont want to retune to end up with the same end result.

I will however, have a ton of questions for you guys.

Here's the first one:

What's best for a single cylinder, 4 cycle engine:
* Speed density
* Alpha-N
* Hybrid

I see that quite a few bike engines use Alpha-N.

What do you guys think?

Depends, can you get a decent MAP signal? You could do hybrid/ITB mode if your ecu supports that.