Mapping a bike running oxygenated fuel

[Kurlon]

How does one go about building a custom map for a bike running oxygenated fuel using a dyno and a Power Commander?  The fuel throws off the O2 sensor so it always reads way lean.  Do you just have to do it the olde fashioned way, make a baseline run at X throttle, adjust the map rich or lean based on intuition, try again, and do a stare and compare at the results?  Or is there a different O2 sensor you can get that'll read properly, or what?

[Super Dave]

It reads lean because it is lean.  The introduction of an oxygenate, an oxygen carrying part of the fuel or an additive, will make the AF ratio lean.  Increase the amount of fuel to bring the ratio to what you're looking for with your Power Commander or other options that are available.  Still based on experience and intuition, yeah.

[danch]

If it reads lean, you want to richen it, as normal, right? Isn't that the point of oxygenated fuel - to allow you to burn more actual fuel than air alone would allow?

Wouldn't an EGA help?

[123user]

Its a pretty good assumption that nearly-all race engines will make the best power at something other than 14.7:1 AFR.  This means, regardless of fuel, if you run an O2 sensor with feedback control, you are likely unable to make best power/torque.  Also, almost all oem O2 sensors are of the "narrow band" variety.  This means that they only output a linear voltage signal to the ECU within a very narrow air/fuel ratio.  So even if you can change the "target" AFR value, its likely to only make the bike run worse.

Step 1 is to get rid of that stupid O2 sensor.  Depending on what type of bike you got, there are a few "tricker-modules" available that will tell the ECU that its running perfect all the time.  After dealing with the O2 problem, then you can develop a map

Another thing to keep in mind is that the published ideal AFR is based upon a bunch of chemistry equations that have nothing to do with the actual combustion efficiency of your engine.  At different RPM's your particular engine will operate under varying pumping efficiencies and requires different AFR's- that means that the O2 method of tuning (which just measures residual oxygen) will result in NOT having the perfect tuning.

The best way to develop a map (or to tune carbs) is on a "load control" dyno.  These type of dyno's are able to hold the engine at any rpm and throttle position.  It can take a real long time, but the best "tune" involves changing and holding different rpms and steady throttle positions (say, at 1/8, 1/4, 1/2/, 3/4, and full throttle)  In recent years the inertia type dynos have gotten popular due to they're lower cost.  While these are way better than you're butt-dyno, they are inferior to the load control type.

The most important question is this:  What is you're goal?  If you've got a basically superstock setup, you're a part time racer, and not really worried about finding the last 1/4 HP... then you should just not worry about, buy some MR9 and go have fun.  But if you're serious, you should find a tuner that really knows what they're doing and talk to them.  And I don't mean just your local dealership with dyno, I mean somebody like 4&6, or DucShop, or Doug Lofgren, or BCM, or KWS... well you get the picture.

[honda60071]

Nice feed back man!!

[Kurlon]

The problem I've been having is using a wideband O2 sensor, I can throw fuel at a bike till it's so rich it won't run, and the O2 sensor is telling me I'm still 'lean'.  I like to use the 02 sensor to get the fueling in the ballpark, so I don't have to spend as much time working the load control routine.  Based on what I'm hearing, it sounds like there is something up with the wideband unit I'm using, as  it seems it should still read properly when running oxygenated fuel.

[Super Dave]

Are you running an unleaded oxygenated fuel?

[Noidly1]

Its a pretty good assumption that nearly-all race engines will make the best power at something other than 14.7:1 AFR.

True. Usually around 12.6-13.4.

This means, regardless of fuel, if you run an O2 sensor with feedback control, you are likely unable to make best power/torque.

False. That depends on the system, OE vs Aftermarket ECU, and who set it up.

So even if you can change the "target" AFR value, its likely to only make the bike run worse.

False. It is the system used and the person who set it up that determines the effects.

FWIW, An OE manufacturer builds a system to meet finely regulated emission outputs and does what they can to make their product perform within those criteria.
Using a band-aid, like a Power Commander, to over-lay outputs to the injectors and coils, will make great improvements but is not a cure-all.
Converting a bike, or any vehicle for that matter, to a full "Stand-Alone" aftermarket system will yield best results.

[123user]

Yeah, I totally agree that aftermarket programable ecu's are the way to go... I feel the same way about the power commander... to me its just another electrical device on the bike waiting to ruin your weekend. 

I also agree that the right tuner can tune to AFR feedback... but almost none of the shops out there are willing or able to do it.   The right AFR is load dependent... so if you're not using a load control dyno, I personally think its only valuable for "rough" tuning.  Also, the ideal AFR for your engine varies throughout the torque curve...  so unless you just happen to know the perfect ratio at each RPM, then you're better off tuning for power.

The largest issue is with leaded fuel and the lambda sensor.  If you wanna run the good stuff, its gonna leave deposits on your O2 sensor and kill it within a few hours.  Better to disable it and run in straight Alpha-N mapping- if you're ecu allows it. 

On the surface, continous exhaust feedback seems like a good idea... but you must remember that its adding another variable into your map... one you may not be able to control.  I do think that its a great idea to add a w/b lambda sensor and couple it to your data logger!

[Noidly1]

Agreed...

Usually, (at WFO) A richer AFR is ideal for low speed/high load apps and leaner AFR for higher speeds w/less load and blend in between.

If you use lead, drop the O2, but if you use unleaded, you can fully utilize the wideband in all conditions.
Just remember, one of the aspects of using an O2 is to help the ECU tune for atmosphiric conitions.
However, some of the aftermarket systems utilize an atmosphiric bar sensor which can be used to fine tune for atmosphiric conditions but one aspect is, even with an atmo/bar sensor. it cannot compensate for humidity.
These are some of the reasons I prefer O2 over Alpha-N.

[123user]

Yes, and there are some decent oxygenated unleaded fuels made by VP...  but compared the U4.2 they just don't represent the same value.

Somewhere in the distant neather-regions of my mind I can remember a lambda sensor (perhaps made by Bosch?) that is lead tolerant.  I also seem to remember that its expensive.

Yeah humidity is a big suck especially if talking two-stroke... of course if it changes that much you've probably already mounted the rains and the point is moot.  On the other hand, there are still guy's running I4 microsprints making tons of power on the venerable flat-slide.  I think that if you're that "into it", you'll probably know how to compensate for humidity changes regardless of what you run. 

Back when I was still in engineering school the ME dept. would run this ford escort motor on the dyno for hours on end.  This wasn't a highly tuned engine, but you could really lean or rich it out with suprisingly little change in torque output.  Only way off the scale would torque suffer.  So, while I don't necessarily agree that AFR is the end-all tuning guide... if you're in the ballpark, the motor will make power.

For most guys, this is enough.

[Noidly1]

Agree again...

I think NTK has one as well.

As far as unleaded goes, Sunoco has a few that may be close to U4.2.
This one has the highest O2
http://www.sunocoinc.com/Site/Consumer/RaceFuels/UnleadedFuels/Sunoco260GTPlus.htm

One advantage to using an O2, or an atmo/bar, is you can run at tracks with different altitudes and not have to change a thing.

BTW, The bad things about U4.2 are that 1- you have to flush your system and 2- cost.
MO2X to me is a bargin because it performs well, it doesn't cost as much and you don't have to flush your system.