Single channel O2

Michael Beard · 07-12-2011, 10:54 PM

Quote:

Originally Posted by Danny Ashley

I have racers call and ask what number to look for and I tell them there's no magic number for everyone. I have customers that range from 12.8 to 13.6 each with fast cars. When you get a wide band Dan, you'll need to go to a test session and work on calibrating your Q-Jet to run the fastest and that will be your "Sweet Spot". Then when you get in different weather conditions your wide band will tell you if you need to lean or fatten it up.

x2! I'm brand spankin' new to EFI, just off my 3rd weekend out. Even if someone runs the same combination as you, there can be something different in either the data collection (type or location of the sensor) or other variables that make things radically different. Ultimately, you have to listen to what the car is telling you on the race track to determine what A/F ratio works best for YOUR setup. Took me til 1st round of eliminations this weekend to figure that out! LOL In the ballpark now, though. I still have a TON of learning to do. One of my issues right now is that I have no basis for what the numbers mean relative to each other. Is half a point in A/F ratio a lot, .25, or is a full point a big swing? Along the same line, I'll need to figure out how much change a single number or single percentage point on the fuel table really is.

Ed Wright · 07-13-2011, 08:59 AM

Michael, if your VE table & injector flow rate are setup correctly a 1% change will get you a .1 change in air/fuel. For instance: +.1% will change 13.0-1 to 12.9-1, or -1% would make 13.0-1 to 13.1-1. If your 13-1 and want 12.5-1 subtract 5%. Are you using FAST XFI, or BigStuff3?

Adger Smith · 07-13-2011, 10:39 AM

Michael,
There are sooo... many varaibles in tuning with O2's. I really agree with the idea that there is no "one" number for every combination. Cam overlap is one of the biggest players in what goes out the ex pipe, even low compression vs high compression will make a slight difference in the best O2 number.When you change cam C/L or valve lash or timing on your own combination that you are familar with and have data.. the O2's can change, usually do. The new O2 reading may or may not be the place the engine is happy and making peak power. The old O2 point may not be the best power setting with the changes. You have to search the combination/tune up for what makes the engine happy. A happy engine will usually make you happy because it is making power.
Oh, Please Read the plugs when making changes.... (don't be lazy.. does a plug wrench still fit your hand?) I know, I know it is so easy to take a reading of the data and pound that key board to make changes,,,, but reading the plug is the way to tell what is really going on in the combustion chamber. :~)

Charles Rainey · 07-13-2011, 12:43 PM

Adger
I feel as you and others have stated, that there are so many variables, you cannot compare any two motors. What I like to do is have two (2) O2 sensor. One on each side. I do make sure they read the same side too side. But I also like to have at least one EGT on a cylinder that tells me when I have gone unresonably lean. I read spark plugs to keep me honest, but reading spark plugs, is very subjective from one person to another. And on top of that I have customers that just flat cant read spark plugs for crap. So I try to give them as much data as they can download and see. I tell them to always start out rich and lean down and watch time slips. When you get there, write down both EGT and both O2 readings. All this data are nothing but indicators. They are not the Bible. Some of it is scientific and some is black magic. It can mean the difference in .01 and .1 on the time slip.
sorry my .02 worth

Michael Beard · 07-13-2011, 11:25 AM

Quote:

Originally Posted by Ed Wright

Michael, if your VE table & injector flow rate are setup correctly a 10% change will get you a .1 change in air/fuel. For instance: +.10% will change 13.0-1 to 12.9-1, or -10% would make 13.0-1 to 13.1-1. Are you using FAST XFI, or BigStuff3?

FAST XFI. Currently running in Alpha-N, closed loop, Target A/F at 12.5. Got it to 13.3 on Run #3 of the weekend at MIR, and it wouldn't get out of it's own way.

Question is, is 13.3 to 13.2 a big jump, is 13.3 to 13.0 a big jump, or is 13.3 to 12.5 a big jump? How much is 1,000' DA change likely to affect the A/F ratio (ballpark)?

Ed Wright · 07-13-2011, 01:29 PM

Quote:

Originally Posted by Michael Beard

FAST XFI. Currently running in Alpha-N, closed loop, Target A/F at 12.5. Got it to 13.3 on Run #3 of the weekend at MIR, and it wouldn't get out of it's own way.

Question is, is 13.3 to 13.2 a big jump, is 13.3 to 13.0 a big jump, or is 13.3 to 12.5 a big jump? How much is 1,000' DA change likely to affect the A/F ratio (ballpark)?

Michael, 12.5 to 13.0 is a big jump. If you want to email me your calibration file (.gct) file and a log file of a run using it, I can probably put it to, or very close to, 12.5-1, then email it back to you.

Dan Fletcher · 07-13-2011, 02:54 PM

Thank you very much to everyone for the input. I decided to go the Racepak direction through Greg Kelley at Motor Sports Innovations. He came highly recommended from everyone I spoke to, and my phone conversations with him have been outstanding. I'm certainly looking forward to getting the system installed and finally getting my stocker lined out. I know from the comp car how valuable the Racepak is, so even though I'm only getting the Sportsman version, I'm really excited to start acquiring data. Obviously, I'm a moron for not having one before. Now I just need to break down and get one for the poor SS car...LOL...

Thanks again to all...

billy leber · 07-13-2011, 04:02 PM

Obviously...

Chad Rhodes · 07-13-2011, 04:06 PM

Quote:

Originally Posted by Dan Fletcher

Thank you very much to everyone for the input. I decided to go the Racepak direction through Greg Kelley at Motor Sports Innovations. He came highly recommended from everyone I spoke to, and my phone conversations with him have been outstanding. I'm certainly looking forward to getting the system installed and finally getting my stocker lined out. I know from the comp car how valuable the Racepak is, so even though I'm only getting the Sportsman version, I'm really excited to start acquiring data. Obviously, I'm a moron for not having one before. Now I just need to break down and get one for the poor SS car...LOL...

Thanks again to all...

Dan, with your record ( and the one our kids are quickly acquiring ), I don't think anyone can call you a moron.

Adger Smith · 07-13-2011, 04:24 PM

Charles,
You hit the nail on the head with your last post.
It is just Data....not written in stone... I like to use the EGT cross reference along with reading plugs. As far as customers being able to read them you are right.. Some know a little about it some know a lot and some know a lot less than they think. Most of my customers/friends are told to learn as you go. Look at the plug and make a change you think is correct (that all other data suggests). Then after the tune up change look at the plug and see what changed. They should learn trends and what to expect. Like you said...Reading the plug Keeps the tune up honest..
Let's talk "Air" ...
Someone has mentioned DA, a lot. Well I'm not so sure all your faith should be put in DA. Doesn't everyone know you can get the same DA by having several totally different conditions? (Baro, Vapor Pressure, Humidity, Temps, ect..) It's when the conditions change that the engine goes from lean or rich or rich to lean. A good carb tuner knows he has a slight window that the carb will take care of when conditions change, a little, but not when they move a lot. I've always worked with mechanical FI that is Stupid. It only changes when you make the change or the pump is going away and you loose pressure, volume or both.....
This could be a good discussion..
OK What you guys say???
Beard, do you remember when we got bitten when we forgot to monitor the vapor pressure? :~)

07-13-2011, 08:59 AM	#2
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Single channel O2 Michael, if your VE table & injector flow rate are setup correctly a 1% change will get you a .1 change in air/fuel. For instance: +.1% will change 13.0-1 to 12.9-1, or -1% would make 13.0-1 to 13.1-1. If your 13-1 and want 12.5-1 subtract 5%. Are you using FAST XFI, or BigStuff3? __________________ Ed Wright 4156 SS/JA Last edited by Ed Wright; 07-15-2011 at 06:06 AM.

07-13-2011, 12:43 PM	#4
Charles Rainey Junior Member Join Date: May 2011 Posts: 40 Likes: 0 Liked 0 Times in 0 Posts	Re: Single channel O2 Adger I feel as you and others have stated, that there are so many variables, you cannot compare any two motors. What I like to do is have two (2) O2 sensor. One on each side. I do make sure they read the same side too side. But I also like to have at least one EGT on a cylinder that tells me when I have gone unresonably lean. I read spark plugs to keep me honest, but reading spark plugs, is very subjective from one person to another. And on top of that I have customers that just flat cant read spark plugs for crap. So I try to give them as much data as they can download and see. I tell them to always start out rich and lean down and watch time slips. When you get there, write down both EGT and both O2 readings. All this data are nothing but indicators. They are not the Bible. Some of it is scientific and some is black magic. It can mean the difference in .01 and .1 on the time slip. sorry my .02 worth

07-13-2011, 02:54 PM	#7
Dan Fletcher Sponsor Join Date: Feb 2006 Location: Churchville, NY Posts: 493 Likes: 129 Liked 1,045 Times in 70 Posts	Re: Single channel O2 Thank you very much to everyone for the input. I decided to go the Racepak direction through Greg Kelley at Motor Sports Innovations. He came highly recommended from everyone I spoke to, and my phone conversations with him have been outstanding. I'm certainly looking forward to getting the system installed and finally getting my stocker lined out. I know from the comp car how valuable the Racepak is, so even though I'm only getting the Sportsman version, I'm really excited to start acquiring data. Obviously, I'm a moron for not having one before. Now I just need to break down and get one for the poor SS car...LOL... Thanks again to all... __________________ Dan Fletcher 1781 STK, SS, COMP, SG, SC DAN FLETCHER TRAILER SALES

07-13-2011, 04:02 PM	#8
billy leber Member Join Date: Apr 2009 Location: most places Posts: 211 Likes: 0 Liked 10 Times in 1 Post	Re: Single channel O2 Obviously... __________________ Billy Leber 1150 SS, 1050 SG, 1962 STK, 185 SC

07-13-2011, 04:24 PM	#10
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Single channel O2 Charles, You hit the nail on the head with your last post. It is just Data....not written in stone... I like to use the EGT cross reference along with reading plugs. As far as customers being able to read them you are right.. Some know a little about it some know a lot and some know a lot less than they think. Most of my customers/friends are told to learn as you go. Look at the plug and make a change you think is correct (that all other data suggests). Then after the tune up change look at the plug and see what changed. They should learn trends and what to expect. Like you said...Reading the plug Keeps the tune up honest.. Let's talk "Air" ... Someone has mentioned DA, a lot. Well I'm not so sure all your faith should be put in DA. Doesn't everyone know you can get the same DA by having several totally different conditions? (Baro, Vapor Pressure, Humidity, Temps, ect..) It's when the conditions change that the engine goes from lean or rich or rich to lean. A good carb tuner knows he has a slight window that the carb will take care of when conditions change, a little, but not when they move a lot. I've always worked with mechanical FI that is Stupid. It only changes when you make the change or the pump is going away and you loose pressure, volume or both..... This could be a good discussion.. OK What you guys say??? Beard, do you remember when we got bitten when we forgot to monitor the vapor pressure? :~) __________________ Adger Smith (Former SS)

07-13-2011, 10:39 AM	#3
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Single channel O2 Michael, There are sooo... many varaibles in tuning with O2's. I really agree with the idea that there is no "one" number for every combination. Cam overlap is one of the biggest players in what goes out the ex pipe, even low compression vs high compression will make a slight difference in the best O2 number.When you change cam C/L or valve lash or timing on your own combination that you are familar with and have data.. the O2's can change, usually do. The new O2 reading may or may not be the place the engine is happy and making peak power. The old O2 point may not be the best power setting with the changes. You have to search the combination/tune up for what makes the engine happy. A happy engine will usually make you happy because it is making power. Oh, Please Read the plugs when making changes.... (don't be lazy.. does a plug wrench still fit your hand?) I know, I know it is so easy to take a reading of the data and pound that key board to make changes,,,, but reading the plug is the way to tell what is really going on in the combustion chamber. :~) __________________ Adger Smith (Former SS) Last edited by Adger Smith; 07-13-2011 at 10:52 AM. Reason: SP

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