Juice Box, EGT and O2 Sensors..........

[Latemarch]

Bear with me as I think out loud (so to speak) here.

Many years ago I used to fly an Aeronca Champion. It had a Lycoming 4 cylinder air cooled engine with updraft carborator. Now because it was an airplane and we were constantly changing altitude there was a mixture adjustment on the carb so that you could lean out the mixture as you went up in altitude. You wanted the mixture lean but not too lean so that wouldn't burn the valves. To get it right we had an EGT gauge (Exhaust Gas Temperture) Adjusted it into the green on the gauge and you knew that you had the ideal mixture for altitude and outside air temperature.

Today with O2 sensors we accomplish a similar task by checking for the amount of residual O2 in the exhaust gases. Too much O2 and the mixture is too lean, too little O2 and the mixture is too rich. There are however limits set in the computer for how rich or lean you can go. Thus the invention of the Juice Box which adjusts the pulse width of the injectors to either increase (rich) or decrease (lean) the fuel to the cylinder. What you don't know is what is actually going on there in the cylinder. Am I too rich or too lean?

Is it possible that the EGT may be exactly what we need to get just the right adjustment for the engine, particularly those that have been modified with lower restrictions in the intake and exhaust. Rich for power and lean for economy on the highway? It wouldn't take much to add the gauge, but is it sensitive enough for these high tech engines? I don't know.

Like I said.......just thinking out loud.

 

[Magic Man]

O2 sensors read the exhaust gas and send inputs 10 times a second to the ECU.

A gauge will work but it will be so S L O W when compared to an O2 and so will you as a human reading it. There is no way you can be fast enough to read then make adjustments in the "real time" millisecond world the ECU works in.

However, to just see what the O2 sees, there are O2 gauges that let you see the signal the O2 is sending to the ECU. It's the "big picture" kind of thing to know if your map has enough adjustment to keep you in the "sweet spot" or if you need to remap.

Many car guys have them and have had for years.

MM

 

[Diver]

an airplane usually runs at a constant RPM. after take off, and again after reaching altitude, any changes to the RPM are gradual. constant on and off throttle on the ground here will throw EGT all out of whack.
And when you are opening, carbs used to use an accelerator pump. now it the same, but with EFI...gives it just a bit extra. the O2 and a god MAP tend to be a little more effective for this use


Diver

 

[Latemarch]

an airplane usually runs at a constant RPM. after take off, and again after reaching altitude, any changes to the RPM are gradual. constant on and off throttle on the ground here will throw EGT all out of whack.
And when you are opening, carbs used to use an accelerator pump. now it the same, but with EFI...gives it just a bit extra. the O2 and a good MAP tend to be a little more effective for this use


Diver

1. Nobody currently offers a different MAP for the Spyder. Untill then......
2. The Juice Box just varies the width of the injector pulse as sent from the ECU. It is not a new MAP it only shifts the MAP.
3. So after your engine mods, where are you? Rich or Lean? How Rich? How Lean?
4. An O2 sensor is quick and thus an O2 gauge might be just the ticket to make sure you've adjusted the Juice Box in the right direction and enough for variable throttle work around town.
4. As a highway kind of guy I was thinking of adjusting the Juice Box and watching the EGT as I cruised down the road for max mileage without burning up the engine.

What do you think NMN Man....should we mount an O2 gauge or EGT or both with the Juice Box?

 

[Magic Man]

There are 6 adjustment modes on the Juice Box. Getting into them and from one mode to the next takes a bit of looking at it to see and then do.

Not something I would recommend doing while moving down the road for sure! :yikes:

All that said...

I would put and O2 gauge on my Spyder and adjust off of that. Quite frankly, there is a direct relationship between the exhausts temp and the amount of O2 left in the gases (rich or lean). So, if you see the same things the ECU sees (amount of O2 left in the exhaust gases) and adjust off of those readings you will be able to adjust to where you should be in the great scheme of things.

As for the map profile augmenting type of adjustment systems (AKA Juice Box type of devices)

There in no automatic reason to say the stock map profile is bad other than it has to always be EPA compliant, and at certain times could be lean. Reason being, there are not EPA fines to a manufacturer for being under EPA limits. But the fines are HUGE if they make a unit that goes over these limits! So, usually the OEMs error on the side of "clean" (AKA lean) to cover themselves at all costs, as the EPA fines are per unit manufactured that are dirty!

Unfortunately, this always to the "clean" (AKA lean) side of a map profile can cause stumbles, pops, misfires, flat spots or higher engine temps at times.

However, take this map profile and richen it up just a bit (AKA Juice Box) and it can make all the difference in the world, and then it can work pretty good for the most part.

Remember, it was not too long ago that we used to change jets in carbs to do this. Want to talk about crude and broad sweeping changes! :yikes:

So, while not as good as a full on custom map being written and downloaded for your bike and it's mods. These type of map profile augment systems can work very well for most people. Remember, most people make real similar changes to their bikes and these companies make their augment systems to work well with just these kind of common changes.

EGT gauges work well on things like carb motors, or 2 stroke motors like on snowmobiles. However, they are not really as good as a O2 gauge IMHO for fuel injected vehicles.

For something like a CanBus O2 feedback system like the Spyder has, I'd say the O2 gauge is the way to go for sure. :thumbup:

MM

 

[Magic Man]

The Juice Box intercepts the O2 signal then "lies" to the ECU (modifies the true signal) that's one of the ways it fools the ECU to do what it needs it to do.

It also intercepts the signals to the injectors and changes them as well.

MM

 

[Latemarch]

The Juice Box intercepts the O2 signal then "lies" to the ECU (modifies the true signal) that's one of the ways it fools the ECU to do what it needs it to do.

It also intercepts the signals to the injectors and changes them as well.

MM

If I got a Juice Box and also wanted an O2 gauge would I need to install a second O2 sensor or will the gauge piggy-back off of the original sensor?

 

[Magic Man]

Two Bros already has done the base set up for a Spyder with stock air filter and after market single or dual can two bros pipes.

MM