Street tuners..

[aaron.amrace]

How do all you guys who street tune, tune the AFR without a wideband? I have seen a couple local people who street tune all there cars but i was wondering what they used to get there AFR close.

[gn2beatu]

Allot of street tuners tune thier WOT to .890mv on the O2's. I dont like tuning without a wideband and personaly will not do it. The narrow bands just arent accurate enough. At 890mv my AFR is in the high 11's and too rich. But every car will be a little differant. So I guess if your going to err, err on the rich side. Not worth a motor for a $200-$300 wideband in my opinion.

[SSUte01]

Without a Wideband or EGT sensor(s) or some other method of measuring AFR, the simple answer is at any other than stoich they aren't measuring; they are guessing and even at lambda once headers are added or sensor location changed factory sensors can (not always) become inaccurate.

[sarg]

I use a wideband on street and dyno. A LC-1 is less than $200 which is cheap insurance for your $4000+ motor.

[HoP]

To answer your question :

For Part Throttle Operation :

You fail the maf or put the car in OL then you tune the VE up to 4000 rpm's or so based off of LTFT error. Then once the VE has been established to within an error of + or - 5% you put the car into CL disable the LTFT and tune the MAF as close to 0% maybe to -1% up to 7000hz.

Tuning part throttle operation off of the narrow bands is fine as long as they are in good working condition. Trying to tune WOT with a narrow band is not recommended use a wide band O2 for that.
A lot of old tuners would use a narrow band measurement say .900 at WOT for an AFR of 11.2:1, realistically the O2 could be off and your final AFR could actually be 12.8:1 and that's not good for forced induction motors.

But if you are not checking your wide band O2 for proper calibration your just doing the same thing.......assuming.

[LSxpwrdZ]

To answer your question :

For Part Throttle Operation :

You fail the maf or put the car in OL then you tune the VE up to 4000 rpm's or so based off of LTFT error. Then once the VE has been established to within an error of + or - 5% you put the car into CL disable the LTFT and tune the MAF as close to 0% maybe to -1% up to 7000hz.

Tuning part throttle operation off of the narrow bands is fine as long as they are in good working condition. Trying to tune WOT with a narrow band is not recommended use a wide band O2 for that.
A lot of old tuners would use a narrow band measurement say .900 at WOT for an AFR of 11.2:1, realistically the O2 could be off and your final AFR could actually be 12.8:1 and that's not good for forced induction motors.

But if you are not checking your wide band O2 for proper calibration your just doing the same thing.......assuming.

Wrong...
OL/CL has NOTHING to do with SD(VE) or MAF. It is a routine of whether the PCM references the narrowband o2's for fuel trimming.

Without a wideband or a good plug reader you are shooting blind for WOT fueling much less timing (because adjusting the airflow tables will also effect cylinder airmass and effect ignition timing).

If you want to tune partial throttle fueling without a wideband by using the stock narrowband o2's then you need to put the tune in either MAF or SD mode only to calibrate one or the other at a time. If the PCM is still running SD/MAF mixed like stock then how do you know which airflow table to calibrate? To setup the narrowbands to tune the easiest I always use STFT and disable LTFT. This way there is only one correction at a time getting calculated. Plot the % on whichever airflow table histogram you are calibrating and I always multiply %-half because it always seems to me the percentage the narrowbands spit out are usually on the high side of things. Do a few drives and hit as many cells as possible with the smoothest throttle transitions as possible and eventually you will get it to within 1-2%. If you get it that close then call it done cause the narrowbands will vary as much or more than that much with its readings.

[oakley6575]

I tuned my part throttle VE up to 4000rpms by putting the truck in SD mode, as stated above, and it worked great. I got all my trims under 2%. I would never tune WOT without a wideband but part throttle tuning was easy and effective using the narrow bands.