This is a graph of target AFR, vs WBO2 measured AFR, and knock. In third gear just before 7000 rpm WBO2 starts to climb up away from target AFR, getting leaner. You dont see it in 4th gear since I only go to about 7000 rpm to reach the 126 mph trap speeds.

Here is another graph of the same type but for the following run at 29 psi. As boost/fuel pressure go up, pump flow rate goes down. The gap in 3rd is wider. 4th is about the same, except for the odd behavior at the end of the gear. By then the motor was blown (compression 0-50-0-200, spark plugs from 1 and 3 missing electrodes and insulators) and the water pipe blown out of the pump. The car was stumbling there as I lifted. This was the 11.3 at 126 pass. At the top of third gear WBO2 has gone to 13.5 to 14:1, yet there is still no knock (117 octane) The knock at the beginning of gear is just from the no lift shifting, which I didnt do in the above run (12.0 @ 126). At any rate, it seems the pump is out of flow capacity.

This is the same graph but with both the 27 and 29 psi WBO2 graphs overlaid. You can see that its leaner at the top of third, yet I made no changes to the fuel settings. 4th gear is also noticeably longer. The additional 2 psi of boost didnt help, since the motor completely croaked on the top end, 1-200 feet before the traps. And it would seem it didnt go to hell until the very end, based on the 1/8th speed of 97.75 and quater trap of 125.95, about what I would expect from a half track speed of 97 on my car.

I decided to do some math using flow rates from the 255 LP, 255 HP, and the Aeromotive that I was going to run inline. The 255 lp moves 50 gph at 70 psi rewired. Thats about 300 lbs/hr. At 13:1 AFR, thats 3900 lbs/hr of air, or 65 lbs/min. I measured 64.x on the last run where I ran out of fuel. Damn, thats almost right on. I was actually closer to 12.6-12.8:1 so it would start to climb at a lower airflow rate than 65. Very interesting. On the 27 psi run I was only moving 62 lbs/min. If I had a 255HP, I would be all set at my current airflow... Just for shits and grins, the 255hp under the same conditions above would have been good to 75 lbs/min, 10 more than the standard pump. The Aeromotive would be good to 100 lbs/min airflow at 70 psi, and 83 pounds per minute at 80 psi.

Here are some pics of the carnage. The cyilinders that had missing sparkplug parts were absolutely wrecked. Same thing as the last time a spark plug came apart on the stage 2 block. The porcelain was embedded in the flat portion of the head, and the piston top in that area was demolished. In the pic of piston #1 below, there is a crack at 9 oclock, you can just make it out. Cylinder 4 looks great (still had 200 psi compression). Head gasket was beat up, but wasnt obviously blown in any one spot.

I have been saying for years that my front O2 is always in the .96 to .98 volt range when the wideband is 10:1 to over 13:1. Here is a screen capture from the above log that illustrates this.