UPDATE: November 24, 2020 A limited supply of original Lextreme parts back in stock including EGR Delete Kits, torque converters, supercharger brackets, etc! Please note that the SC400 turbo kit is all sold out and won't return. Email me at [email protected] which original Lextreme parts you need and I'll check availability. (Please note that we're not an auto parts supplier.)
The table below was transferred from Corky Bell’s book Supercharged! ISBN # 0-8376-0168-1 Page 8
Characteristic
Roots
Centrifugal
Screw
Low Speed boost capability
A
D
A
High boost – Pressure capability (10+ psi)
B
A
A
Fast boost rise
A
B
A
Thermal Efficiency
C
A
A
Volumetric Efficiency
B
B
A
Ease of Intercooling
C
A
C
Power Loss through supercharger
C
C
C
Simplicity of installation
B
A
B
Noise
C
C
C
Vibration
B
B
B
Space Requirement
C
B
C
Installation Convenience
C
B
C
Cost
B
A
C
Score
2.69=B-
3=B
2.77=B-
A= Excellent-4; B=Good-3; C=Fair-2; D=Poor-1
The final score is the total points divided by the total. I am getting the average of all the scores.
Root Score: 2.69 is B-
A-2 = 8
B-5 = 15
C-6 = 12
Centrifugal: 3.0 is B
A-5 = 20
B-5 = 15
C-2 = 4
Screw: 2.77 is B-
A-5 = 20
B-2 = 6
C-5 = 10
Here is another comparison of supercharger types:
Type
Fix Displacement
Internal Compression ratio
Roots
Yes
No
Centrifugal
No
Yes
Screw
Yes
Yes
Thermal Efficiencies of typical superchargers
Type
Et (%)
Temp increase with 1 psi
Roots
55
18.5
Screw
70
14.6
Centrifugal
75
13.6
Turbocharger
75
???
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