Project "Ghetto Flow" - MAF and Cat data
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Project "Ghetto Flow" - MAF and Cat data Gimping along with some pretty lame blowers until my hardware arrives,
nonetheless I took some interesting data today using my "ghetto flow
bench" bits-n-pieces...
Tested draw-through (suction blower):
Delphi 85mm MAF screened 6500 Hz (66 gm/sec) 1/4"H2O k=3.8E-3 "H2O/(gm/sec)
Delphi 85mm MAF descreened 6700Hz (75 gm/sec) 1/16" H2O k=8.3E-4 "H2O/(gm/sec)
Figuring 1"H2O is roughly 1HP, if you're a 400HP sort of car, the descreening
of an 85mm MAF should give you between 2 and 12HP (that narrows it down,
eh?) at the big end, depending on whether the pressure drop goes linear
or square-law with velocity (mass air flow).
Cats & OR tubes tested blow-through (pressure using leaf blower)
Stock '02 Cat 7020Hz (87 gm/sec) 7.5" H2O k=8.6E-2 "H2O/(gm/sec)
Stock '02 Cat 7150Hz (92 gm/sec) 7" H2O k=7.6E-2 "H2O/(gm/sec)
Gutted '02 Cat 7600Hz (110 gm/sec) 6" H2O k=5.5E-2 "H2O/(gm/sec)
Gutted '02 Cat 7650Hz (115 gm/sec) 5.5" H2O k=4.8E-2 "H2O/(gm/sec)
RT High-Flow Cat 7560 Hz (108 gm/sec) 5.5" H2O k=5.1E-2 "H2O/(gm/sec)
RT High-Flow Cat 7350 Hz (100 gm/sec) 6" H2O k=6.0E-2 "H2O/(gm/sec)
Mufflex OR Tube 7800Hz (120 gm/sec) 5.5" H2O k=4.6E-2 "H2O/(gm/sec)
Mufflex OR Tube 7800Hz (120 gm/sec) 5.75" H2O k=4.8E-2 "H2O/(gm/sec)
Notes: "exhaust gas" temp=75F, not the in-use ~ 1000F
The stock cats are quite a bit of restriction relative to other options.
Best of these being the Mufflex 3" OR tubes. Gutted cats are slightly
better than the RT high-flows (the latter being at least semi-legal).
nonetheless I took some interesting data today using my "ghetto flow
bench" bits-n-pieces...
Tested draw-through (suction blower):
Delphi 85mm MAF screened 6500 Hz (66 gm/sec) 1/4"H2O k=3.8E-3 "H2O/(gm/sec)
Delphi 85mm MAF descreened 6700Hz (75 gm/sec) 1/16" H2O k=8.3E-4 "H2O/(gm/sec)
Figuring 1"H2O is roughly 1HP, if you're a 400HP sort of car, the descreening
of an 85mm MAF should give you between 2 and 12HP (that narrows it down,
eh?) at the big end, depending on whether the pressure drop goes linear
or square-law with velocity (mass air flow).
Cats & OR tubes tested blow-through (pressure using leaf blower)
Stock '02 Cat 7020Hz (87 gm/sec) 7.5" H2O k=8.6E-2 "H2O/(gm/sec)
Stock '02 Cat 7150Hz (92 gm/sec) 7" H2O k=7.6E-2 "H2O/(gm/sec)
Gutted '02 Cat 7600Hz (110 gm/sec) 6" H2O k=5.5E-2 "H2O/(gm/sec)
Gutted '02 Cat 7650Hz (115 gm/sec) 5.5" H2O k=4.8E-2 "H2O/(gm/sec)
RT High-Flow Cat 7560 Hz (108 gm/sec) 5.5" H2O k=5.1E-2 "H2O/(gm/sec)
RT High-Flow Cat 7350 Hz (100 gm/sec) 6" H2O k=6.0E-2 "H2O/(gm/sec)
Mufflex OR Tube 7800Hz (120 gm/sec) 5.5" H2O k=4.6E-2 "H2O/(gm/sec)
Mufflex OR Tube 7800Hz (120 gm/sec) 5.75" H2O k=4.8E-2 "H2O/(gm/sec)
Notes: "exhaust gas" temp=75F, not the in-use ~ 1000F
The stock cats are quite a bit of restriction relative to other options.
Best of these being the Mufflex 3" OR tubes. Gutted cats are slightly
better than the RT high-flows (the latter being at least semi-legal).
