Dyno load/no-load Rich or lean?

[Feanor]

I was thinking about this question and my mind just started spinning in circles without being able to figure it out empirically...

Question:

If you did a map for a fuel control unit (It doesn't matter which one) on a dyno with minimal load, or even with the wheel simply suspended in the air...

When the bike was then ridden on the street (load) with that mapping, would the A/F ratio be artificially rich? or lean? and why?

Thanks in Advance... Just a question I was thinking about...

 

[DannoXYZ]

It's not so simple. It really depends upon the tuning-device you used. Is it a piggyback input-signal massager? Or is it an output interceptor? Does it have 3D-mapping using RPMxLOAD? How is load determined? By MAP-sensor values or throttle-position or a weighted combination of both? All these factors ultimately determines the methods by which it modifies the underlying ECU mappings. And how those adjustments take effect at all operating points on the 3D map.

There are some adjustment devices that will modify mixtures across the board. So if you added a 3% enrichment at low-load, it will result in 3% enrichment under ALL conditions; medium-throttle to WOT. There are other devices with finer granular adjustments with true 3D RPMxLOAD mapping and if you made adjustments for low-load... say 5-10% throttle from 1000-15000rpms, ONLY that operating condition will be adjusted. Medium to full-throttle operation will be completely unaffected by the low-load adjustment and remain at stock values.

So... we need more info:

1. what kind of bike?
2. how does the factory ECU determine load?
3. what kind of adjustment device used?
4. how does it make it's adjustment? to the input signals? Or to the output signals?
5. does it have 3D mapping? And is adjustable for individual cells of the 3D map?

 

[rapidrobbie]

That's not how a dyno works,it is used to simulate the same load you would get when riding.

 

[afm199]

I was thinking about this question and my mind just started spinning in circles without being able to figure it out empirically...

Question:

If you did a map for a fuel control unit (It doesn't matter which one) on a dyno with minimal load, or even with the wheel simply suspended in the air...

When the bike was then ridden on the street (load) with that mapping, would the A/F ratio be artificially rich? or lean? and why?

Thanks in Advance... Just a question I was thinking about...

Makes no sense. Dynos read work required to spin a weight or overcome electrical resistance. No weight or resistance, almost no work. If you did this, it would simply show that you were way rich in most areas (if the dyno guy actually remapped to the A/F or 4 gas figures.)

 

[Feanor]

Makes no sense. Dynos read work required to spin a weight or overcome electrical resistance. No weight or resistance, almost no work. If you did this, it would simply show that you were way rich in most areas (if the dyno guy actually remapped to the A/F or 4 gas figures.)

It's difficult for me to frame the question in anything but simplistic terms because I have very little understanding about how the load is implemented, calculated, sensed, etc...

If it helps, my bottom line question has nothing to do with the dyno "readings" themselves as in HP output torque etc, in this question the dyno unit is being used to create a fuel map. To read the bike's numbers during a run, for mapping something like a Bazzaz or PCV if you made an A/F map under load, and then a second map with no load at all all other things being the same.

i.e. If you held the throttle at a point where you were holding 6000 rpm on the dyno with load, and the Bazzaz or PCV set an adjustment number to hit 13.2 A/F at that point. Would that number be different if you did the same thing (held the throttle wherever you needed to to hold 6000rpm) with the dyno set to no-load, and if the number was different for no-load adjustment that the PCV or Bazzaz stored for that RPM, when you rode it on the street (load) would the Bazzaz or PCV make the bike run rich or lean at 6000rpm? Or would the fact that it would also sense throttle position and speed along with rpm compensate somehow for different loads? Really confusing to me

 

[afm199]

It's difficult for me to frame the question in anything but simplistic terms because I have very little understanding about how the load is implemented, calculated, sensed, etc...

If it helps, my bottom line question has nothing to do with the dyno "readings" themselves as in HP output torque etc, in this question the dyno unit is being used to create a fuel map. To read the bike's numbers during a run, for mapping something like a Bazzaz or PCV if you made an A/F map under load, and then a second map with no load at all all other things being the same.

i.e. If you held the throttle at a point where you were holding 6000 rpm on the dyno with load, and the Bazzaz or PCV set an adjustment number to hit 13.2 A/F at that point. Would that number be different if you did the same thing (held the throttle wherever you needed to to hold 6000rpm) with the dyno set to no-load, and if the number was different for no-load adjustment that the PCV or Bazzaz stored for that RPM, when you rode it on the street (load) would the Bazzaz or PCV make the bike run rich or lean at 6000rpm? Or would the fact that it would also sense throttle position and speed along with rpm compensate somehow for different loads? Really confusing to me

meaningless question. You need several times as much throttle to hold any specified RPM under load. You can hold 15,000 rpm with 1/4 throttle no load.You need full throttle to hold it under load.

ALL of the values are set for partial throttle openings just as full throttle. Whatever opening and RPM you are at will bring up the preset value in the map. Period.. Load won't affect it.

I will try again. Download Bazzazz or dynojet software, it's free. Open the program. You will see hundreds of boxes that need values set... for every position from 0% throttle at 3000 rpm to 10% throttle at 3000 rpm to 20% at 3000 rpm, etc etc all the way to 15,000 rpm at 100% throttle and everything inbetween. There are values to be set all the way from closed throttle to 100% throttle at all rpms ( usually 500 rpm jumps, IIRC).

So zero load maps will be set with much lower throttle openings. You would never hit full throttle at any rpm so no values to set in the higher rpms

 

[aram]

When I used to to tune cars on the dyno the a/f ratio would change because you aren't simulating the load of a car on the street in a certain gear perfectly on the dyno (I used dynojet).. but it seems like the weight of the car would actually make the most difference as to how far off the a/f was. Usually it wasn't off too much. Dyno was good though for seeing how timing a/f affected different cars power output rather than trying to just nail a specific air/fuel ratio or amount of timing.

I would think it would be similar with bikes, a goldwing has to overcome much different load than a ninja 250 but the load they are overcoming on the same dyno doesn't change.

With cars, I would usually get the car in the ballpark on the dyno, then drive it or drive it at the race track and use an on-board wideband o2 sensor, and then tweak the fueling if and see if there was a difference at the race track.

EDIT: for fueling I would usually make sure that modifiers that I didn't trust to make good decisions would not adjust my final fuel calculation were zeroed out (but obviously modifiers like engine temp, intake air temp, etc.. needed to stay) then I was doing most adjustment on non mass air controlled cars (similar to bikes) and doing my main tweaks on a table that used the MAP sensor on one end and the RPM on the other..

The actual complicated part of it usually isn't the wide open or high throttle stuff.. it's the low throttle or transitional throttle stuff though.

I THINK that the dynoject units just take the TPS signal and then modify the fuel injector signal based only on that.. which is a pretty basic and IMHO really tough way to tune something properly but is easy for giving gross adjustments to the fueling across the board.

I don't know about bazzaz or anything. I also don't know how sophisticated bike fuel injection is now, but I would think it's pretty good.. on cars it's downright scary how complicated the equation can get (references a LOT of tables) to reach your final fueling number or timing number.

 

[Ironbutt]

On a dyno w/no load cell or brake, you're getting 8 seconds of sweep data. There is a load cause the wheel weights something; but you don't get any granularity to a specific RPM. It passes by quick and you can't hold an RPM to see a problem area. You have to extrapolate and guess a little cause the data's just not there..

 

[DannoXYZ]

When I used to to tune cars on the dyno the a/f ratio would change because you aren't simulating the load of a car on the street in a certain gear perfectly on the dyno (I used dynojet).. but it seems like the weight of the car would actually make the most difference as to how far off the a/f was. Usually it wasn't off too much. Dyno was good though for seeing how timing a/f affected different cars power output rather than trying to just nail a specific air/fuel ratio or amount of timing.

DynoJets are inertial dynos and are fine for doing full-throttle mapping. Which is where most people need to make adjustments 99% of the time anyway. For doing partial-throttle mapping that gives an upgraded or boosted car more normal driveability, I prefer the Mustang load dynos which can hold a car at a specific load & RPM.

For convenience and speed in tuning, I would make 5 passes through the entire rev-range from 1000rpm to redline at 10%, 30, 50, 80 and 100% throttle and datalog AFR. Then go back through and make adjustments in the ECU's mapping to match the targets. I prefer to change the actual maps inside the ECUs rather than using overlay corrections like piggyback and interceptor-type aftermarket adjusters. On cars with non-flashable ECU maps, I would replace the ROM with a EEPROM and chip-emulator software so I can make adjustments on-the-fly. Then burn the final map and drop in a new chip at the end.

 

[KC@ BRG Racing]

I was thinking about this question and my mind just started spinning in circles without being able to figure it out empirically...

Question:

If you did a map for a fuel control unit (It doesn't matter which one) on a dyno with minimal load, or even with the wheel simply suspended in the air...

When the bike was then ridden on the street (load) with that mapping, would the A/F ratio be artificially rich? or lean? and why?

Thanks in Advance... Just a question I was thinking about...

The simple answer is rich. By about 2 to 3 points. The problem with no load Dyno is they don't generate realistic combustion chamber temps. So it like tuning a motor that is not all the way warmed up. tuning with only A/F is like looking through a knot hole. You only get a small part of the picture. 4 gas and the new 5 gas would get to see what is going on the the combustion chamber. Co HC Co2 O2. and now NOx. You can make your adjustment in fuel and in timing having a much better idea what direction you need to go in. And when your numbers come into the range you are looking for you know when to stop.

 

[Feanor]

The simple answer is rich. By about 2 to 3 points. The problem with no load Dyno is they don't generate realistic combustion chamber temps. So it like tuning a motor that is not all the way warmed up. tuning with only A/F is like looking through a knot hole. You only get a small part of the picture. 4 gas and the new 5 gas would get to see what is going on the the combustion chamber. Co HC Co2 O2. and now NOx. You can make your adjustment in fuel and in timing having a much better idea what direction you need to go in. And when your numbers come into the range you are looking for you know when to stop.

Thanks KC, I know its a simplistic answer for a malformed questioned and I see also what Ernie was saying about zipping by the RPM settings for the lower 25% of throttle position really screwing things up...

The question came up (and I left this out because it would have made the original question too long) but a friend of my Brother's wanted to borrow a bunch of my tie downs and my rear wheel pitbull stand to do his own version of a mapping run for his PCV and Autotune in his garage That is stick a fan in front of the intake, strap everything down and literally run the motor to WOT in 3rd or 4th gear with the rear wheel up in the air and spinning... First thing I said was that he was going to damage my pitbull, second thing was that he was going to kill himself if the thing let go. THe image of doing that kind of brought up that picture in my mind of the guy who made his own bike hoist with a ladder and a few 2x4s and a work bench...

I tried to explain that the readings, whatever he got wouldn't be accurate because there was no load, but his counter was that it wouldn't be that far off... All I was offering in counterargument was that there was no load so less fuel to hold higher RPM so lower temps in the cylinders and that would screw up the AFR, but really I wasn't understanding the complete picture, as Ernie was saying you couldn't hold a realistic run thru RPM because you would rocket past to redline at 24% throttle position with no load on the wheel (that was something I never factored in top my argument but will now)

Thanks for the info guys... I'm one small step closer to understanding it a bit better and the issues involved. and no, he won't be borrowing my pitbull and tiedowns

 

[KC@ BRG Racing]

Thanks KC, I know its a simplistic answer for a malformed questioned and I see also what Ernie was saying about zipping by the RPM settings for the lower 25% of throttle position really screwing things up...

The question came up (and I left this out because it would have made the original question too long) but a friend of my Brother's wanted to borrow a bunch of my tie downs and my rear wheel pitbull stand to do his own version of a mapping run for his PCV and Autotune in his garage That is stick a fan in front of the intake, strap everything down and literally run the motor to WOT in 3rd or 4th gear with the rear wheel up in the air and spinning... First thing I said was that he was going to damage my pitbull, second thing was that he was going to kill himself if the thing let go. THe image of doing that kind of brought up that picture in my mind of the guy who made his own bike hoist with a ladder and a few 2x4s and a work bench...

I tried to explain that the readings, whatever he got wouldn't be accurate because there was no load, but his counter was that it wouldn't be that far off... All I was offering in counterargument was that there was no load so less fuel to hold higher RPM so lower temps in the cylinders and that would screw up the AFR, but really I wasn't understanding the complete picture, as Ernie was saying you couldn't hold a realistic run thru RPM because you would rocket past to redline at 24% throttle position with no load on the wheel (that was something I never factored in top my argument but will now)

Thanks for the info guys... I'm one small step closer to understanding it a bit better and the issues involved. and no, he won't be borrowing my pitbull and tiedowns

Wow Relay. tie downs and a pit bull.... Man why didn't I think of that I could have save soooo much money on my Dino set up i have now. If you like and are in the area please stop by. Where very proud of are set up here. Would love to show it to you and explain the best we can, how it all works and why.

 

[afm199]

Feanor: Tell him go for it and be sure and video!

 

[DannoXYZ]

The simple answer is rich. By about 2 to 3 points. The problem with no load Dyno is they don't generate realistic combustion chamber temps. So it like tuning a motor that is not all the way warmed up. tuning with only A/F is like looking through a knot hole. You only get a small part of the picture. 4 gas and the new 5 gas would get to see what is going on the the combustion chamber. Co HC Co2 O2. and now NOx. You can make your adjustment in fuel and in timing having a much better idea what direction you need to go in. And when your numbers come into the range you are looking for you know when to stop.

It would be ricer with a PC under full-throttle when only adjusted at the low-load row?

 

[KC@ BRG Racing]

It would be ricer with a PC under full-throttle when only adjusted at the low-load row?

The problem is not throttle position, the problem is. The motor isn't allowed to work hard enough to make it necessary to develop real world temperatures. All you're doing is spinning a very large hamster wheel, witch at the end of the day doesn't apply enough load to create said temperature. If you're tuning for horsepower, on the Dyno get Dyno. You'll get max horsepower at X setting. Then you put the bike on Eddie current Dyno, and the fuel map will be easily 2 to 3 points, richer than it actually needs to be. You couple that with the four gas analyzer, and someone knows what they're doing and you can really come up with some awesome tunes.
these pictures below are good example of what I'm talking about in the horsepower differences that can be had.the bluegrass line is. Chris Siglin's 04 R1 that was tuned by Dyno jet,add Fontana racetrack. The green line, is a BRG map. You can see the difference in the CO count , and certainly in the horsepower.

 

[Feanor]

Ernie, lol! I know! when my brother told me what he was doing, i kind of looked like Dan Akroyd in Ghostbusters with the cigarette stuck on my lip lol! My next question was if the guy posted under the name Shervin, and if he could punch thru mountains and sruff!

 

[Feanor]

KC, you're in Pacheco! I wasn't planning on doing a map for my own Bazzaz unit in the near future, but you're close, and convenient, so now I am lol!

Do you work with Bazzaz fuel controllers? I may just swing by on a weekday to visit... I still get nervous about the stress a dyno run puts on a bike, but I've got enough miles on the bike now where I feel more comfortable about it

 

[afm199]

KC, you're in Pacheco! I wasn't planning on doing a map for my own Bazzaz unit in the near future, but you're close, and convenient, so now I am lol!

Do you work with Bazzaz fuel controllers? I may just swing by on a weekday to visit... I still get nervous about the stress a dyno run puts on a bike, but I've got enough miles on the bike now where I feel more comfortable about it

Feanor, KC will definitely take care of you.. As far as dyno stress, it's no more than a tickle. I've got motor with forty dyno runs on them.

 

[DannoXYZ]

The problem is not throttle position, the problem is. The motor isn't allowed to work hard enough to make it necessary to develop real world temperatures. All you're doing is spinning a very large hamster wheel, witch at the end of the day doesn't apply enough load to create said temperature. If you're tuning for horsepower, on the Dyno get Dyno. You'll get max horsepower at X setting. Then you put the bike on Eddie current Dyno, and the fuel map will be easily 2 to 3 points, richer than it actually needs to be. You couple that with the four gas analyzer, and someone knows what they're doing and you can really come up with some awesome tunes.
these pictures below are good example of what I'm talking about in the horsepower differences that can be had.the bluegrass line is. Chris Siglin's 04 R1 that was tuned by Dyno jet,add Fontana racetrack. The green line, is a BRG map. You can see the difference in the CO count , and certainly in the horsepower.

Thanks for the info. I was referring back to the OP's post about adjustments made on the PC or Bazzaz. If we made an adjustment to a low-load cell, like [8000rpm X 10% throttle], it will actually affect mixtures in other zones? Like full-throttle?

 

[KC@ BRG Racing]

KC, you're in Pacheco! I wasn't planning on doing a map for my own Bazzaz unit in the near future, but you're close, and convenient, so now I am lol!

Do you work with Bazzaz fuel controllers? I may just swing by on a weekday to visit... I still get nervous about the stress a dyno run puts on a bike, but I've got enough miles on the bike now where I feel more comfortable about it

Yes were Pacheco, one street over from FedEx. Please come by and check us out. You can see some of the crazy stuff we get to play with ... Oops I mean work on . The Bazzaz unit is really good. We like using it as a turning platform. The only thing I don't like it doesn't give us access to the ignition. But the last time I talked to Bazzaz. They said they were working on getting that into the program. I have a standard guarantee when it comes to our tuning. If you're not happy with what we've done. It's free. In the years that we've been doing this. I have yet had to make good on that guarantee.

Feanor, KC will definitely take care of you.. As far as dyno stress, it's no more than a tickle. I've got motor with forty dyno runs on them.

thanks Ernie for the thumbs up.

Thanks for the info. I was referring back to the OP's post about adjustments made on the PC or Bazzaz. If we made an adjustment to a low-load cell, like [8000rpm X 10% throttle], it will actually affect mixtures in other zones? Like full-throttle?

I'm not sure if this is going to answer your question, but on the Bazzaz and or Power Cmdr. There is some bleed over from cell to cell. Generally it takes 2 to 3 cells of separation. But way that we tune is much different Dyno jet Dyno. With the eddy current, type Dyno, we can stop the engine at whatever rpm we want look at the fuel requirements add whatever throttle position. We want and then calibrate the fuel system using the for gas analyzer for optimal horsepower. No matter how quick you are, you just can't do that on the Dyno jet Dyno. We get a lot of bikes in that you have the Dyno jet canned map installed. We'll go ahead and do a baseline. Then we'll zero the map out start fresh, and you can see the results on the Dyno graphs I posted earlier. We get quite a few bikes in it have been dying to on the Dyno jet with the same results.