Here is a "copy & paste" of an article from HotRod.

I have the 'boost is boost?' article right here in front of me... So, here's a basic rundown straight from the article:
(too bad they didn't measure intake temps.)

327ci A4 block
Victor Jr heads
Performer RPM intake (carb)
Demon 750 carb
Comp XE266HR camshaft
8.4 to 1 compresion

Holly174ci blower
Paxton 1200 centrifugal blower
HP Performance turbo kit without intercooler

Boost at 2500rpm:
Roots: 4.8psi
Paxton: 1.7psi
Turbo: 5.7psi

Max boost:
Roots: 8psi @6000rpm
Paxton: 9.5 @6000rpm
Turbo: 9.5 @5100rpm

Max HP/TQ: (all figures are flywheel)
Roots: 535@6000rpm/513@4600rpm
Paxton: 617@6000rpm/561@5200rpm
Turbo: 600@6000rpm/617@4200rpm

AVG HP/TQ from 2500-6000rpm:
Roots: 394/483
Paxton: 412/494
Turbo: 460/564

AVG HP/TQ from 4000-6000rpm (dragstrip power):
Roots: 472/497
Paxton: 518/542
Turbo: 555/585

Notes:
1. Roots blower made 8psi max compared to 9.5 with the turbo & SC..
2. No intercooler was used on any setup.
3. Turbo boost peaked at 9.5psi at 5100rpm, then dropped to 8.5psi by 6000rpm.
4. The cam was installed 'dot-to-dot' & favors the exhaust heavily. The cam was a comprimise but favors SC motors....turbo's like heavy reverse-splits.

 

Now I have to Ask which one is better on Gas
Great post
With the Proper Cam and intercooler the turbo would kill all of the others it seems
Great post !

 

I'd probbaly say the turbo is best on gas because of it's efficiency Hehehe

The only thing I wish they had done was a Twin-screw blower for the comparo also. I bet the #s would have been similar to the roots blower though depending on heat since none of these kits were intercooled and we al know how well twin-scews do without cooling. LOL

 

What kind of "roots" blower was it? Certainly not an Eaton.

 

blower takes 75hp or so turn; theres the missing power
best regards,
sherlock homes

 

yes that holley roots blower is pretty inefficient and probably outputs temps near that of the turbo.