When I log, MAF flow shows a few spots where there are dips. Nothing else odd going on at those points in terms of timing, knock/retard or mixture. Stock head/TR224 car. Normal ? Searched for other logs to compare but didn't find much. Appreciate anybody taking a look at their logs.

MAF O2s RPM

32.11 0.92 0.91 4811.5
32.11 0.92 0.91 4811.5
32.11 0.92 0.91 4926.8
33.64 0.91 0.91 4926.8
33.64 0.91 0.91 4926.8
33.64 0.91 0.91 5070.8
35.41 0.91 0.91 5070.8
35.41 0.91 0.91 5070.8
35.41 0.91 0.91 5217.3
33.23 0.9 0.92 5217.3
33.23 0.9 0.92 5217.3
33.23 0.9 0.92 5378
34.37 0.91 0.9 5378
34.37 0.91 0.9 5378
34.37 0.91 0.9 5543
38.87 0.91 0.9 5543
38.87 0.91 0.9 5543
38.87 0.91 0.9 5680.5
39.96 0.91 0.9 5680.5
39.96 0.91 0.9 5680.5
39.96 0.91 0.9 5839.8
40.34 0.9 0.9 5839.8
40.34 0.9 0.9 5839.8
40.34 0.9 0.9 5979.3
38.03 0.9 0.9 5979.3
38.03 0.9 0.9 5979.3
38.03 0.9 0.9 6116
39.14 0.9 0.9 6116
39.14 0.9 0.9 6116

 

My MAF is descreened. But I can't believe that should cause 2 point drops in MAF where it should be rising.

 

That drop in Maf air flow rate is a sign of an intake restriction normally. Did you log your map pressure as well?

 

Thanks. Didn't log map in that exact one. I can't think what could be a restriction- maybe I should try with the K&N filter out just to see. Looking at logs where I have MAP logged, I usually never waver more than 97-100 KPA. I have an example of it holding steady at 99 through a 1.5pt MAF drop at WOT/2nd gear.

Anybody have MAF in 2nd or 3rd gear for their good running cam or heads/cam car?

 

Bump- please help out with a few logs to compare to ...

 

Are those from one pull? Or similar rows from multiple pulls? (looks odd that you would have 3 rows for the exact same rpms, in several places.)

Is any kr coming into play at those points? (never mind, I see where you answered that already)

Where is your rev limiter?

What is your shift point rpm? Do you have torque management on or off?

 

The above is all the same pull and the same gear. I have much more detail and logs. This is from the Ease scanner and this just the way the things logs- shows a record every tenth second but every point obviously doesn't get updated quite that fast... though the actually changes are reasonably frequent. Rev limiter is up at 67-6800. Torque mgmt is off (set to 639 or whatever, zero'd tables). Shift rpm effectively is in the 6400-6500 rpm range. Here's another scan from today:

Time CURR_GEAR DELTORQ MAF _ O2S11 O2S21 RPM TP
Elapsed Time Current Gear Delivered Torque Air Flow Rate MAF Sensor O2 Sensor Out Volts B1/S1 O2 Sensor Out Volts B2/S1 Engine RPM Absolute Throttle Position
Sec N-m lb/min_ V V RPM %
531.04 2 380.3 37.08 0.9 0.91 6294.5 86.7 455.787957
531.16 2 380.3 38.69 0.9 0.91 6587.5 85.5 477.0042365
531.22 2 363 38.69 0.92 0.91 6587.5 85.5 455.3051219
531.4 2 363 38.87 0.92 0.91 5568.8 100 384.8961158
531.4 2 433.4 38.87 0.91 0.88 5568.8 100 459.5426352
531.58 2 433.4 34.27 0.91 0.88 5136.8 100 423.8935872
531.64 2 442.5 34.27 0.9 0.89 5136.8 100 432.7939832
531.83 2 442.5 32.12 0.9 0.89 4779.3 100 402.6733149
531.83 2 454 32.12 0.9 0.91 4779.3 100 413.1382711
532.07 2 454 31.2 0.9 0.91 4733.8 100 409.2051028
532.07 2 443.4 31.2 0.91 0.88 4733.8 100 399.6509749
532.19 2 443.4 30.71 0.91 0.88 4808.3 100 405.9406359
532.25 2 440.8 30.71 0.9 0.89 4808.3 100 403.5602894
532.43 2 440.8 32.61 0.9 0.89 4917.8 100 412.7506169
532.43 2 438.6 32.61 0.91 0.9 4917.8 100 410.6906093
532.67 2 438.6 33.64 0.91 0.9 5026.8 100 419.793313
532.67 2 442.2 33.64 0.9 0.9 5026.8 100 423.238949
532.85 2 442.2 35.41 0.9 0.9 5154.3 100 433.9740023
532.85 2 440.2 35.41 0.9 0.9 5154.3 100 432.0112072
533.03 2 440.2 33.23 0.9 0.9 5287 100 443.1335491
533.09 2 433.8 33.23 0.9 0.91 5287 100 436.6908987
533.27 2 433.8 35.56 0.9 0.91 5399.3 100 445.9665537
533.27 2 427.7 35.56 0.9 0.9 5399.3 100 439.6954703
533.45 2 427.7 34.96 0.9 0.9 5535.8 100 450.8114356
533.51 2 425.8 34.96 0.9 0.91 5535.8 100 448.8087662
533.69 2 425.8 36.82 0.9 0.91 5667.8 100 459.5105179
533.69 2 426.4 36.82 0.91 0.89 5667.8 100 460.1580198
533.87 2 426.4 35.91 0.91 0.89 5770.3 100 468.479802
533.93 2 423.7 35.91 0.9 0.91 5770.3 100 465.5133492
534.17 2 423.7 35.91 0.9 0.91 5922.8 100 477.8161386
534.17 2 419.4 35.91 0.91 0.89 5922.8 100 472.9669307
534.35 2 419.4 39.57 0.91 0.89 6008.3 100 479.7945583
534.35 2 414.6 39.57 0.9 0.9 6008.3 100 474.3033473
534.53 2 414.6 38.34 0.9 0.9 6128.5 100 483.7920982
534.53 2 407.7 38.34 0.91 0.9 6128.5 100 475.7405655
534.77 2 407.7 38.34 0.91 0.9 6227.8 100 483.4489832
534.77 2 403.7 38.34 0.91 0.9 6227.8 100 478.7057997
534.95 2 403.7 38.34 0.91 0.9 6321 100 485.8697068
534.95 2 397.2 38.34 0.91 0.89 6321 100 478.046687
535.13 3 397.2 40.41 0.91 0.89 6432 100 486.4414318
535.19 3 385 40.41 0.92 0.9 6432 100 471.5003808
535.31 3 385 39.07 0.92 0.9 6521.5 100 478.0612148
535.37 3 382.9 39.07 0.91 0.9 6521.5 100 475.4536081
535.49 3 382.9 39.96 0.91 0.9 6558.8 100 478.1729855
535.55 3 378.6 39.96 0.9 0.91 6558.8 100 472.8030617
535.73 3 378.6 36.6 0.9 0.91 5888 100 424.4472201
535.73 3 416.3 36.6 0.88 0.89 5888 100 466.7125666
535.91 3 416.3 30.74 0.88 0.89 4735.5 100 375.3596059
535.97 3 444.6 30.74 0.9 0.88 4735.5 100 400.8764851
536.15 3 444.6 29.31 0.9 0.88 4717.5 100 399.3527228
536.21 3 443.8 29.31 0.9 0.88 4717.5 100 398.6341394
536.39 3 443.8 30.3 0.9 0.88 4741.3 100 400.6452666
536.39 3 442.1 30.3 0.89 0.89 4741.3 100 399.1105731
536.63 3 442.1 29.39 0.89 0.89 4780.8 100 402.4355826
536.63 3 443.1 29.39 0.9 0.9 4780.8 100 403.3458644
536.87 3 443.1 29.46 0.9 0.9 4816 100 406.3156131
536.87 3 442.5 29.46 0.9 0.9 4816 100 405.7654227
537.11 3 442.5 29.31 0.9 0.9 4845.5 100 408.2509044
537.11 3 445.1 29.31 0.9 0.9 4845.5 100 410.6496668
537.29 3 445.1 29.76 0.9 0.9 4884.3 100 413.9379151
537.35 3 440.7 29.76 0.9 0.9 4884.3 100 409.8459653
537.47 3 440.7 32.12 0.9 0.9 4914.5 100 412.3800743
537.53 3 442.6 32.12 0.9 0.89 4914.5 100 414.1579779
537.71 3 442.6 33.64 0.9 0.89 4937.3 100 416.0793945
537.71 3 442.9 33.64 0.89 0.88 4937.3 100 416.3614185
537.89 3 442.9 32.61 0.89 0.88 4980 100 419.9623001
537.95 3 442.8 32.61 0.9 0.88 4980 100 419.8674791
538.13 3 442.8 33.71 0.9 0.88 5033.3 100 424.3612414
538.13 3 440.4 33.71 0.9 0.88 5033.3 100 422.0611805
538.31 3 440.4 32.65 0.9 0.88 5048.5 100 423.3357578
538.31 3 443.4 32.65 0.89 0.89 5048.5 100 426.2195164

 

That does look weird. I remember when I had the v6, and started playing with porting the maf, removing the screen, etc. I would get dips like that on acceleration...

Stock maf? Screened or not?

That's all I can think of...

 

I appreciate the help. Stock descreened MAF. Wonder if I should try clocking the MAF differently.

 

Maybe try a stock paper filter...?

 

Good idea & a way to do without risking the MAF ... I'll look to try that. Thanks.

 

Tested with a paper Fram filter- no change in performance or dips in MAF.

Put the K&N back in & put the screen back in MAF (wasn't too brutalized when I removed it)---- no change in dips in MAF flow, BUT I think I picked up about 20hp. It's hard to tell for sure, since my runs were done on different stretches of road. Seat-of-the-pants I definitely thought I had better runs. I'd love to redo without the screen under more controlled conditions, but I don't want to bang up the screen.