What is all the hoopla about disabled O2 sensors

[sleeper_777]

What is the hoopla about? Almost a religious polarization. I know what O2 sensors are and what function they provide, but I also have not seen any issues with them disabled on cage vehicles (you know, cars).

Someone help a bother out please.

[xb9fog]

Good Question, I have for years now been trying to figure this mindset out. It does not make sense. They seem to feel the engine will not run properly at all and grenade if the O2 sensors are not used on a system that was OEM designed with narrowband O2 feedback. And they seem to attack and ridicule anyone who chooses a different path. It's my way or the highway!!

Many other EFI systems do not utilized narrowband O2 sensors by design, so how can those systems possibly work correctly?
The beautiful thing about the Buell ecms is you can easily turn the closed loop O2 functions off with no ill effects. The only requirement is that you have well developed fuel maps and set the global AF ratio properly for each particular example.

One has to go back in time just a bit and look at the reason these narrowband O2 sensors were developed and became widely used with motor vehicles. Governments started to mandate strict emission levels, and tighter control over fuel mixture (with stoichiometric being the target) was required to meet these emission requirements. The truth is in the design of the modern narrowband O2 sensor - it is a device that is designed to generate a voltage signal the ECM uses to maintain a stoichiometric A/F ratio. This is an emission control device. In a basic sense, if you want your engine to run at an A/F ratio that is something other than stoichiometric, they are pretty much useless. So this is fine and very useful if you want to fuel your engine at stoichiometric and target low emissions. If you are tuning for performance as a target then they are, like I said, pretty much useless. I don't know of any REAL Tuner worth his salt that would target >=14.7:1 AF ratio for performance. That's a bit absurd when you think about it. Today this lean mixture has become the norm for a 'street' OEM tune, but back in the day when these emission systems were first introduced (back in the '70's), 14.7:1 was considered extremely lean and acceptance was very difficult then with a lot of the same drivability and heat problems we see today with the lean burn systems. Nothing in that regard has changed over time, lean is, quite frankly lean and will never change.

Some of this recent 'hoopla' can also be attributed to a couple of different individuals that have ulterior motives. Newer competition in a relatively exclusive market seems to have driven some people to say and do unscrupulous things. Due to this and other issues that have gone as far as copyright infringement, their motives are to tarnish the ohiosportbike.com name and products; and attempt to defer potential business away from us and in a direction of their preference.
Enough on that sore, sad subject.

FWIW I have used both methods (with and without O2) of tuning in the past, and everyone knows my choice and preference is not to utilize narrowband O2 sensors in a performance calibration. If one were tuning for low emissions as their primary target, it would make sense. Typically we tune for performance, not lowest emissions. Sadly, tuning for low emissions has already been done for us, mandated, and most of us don't like the results. I think that is one statement everyone can agree with?

To end, neither method I would consider to be "incorrect". The end result will be different, but both may be acceptable. It depends on your expectations. Based on what I have learned through trying both methods, I feel the end result is much better without the narrowband O2 feedback. More power and performance.

[bigschwerm]

Great explanation Dave!

[sleeper_777]

Hi Dave,
To verify, when I switch back to the stock tune, the o2 sensors are re-enabled?

When switching to the superstock the o2 sensors are disabled?

When moving back to stock, the PFU shows f/r 109/109 AFV, do I need to manually set it back to f/r 100/100 for true stock AFV before I download?

Regards

[xb9fog]

Hi Dave,
To verify, when I switch back to the stock tune, the o2 sensors are re-enabled?
YES
When switching to the superstock the o2 sensors are disabled?
YES
When moving back to stock, the PFU shows f/r 109/109 AFV, do I need to manually set it back to f/r 100/100 for true stock AFV before I download?
Check AFV values via the Instrument cluster (via Diag mode) to see what's in the bike. It should be 100/100 after flashing to the stock cal.
When you flash the stock calibration, the actual AFV values in the bike are set to 100/100. You can, if you wish, set them to something else AFTER flashing to the stock cal. If you know what your Learned AFV's where with the stock calibration you can set them where they were - it saves having to wait for the bike to relearn again.
What shows in the PFU program's AFV tab is the default values for the Performance & Superstock Calibrations. The PFU does not read and show what the AFV's are in the bike.
Hope this clarifies.
Regards

[sleeper_777]

Appreciate your quick responses. Doing further work, I changed the tune back to stock because I failed to record the AFR readings in diag mode before the perf.tune. Stock AFR front is 100/AFR rear is 110.5 after 150 miles of interstate riding. Based on this reading, would it be wise to set both f/r to 110-111 as a start when moving back to the Perf.Tune?

I have been using the guidlines on AFR recommended; was not experiencing any decel popping or stumbles at 109/109 locked, but it smelled a wee bit rich. I know now the back cylinder needs at least 110-111?

Also, that stock reading front/back was surprising to me;would have thought the cylinders would be a little closer; although not unheard of by others with a 1125.

Regards and thanks for your help.

[xb9fog]

Appreciate your quick responses. Doing further work, I changed the tune back to stock because I failed to record the AFR readings in diag mode before the perf.tune. Stock AFR front is 100/AFR rear is 110.5 after 150 miles of interstate riding. Based on this reading, would it be wise to set both f/r to 110-111 as a start when moving back to the Perf.Tune?
The learned AFV values set with the stock calibration are irrelevant to the OSB performance calibration. Don't correlate one to the other, they are two totally different calibrations. Put the stock learned AFV values out of your mind, and just follow the steps in the AFR adjustment procedure to the letter.
I have been using the guidlines on AFR recommended; was not experiencing any decel popping or stumbles at 109/109 locked, but it smelled a wee bit rich. I know now the back cylinder needs at least 110-111? No, again refer to the statement above. The exhaust will smell different with the performance calibration compared to stock when the AFV's are properly dialed in because it's not running so damn lean. It may smell 'a wee bit rich' to you because it is 'different' now and you are used to it smelling 'lean'. "Too rich" is usually obvious with an almost 'raw' gas smell, and or black sooty exhaust. And should only evaluate the smell after warm up, as during warm up it is supposed to be on the rich side (like a choke). Again, if you follow the written adjustment procedure (all the steps, including #1 in the road test procedure) it should get you dialed in. Think of it this way regarding smell (all three being different) lean smell(stock) / normal smell(dialed in) / overly rich smell.
Also, that stock reading front/back was surprising to me;would have thought the cylinders would be a little closer; although not unheard of by others with a 1125.

Regards and thanks for your help.

[sleeper_777]

Thank you. As always, you are quick to help answer questions. Your software has been very easy to understand and use, which I appreciate very much.

I'll switch back to the Perf.Tune with 109/109 and go by the procedures in the document using the roll-on/roll-off and listen for popping on decel. I hope to get the Dynotune w/sniffer but I'm a bit strapped lately. I will be partially blind in not being able to see the AFR numbers, so 109/109 is still a good place to start or should I start higher?

Regards,
Chris

[xb9fog]

Yes, start with the default values.