4-5 Gas Dyno Tuning 101

[1931jamesw]

This post was moved here from another thread and is in my opinion a little out if context. I did not put it here and did not ask for it to be out here but it is here and is not intended to be the opening statement of this thread. I was simply being obnoxious but I do believe there is a lot of truth in the post. Hopefully you know when I'm serious and when I'm just being obnoxious. Thanks for taking the time to read my 4 gas thread. I was asked several times by several people over a time of period to post here on 4 gas and finally decided I would. My Original Post for this thread is post #6. Thanks again.

I don't really remember a lot of the old days here and 10 pages of name calling but since the newer way is not always the best way on many of subjects even pertaining to the norm around here be it cams, heads, pipes or tuning closed loop and beyond that, running a bike in closed loop on the final map, I don't mind saying that I subscribe to the old ways. I tune open loop on every bike and leave it that way when it rolls out of the shop. Why? Several reason I suppose.
1. It's the way I was taught.
2. I run a 4 gas analyzer and I don't see AFR so how would I know if its in the perameters of closed loop anyway without doing a crap VTune or whatever they call them these days.
3. I have retuned bikes that have had the same issue as the OP posted. The AFV fubared the tune and the bike wound up running like crap leaving the owner to pay for yet another tune that could very well fail again if its tuned and left in closed loop.
4. I don't subscribe to the notion that an O2 sensor knows more about the combustion process than a trusty 4 gas analyzer.
5. Most of the bikes I've retuned that were running closed loop picked up decent power and can run cooler if they are a little richer than what I think stoichiometric (closed loop) typically does.
6. I don't like bikes that surge and I have noticed that as a potential problem with closed loop bikes.
7. I don't necessarily like the idea of the government (EPA) dictating the way my Harley runs and I like to be different!
8. You still knock down 40 plus MPGs in open loop.
9. O2 sensors like anything else, can fail or give false information.
10. Look at all the BS that goes on in these forums about tuning wih O2 sensors and the bitterness it causes some of its subscribers and our fellow man in the industry. I've been able to avoid all the bickering about this BS and my tunes rock! Just ask a previous customer.
11. Stoichiometric is only a thing of beauty in the eyes of the EPA and your chemistry classes, not in the world of performance where I live!
12. Closed loop and performance are like water and oil. They just don't mix!

There's a quick bakers dozen and a  toast to the old days. We don't need no stinking O2 sensors!!

PS. In case you found one of my reasons to be bogus, for good measure heres a

13. I don't post much here because of O2 sensors. They are the dominant force in tuning today and I don't have a lot of good things to say about them! So, since I don't have much of anything good to contribute to the O2 sensor world we are living in today. I usually just read the posts and keep to myself here and dream of a day when the EPA will be so far up our asses that the O2 sensors seem way towards the exit end of your exhaust pipe and will be deemed inadequate for tuning street driven bikes. Hey, it could happen! Look what the CARB board uses to test automobiles for emissions standards! It's 4-5 gas analyzers. I think its unfortunate the industry has gone so heavily to O2 sensor based tuning but hey, that's my opinion and we all know about those. That's my post for the AFR section and if you are still reading this post, in certain circumstances, I suppose closed loop has its place in the industry, just not as much of a place it currently seems to have. 

[1931jamesw]

Sorry for the obnoxious post but it seemed like a good way to get a few points across in an not so serious way with the hope of making some good points without falling into an ambush. I am a one man army here in the shop for now and on this forum. I'll be completely and openly honest. It's a little intimidating discussing 4 gas tuning because so many people seem to think they need to get combative and whoop out the perverbial word whippings and I can completely understand and appreciate that because most of us here take this stuff very seriously. For some of us, its the way we pay the bills and feed the family and nobody wants to look like they might not know as much as the next guy. For a lack of a better way to put it, it becomes a d!ck contest and surely most of us know by know that tuning these bikes is an art form and in art, I guess nobody can paint an ugly picture or at least they don't want to be told its ugly if they are taking pride in their work and trying to give the customer an honest to goodness best shot at adjusting all the tables to make the bike run a seemlessly as possible and with hopes that the owner truly appreciates how much better it runs every time he rides it. For me, I'm a bit of a perfectionist and they probably comes through when I'm painting. I mean tuning. It comes through in a lot of things I do. My yard looks like a damn golf course. It's almost embarrassing sometimes and it is like a disease and for those that feel my pain, you know exactly what I mean when I say it will drive you crazy sometimes. If you are never satisfied with things, life can get miserable sometimes but I do love tuning and I rea about it and do it nearly every day. Mike, no, I do not tune for a certain CO2. CO2 is another one of those stoich or EPA gasses but it I one of the 4 gasses I see. CO2 is carbon dioxide and when completely burned up hydrocarbons (another of he 4 gasses) and Oxygen (another one of the gasses) get completely burned up in the combustion event, carbon dioxide is produced as well as water. If the EPA had it their way and in a perfect world, CO2 an water is all that would come out of your tailpipe! Excellent for the atmosphere and feeding and watering plants but pure crap for performance in an of themselves. CO2 can help give an indication of how efficient an engine is operating though and maybe more specifically, it might give insight to how well the port work on your heads are working. O2 is yet another gas that can help with letting you know what to do with timing and how effecient the engine is burning the Oxygen and Hydrocarbons. Those two gasses are important in any engine. They are the two molecules we want to burn the most of for moray efficiency and power. Hydrocarbons can also be a good gas to look at when you are checking startup and accelerator enrichment. It coul also give clues as to how well the fuel is atomizing as well as other engine effeciency. The other gas is CO (Carbon Monoxide) this is a big indicator of fuel mileage to be expected and what I would possibly be similar to AFR a little bit. I'm not the best at typing these answers out so bear with me and don't read overly much into any one thing state here. It all works together! CO by the way is partially burned hydrocarbons (gasoline in the case of 4 stroke Harley) and oxygen. The gas we work so hard to get as much as possible into the cylinders because the more oxygen we can get in the combustion chamber, the more hydrocarbons we can attach to those oxygen molecules and that is what makes power! It's what the performance guys constantly want more of and its why NOS is so effective as well as superchargers and turbos. Hope this is more helpful than harmful and I don't know if I mean for you, Mike, or myself. Lol.

[Powerglides]

James, please start a new topic, 4 gas 101, so that those of us with open minds can hopefully learn from it.

[HD/Wrench]

I agree   would be nice to see real data on the 4 gas.I believe there is as much merit with that type of tuning as the 02 set up. You can label the post  "closed loop tuning is the DEVIL"   

[hrdtail78]

James, please start a new topic, 4 gas 101, so that those of us with open minds can hopefully learn from it.

I was taught O2 tuning.  I have a very small understanding of 4 gas and a thread would be great.

[1931jamesw]

I reckon I could, Boz. I know you are interested based on past conversations we've had. Maybe I wouldn't feel so vulnerable either. I feel like I stand out like hot nun in front of a bunch of sacreligeous 300 lb guys who've been in isolation and somehow got a triple dose of Cialis. I could get bent over and all barrels loaded. I'll shut up now and start the thread. It'll be in the AFR area. Also, if anyone is interested, the blog section of my website has some good information as well as Big Boyz website. 

[1931jamesw]

Just to start off, I use a 4 exhaust gas analyzer to break the combustion process down on a chemical level to help tune the engine. Tuning in mind is about understanding exactly what is occurring on a chemical level in the combustion event of and engine and altering the tables and parameters of a tuning device to allow the engine to operate at its peak potential in all scenarios and loads and engine might find itself in during its operational life. 4 Gas is not something that is a snake oil or something designed as a hokey way to tune. It is science and as most any intelligent soul knows, science is science and it is constant in that it is not a hypothetical or a hypothesis. It's a proven fact of combustion chemistry. 4 Exhaust gas analyzers have been aroun for years. I don't know who invented them but they are probably quite a bit sharper than I am.

Real quick I'll add, I you are interested in reading a good book about tuning and a little bit of theory on combustion chemistry, I highly recommend getting the book by Adam Wade titled: Motorcycle Fuel Injection. It's very well written and is enlightening. The problem is that last time I checked it was out of publish and paper backs that could be found on the www were in the $235 range. I hated to do it but I found a rip off of it on google books and I keep it downloaded in my iPhone which is were I'm posting this ridiculously long post from. I didn't like having to get a rip off version because Adam Wade is not making the money off his work, google books is. To me, that's just wrong but hey, who can afford $235 for an old book on motorcycle fuel injection that is in this business? I can't! I think I paid like $10 for my downloaded copy and I read it from my phone.

Anyway, the gasses, they are and in no particular order of importance, I'm just going off he way they appear when I'm tuning. They are, CO (Carbon Monoxide), HC (hydrocarbons), CO2 (Carbon Dioxide) and last is O2 (Oxygen). Carbon monoxide is formed when a molecule of HC attaches itself to an O2 molecule and gets partially burned in the combustion process. The next has is CO2 this gas is residual of the combustion event when a molecule of HC and O2 are completely burned up. Lastly, is O2. In the case of analyzing the combustion event, O2 can be a good indicator of whether you need to advance timing or not as well as give clues to the efficiency of the engines performanance. The O2 may be an indication of how efficient the heads are working also or possibly if the injectors are not atomizing fuel enough to allow the HC molecules to mix with the O2 on a combustible level. Lots of these gasses can help clue you in to how the engine is functioning as well as diagnose combustion and efficiency issues. In any internal combustion engine, the more O2 you can get in, the more HC you can attach to those O2 molecules and the more power and efficient the engine will perform. Clean combustion is critical to power and longevity. Dirty or inefficient combustion can lead to excessive carbon buildup, fouled plugs and shorter engine life.

I think that should be a pretty good start to the thread but I will try to answer questions if they are asked and I also invite you to take a look at the blog section over 4 gas tuning on my website. The site is currently a little watered down so please excuse that but the blog section is ok. Also, Big Boyz has some great information regarding 4 has tuning on their website. 

[Powerglides]

good man, keep it coming...

[q1svt]

Where 4 gas provides insight on the build, most people are not going back into their motor to correct design short comings... It would be helpful if you can share how you use the specific readout [CO (Carbon Monoxide), HC (hydrocarbons), CO2 (Carbon Dioxide) and O2 (Oxygen)] to know what to change for the parts of a tune you have some control over... Timing, Head Temperature and Air/Fuel mixtures.  Actual before and after readouts and the corrected measures you took. 

[1931jamesw]

Not exactly sure what the first part of your post means. I didn't mean to suggest that 4 gas tells you all the problems with the engine if that's what you mean. It simply has more information to help clue you in to the efficiency or the engine. The CO helps with dialing in the VE tables (fuel) and gives insight to how rich or lean the engine is running. If I saw the bike was not pulling timing in the data and that the O2 reading is more than I'd like to see, that would give me a clue that I can advance timing to give the engine a chance to burn up that O2 before it slipped out the exhaust. If I was able to advance the timing, I might also see the CO drop now because the extra timing is also burning up the HC's that mix with that O2 we were trying to burn up. That's is a couple of scenarios that are common.

[marc99]

4 Gas EGA

With multi-gas information, you get hints and clues about what you might do to improve tuning.

Like Independent 1 said, the different gases highlight potential avenues by which to improve the tuning process. The quicker the tuning goes, the more time can be allotted to fine tuning detail, like in town cruise smoothness and highway cruise mileage.

If, when making Best Power at some point, the CO is "in the hunt, but kinda on the low usual side" and O2 is "kinda on the high side" when making best power, that's like a flashing sign that you should try a couple degrees more timing and richening a bit and recheck. And repeat.

At some point, you'll get no more power when advancing another 2 degrees and you'll check the Best Power fueling and be confident that you will lose power if you adv or retard the timing or if you richen or lean the fueling.
Basically, you are at the peak of the "Bell Curve"

It takes WAY longer to describe it than actually do it.

Process (at least in my head). We'll describe a power commander (as it's easier to describe).
Example: Testing 3000 rpm, 100% throttle
Roll throttle on, dyno holds the engine at 3k.
Hold for 5-7 secs.
Dyno records hp and 4 gas info.
Look at hp and gas, Looks a bit low in co and high in O2.
Add 4 fuel numbers to 3k/100% TH in the pc.
Test again.
Power goes up? Add another 4 fuel numbers.
Power goes up? Add another 4 fuel numbers.
Power goes down? subtract the last 4 fuel numbers.
There.
You have Fuel Best Power.

Now look at the 4 gases.
If co is kinda low, and o2 a bit high,
Add 2 to ign, Better? Add another 2 ign,  better? Add another 2 ign.
Worse? Subtract that last 2. That's within 1 degree of perfect.

A 2 degree change in ignition timing makes about a 1% power change

Now, add 4 numbers of fuel and power will prob go up a bit.
Repeat till power doesn't increase when richening

Now, after finding out how much fuel and ignition timing the engine wants, you have the Best Timing and the Best Fuel and Best Power.

It can't be too lean or too rich or to advanced or retarded - or it would make less power.

Now, when at Best Power, you can, once again, look at the CO, HC, CO2 and O2 get a clue as to how happy the engine package contents are.
If it makes best power at relatively low HC numbers, then you are pretty sure it's a well balanced set of components and combustion chamber.
Suspicious points, like full throttle / 2500 rpm, that require lots of leaning and still have extra o2 in the exhaust and a torque dip, are likely to have an unhappy cam / head / exhaust choice.

High HC numbers, when done tuning, can make one suspicious of excess piston to head squish cl, poor injector condition or inefficient ignition.

There are other things that can be inferred from reading 4 gases, too.

It's like having three extra tools to tune with.

Marc Salvisberg

[Powerglides]

Couple of questions.
1) How do we take samples? Lets say, for instance, that we are using a Supertrapp Supermeg (2-1) with a closed cap and 12mm sensor bosses. Can we use something similar to the Herko blocks to get our samples?
2) How long is the sampling time, in order to get accurate readings?
3) Are there voltage outputs, for each gas, from the controller, that can be input into different dyno software? (I know I can add many extra channel inputs on my Superflow sensor box). Being able to record the gas readings against tq and hp (as I do now with O2), would be helpful.
4) What sort of cost are these analysers? I would need 2, one for each cylinder.
5) What is the maintenance requirement?
6) Do the sensors have a lifespan?
7) How are they calibrated?

[marc99]

Couple of questions.
1) How do we take samples? Lets say, for instance, that we are using a Supertrapp Supermeg (2-1) with a closed cap and 12mm sensor bosses. Can we use something similar to the Herko blocks to get our samples?
2) How long is the sampling time, in order to get accurate readings?
3) Are there voltage outputs, for each gas, from the controller, that can be input into different dyno software? (I know I can add many extra channel inputs on my Superflow sensor box). Being able to record the gas readings against tq and hp (as I do now with O2), would be helpful.
4) What sort of cost are these analysers? I would need 2, one for each cylinder.
5) What is the maintenance requirement?
6) Do the sensors have a lifespan?
7) How are they calibrated?

The data output for the EGA is digital (not voltage) - so unless the software is specifically written to accept additional specific model language digital data streams, it's not possible. Each brand of EGA uses different commands and data format.
It's a huge, messy add-on software integration project.
The Factory Pro dynos were originally designed to use digital, not voltage, data and always had multi-gas EGA data.

Marc Salvisberg

[Powerglides]

Ok, thanks Marc, I would need to do more homework on this, then, so I could ask the appropriate questions.
Do you have answers to the other questions? I might add that I'm looking for reasons to consider going this route, rather than looking for reasons not to. I just need to understand all of the implications.

[mayor]

Anyway, the gasses, they are .... They are, CO (Carbon Monoxide), HC (hydrocarbons), CO2 (Carbon Dioxide) and last is O2 (Oxygen) .

Carbon monoxide is formed when a molecule of HC attaches itself to an O2 molecule and gets partially burned in the combustion process. The next gas is CO2 this gas is residual of the combustion event when a molecule of HC and O2 are completely burned up. Lastly, is O2. In the case of analyzing the combustion event, O2 can be a good indicator of whether you need to advance timing or not as well as give clues to the efficiency of the engines performance. The O2 may be an indication of how efficient the heads are working also or possibly if the injectors are not atomizing fuel enough to allow the HC molecules to mix with the O2 on a combustible level. Lots of these gasses can help clue you in to how the engine is functioning as well as diagnose combustion and efficiency issues. In any internal combustion engine, the more O2 you can get in, the more HC you can attach to those O2 molecules and the more power and efficient the engine will perform. Clean combustion is critical to power and longevity. Dirty or inefficient combustion can lead to excessive carbon buildup, fouled plugs and shorter engine life.

this is all very broad in theory, let's get more to the point.  As someone who has suggested that afr tuning isn't as up to the task as 4 gas when tuning, please feel free to give us the red meat.  What I want to know specifically is how is the 4 gas better than just looking at one of the 4?  what specific value are you trying to tune to, and how are the value different than if someone just tuned based on residual oxygen?

does all fuel delivery control in 4 gas tuning occur in the VE tables?  or is there some manipulation of the afr tables as well when adjusting the calibration to the 4 gas analysis?  If you are tuning both, how do you over come potential transients when bikes have a MAP based afr table and TPS based ve tables? 

in terms of afr tuning, I know that peak power can occur at a very broad afr range.  In terms of spark angle, I know that MBT can occur over a range of advances as well depending on the engine load.  Since there is only these two variables and both offer allowable deviations for the same results, how does tuning to four gas analysis going to improve the operation of the motorcycle?  do you typically see a cruise sweet spot limited to 1 degree of spark angle range?  do you typically see a sweet spot based on 1/2 VE value change?  I know one of the points that you posted is that running at stoich does not allow for maximum performance, but I doubt that there are many afr tuners who are running full load at stoich.  I also fall to see what you would want for cruise afr to be that far from stoich, since that is the most efficient use of the fuel.  How is tuning with 4 gas different in this aspect?

[strokerjlk]

This is the book by Adam Wade .
Bean recommended this book to me some years ago . Very good book BTW
If you two could ? When  you copy and paste from Adams book , could you make references to the page and chapter ? Those of us that have the book would like to read the quotes in there actual context .

[q1svt]

Not exactly sure what the first part of your post means. I didn't mean to suggest that 4 gas tells you all the problems with the engine if that's what you mean. It simply has more information to help clue you in to the efficiency or the engine. The CO helps with dialing in the VE tables (fuel) and gives insight to how rich or lean the engine is running. If I saw the bike was not pulling timing in the data and that the O2 reading is more than I'd like to see, that would give me a clue that I can advance timing to give the engine a chance to burn up that O2 before it slipped out the exhaust. If I was able to advance the timing, I might also see the CO drop now because the extra timing is also burning up the HC's that mix with that O2 we were trying to burn up. That's is a couple of scenarios that are common.

There are many factors that effect the combustion chamber turbulence 'Burn Rate' long before the tune [combustion chamber shape, piston shape, port/intake velocity, exhaust, etc.]... Engineers use 4+ gas analyzers to develop and test motor designs.  I'm not being critical, there are tens of thousand of Gas Analyzers in my state, we call them California Smog Stations.  Many of us would like to take advance of all the 4 gas dyno's out there.

Each Harley build is different in someway... so how do know what is a good baseline for the motor you're tuning.

Since each motor can very greatly in quality of the Burn Rate because of the parts involved, how do you know if it's the tune or the parts.

Many people talk about the benefits of this approach, but are short on details...

It would be helpful if you can share how you use the specific readout [CO (Carbon Monoxide), HC (hydrocarbons), CO2 (Carbon Dioxide) and O2 (Oxygen)] to know what to change for the parts of a tune you have some control over... Timing, Head Temperature and Air/Fuel mixtures.  Actual before and after readouts and the corrected measures you took.

Edited: FWIW, 4 gas is used many times a day throughout out the state to find and correct problems with a motor...
http://www.autoshop101.com/forms/h56.pdf

[hrdtail78]

4 Gas EGA

With multi-gas information, you get hints and clues about what you might do to improve tuning.

Like Independent 1 said, the different gases highlight potential avenues by which to improve the tuning process. The quicker the tuning goes, the more time can be allotted to fine tuning detail, like in town cruise smoothness and highway cruise mileage.

If, when making Best Power at some point, the CO is "in the hunt, but kinda on the low usual side" and O2 is "kinda on the high side" when making best power, that's like a flashing sign that you should try a couple degrees more timing and richening a bit and recheck. And repeat.

At some point, you'll get no more power when advancing another 2 degrees and you'll check the Best Power fueling and be confident that you will lose power if you adv or retard the timing or if you richen or lean the fueling.
Basically, you are at the peak of the "Bell Curve"

It takes WAY longer to describe it than actually do it.

Process (at least in my head). We'll describe a power commander (as it's easier to describe).
Example: Testing 3000 rpm, 100% throttle
Roll throttle on, dyno holds the engine at 3k.
Hold for 5-7 secs.
Dyno records hp and 4 gas info.
Look at hp and gas, Looks a bit low in co and high in O2.
Add 4 fuel numbers to 3k/100% TH in the pc.
Test again.
Power goes up? Add another 4 fuel numbers.
Power goes up? Add another 4 fuel numbers.
Power goes down? subtract the last 4 fuel numbers.
There.
You have Fuel Best Power.

Now look at the 4 gases.
If co is kinda low, and o2 a bit high,
Add 2 to ign, Better? Add another 2 ign,  better? Add another 2 ign.
Worse? Subtract that last 2. That's within 1 degree of perfect.

A 2 degree change in ignition timing makes about a 1% power change

Now, add 4 numbers of fuel and power will prob go up a bit.
Repeat till power doesn't increase when richening

Now, after finding out how much fuel and ignition timing the engine wants, you have the Best Timing and the Best Fuel and Best Power.

It can't be too lean or too rich or to advanced or retarded - or it would make less power.

Now, when at Best Power, you can, once again, look at the CO, HC, CO2 and O2 get a clue as to how happy the engine package contents are.
If it makes best power at relatively low HC numbers, then you are pretty sure it's a well balanced set of components and combustion chamber.
Suspicious points, like full throttle / 2500 rpm, that require lots of leaning and still have extra o2 in the exhaust and a torque dip, are likely to have an unhappy cam / head / exhaust choice.

High HC numbers, when done tuning, can make one suspicious of excess piston to head squish cl, poor injector condition or inefficient ignition.

There are other things that can be inferred from reading 4 gases, too.

It's like having three extra tools to tune with.

Marc Salvisberg

How is the transition from steady state tuning to transition state performed?  IE accel table activated.

I never understood that about the books.  The Denish books went away and now they are $2?? also. 

[1931jamesw]

I'll try to post up a sheet of sampling a from a tune so you can see the information I work with after making a run and using that information to make the adjustments. As far as the information I posted being general, Mike, I wanted to start out with the basics so everyone has a good foundation of the fundamentals of tuning this way. Bean is a fabulous mechanic and tuner and he could really help here too as well as springer but neither care to spend time posting in a public setting like an open forum on a topic that gets so specific. Marc that has already posted here is Factory Pro and he is very intelligent also. Hopefully he will stick around for the life of this thread. I don't think for some reason that he is notified when a new post is made but I'll try to keep him up to speed on the thread if he falls out. As for the book, stroker, as you know, it contains a lot of the general information like I have posted on the gasses. I basically tried to post what the information regarding the gasses are from the book but only from memory of the book. I didn't quote anything from the book. If I remember right I think there is a chapter on combustion chemistry so that is where you could reread te information if you have already read the book. Boz, I am using my phone to reply in this particular post so I can't remember all your questions and since this thread has come up, I do want to try to let everyone who is interested get a better understanding and not just dodge questions or leave anyone hanging but as for the question about closed end caps or mufflers that you can't put te sniffer up the tailpipe, I use rivnuts a lot of times and just drill the headers out near where the O2 sensors used to be on like say an 09 model Bagger except on the outboard side like I see you guys do with the Herko blocks. Mike, back to you, I want to get to the red meat also, please bear with me. As for the post about stoich in the WOT areas, incompletely understand that and I would think any tuner worth their salt wouldn't do such a thing. I hope we don't get into a bantering about O2 tuning vs EG tuning. That's not what I would like to see this thread turn to but I understand that there will be legitimate analogies and comparisons of one vs the other. That said, you guys that are involved here in this thread already know more about O2 tuning than I so it will take effort from both sides to get this thread shaping up the way I intended for it to. That said Marc does have a good understanding of both and he will be an asset to this thread because of that. Real quick on qsvt1, the 4 gas analyzing can't repair inefficient engines but it can give you all of the information to let you tune any combination of parts and give you good clues about where an engine could be improved. I know that's pretty vague but that's the answer. It is not some kind of magic wand that can helps guy tune a bike with let's day a crappy exhaust and make it run as if it doesn't have a crappy exhaust. And oh yeah, Mike, back to you, the VE's do dictate fuel metering at least the way I do it. Maybe Marc does something different.  Did that answer your question on that? Seems almost too simple of an answer to the question so I'm not sure I did but I didn't know there was really any other way to meter the fuel. And as for the changing the VE's in half point increments, I do that sometimes, yes, it does effect te gas readings by doing so but as you stated about tuning AFR, these antiquated Harley engines sometimes don't really change much in power by not having the fuel set perfect but all of the details in a tune add up in the final map you load and they do seem to run smoother by getting the fuel perfect but it does take some extra time and patience sometimes to tune one that tight. As you might imagine, some of the higher performance motors do respond better with the real fine tune but some of the lower performance stuff doesn't seem to be as critical. All of the parts on the bike, exhaust being a huge factor usually make a big impact on how the bike turns out if you take the tune out of the equation. I have used the Power Vision now a couple times and the resolution it has with the .1 change ability in the VE's really just seems like a ridiculous pissing contest among the tuner manufacturers but on my own personal bike if I were using the vision and I had nothing better to do and I wanted to tune on my bike, I might play around with those but its really starting to get to splitting hairs that have already been split. Maybe some of the import stuff with newer technology in the design of their engines respond better to the super fine adjustments.

[Soft 02]

Over my head but a good read.

[marc99]

Ok, thanks Marc, I would need to do more homework on this, then, so I could ask the appropriate questions.
Do you have answers to the other questions? I might add that I'm looking for reasons to consider going this route, rather than looking for reasons not to. I just need to understand all of the implications.

Hi  -

It's a different test procedure than a dj style sweep test.
Instead of doing sweeps and using a preselected AFR as a goal, you target an rpm point and optimize that rpm area. Then move to a different area.

The 3 extra "gases" provide information that can tell the tuner that he should look at other things, like ignition timing.
There are gas number relationships that indicate that the ign timing is pretty much probably right.

We build the EGA's to be high speed and to have a robust duty cycle and multiple, high capacity filters. The EGA's are expensive, $7000 - $8000 - and due to the cost, you can see why other dyno companies encourage the use of $100 wideband sensor as the other choice for tuning.

The only sensor that has a useful published periodic lifespan is the O2 sensor. About a year and it tells you on our dyno software that it's reaching the end, based on zero offset values.. It still zeros and reads right, but nags that it needs to be replaced.
Not affected by leaded fuels and zeros itself on boot-up. The other 3 "gases" are determined with a infrared spectrometer and sensors don't get consumed.
Clean filters every 100 hours or when readings are sluggish.

I'm not familiar with Superflow's o2 sensor zeroing / replacement procedure.

Marc Salvisberg

[marc99]

Where 4 gas provides insight on the build, most people are not going back into their motor to correct design short comings... It would be helpful if you can share how you use the specific readout [CO (Carbon Monoxide), HC (hydrocarbons), CO2 (Carbon Dioxide) and O2 (Oxygen)] to know what to change for the parts of a tune you have some control over... Timing, Head Temperature and Air/Fuel mixtures.  Actual before and after readouts and the corrected measures you took.

Engine build:
As unpopular as it might make the tuner with the engine builder, it's personally comforting to be able to confidentially relate that that torque dip at full throttle/2500 rpm is absolutely due to the choice of engine components. Then the engine builder knows to, generally, pick another cam on his next similar build.

Who am I fooling? 50% of engine builders will tell the owner that the tuner doesn't know how to tune...

[q1svt]

 
So please explain how using one of your Factory Pro Dyno's with 4 Gas analyzer will tell me [the tuner]  if the dip is the Cam or Exhaust choice?

Actually I no longer care since I feel the thread is more about Indy1 helping you sell your product.  Personally if that's your goal then you should pay your dues and become a Vendor. 

[1931jamesw]

I was asked by multiple members of this forum to post on 4 gas multiple times before I finally did. I am not trying to sell dyno's and I don't see anything in Marc's post that would suggest that he is.

[marc99]

It's like having three extra tools to tune with.

Marc Salvisberg

How is the transition from steady state tuning to transition state performed?  IE accel table activated.

In all the tuning that I've done and the plethora of different brands, types and versions of software, they all based the "acc mode" on top of the "base" (steady state) fuel map.
There needs to be a "foundation" for acc enrichment % or offset amount.
Need to build that main fuel foundation table first.

Then, you can do whatever your tuner's heart wants to do with the acc enrichment algorithm or acc table (if present).

How do you tune an acc table?

One of the occasional issues with doing quick sweep tests on an inertia dyno is that a high hp bike can acc so quickly that the "acc mode" can kick in during a test and the tuner might not realize it unless they did steady state testing, also. They'd lean out the main fuel map to make the AFR right. I think that noticeably happened on a Honda VTX.