A/F tuning (narrow band)

[V8Pinto]

I can't run a wide band O2 setup but I have come up with a narrow band A/F setup that is class legal.

How well does the stock ECU compensate from base map at sea level to altitude?

I map the bike at sea level and then when we race, the corrected altitude is very very high so I'm curious how much the mix is off.

I'm going to adjust it (if necessary) going by my calibrated narrow band stuff but I'm just curious what I'm going to see.

I hope I see that the stock ECU already took care of it :)

[Quasar]

I can't run a wide band O2 setup but I have come up with a narrow band A/F setup that is class legal.

How well does the stock ECU compensate from base map at sea level to altitude?

I map the bike at sea level and then when we race, the corrected altitude is very very high so I'm curious how much the mix is off.

I'm going to adjust it (if necessary) going by my calibrated narrow band stuff but I'm just curious what I'm going to see.

I hope I see that the stock ECU already took care of it :)

What generation of Hayabusa are you referring to?

GenI Hayabusa's do a fair job of correcting a completely STOCK Hayabusa engine, but they cannot appropriately correct fueling for a significantly modified engine, as they had no O2 sensor, so they didn't run closed loop fuel injection.

Even if you have a 2008 Hayabusa (which runs closed loop fuel injection), closed loop operation typically only maintains the A/F ratio at idle, cruise, and small throttle openings (up to about mid throttle). From Mid throttle to 100% throttle positions, the ECM typically depends upon the static fuel cells entries in its fuel table. This means it also will not be able to appropriately adjust for a significantly modified 2008 Hayabusa engine. Yes, there will be some fueling modifications made based upon altitude, but the ECM follows its preprogrammed algorithms for a completely STOCK engine, which means it doesn't reduce fueling proportionately (when going to high altitudes) for an engine that has been tuned to provide greater fueling at lower elevations.

[V8Pinto]

I'm asking about a Gen I bike (my 2006).

The motor is stock internally. Only mods are in the air intake tract (before the throttle bodies), pair valve, filter, and the stock cans have been introduced to my power tools. Stock compression, cams etc.

I want to monitor where I'm at A/F-wise for the last 1/4 mile of the race (1.3mile track) to know if I'm pulling the last few rpm out of her.

For the most part, I've got the A/F monitor thing worked out (made my own setup that's production class legal). I'm spending all my cash on the 08' bike though - so I don't know if I'll get to map my 06' before I go up to the desert to race. Just curious what's going to happen - if the bike is mapped at sea level, when I go to 2,800 feet will the ECU "compensate" for the altitude change?

It sounds like what you're saying is that the ECU will "compensate" based on a pre-defined map which was generated based on the stock engine and it's airflow requirements. So if I'm far from stock as far as airflow/fuel goes, the altitude compensation will be off? Is that right?

Thanks for the help! This helps a lot.