all in conjunction with the O2 sensors. They work together as a team. And the effect is not as dramatic as a carb, yet there is an effect.

 

Doesn't the FuelMoto EFI tuner work by replacing the O2 input to the ECM? If so, this will effect the closed loop areas only. Closed loop operation is controlled by the O2 sensors only. So you will have no control over open loop areas of the map.

You might be satisfied with this, but the best results will come from using a real tuner like an SESTP or TTS.

 

There is an article in July AIM by Dr. Dyno. He kinda suggests that in Closed loop operation the only thing that comes into play are the O2 sensors. If they sense a lean condition (greater than 14.6) they tell the ECM to go richer, if they sense a rich condition (lower than 14.6) they tell the ECM to go leaner.

The other sensors and tables come into play in open loop Operation. This according to Dr. Dyno.

 

The Fuelpak requires a Stage I filter.

I don't understand why it would run too lean if all you do is replace your pipes and leave everything else alone. Unless you're going with something totally absurd, which I don't think you are.

But..... There's a lot of things I don't 'get.'

 

Thanks for all the replies on this subject guys. I'm not completely oblivious to the tuning process...I've done my cars, I've just never done anything with a bike. That is why I like the ideal of keeping the O2s. Like I said before I'm not looking to make huge power with my Bob. I just want it louder which is why I'm not too concerned with a stage 1. I like K&Ns products and the fact that they are reusable so I plan on sticking with a drop in. But I know enough about EFI that changing out the pipes is gonna have an effect on the tune. I'm looking for something simple that will keep the bike safe and not have to worry about the problems that come with messing with too many paramiters.

 

Nothing I've read said anything about needing a stage 1 with pipes. I could be wrong as I'm going off of what V&H has on the web page.

 

Why would changing out the pipes affect your tune? Your O2 sensors are before the muffler bodies and, therefore, before the cats. On a car, if you change out the exhaust and remove the cats, and the rearward O2 sensors notes the absence of a cat, it will trigger a code.

But you (we) don't have four O2 sensors, just two, and they're before the exhaust body. And I don't believe the O2 sensors and 'backpressure' have anything to do with each other. All the O2 sensor does is measure the amount of oxygen present in the exhaust gas. And it only works in closed loop for the most part.

Besides, as I've noted before, 'backpressure' is probably the most misunderstood term in the internal combustion engine world. Velocity, wave reversion, scavenging, all mean something to me. 'Backpressure'? I dunno.

I'm NOT trying to tell you what to do. It's all very mysterious to me.

Before I installed my slip-ons, I took note of a lot of back-and-forth on this forum. Especially about 'decel-pop' etc. I listened to my stock exhaust and -- Know what? It was there BEFORE I put my slip-ons on the bike. It's just G.D. near impossible to hear because the stockers are so quiet.

Now, I can hear it but I kinda dig it. But I've been accused of being different.

 

The biggest difference between tuning a car and these HD bikes is HD's airpump efficiency is restricted by the air intake The exhaust pipes are too short to matter much. You can basically do anything with the pipes and not affect the tune much (you do lose a bit of torque because the stock mufflers do provide just a bit of back pressure). So play with the pipes as much as you want, it won't hurt nuttin. Play with the intake much and you also should think about the effects of a too lean A/F mix.

 

The O2 sensor only work in a narrow band, if you go up 8000 feet the MAP will adjust for it, 108* in the desert the IAT will adjust for it with or with out the O2s.
CB

 

Those sensors affects what the ECU targets for AFR but do not indicate what AFR you are actually running. So the ECU working in the blind without some kind of AFR feedback (O2 sensors indicate AFR indirectly). Thats OK if you want to sacrifice some power and efficiency to have plenty of fuel margin built in.

Which sensor adjusts for a tank of 15% ethanol then 10% and then 0%, then 5%.... ?

I dunno.