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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/ManufacturerNamed SizeC.I.D./Rev (approx)Style Of RotorCenter Case/Rotor LengthCenter Case Height
Detroit Diesel "GMC" Straight 71 series2-71136 c.i.d./rev3 lobe 30º
helix
Ball/Roller bearing
4.875
inches
Non-standard case side inlet
Detroit Diesel "GMC" Straight 71 series3-71210 c.i.d./rev3 lobe 30º
helix
Ball/Roller bearing
7.500
inches
7.500
inches
Detroit Diesel "GMC" Straight 71 series4-71280 c.i.d./rev3 lobe 30º
helix
Ball/Roller bearing
10.000
inches
7.500
inches
Detroit Diesel "GMC" Straight 71 series6-71420 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)
8-71448 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
15.900
inches
7.500
inches
Detroit Diesel "GMC" "V" 71 series6V71338 c.i.d./rev3 lobe 30º
helix
Ball/Roller bearing
12.000
inches
7.500
inches
Detroit Diesel "GMC" "V" 71 series8V71448 c.i.d./rev3 lobe 30º
helix
Ball/Roller bearing
15.900
inches
7.500
inches
Detroit Diesel "GMC" Straight 53 series2-5370 c.i.d./rev2 lobe straight
Friction NON ball bearing
4.375
inches
5.750 inches Non-standard case side inlet
Detroit Diesel "GMC" Straight 53 series3-53104 c.i.d./rev2 lobe straight
Friction NON ball bearing
6.500
inches
5.750 inches
Detroit Diesel "GMC" Straight 53 series4-53 SHORT BORE120 c.i.d./rev2 lobe straight
Friction NON ball bearing
7.500
inches
5.750 inches
Detroit Diesel "GMC" Straight 53 series4-53 LONG BORE139 c.i.d./rev2 lobe straight
Friction NON ball bearing
8.700
inches
5.750 inches
Detroit Diesel "GMC" "V" 53 series6V53 SHORT BORE174 c.i.d./rev2 lobe straight
Friction NON ball bearing
10.900
inches
5.750 inches
Detroit Diesel "GMC" "V" 53 series6V53 LONG BORE209 c.i.d./rev2 lobe straight
Friction NON ball bearing
13.100
inches
5.750 inches
Detroit Diesel "GMC" "V" 53 series8V53330 c.i.d/rev3 lobe 30º
helix
Ball/Roller bearing
15.000
inches
6.500 inches
EatonM-4545 c.i.d./rev3 lobe 60º helix
Ball/Needle bearing
4.921 inchesNon-standard case rear inlet
EatonM-6262 c.i.d./rev3 lobe 60º helix
Ball/Needle bearing
4.921 inches (taller rotors)Non-standard case rear inlet
EatonM-9090 c.i.d./rev3 lobe 60º helix
Ball/Needle bearing
5.433 inches 
EatonM-112112 c.i.d./rev3 lobe 60º helix
Ball/Needle bearing
5.386 inches (taller rotors)Non-standard case rear inlet
B & M144144 c.i.d./rev2 lobe straight
Ball/Ball bearing
8.700
inches
5.750
inches
B & M174174 c.i.d./rev2 lobe straight
Ball/Ball bearing
  
B & M250250 c.i.d./rev2 lobe straight
Ball/Ball bearing
  
Weiand/Holley Pro Street 142Pro 142142 c.i.d.2 lobe straight
Ball/Ball bearing
8.700
inches
5.750
inches
Weiand/Holley Pro Street 144Pro 144144 c.i.d./rev2 lobe straight w/teflon
Ball/Ball bearing
8.700
inches
5.750
inches
Weiand/Holley Pro Street 174Pro 174174 c.i.d./rev2 lobe straight w/teflon
Ball/Ball bearing
  
Weiand/Holley Pro Street 177Pro 177177 c.i.d./rev2 lobe straight
Ball/Ball bearing
  
Weiand/Holley Pro Street 250Pro 250250 c.i.d./rev2 lobe straight w/teflon
Ball/Ball bearing
  
Weiand/Holley Pro Street 256Pro 256256 c.i.d./rev2 lobe straight
Ball/Ball bearing
  
Weiand/Holley
6-71
6-71411 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
15.000
inches
7.500
inches
Weiand/Holley
8-71
8-71436 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
15.900
inches
7.500
inches
Weiand/Holley
10-71
10-71469 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
17.100
inches
7.500
inches
Weiand/Holley
12-71
12-71497 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
18.100
inches
7.500
inches
Weiand/Holley
14-71
14-71522 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
19.000
inches
7.500
inches
Weiand/Holley
16-71
16-71549 c.i.d./rev3 lobe 30º
helix
Ball/Ball bearing
20.000
inches
7.500
inches
CamdenFive Inch80 c.i.d./rev2 lobe straight w/teflon
Ball/Ball bearing
5.000
inches
5.500
inches
CamdenSeven Inch112 c.i.d./rev2 lobe straight w/teflon
Ball/Ball bearing
7.000
inches
5.500
inches
CamdenNine Inch144 c.i.d./rev2 lobe straight w/teflon
Ball/Ball bearing
9.000
inches
5.500
inches
CamdenTwelve Inch192 c.i.d./rev2 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." Blower142 c.i.d./rev
boost up to 10+ psi
2 lobe straight billet rotor
Ball/Ball bearing
8.700
inches
7.750
inches


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