mr_munro

http://www.hondata.com/techenginetuning.html


I dont really understand it. Where it says

"-Tune for 14.7 from column 1-5, and 6 for 13.6 up to VTEC or 6k or so"

If he says this, what is the need for a dyno? Cant you enter the values in stated above for an near stock NA engine with basic bolt ons, and your car is already partly tuned for running a good set of AFRs? Forgive me for the noobness but i'm going over MANY articles on tuning basics.

Another thing i dont get with that article demo, is why ISNT he making the mixture LEANER as he goes up the thorttle position columns? Wouldnt a leaner yield the engine more power/torque, hence colums 6 and up should be greater than 14.7 to maybe in the 15 range? Also where are these figures coming from, the o2 sensor that reports back to the ECU? Does this mean if o2 sensor is not operational or non existant, no AFRs would appear on the matrix?

ddd4114

Lean mixtures make less power. Burning fuel makes energy, so if you burn less fuel per cycle, you make less power. You make the most power when you can use all oxygen in the cylinder, which generally occurs when the mixture is 10%-15% rich. There are some exceptions though.

Those AFR targets are just rules of thumb. They won't necessarily be best for any engine and application. The only definite is that you'll need to target 14.7 at low-mid load if you need to pass an emissions test that measures NOx.

All of these AFR measurements can only be obtained by using a wideband oxygen sensor and controller, such as the Innovate LC-1, NGK AFX, AEM UEGO, etc.

mr_munro

Ah ok that sums that up.
Ok, so that takes car of colums 1-5 say. I guess i won't be able to determine the other figures until i go to a dyno then to check the engines power?

So if i plug the ECU into my laptop AT HOME and disable closed loop, does this disable the o2 sensor sending information to the ECU and i wont have any AFR figures in the matrix?

ddd4114

The rules of thumb are fine at first. AFR doesn't affect power that much as long as you're ballpark correct.

Disabling closed loop just disables feedback, not the oxygen sensor reading itself.

mr_munro

Ok so if i can get readings from the o2 sensor, then why is a wideband necessary? I mean, can the car still be tuned without a wideband?

ddd4114

No, look up the difference between a wideband and a narrowband oxygen sensor.

mr_munro

Ok i see the wideband being more accurate as it reads 0-5v. I ask because i just wanted to have a look at the figures and see how the change under throttle in my driveway. I will not need to purchase 1 as my tuner has one built into the dyno.

My understanding is it replaces the o2 sensor. But some forums read that you only need the wideband in for tuning and you disconnect it after the tune and replace with the o2 sensor. Does that sound right?

ddd4114

I would really encourage you to read a lot more about this subject, because it has been covered in great lengths many, many times before. A quick Google search will give you a lot of information about this.

mr_munro

Yea will do and have been, they just give me the same information, thanks.