While I tickled the Knock sensor, I'd consider this pretty close.
Leaving from an idle, 3/4 throttle, ~20 PSI, 0-60 5sec., 91 octane.


**BTW, for those that think the osm Os sensors are good for more the stoich, take a gander at what thry're doind here.


TimeStamp: 12/09/2004 - 10:41:41

Run Mph Rpm Map VE% Tps CTS MAT O2 Sa Rt DC% AFR rrWB
:47 0 2000 102 88 60 171 95 628 28 0 12 12.5 10.5
:47 4 2050 102 87 61 171 95 783 28 0 13 12.5 10.4
:47 4 2125 104 85 61 171 86 819 29 0 13 12.5 10.6
:47 4 2175 105 83 63 171 86 757 29 0 13 12.5 11.7
:47 7 2275 109 81 63 171 86 650 29 0 14 14.7 12.8
:47 8 2325 110 80 63 171 86 633 29 0 14 12.5 12.6
:47 12 2375 113 79 63 171 86 704 30 0 14 12.5 12.8
:47 12 2425 115 79 63 171 86 562 30 0 15 12.5 13.1
:47 12 2475 116 80 63 171 86 646 30 0 16 12.5 13.2
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa Rt DC% AFR rrWB
:48 12 2550 119 81 63 171 86 761 30 0 17 12.5 13.1
:48 15 2625 123 82 63 171 86 650 27 2 18 12.5 13.0
:48 13 2700 125 83 63 171 86 473 27 2 19 12.5 12.9
:49 33 3500 198 80 46 171 77 504 21 2 40 12.5 12.9
:49 35 3550 205 80 52 171 77 465 20 2 42 12.5 12.5
:50 37 3700 228 80 74 171 77 597 14 4 50 12.5 12.2
:50 39 3725 232 80 74 171 77 606 14 4 51 12.5 12.8
:50 40 3750 234 80 74 171 77 757 14 4 53 12.5 13.0
:50 40 3775 234 80 74 171 77 513 15 4 54 12.5 12.5
:50 41 3850 236 80 74 171 77 633 14 4 55 12.5 12.6
:50 42 3875 237 80 74 171 77 606 15 3 56 12.5 12.6
:50 44 3925 238 80 74 171 77 690 15 3 56 12.5 12.4
:50 45 3950 238 80 74 171 68 580 15 2 57 12.5 12.6
:50 46 4000 239 80 74 171 68 513 15 2 57 12.5 12.5
Run Mph Rpm Map VE% Tps CTS MAT O2 Sa Rt DC% AFR rrWB
:51 47 4050 239 80 74 171 68 650 15 2 59 12.5 12.8
:51 47 4050 241 80 74 171 68 549 15 2 59 12.5 12.6
:51 48 4050 241 80 74 171 68 735 12 6 60 12.5 12.4
:51 49 4050 242 80 74 171 68 730 13 5 60 12.5 12.3
:51 49 4100 243 80 74 171 68 655 13 5 61 12.5 12.1
:51 51 4100 243 80 74 171 68 664 13 4 61 12.5 12.3
:51 52 4150 243 80 74 171 68 491 13 4 62 12.5 12.2
:51 53 4175 244 80 74 171 68 513 14 4 62 12.5 12.2
:51 53 4225 244 80 74 171 68 584 14 4 63 12.5 12.7
:51 55 4300 246 80 74 171 68 509 14 3 65 12.5 12.1
:53 66 3575 247 80 73 169 68 473 13 4 54 12.5 12.4

All I can say is that you're about a full point leaner than I'd try at 20 psi.

I've seen O2s go limp with heat. Do you have an EGT in your exhaust somewhere? Just curious.

Actually, in the past few runs, when the WB was leaner then the commanded, there was less knock.

Yes, but the O2 sensors are far enough back to be too greatly influenced by EGT.

does it run good ??? if so then the AFR isnt the only thing that matters. at least AFR as observed by the WB02. while the WB02 is a useful tunning tool knowing the amount of air vs quantity of fuel actually dictates the actuall pre combustion afr. remeber the wb02 monitors post combustion afr and that often enough due to changes in timing etc may not be as accurate as we would like.

No fair having the MAP go over 100

thanks for sharing

Yes, but, intially tuning the numbers to match, gives, a baseline, and then to change things, a quick change of the PE commanded AFRs make tuning alot easier then trying to go thur and match %'s to get to where you want.

Seems fair to me

200 is where it just starts being fun, the 300 mark is when things get real interesting..

im not going to dispute that point. its a good solid way to acomplish the goal. i was simply reffering to the interaction between actuall AFR and wb02 derived afr. it is something to keep an eye on.

Are they heated sensors?

Looks like fun but I wonder what 200kpa would feel like with 2 more cylinders and more cubes .

Is it time to test out the alky?

That might be ideal if you were into research but for tuning a car it's not necessary. Remember the wideband get's you in the ballpark and even though it doesn't represent the pre-combusted AFR exactly it is still proportional! That's all that matters. Nobody should be tuning their cars for an AFR, they should be tuning them for real world work, like ET, or gas milage.

well its not really proportional unless there is good combustion.

Yes it is. Unless you have a tune that takes out 30 degrees of timing at 3000rpm and then adds it all back in at 3200rpm. Then it might hickup but the same could be said about an o2 sensor dragging on the ground behind the vehicle... wouldn't be proportional there either .
Obviously there has to be good combustion but it doesn't have to be great, it just needs to combust meaning it can't be so lean that it doesn't ignite. We already talked about this. If you're engine likes cruising with AFRs so lean that you get a misfire then upgrade your ignition system to a CNP setup and go some more.
The idea is that with a mechanically sound motor the wideband WILL be proportional to the desired AFR.