4-5 Gas Dyno Tuning 101

[Powerglides]

Wow, result! This thread is nearly staying on track! Makes it very difficult to learn if it doesn't.
James, on that sheet you posted, TP and MAP is presented next to the rpm and gas values. Would I be correct in assuming that these values (TP and MAP) are taken from the ECM? If that is the case, how are the ECM readings linked in with the dyno software?
Marc, Superflow supply other manufacturers wideband controllers. In my case, Innovate LM1s. The 0-5 voltage outputs are linked into the sensor box, so that they can be overlayed against the other measured parameters.
Ryder 57, I would be interested in your input, particularly since you use a Cycledyn also. Can your 5 gas outputs be linked into the Superflow sensor box, and displayed by the Superflow software?

[joe_lyons]

Sory I was misunderstood.  How long for a roll on test for collecting data at wot. 10seconds 20 Seconds?

[rbabos]

So does the balance of the 4 gases differ from the "cruise" area of the map to the wot?

You asked a tuning "artwork" question. :-)
The WOT Best Power tuning is pretty distinct in it's fuel and ign. Not much latitude there.
What you do to the "cruise" area is often one of the things that creates a tuner reputation.
Of the 4 gases, I find that CO% is the best mixture strength indicator.

Marc Salvisberg

How are light load areas dealt with in regards to what's optimum to run smooth? I've only been able to cure it with more fuel and sometimes dropped timing and obviously open loop it to retain the settings. This would show some odd gas results, so how do you look for in the gases? For me with limited tuning knowledge and only basic narrowbands to work with, basically I keep adding fuel until runs smooth. Viewing the cal after makes me  but don't run worth crap with a pretty ve table.  What's the 4-5 gas method?
Ron

[1931jamesw]

Wow, result! This thread is nearly staying on track! Makes it very difficult to learn if it doesn't.
James, on that sheet you posted, TP and MAP is presented next to the rpm and gas values. Would I be correct in assuming that these values (TP and MAP) are taken from the ECM? If that is the case, how are the ECM readings linked in with the dyno software?
Marc, Superflow supply other manufacturers wideband controllers. In my case, Innovate LM1s. The 0-5 voltage outputs are linked into the sensor box, so that they can be overlayed against the other measured parameters.
Ryder 57, I would be interested in your input, particularly since you use a Cycledyn also. Can your 5 gas outputs be linked into the Superflow sensor box, and displayed by the Superflow software?

Boz, yes on the ECM data, I leave the data running making a recording while I am doing the gas sampling. All data is running and I am watching it in real time while I am sampling so, I know where the adjustments can be made in the tuning software whether its broken down in MAP or TP and at what rpm each of those are. So, I roll up on each cell as shown in the sheet and get on he eddy brake and sample that spot and when the gasses stabilize I let off the throttle at whatever position I sampled and the dyno software records a line like you see on the sheet. Then at the end of that line, I type in the manifold pressure and TP and roll on up to the next sampling. Typically on the tuning software you can have 5 things or whatever it is showing during the data recording on the graph that the recording makes. I usually have in those five selections, Engine Temp, RPM, TP, MAP, Knock retard front, Knock retard rear. Those are the ones I pay most attention and show in real time on the recording graph but all o the ECM data is shown in real time, they are just not on the graph unless you select one of them. If you select something else like warmup fuel for example, it will also show on the recording graph. You can select any of the data options to be shown I just used that as an example.

[marc99]

So does the balance of the 4 gases differ from the "cruise" area of the map to the wot?

You asked a tuning "artwork" question. :-)
The WOT Best Power tuning is pretty distinct in it's fuel and ign. Not much latitude there.
What you do to the "cruise" area is often one of the things that creates a tuner reputation.
Of the 4 gases, I find that CO% is the best mixture strength indicator.

Marc Salvisberg

How are light load areas dealt with in regards to what's optimum to run smooth? I've only been able to cure it with more fuel and sometimes dropped timing and obviously open loop it to retain the settings. This would show some odd gas results, so how do you look for in the gases? For me with limited tuning knowledge and only basic narrowbands to work with, basically I keep adding fuel until runs smooth. Viewing the cal after makes me  but don't run worth crap with a pretty ve table.  What's the 4-5 gas method?
Ron

Are you tuning with AFR?
What are you tuning with?
What does the manufacturer of your "tuning device" say?
It would be good to post what they say about tuning - since they wrote the software.
You aren't the only one with that problem.

Marc

[rbabos]

So does the balance of the 4 gases differ from the "cruise" area of the map to the wot?

You asked a tuning "artwork" question. :-)
The WOT Best Power tuning is pretty distinct in it's fuel and ign. Not much latitude there.
What you do to the "cruise" area is often one of the things that creates a tuner reputation.
Of the 4 gases, I find that CO% is the best mixture strength indicator.

Marc Salvisberg

How are light load areas dealt with in regards to what's optimum to run smooth? I've only been able to cure it with more fuel and sometimes dropped timing and obviously open loop it to retain the settings. This would show some odd gas results, so how do you look for in the gases? For me with limited tuning knowledge and only basic narrowbands to work with, basically I keep adding fuel until runs smooth. Viewing the cal after makes me  but don't run worth crap with a pretty ve table.  What's the 4-5 gas method?
Ron

Are you tuning with AFR?
What are you tuning with?
What does the manufacturer of your "tuning device" say?
It would be good to post what they say about tuning - since they wrote the software.
You aren't the only one with that problem.

Marc

Both TTS and PV behaved the same way when using NB onboard sensors. Neither deliver correct fuel for light load smooth running. My three examples would be 113 ci, 120ci and my present almost stock v rod. All had skipfire and bucking issues after the road tuning.  One manufacturer continually blamed my components, and repeatedly failed to provide a solution and at the time open loop was taboo. With the v rod the I got good advice from the manufacturer and it all worked out. I had it running good with the same approach as the other two but wouldn't hold the tune for long in the open area where the problem was due to addaptive influence.  Basically what I'm asking is with 4 gas, what shows up in the ill running compared to just O2 sensors in this area as in identify it and fix it? Straight NB tuning in this area seems like guesswork and in the end you really don't know what the afr is. It's been the cause of many a battle here.
Ron

[Rider57]

Wow, result! This thread is nearly staying on track! Makes it very difficult to learn if it doesn't.
James, on that sheet you posted, TP and MAP is presented next to the rpm and gas values. Would I be correct in assuming that these values (TP and MAP) are taken from the ECM? If that is the case, how are the ECM readings linked in with the dyno software?
Marc, Superflow supply other manufacturers wideband controllers. In my case, Innovate LM1s. The 0-5 voltage outputs are linked into the sensor box, so that they can be overlayed against the other measured parameters.
Ryder 57, I would be interested in your input, particularly since you use a Cycledyn also. Can your 5 gas outputs be linked into the Superflow sensor box, and displayed by the Superflow software?

I took a different route and wrote software for the Horiba and based on what it was seeing, send control signal to the dyno. Sort of automated it a little. Gives me more time to look at the gases at RPM's.

[marc99]

So does the balance of the 4 gases differ from the "cruise" area of the map to the wot?

You asked a tuning "artwork" question. :-)
The WOT Best Power tuning is pretty distinct in it's fuel and ign. Not much latitude there.
What you do to the "cruise" area is often one of the things that creates a tuner reputation.
Of the 4 gases, I find that CO% is the best mixture strength indicator.

Marc Salvisberg

How are light load areas dealt with in regards to what's optimum to run smooth? I've only been able to cure it with more fuel and sometimes dropped timing and obviously open loop it to retain the settings. This would show some odd gas results, so how do you look for in the gases? For me with limited tuning knowledge and only basic narrowbands to work with, basically I keep adding fuel until runs smooth. Viewing the cal after makes me  but don't run worth crap with a pretty ve table.  What's the 4-5 gas method?
Ron

Are you tuning with AFR?
What are you tuning with?
What does the manufacturer of your "tuning device" say?
It would be good to post what they say about tuning - since they wrote the software.
You aren't the only one with that problem.

Marc

Both TTS and PV behaved the same way when using NB onboard sensors. Neither deliver correct fuel for light load smooth running. My three examples would be 113 ci, 120ci and my present almost stock v rod. All had skipfire and bucking issues after the road tuning.  One manufacturer continually blamed my components, and repeatedly failed to provide a solution and at the time open loop was taboo. With the v rod the I got good advice from the manufacturer and it all worked out. I had it running good with the same approach as the other two but wouldn't hold the tune for long in the open area where the problem was due to addaptive influence.  Basically what I'm asking is with 4 gas, what shows up in the ill running compared to just O2 sensors in this area as in identify it and fix it? Straight NB tuning in this area seems like guesswork and in the end you really don't know what the afr is. It's been the cause of many a battle here.
Ron

From 30+ years of tuning experience:

We use 4 gases, including O2 (AFR).
In using the gases as hints and clues as to what you might change, this is my order of importance when tuning fuel:
1. CO% (for tuning fuel)
Well, actually, I use CO% mostly for a primary indicator of fuel mixture.

I don't use O2% for a primary indicator of fuel mixture as you've found, it can be greatly affected by ignition timing (for one thing).

Using CO% as a gas marker results in less apparent "weird looking AFR" gas readings to make the bike run smoothly.
CO% is more linear and less affected by improper ign timing.

As you've found out, in your hundreds of hours of experimentation, a gas reading is not a "goal", good running is the goal.

Closed loop?
According to "riders", it works ok on some bikes, so-so on some bikes and not at all on others.

Marc Salvisberg

[rbabos]

So does the balance of the 4 gases differ from the "cruise" area of the map to the wot?

You asked a tuning "artwork" question. :-)
The WOT Best Power tuning is pretty distinct in it's fuel and ign. Not much latitude there.
What you do to the "cruise" area is often one of the things that creates a tuner reputation.
Of the 4 gases, I find that CO% is the best mixture strength indicator.

Marc Salvisberg

How are light load areas dealt with in regards to what's optimum to run smooth? I've only been able to cure it with more fuel and sometimes dropped timing and obviously open loop it to retain the settings. This would show some odd gas results, so how do you look for in the gases? For me with limited tuning knowledge and only basic narrowbands to work with, basically I keep adding fuel until runs smooth. Viewing the cal after makes me  but don't run worth crap with a pretty ve table.  What's the 4-5 gas method?
Ron

Are you tuning with AFR?
What are you tuning with?
What does the manufacturer of your "tuning device" say?
It would be good to post what they say about tuning - since they wrote the software.
You aren't the only one with that problem.

Marc

Both TTS and PV behaved the same way when using NB onboard sensors. Neither deliver correct fuel for light load smooth running. My three examples would be 113 ci, 120ci and my present almost stock v rod. All had skipfire and bucking issues after the road tuning.  One manufacturer continually blamed my components, and repeatedly failed to provide a solution and at the time open loop was taboo. With the v rod the I got good advice from the manufacturer and it all worked out. I had it running good with the same approach as the other two but wouldn't hold the tune for long in the open area where the problem was due to addaptive influence.  Basically what I'm asking is with 4 gas, what shows up in the ill running compared to just O2 sensors in this area as in identify it and fix it? Straight NB tuning in this area seems like guesswork and in the end you really don't know what the afr is. It's been the cause of many a battle here.
Ron

From 30+ years of tuning experience:

We use 4 gases, including O2 (AFR).
In using the gases as hints and clues as to what you might change, this is my order of importance when tuning fuel:
1. CO% (for tuning fuel)
Well, actually, I use CO% mostly for a primary indicator of fuel mixture.

I don't use O2% for a primary indicator of fuel mixture as you've found, it can be greatly affected by ignition timing (for one thing).

Using CO% as a gas marker results in less apparent "weird looking AFR" gas readings to make the bike run smoothly.
CO% is more linear and less affected by improper ign timing.

As you've found out, in your hundreds of hours of experimentation, a gas reading is not a "goal", good running is the goal.

Closed loop?
According to "riders", it works ok on some bikes, so-so on some bikes and not at all on others.

Marc Salvisberg

Ok, then CO is your indicator. What I can't seem to get my head around is if these light load fuel areas are wrong as tuned via narrow bands what really goes on? I'm assuming dilution/reversion has displaced available O2 to the mixture so in theory the mixture should be rich. However in my cases the mixture needs to be fattened to make it run smooth. Would CO be low and HC be high in this ill running state as well as 02 being low too? Probably totally bass ackwards but it's a start.  Say we start out with % of gasses for optimum burn, then what would the gasses look like in poor running light load and viewing each what direction to take to resolve it.
Ron

[1931jamesw]

Very intelligent questions, Ron! You are really giving this some thought and I like it! I'll let Marc continue to coversate with you but you are on the right path. Again, glad you chimed in here.

[rbabos]

Very intelligent questions, Ron! You are really giving this some thought and I like it! I'll let Marc continue to coversate with you but you are on the right path. Again, glad you chimed in here.

Intelligent might be pushing it. None the less, will absorb what I can. Every little bit helps.
Ron

[Powerglides]

Ryder 57, I would be interested in your input, particularly since you use a Cycledyn also. Can your 5 gas outputs be linked into the Superflow sensor box, and displayed by the Superflow software?

I took a different route and wrote software for the Horiba and based on what it was seeing, send control signal to the dyno. Sort of automated it a little. Gives me more time to look at the gases at RPM's.
[/quote]
So does your software then express the gases as a voltage output, that then goes to the sensor box?

[Tsani]

Interesting. Good questions Ron. Bookmarked.

[marc99]

Ok, then CO is your indicator. What I can't seem to get my head around is if these light load fuel areas are wrong as tuned via narrow bands what really goes on? I'm assuming dilution/reversion has displaced available O2 to the mixture so in theory the mixture should be rich. However in my cases the mixture needs to be fattened to make it run smooth. Would CO be low and HC be high in this ill running state as well as 02 being low too? Probably totally bass ackwards but it's a start.  Say we start out with % of gasses for optimum burn, then what would the gasses look like in poor running light load and viewing each what direction to take to resolve it.
Ron

Let's do a massive paradigm shift.

Instead of "giving" the engine some tuning table numbers that provides "some" gas reading, let's just blow off the whole gas reading thing.

In simplest function, we could just add and subtract fuel and add and subtract ignition timing and in a day, or two or a week or a month, we'd eventually end up with tuning that the engine liked.
It wouldn't be too rich or too lean - or it would make less power.
It wouldn't be too advanced or too retarded or the engine would make less power.
There wouldn't be detonation - if there was, then the engine would make less power.

So - Give the engine what it wants and it will reward you with Best Power and smooth running, at every throttle position and rpm.

The 4 gas readings are there, not as a numeric goal, but as a hint and clue about which way to change fuel and ignition. With 4 gases, you can get hints and clues as to whether there's potential in changing ignition timing or is it likely to be "darned close" already - That's a major time benefit in fine tuning.
But I tend to poke and prod the ign as a matter of habit, even if the "numbers say" it's pretty close.

Using reliable gas numbers allow the tuner to get more done in the same amount of time.

As far as gases and your example -
So, whatever your O2 sensor and software were telling you and AFR you were trying to tune to, it was too lean for the engine to run consistently.
In simplest terms, you did whatever you needed to do to the mixture to make the engine run smoothly. Good.
The question, isn't "'why the engine has to be so rich", but it's more a question of "why is the gas reading so off"?

As far as me trusting CO% more than O2%?
It's less affected by engine factors and reversion and exh air leaks. There's very very little CO in air - but loads of O2 in air.

James posted it in one of his posts, but I'll repeat it in a diff example.

Maybe you made table changes and made Best Power at 3000/WOT and you ended up with 4% CO, 600 ppm HC, 10.1% CO2, .5% O2.
I'd look at that and say, if I add or subtract fuel, I make less power (because I've already done it) and 600ppm is pretty clean burning and 10.1 and .5 are pretty good CO2/O2 pairings, so the ignition is pretty close - So., it's likely that I could tweak, poke and prod 3000/WOT more but I'm prob "right there" as far as fuel and ignition.

"In theory" (and it's not the way that we tune), you could now make ALL the throttle positions and rpms "4% CO" and the bike would probably run pretty well and the customer would be pretty happy - but the cruise mileage wouldn't be as sweet as it could be. So, most of us lean out the cruise areas.
How much?
Well, I kinda know what CO% a Harley cruises at in closed loop (around .5 CO%) and that's my lean limit but I am closer to 2ish when I'm tuning the cruise areas - People chose from that .7 to 4.0ish as a personal preference.

What will you use? It's up to you. 50 shades of personal choice.

I just made it easier to learn.

Marc Salvisberg

[rbabos]

Almost makes sense. I'll read it a couple more times to be sure.
Ron

[wolf_59]

I use a TTS tuner when Vtuning I tune everything with the CLB set at 447 which is as close to the 450 stoich that the tuner will let me set it, After Vtuning is completed I then set the CLB a little richer not much then set my areas that I want in open loop to what ever it is that I desire be it at 13.8,13.5 or 13.2 and adjust timing from there adding timing until knock retard kicks in then back it off 2 degrees for margin of error. Since I started tuning my bikes like this I have not had any deterioration of the tune after several thousand miles.
Now what I'm understanding is with the 4 gas tuning you would be looking at and adjusting the VE and Timing tables to to get the best gas chemistry from the engine optimizing the tune because 13.2 may or may not be the AFR needed for best power at WOT in each and every cell through out the RPM range and the same for the cruise area in closed loop.
Am I understanding this correctly?
What do you set the Desired AFR at?
What type of tuning device to you use?

Good thread so far 

[rbabos]

Seems CO is my furnace guys favourite as well. Explains why he shoves a probe in the pipe an dials in the air on the blower for the correct CO%. Never thought about it much until this thread.
In the 5 gas system how does the NOx play out as for indicator of what needs tweeking?
Ron

[strokerjlk]

Maybe you made table changes and made Best Power at 3000/WOT and you ended up with 4% CO, 600 ppm HC, 10.1% CO2, .5% O2.
I'd look at that and say, if I add or subtract fuel, I make less power (because I've already done it) and 600ppm is pretty clean burning and 10.1 and .5 are pretty good CO2/O2 pairings, so the ignition is pretty close - So., it's likely that I could tweak, poke and prod 3000/WOT more but I'm prob "right there" as far as fuel and ignition.

when you sampled the 3000/WOT was that steady state ? (I will assume it was)  so lets just say you did.
depending on what gear you used its going to go to 100 kpa between 45-60 % throttle .

do you continue on through the 60-100 % throttle positions and sample ?


so same scenario as above you sampled at steady state and  4% CO, 600 ppm HC, 10.1% CO2, .5% O2. was/is what the motor likes.
so you moved on and are finished tuning all the other  rpms . you switch cylinders and tune the other cylinder
the same . now after your all done and make WOT runs,is you reading at 100% throttle 100 kpa  @ 3000 rpms still . 4% co, 600 ppm HC 10.1% co2, .5 % 02.  ?

[marc99]

Maybe you made table changes and made Best Power at 3000/WOT and you ended up with 4% CO, 600 ppm HC, 10.1% CO2, .5% O2.
I'd look at that and say, if I add or subtract fuel, I make less power (because I've already done it) and 600ppm is pretty clean burning and 10.1 and .5 are pretty good CO2/O2 pairings, so the ignition is pretty close - So., it's likely that I could tweak, poke and prod 3000/WOT more but I'm prob "right there" as far as fuel and ignition.

when you sampled the 3000/WOT was that steady state ? (I will assume it was)  so lets just say you did.
depending on what gear you used its going to go to 100 kpa between 45-60 % throttle .

do you continue on through the 60-100 % throttle positions and sample ?


so same scenario as above you sampled at steady state and  4% CO, 600 ppm HC, 10.1% CO2, .5% O2. was/is what the motor likes.
so you moved on and are finished tuning all the other  rpms . you switch cylinders and tune the other cylinder
the same . now after your all done and make WOT runs,is you reading at 100% throttle 100 kpa  @ 3000 rpms still . 4% co, 600 ppm HC 10.1% co2, .5 % 02.  ?

If the tuning device decouples the cyls, it would be the same. If the tuning device doesn't fully decouple the cyls, it will change a bit.

This is a thread about what having 4 gases does for tuning - not a thread about tuning software issues.

Maybe start a new thread and we can talk about tuning devices?

Marc Salvisberg

[98fxstc]

This is a very informative thread and while intended as an information session about 4-5 Gas Dyno Tuning there is obviously a bit of debate about the merits compared with O2 sensor tuning.

I think I'm on topic and I'd like to add a little story and hope I don't step on too many toes.

I don't have access to an experienced tuner , EGA or O2 , so I am a happy? and committed? DIY tuner.
A DIY tuner really only has two options , TTS or PV , and then OL or OL/CL.
I believe the EGA has the potential to give a better tune under dyno room conditions , but I don't ride my bike in a dyno room.

Going back about 10 years I had some sensor bungs welded into the header pipes on my 98 fxstc.
I was using Innovate LM2 and wide band sensors to get the best tune that I could for my 40mmCV.
I came back from a ride one day and looked at the data that I had and the front cylinder had gone leaner than the rear. I checked for exhaust leaks and tried to nut it out.
I was a member on the innovate users forum and I pm'd one of the resident gurus there , a fellow Australian who was part of a drag car racing team and responsible for the tuning (5gas EGA) and data logging (Innovate).
I told him what I was doing and his first question was "What was the weather like?"
(He knew a bit about the weather where I lived at that time of year.)
That particular day I was riding into head on wind driven rain and hail !
He explained that the front head was not reaching temperature for efficient combustion and that more CO would be produced and this was being picked up by the sensors as extra O2 ,giving lean readings.
I asked how to fix it and he replied "Make a shroud for the front head or ride your bike backwards!"

I guess softails and dynas will be more affected than baggers in the colder months and the reverse in the warmer months.

So O2 sensors can give a bit of feedback while you're on the road but then you have the question about the data that the sensors are giving!

[strokerjlk]

Maybe you made table changes and made Best Power at 3000/WOT and you ended up with 4% CO, 600 ppm HC, 10.1% CO2, .5% O2.
I'd look at that and say, if I add or subtract fuel, I make less power (because I've already done it) and 600ppm is pretty clean burning and 10.1 and .5 are pretty good CO2/O2 pairings, so the ignition is pretty close - So., it's likely that I could tweak, poke and prod 3000/WOT more but I'm prob "right there" as far as fuel and ignition.

when you sampled the 3000/WOT was that steady state ? (I will assume it was)  so lets just say you did.
depending on what gear you used its going to go to 100 kpa between 45-60 % throttle .

do you continue on through the 60-100 % throttle positions and sample ?


so same scenario as above you sampled at steady state and  4% CO, 600 ppm HC, 10.1% CO2, .5% O2. was/is what the motor likes.
so you moved on and are finished tuning all the other  rpms . you switch cylinders and tune the other cylinder
the same . now after your all done and make WOT runs,is you reading at 100% throttle 100 kpa  @ 3000 rpms still . 4% co, 600 ppm HC 10.1% co2, .5 % 02.  ?

If the tuning device decouples the cyls, it would be the same. If the tuning device doesn't fully decouple the cyls, it will change a bit.

This is a thread about what having 4 gases does for tuning - not a thread about tuning software issues.

Maybe start a new thread and we can talk about tuning devices?

Marc Salvisberg

no its about sampling at 100 kpa with EGA . with any tuning device.
when you sample 3000 rpms steady state at 100 kpa 100 % t/p ,is your reading the same as when you do a WOT  run for hp/tq readings?

[1931jamesw]

No toes stepped on here.

I'm not understanding the innovate thing and the 5 gas thing. I thought innovate is an AFR type tuning device and a completely different thing obviously from 5 gas? As for your comment on a 5 gas making your bike run better in a dyno room, why did the tune deteriorate?

Being a carbed bike, there's only so much you can do. EFI has its limitations also but is almost endlessly more adjustable than a carb. As Marc just posted, that's a different topic and I would like to keep this thread about 4-5 gas and we can talk about the tuners weaknesses and strong points in another thread. Yours being carbed I'm not sure its applicable for you though.

[marc99]

Maybe you made table changes and made Best Power at 3000/WOT and you ended up with 4% CO, 600 ppm HC, 10.1% CO2, .5% O2.
I'd look at that and say, if I add or subtract fuel, I make less power (because I've already done it) and 600ppm is pretty clean burning and 10.1 and .5 are pretty good CO2/O2 pairings, so the ignition is pretty close - So., it's likely that I could tweak, poke and prod 3000/WOT more but I'm prob "right there" as far as fuel and ignition.

when you sampled the 3000/WOT was that steady state ? (I will assume it was)  so lets just say you did.
depending on what gear you used its going to go to 100 kpa between 45-60 % throttle .

do you continue on through the 60-100 % throttle positions and sample ?


so same scenario as above you sampled at steady state and  4% CO, 600 ppm HC, 10.1% CO2, .5% O2. was/is what the motor likes.
so you moved on and are finished tuning all the other  rpms . you switch cylinders and tune the other cylinder
the same . now after your all done and make WOT runs,is you reading at 100% throttle 100 kpa  @ 3000 rpms still . 4% co, 600 ppm HC 10.1% co2, .5 % 02.  ?

If the tuning device decouples the cyls, it would be the same. If the tuning device doesn't fully decouple the cyls, it will change a bit.

This is a thread about what having 4 gases does for tuning - not a thread about tuning software issues.

Maybe start a new thread and we can talk about tuning devices?

Marc Salvisberg

no its about sampling at 100 kpa with EGA . with any tuning device.
when you sample 3000 rpms steady state at 100 kpa 100 % t/p ,is your reading the same as when you do a WOT  run for hp/tq readings?

I don't understand.
If I do a steady state test, I already have the horsepower and torque.

That's the methodology. Get hp, make change fuel or ign and test HP again, use the gas readings to give hints and clues. Make Best Power.

[hrdtail78]

Marc,

From what I am understanding.  We can take all the gases away and just add or take away fuel and timing until we find best power at steady state. Reading the 4 gas helps in making that choice of adding or subtracting but it all comes down to:

Make a change, better or worse?.  Make a change, better or worse?.  Make a change.......... all at steady state?

[marc99]

Marc,

From what I am understanding.  We can take all the gases away and just add or take away fuel and timing until we find best power at steady state. Reading the 4 gas helps in making that choice of adding or subtracting but it all comes down to:

Make a change, better or worse?.  Make a change, better or worse?.  Make a change.......... all at steady state?

That's a PERFECT understanding.

Marc Salvisberg