Verifying what I've learned about EFI on the FZ6

[Chris Parker]

Ok, so I've been looking around a bit and want to make sure I have a clear picture of how the EFI system works on our bikes. It seems to be a bit primitive.

Basically it has one static fuel curve, which is adjusted up and down on the y-axis from feedback from the o2 sensor, correct?

So the bike is able to adjust for humidity and altitude, but is NOT able to adjust for mods because the mods MAY require a different fuel curve due to different airflow at various RPM's versus stock.

...correct?

EDIT: Forgot to put in that I was referring to the 07-later models.

[biker_dude43]

I wouldn't call the EFI primative by any means and according to the service manual on page 1-3, the ECU utilizes other sensors including O2 to determine the right amount of fuel to inject.....

See highlighted attached extracted pages from the manual.

[Chris Parker]

Yes, I've read that section. But again, it says the bike is able to compensate, but to what extent? Is it simply increasing the fueling based upon a set fuel curve or is it doing real-time adjustments?

In other words, the engine is going to consume air at similar proportions throughout the RPM range even at different air densities when it's stock.

But the airflow may not follow the same curve once and exhaust and intake has been added. It may require more fuel in certain parts of the RPM range than the proportions provided by the stock curve.

Is the ECU able to do this? Or is a programmer required to change the algorithm?

[jsw4178]

I am pretty happy with my EFI. I added a Two Bros Juice Box to my FZ6 and it seems to make an overall difference with the added Carbon exhaust and K&N air filter.

[Hellgate]

Chris - Well yes and no, sort of. I am not an expert but here is what an expert told me as he was dyno tuning my '07.

From 0 to 7,000 rpm and 0 to 10% throttle opening our bike is closed loop due to the 02 sensor.

With a tuning device, Power Commander, Juice Box, Bazzaz Box, etc. you can by pass the CPU and tune to your hearts desire within a "safe" range.

If you mod you bike, exhaust, air box/filter, CAT eliminator you should disconnect your battery and the bike with "retune" itself, for the most part, for the changes you made.

You can also tune through the CPU via the o2 sensor and make some nice gains.

Our bike does not have a Mass Flow Sensor, only a temp sensor in the airbox so I don't think it will adjust automatically for humidity and altitude, how ever the 02 sensor with keep you in a "safe" range. A dyno tune will do that for you.

And yes you are correct, it is primative compared to a modern MoTec system.

With a PCIII or other box you can made a nice improvement in smoothness, torque and a bit more top end power. The most I've seen out of our bike is 100hp at the wheel in an inertia type dyno. An Eddie Current dyno will read about 15% less.

That is what I know and I'm sticking to it.

How come, gotta project planned???

[Chris Parker]

Thanks for the information!

I have some vague plans in mind for the intake, I'm more or less just trying to learn as much as I can before trying to attempt any projects. I have a lot of resources and I'm a perpetual efficiency freak.

So here is my next question: do you have to buy a power commander to get dyno tuned?

There is a harley dealership close by that does dyno tuning... but I'm hesitant to get a four cylinder bike tuned by harley guys. I'm always VERY skeptical of letting anyone touch my machines, I do all my own work unless it requires equipment I don't possess.