not all tuners . oxymoron ... how can something be called a tuner when you delete , then its not a tuner , its just a guesser....

 

Because I can't imagine a logical reason for having open holes in the header pipes.

 

The pipes came with holes to install the oxygen sensors. However, the fuel injection module thingy was the model that doesn't use oxygen sensors. Rather than leaving big holes in the pipes, you "plug" them.

If I did it all over again, I would know that the Cobra Fi2000 model that I ordered (through the dealer) wasn't meant to be used with oxygen sensors and I would order the other model instead (the one that IS meant to use oxygen sensors.)

The dealer didn't tell me anything. When I picked the bike up, I noticed a small charge for the oxygen sensor "plugs" (to plug the holes in the exhaust) and then I realized I could've gotten the other model Cobra Fi2000.

I'll never know why the parts guy didn't realize this OR why the guy installing the stuff didn't catch it and ask if I wanted to order the Fi2000 that uses the oxygen sensors, instead of putting everything on there I ordered.

But the question in this thread is about the preferred method. Do people normally prefer using oxygen sensors or no? What are the benefits/disadvantages to either setup? Any at all or were the oxygen sensors just there for the stock stuff anyway?

 

My dad just recently had a Power Commander installed on his bike. This tuner also has the option of using the o2 sensors or not. The tech told him that taking away the o2 sensors allows more total control. You would be able to control what the AFR was at all times because the fuel injection would always be running in open loop (o2 sensors off. examples: cold start up, heavy rapid acceleration, WOT) where it is dumping in the amount of fuel that it thinks should go with the measured amount of air coming in to obtain an AFR that the users sets without checking to see if the calculations were correct (o2 sensors). In closed loop (o2 sensors on. example: cruising, easy acceleration, warm idle) the bike is checking to make sure the calculations it made are correct, they said the Power Commander would not be able to control the AFR and the target AFR set on the ECM would be used.

The disadvantages of pulling the o2 sensors was said to be decreased full economy (My dad's average fuel millage went down by 10 MPG). But the tech said this decrease could be lessened by a dyno tune.

 

To answer the question on what I prefer. I prefer o2 sensors in. I do a lot of long distance cruises with bikes with much bigger tanks so I need to get good mileage so we don't have to stop for me.

I have experience tuning my own car. I run a wideband o2 sensor which gives me a constant digital readout of my exact AFR (no dyno needed). I have my car tuned to run around 15:1 when cruising. I have 160,000 miles on the motor with no internal engine problems, and I frequently track my car as well (I have another high throttle usage tune to cover that). So I have a turbocharged 400 WHP car that gets 30+ MPG on the highway. In my opinion and experience there is no reason to be running as rich (13-14:1) at cruise and easy acceleration as some of these tuners that delete the o2 sensors run, and this is why there is such a decrease in fuel economy when using the o2 delete feature.

 

Joe,

Thanks for the detailed replies! I put a few hundred miles on my bike before I got the stage 1 upgrade, so I was somewhat familiar with how it rode stock.

I think one of the first differences I noticed after the stage 1 is how punchy the throttle is at cruising speeds. I can be cruising along at 60, slam the throttle, and get on it! It didn't react quite like that before. (unless it's all in my mind, which I believe is totally possible)

The second thing I noticed was the decrease in gas mileage. LOL... Alot of that is how I was riding it after the stage 1, but I'm sure alot of it is from the fuel settings too.

It appears that the tech that installed my stuff did tweak the Cobra Fi2000 a little, because the settings on it are changed from how they come set for a stock bike. That leads me to believe he made adjustments (not dyno, just hopefully riding and making minor tweaks.)

Either way, it runs killer and I'm happy. Just wasn't sure what the deal was with the oxygen sensors. My last two HDs didn't have 'em.

 

I would have told them to send the fuel pac back, and order the one with senors.

 

Too funny. I was searching google about this same thing and hear I am years later reading my own thread. Ha ha

 

Ignorance is not bliss.

 

I don't have personal experience with the Cobra Fi2000. I've read about them here and there. Seen comments for and against. With all that you have to consider the source. Personally, I don't think much of the system.

Based on their claims, the unit monitors crank acceleration during acceleration and adjusts fuel to maximize it. It does nothing with spark.

When not accelerating, what it does - according to the claims - depends on whether you are using it with oxygen sensors or not. First it appears to revert back to whatever tune you are running in your ECM. If it's running with oxygen sensors, it adjust fuel to achieve an AFR of 14.2. Without oxygen sensors, it supposedly looks a changes in mixture, picks the rich end of that variation and goes with it (which creates a few questions in it's own right).

So about that operation without oxygen sensors... So under cruise - or low load conditions - it presumably reverts to whatever tune is in your ECM. OK. So assuming that all is correct... Say that tune is the stock tune. Say you've added a new intake and exhaust. So now your model for air (VE tables) in your tune may no longer be accurate. The additional inaccuracies probably tilts things more to the lean side (on a stock tune that may already be too lean) since you may have increased the air component with new pipes/exhaust. Since you don't have feedback from oxygen sensors you are dependent on accurate/calibrated VE tables - which you may no longer have - to produce the set/commanded AFR's. Also, without the oxygen sensors, you have no compensation for variations in fuel or environment.

Seems to me, that if you want to run it without oxygen sensors that you might at least want to make sure you have well calibrated VE tables. Only a couple ways to do that - one being a dyno and the other being tuners like PV or FP3's. Also, once you get those VE's calibrated, you wouldn't want to changes things that alter their calibration. Even with that you still leave other advantages of the oxygen sensors on the table.

Just my 2 cents.