Re: Single channel O2
 

I have a carb and they have a accessory for RPM. I'm putting that on when I do the second sensor.

Re: Single channel O2
 

That will make it a lot more useful. I know a couple of guys that need that RPM add-on. Guess it's fairly new?

Re: Single channel O2
 

It hasn't been out long. Check their website. I think it's $160 bucks.

Re: Single channel O2
 

How accurate is rpm pickup? My car isn't running yet so I haven't been able to compare it to the tach. I'm actually useing 2 on a siamised port chevy six with a turbo.

Re: Single channel O2
 

Harry_ i am trying the RPM sensor, egt, and oil pressure sensor now. I am recording off the ignition for tach and comparing it to the dyno rpm which I know to be accurate. I also have scope hooked to it to see also. I will know by end of week after more "testes". Price is reasonable. I have 5 of everything here now just to try. I have it hooked in with a FAST, A INNOVATE, NGK. and 4 of these so I can how it compares with each other. I will data log to the PC so I can map in Excel to make a chart/graph. I will PM you with results.
http://14point7.com/Products.php

Re: Single channel O2
 

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.

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?

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. :~)

Re: Single channel O2
 

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)?

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