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Fuel Mapping Spreadsheet, any suggestions?

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Duff750

Computer
Nov 27, 2008
2
First of all, how's everyone doing. I'm new here, and very new to fuel engineering...but I've been googling AFR and stoicheometrics and this and that like crazy lately learning as much as I possibly can. I still have a LONG way to go for sure.
I ride a motorcycle (2006 GSX-R 750) and I've got a Power Commander (fuel injection mapper) installed on it. I recently learned that DynoJet (the company that makes the Power Commander) also has a Wideband Commander that will datalog your real time AFR per RPM and throttle position, and save it to a memory card or to an internal memory, which in turn you can take to your PC and make an analysis of said datalog to make adjustments to fuel change percentages on the fuel map for the Power Commander.
I downloaded the software for the Wideband Commander and also a couple sample datalogs and put myself to work in Excel when I would get bored at work. From everything I've read about AFR's and a lot of trial and error in the spreadsheet, figuring out what percentage of fuel to add or subtract to get your desired AFR, I THINK I have finally come up with a virtually automatic tuning device for the Power Commander fuel map.
I've been trying to find someone that could take a look at the spreadsheet for me, and take a look at the formulas and functions to see if I had done anything wrong, or maybe if there is something I could do better? Can someone here help me out? Anything is much appreciated!
On the spreadsheet...
The WB2 Tab is the datalog .txt imported into Excel...no formulas or functions on this sheet.
The Analyze tab is where the throttle positions are broke down to the available throttle positions in the Power Commander control center. The RPM's "floored" to a significance of 250. and the in the hidden cells, the AFR's are averaged per throttle position and rpm.
The PCIII tab..
The Analyzed AFR per TP and RPM is brought over to the "Current AFR" table.
The "Desired AFR" table, self explanatory
The "Current Fuel Map" table, where you would paste your current fuel map from the power commander if you already have a "base map".
And the "New Fuel Map" table is where the Current AFR is calculated to the desired AFR, and changes are made to the exsisting map if there is one.

There are probably MUCH less sloppy ways of making this spreadsheet than the method I used... such as VBScript and Macros...but I don't know a whole lot about VBScript and Macros so I left it to formulas and functions.
 
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Or you could buy a Bazzaz instead of the Power Commander, which does this by itself!

The Power Commander 5 does it, too, but is only for 2009+ models.

Now, for the big suggestion that complicates everything (and which the Bazzaz doesn't address, either): You do not want to be using the same air/fuel ratio everywhere in the map - and I realize that you have provision for not being the same everywhere in the map. Your target map has 13.1 everywhere. You will get better results if the part-load operation is optimized for economy and it only goes richer than this where absolutely necessary for detonation control, exhaust valve and piston temperature control, etc. Running too rich washes oil off the cylinder walls, fouls spark plugs, etc.

Try aiming for 15:1 air/fuel ratio everywhere below 20% throttle opening and then smooth transition to 13.1:1 above that, then fine-tune from there. I think you'll find a big difference in fuel consumption and range, and probably crisper throttle response as well.

I put a wide-band on my little CBR125, which has a closed-loop fuel injection system, and it stays in closed loop (14.5 - 14.8:1) until remarkably high engine load. With careful throttle hand positioning *just* below the switch-over to open loop (I'd say about 70% throttle position) I managed to see 125 km/h at 9500 rpm, which is darn close to top speed on that bike - at stoichiometric, and no burned valves or pistons. Opening the throttle beyond that made it go richer but didn't make appreciably more power.
 
I've read all about the PCV and am rather disappointed that it's only available to 09 and new bikes. I'm sure the Bazzaz is great, but with all the dealings I've had with Dyno Jet, I just can't bring myself to get away from their product. They have the absolute best customer service of anyone I've ever dealt with.
That being said, I just need to find out of the spreadsheet is throwing the correct results so I don't go and blow somethin up down the road.
I kinda planned on changing it away from 13.1 across the board, but since I don't have the stuff yet, I was just using that for reference purposes. Figured 14.7 and 0,2,5,10, 13.1 at 60,80,100 and average the transition in between 10 and 60

-Duff-
 
I say give it a go and see what it does. You can always keep track manually of what it's doing on each iteration so it doesn't go out of bounds. As long as you are not asking for lean operation at WOT near redline, you won't blow anything up.

I like your idea, I just don't have a bike with the necessary hardware to try it out myself.

Be prepared for odd things happening at 0 and 2 percent throttle. The stock fuel injection cuts fuel completely during deceleration at higher revs, and even in the range where it doesn't, the spark plugs won't reliably fire the mixture during closed-throttle deceleration, so your wide-band will give a false lean reading and it might try to excessively compensate on the rich side.
 
Hi.

I am a bit late in to this but how did your spreadsheet go DUFF750 I tryed to down load it but the link no longer works
 
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