Corky Bell’s Comparison of Superchargers

UPDATE: February 4, 2021 A limited supply of original Lextreme parts are back in stock including the EGR Delete Kit, torque converter, 3/8" cat flange and supercharger fish bracket!

Email me at [email protected] which of these Lextreme parts you need. (Please note that we're not an auto parts supplier and I can't respond to inquries for parts we don't have.) All other parts, including the LS400 and SC400 turbo kit are sold out and won't return.

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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 ???

Do you have any questions? If so, please head over to the forums to get a quick answer or share your experience!

This is a freelance site with no support by huge companies.  I have been doing most of the R&D and technical write-ups by myself with my personal money and literally thousands of hours of my time.  I have taken extra steps to demonstrate in details how things are done.  Currently I am one of the few people doing Lexus V8 research and performance enhancement.  This effort comes from my personal love for this wonderful engine.  Most of the modifications are from trial and error. There's no cookbook for 1UZFE mods and its unknown territory for much of supercharger performance.  The parts, labor, web development and site hosting are 100% paid from my personal hobby money.  If you feel my efforts help you in any form, please do not hesitate to donate any amount of money to support this site. You have no idea how much I and the entire Lexus and Toyota community appreciate it!

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