RPM 1000 2000 3000 4000 5000 6000 7000 8000
Cu. CC
1600 31 39 58 78 97 116 136 155
1750 34 68 102 136 170 204 238 272
1835 36 71 107 143 178 214 249 285
2180 42 85 127 169 212 254 296 339
2800 54 109 163 217 272 326 381 435
3000 58 116 175 233 291 349 408 466
Cu.Inches
215 68 137 205 274 342 411 479 547
289 92 184 276 368 460 552 644 736
302 96 192 288 384 481 577 673 769
327 104 208 312 416 520 624 729 833
350 111 223 334 446 557 668 780 891
400 127 255 382 509 637 764 891 1019
427 136 272 408 544 680 815 951 1087
454 145 289 434 578 723 867 1012 1156
460 146 293 439 586 732 878 1025 1171
502 160 320 479 639 799 959 1118 1278
Jeff Howe of Advanced Air Cleaners,
provided a CFM capacity chart that can
give teams an idea of how much air
a race engine needs at various RPM's
to maintain top performance levels.
Howe created this guideline during
his research years ago to measure,
with some degree of accuracy, what
different size engines need in the way
of air volume.
Take your CFM number for your
engine's operating RPM range, and
double it, this will allow the air filter to
get dirty and to deal with high elevation
without losing horsepower.
EQUATION:
AIR FLOW (CFM) = Displacement (cu. in) x RPM x VE
1728 CF
CYCLE FACTOR (CF)
4 cycle gasoline engine = 2
2 cycle gasoline engine = 1
VOLUMETRIC EFFICIENCY (VE)
ASPIRATION
• Naturally aspirated gasoline engine = .85
• Supercharged (blower scavenged) engine – 1.2
• Turbocharged engine = 1.4
047
SCORE JOURNAL
