Please explain how to read PC maps

[thebbbusa]

Here is an image of my current map. I don't have a printout of or remember the AFR but when it was last run on the dyno it was 'good'.

Do negative numbers mean the PC is pulling out fuel, and the positive mean it's adding fuel? How does changing these numbers affect what is going on?

 

[thebbbusa]

 

[jjmetheny]

Bigger numbers more fuel, smaller numbers less fuel. More fuel makes it richer, less fuel makes it leaner.

 

[thebbbusa]

That's what I think too...just find it interesting to have all these negative numbers with my full system, and make more power than I was with stock stuff. Thought I'd need MORE fuel as opposed to less.

 

[Professor]

Check out these two threads


https://www.hayabusa.org/forum/dyno-kings/92107-pciii-maps.html

https://www.hayabusa.org/forum/engi...stion-about-values-power-commander-flapp.html

 

[thebbbusa]

Thanks for the links Prof.

I am beginning to think this spring I'll have to make my way back to a tuner...just to make sure. I still think the WOT setting is a little suspect cause I would think that with the small box mod, and a full exhaust system, that one would need to add fuel rather than take away. But like I said earlier, last time it was on the dyno the tuner said it was all good. But I just think it's weird that most of the maps is pulling out fuel vs. adding more. ???

This all started a couple days ago when I got home from one of the first rides after winter, and smelled like gas, and had burning eyes and was bucking pretty bad around 3500 - 4000 rpm (which it hadn't really done before). So I hooked my laptop up to my PCIIIUSB to check things out. For some reason, the map was gone...no data came up. It showed the RPM so I know it was connected...but no map...so I loaded the map back on the bike and the smell wasn't as bad. I haven't had a chance to run it yet...but I guess if it was running rich, this is why I smelled so bad the other day. (no jokes please. )

 

[Professor]

My opinion....

If that map was tuned and it is a PCIII usb, it should have steps in 250 RPM steps instead of 500 RPM.

Maybe someone with more experience will step in with an opinion.

 

[thebbbusa]

It's an old map, I do know that. Perhaps that's why it's in 500 increments. I got it from the DJ site, loaded it and went to the tuner. He put it on the dyno, with the sniffer, and did several pulls in several different gears. He showed me the fuel curve graph and pointed out that while it could use some minor tweaking, it was a good map for my bike, and that it wasn't really worth me spending a $150 or more for him to change one or two numbers. He didn't even charge me for the dyno time there that day. I can't remember what the optimal AFR is/was, but I do remember him saying it was decent, and a good map for power.

 

[GPW]

looking at the 2% throttle position only, I can tell you do not have a complete map. If that answers your question....

 

[roadthing]

"If that map was tuned and it is a PCIII usb, it should have steps in 250 RPM steps instead of 500 RPM. "

You are correct sir!

"I can't remember what the optimal AFR is/was, but I do remember him saying it was decent, and a good map for power.
"

The stoichiometric AFR number is 14.7:1 Your bike will run better just north of 13:1, which is a richer mixture.

If somebody told me that my AFR was "decent', and the installed map was "good" for power, I wouldn't feel too confident with the tuner, or be happy with the results.

Find a tuner you are comfortable with, and have it evaluated. Tune as required

 

[thebbbusa]

The AFR reading was two years ago....I couldn't remember the number. My point about the AFR is that the tuner which used to be a reputable tuner in the drag race industry, having his own team and everything, said that the AFR was where it was supposed to be. As I cannot remember the EXACT number, let me assure you that, it was close to what it was supposed to be. I didn't want to give an erroneous number off the top of my head. I am very comfortable with this tuner, unfortunately, as far as I know, his services are no longer available.

500 rpm increments vs 250 rpm increments don't mean much to me. There is a function in the PC software that can expand the map to 250 rpm intervals easily. I could've just easily posted that picture instead.

As for the 2%, partial mapping, other than no fuel being added or taken away above 5500 rpm, unless that is what you are referring to, I don't know how you can tell this is an incomplete map...Unless you provide maps that are from 500 to 10,500 maps for each throttle percentage.

So to get back on point here, my real question, after comparing several different maps, is how are so many full exhaust system apparantly pulling fuel out throughout the range, when the assumption would be more air, more fuel?

 

[jdsbusa]

So to get back on point here, my real question, after comparing several different maps, is how are so many full exhaust system apparantly pulling fuel out throughout the range, when the assumption would be more air, more fuel?

Certainly no expert in self-tuning these complex machines....but I've got a lot of experience with small engine tuning from about 20 years ago. From what I understand the stock map is actually quite rich. More fuel does not necessarily mean more power - an engine can only burn so much depending on the size of the combustion chamber and intake valves. More fuel can actually be a detriment as it equates to unburned fuel which robs power. Back in my tuning days we generated power by leaning out the engine - carefully...or you'll have damage from running too lean which generates much more heat which leads to the engine suffering from detonation or even worse, burning a piston. The tuning I did wasn't exactly scientific or even complex for that matter - the color of the exhaust was primarily what we used, that and the amount of oil coming out of it (2 stroke nitromethane powered engines) - but the theory behind it is basically the same principle used by the Power Commanders. If the stock Busa map is as rich as I've read....it's going to be safer for the engine, but not efficient in terms of power/fuel mileage, which leads to why some people claim an increase in fuel economy with a PC and definitely an increase in power by leaning the engine out and optimizing the intake flow capacity.

 

[Commuta_Busa]

how many miles on the engine? What full exhaust system are you running?

 

[thebbbusa]

Miles then 13k

Miles now 22k

Bike has a full custom exhaust 4-2-2 system on it, non-stepped header.