Basic Blower Measurements

---

To Figure Out The Cubic Feet Per Minute Of Each Revolution Of The Blower:

CFM of Blower:

Regular twist blowers:
Cu in/rev = rotor length X 27.45

High-helix blowers:
Cu in/rev = rotor length X 31.53

Basic Blower Measurements This page is for basic blower measurements and is not intended for blueprint making or for specifics of any one individual blower. Blower Type/Manufacturer Named Size C.I.D./Rev (approx) Style Of Rotor Center Case/Rotor Length Center Case Height Detroit Diesel "GMC" Straight 71 series 2-71 136 c.i.d./rev 3 lobe 30º helix Ball/Roller bearing 4.875 inches Non-standard case side inlet Detroit Diesel "GMC" Straight 71 series 3-71 210 c.i.d./rev 3 lobe 30º helix Ball/Roller bearing 7.500 inches 7.500 inches Detroit Diesel "GMC" Straight 71 series 4-71 280 c.i.d./rev 3 lobe 30º helix Ball/Roller bearing 10.000 inches 7.500 inches Detroit Diesel "GMC" Straight 71 series 6-71 approx. 353 c.i.d./rev (Small Bore) 3 lobe 30º helix Ball/Roller bearing 15.000 inches 7.500 inches Detroit Diesel "GMC" Straight 71 series 6-71 420 c.i.d./rev (large bore) 3 lobe 30º helix Ball/Roller bearing 15.000 inches 7.500 inches Detroit Diesel "GMC" Straight 71 series (converted 8v71 to aftermarket case) 8-71 448 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 15.900 inches 7.500 inches Detroit Diesel "GMC" "V" 71 series 6V71 338 c.i.d./rev 3 lobe 30º helix Ball/Roller bearing 12.000 inches 7.500 inches Detroit Diesel "GMC" "V" 71 series 8V71 448 c.i.d./rev 3 lobe 30º helix Ball/Roller bearing 15.900 inches 7.500 inches Detroit Diesel "GMC" Straight 53 series 2-53 70 c.i.d./rev 2 lobe straight Friction NON ball bearing 4.375 inches 5.750 inches Non-standard case side inlet Detroit Diesel "GMC" Straight 53 series 3-53 104 c.i.d./rev 2 lobe straight Friction NON ball bearing 6.500 inches 5.750 inches Detroit Diesel "GMC" Straight 53 series 4-53 SHORT BORE 120 c.i.d./rev 2 lobe straight Friction NON ball bearing 7.500 inches 5.750 inches Detroit Diesel "GMC" Straight 53 series 4-53 LONG BORE 139 c.i.d./rev 2 lobe straight Friction NON ball bearing 8.700 inches 5.750 inches Detroit Diesel "GMC" "V" 53 series 6V53 SHORT BORE 174 c.i.d./rev 2 lobe straight Friction NON ball bearing 10.900 inches 5.750 inches Detroit Diesel "GMC" "V" 53 series 6V53 LONG BORE 209 c.i.d./rev 2 lobe straight Friction NON ball bearing 13.100 inches 5.750 inches Detroit Diesel "GMC" "V" 53 series 8V53 330 c.i.d/rev 3 lobe 30º helix Ball/Roller bearing 15.000 inches 6.500 inches Eaton M-45 45 c.i.d./rev 3 lobe 60º helix Ball/Needle bearing 4.921 inches Non-standard case rear inlet Eaton M-62 62 c.i.d./rev 3 lobe 60º helix Ball/Needle bearing 4.921 inches (taller rotors) Non-standard case rear inlet Eaton M-90 90 c.i.d./rev 3 lobe 60º helix Ball/Needle bearing 5.433 inches   Eaton M-112 112 c.i.d./rev 3 lobe 60º helix Ball/Needle bearing 5.386 inches (taller rotors) Non-standard case rear inlet B & M 144 144 c.i.d./rev 2 lobe straight Ball/Ball bearing 8.700 inches 5.750 inches B & M 174 174 c.i.d./rev 2 lobe straight Ball/Ball bearing     B & M 250 250 c.i.d./rev 2 lobe straight Ball/Ball bearing     Weiand/Holley Pro Street 142 Pro 142 142 c.i.d. 2 lobe straight Ball/Ball bearing 8.700 inches 5.750 inches Weiand/Holley Pro Street 144 Pro 144 144 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing 8.700 inches 5.750 inches Weiand/Holley Pro Street 174 Pro 174 174 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing     Weiand/Holley Pro Street 177 Pro 177 177 c.i.d./rev 2 lobe straight Ball/Ball bearing     Weiand/Holley Pro Street 250 Pro 250 250 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing     Weiand/Holley Pro Street 256 Pro 256 256 c.i.d./rev 2 lobe straight Ball/Ball bearing     Weiand/Holley 6-71 6-71 411 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 15.000 inches 7.500 inches Weiand/Holley 8-71 8-71 436 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 15.900 inches 7.500 inches Weiand/Holley 10-71 10-71 469 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 17.100 inches 7.500 inches Weiand/Holley 12-71 12-71 497 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 18.100 inches 7.500 inches Weiand/Holley 14-71 14-71 522 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 19.000 inches 7.500 inches Weiand/Holley 16-71 16-71 549 c.i.d./rev 3 lobe 30º helix Ball/Ball bearing 20.000 inches 7.500 inches Camden Five Inch 80 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing 5.000 inches 5.500 inches Camden Seven Inch 112 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing 7.000 inches 5.500 inches Camden Nine Inch 144 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing 9.000 inches 5.500 inches Camden Twelve Inch 192 c.i.d./rev 2 lobe straight w/teflon Ball/Ball bearing 12.000 inches 5.500 inches Original S.Co.T Italmeccanica Italian made 4500cc Same internally 275 c.i.d./rev boost up to 6psi 2 lobe straight cast rotor Ball/Ball bearing 8.700 inches 7.750 inches Original S.Co.T Italmeccanica Italian made 4000cc Same internally 275 c.i.d./rev boost up to 6psi 2 lobe straight cast rotor Ball/Ball bearing 8.700 inches 7.750 inches New improved S.Co.T H&H Flatheads Italmeccanica U.S.A. made "S.Co.T." Blower 142 c.i.d./rev boost up to 10+ psi 2 lobe straight billet rotor Ball/Ball bearing 8.700 inches 7.750 inches

---

Auto Math Book - John Lawlor *****	Performance Automotive Engine Math	Engineering Formulas: by Kurt Gieck *****	Pocket Ref: by Thomas J. Glover *****	Automotive Math Handbook	Chassis Engineering: Chassis Design, Building & Tuning for High Performance Handling

Engine Airflow HP1537: A Practical Guide to Airflow Theory, Parts Testing, Flow Bench Testing and Analy zing Data to Increase Performance for Any Street or Racing Engine	Machinery's Handbook Toolbox Edition	David Vizard's How to Port & Flow Test Cylinder Heads	David Vizard's How to Build Horsepower	David Vizard's How to Super Tune and Modify Holley Carburetors	Internal Combustion Engine Engine Fundamentals

How to Tune and Modify Automotive Engine Management Systems	Supercharged! Design, Testing and Installation of Supercharger Systems	Street Turbocharging by Warner	Car Hacks and Mods for Dummies by Vespremi	Car PC Hacks by Stolarz

How to Tune and Modify Motorcycle Engine Management Systems	Performance Fuel Injection Systems	Engine Management: Advanced Tuning	Performance Fuel Injection Systems HP1557: How to Design, Build, Modify, and Tune EFI and ECU Systems	Turbo: Real World High-Performance Turbocharger Systems