Just had a thought, maybe it would be an idea to make a dummy O2 sensor available, so that it can help remove the guess work out of where an O2 sensor will fit in the exhaust when space is limited.
I used to work in process control in oil refineries along with racing motorcycles and building cars and engines. What you are offering would be an “inferential calculation”, based on guessing altitude and air quality and air humidity. Carbs are good at that, but you must know how and when and when to stop. That is why FI was invented.
In my mind, you have a good idea, but the combination of wide-band O2 on exhaust, MAP sensor, TBP position, makes that adjustable in a micro second…or Nano?
My CRF250L has an OEM O2 narrow band sensor. Just by plugging that and adding a proper mounted wide band sensor, gave me much better low to high mid-range response. Expensive, but what else can you do?
Nice idea, if you only drive in a narrow envelope. My example: I had a Yamaha WR250 in Western Montana. Properly tuned, it never needed much. Ass-kicker. However, it ran from 4800 to 7000 feet. Easy to Tune for, gear for. Shit for fuel economy.
Now? Honda CRF250L. Much less power, but really needs Fuel Injection. We live near sea level, but in 3 hours can run up to 3500 feet. OK…on a good adventure ride, we go the Himalayas. Near 17000 feet. Try that with a carb. Easy enough, but in the fog? Rain? Snow? Oh, and after a good sleep? Coffee and Yak meat then kick that carb bike until your groin hurts.
So, my friend…been there…done that…hate it! You can find rentals, like the Himalayan 500 with carbs…they do not run below 9000 feet.
Sorry, maybe I didn’t explain it well.
I am all for an O2 sensor, especially closed loop.
What I am thinking is something, even plastic, in the size and shape of the O2 sensor that can be used as a template to mark where the bung will be welded onto the exhaust, for positioning and placement of the actual O2 sensor.
Instead of guessing the location for the sensor, then finding that it fouls on the frame or engine, potentially being a costly mistake.
Great reponse D02…That IS the wide band 02 issue. Maybe we just confused the issue.
I have done quite a few, but you will not like the response, Maybe. In my experiences, the location differs greatly, but the results do not really.
I have an AFI unit on my TRX850…hahaha…but I have a super nice set of Lectron carbs…not designed for the track…but OMG! We took the same TPS, API and such and made our own EFI, but with a flats-lide carb. In OEM trim with +1mm oversized head pipes, made 97+ HP with near no loss of economy.
Just playin’. The Lectron’s by themselves made 95.7 in the same setup. MUch to be gained!
Good idea Al. Do you have access to a 3D printer? I can model one of the O2 sensors I’ve been using lately. Should help give a rough idea.
Are you looking at running a narrowband O2 sensor, or full wideband w/ external controller?
If narrowband, they’re usually in the range of $10 - $20 USD. Might be easier to pick one up locally along with the bung/nut for fitting; and you’ll be able to figure out routing for the wiring as well.
I recommend a 1-wire sensor (not heated). Doesn’t take long for them to heat up via exhaust gases. Typically <50 seconds. You don’t have to worry about avoiding thermal shock like you do with heated sensors.
Think I might have access to a 3d printer, so whatever is required to print one out would be great.
Was thinking of a narrow band, but just did some research, and a wideband would probably be much better, as smaller engines would vary much more in their AFR spikes being on and off the throttle more than a passenger vehicle driving down the road.