psi-d versus 16-71 blower

I am building a car for outlaw pro mod with a 526 hemi. which would be the better of the two. A psi-screw blower or 16-71 hi helix? I heard the psi is very hard to manage the power and tearts stuff up easily. Appreciate the insight guys. Thanks sean

 

We've run both! a Kobelco 16-71 last year, then switched to a PSI "C" rotor. I'll tell you this "AS LONG AS THERE ARE SCREW BLOWERS IN EXISTENCE, WE WILL NEVER RUN A ROOTS BLOWER AGAIN!!!" The screw is truly incredible in comparison. We run a heavy door car, and this is the best season i've ever had racing. Parts wise and power wise!!

 

I would say whoever you heard that from has never run a screw blower. Crank life alone is worth the switch. It takes a lot more power to spin a roots, and that's especially hard on the front inside of the #1 rod journal. The freed up extra power is worth it and it's really not any harder to control. Plus, significantly reduced manifold temps keeps damage down to a minimum whenever you make a tuning error or have a problem.

 

Appreciate the responses. I will go with a PSI. Will a PSI-D be ok? Is ther eany good software to use as a tuning tool? I heard les davenport has a good one. What about a good clutch set-up crower or AFT? Sorry so many questions you guys are great Thanks! sean

 

Ever had to strip a roots blower? If you have, you'll appreciate the psi that much more. The psi requires very little maintainance, where the roots is a constant battle to keep up to top performance because of the strip wear.If you have a choice, definately go with the screw.....

 

If there's no rules, why not get a "C". If you're gonna buy a new one, you might as well buy the best one they make. It makes more boost at lower rpm. I assume you'll be running mostly eighth mile, which would be perfect. Could someone explain again the exact advantage of a C over a D.

bryan

 

I'd go with a D. There is a bigger market to sell it to whenever you decide to move it. If you really don't care about that, then I'd definately get a C.

 

What is the differance between a C And D PSI? Thnaks sean

 

The C has slightly larger diameter rotors than the D, 8 1/8" vs 8 1/4", or 8 1/4" vs 8 1/2" or something like that. So the C has a larger swept volume, or moves more air per revolution. Only the D is legal in NHRA competition.
Chris

 

The "C" Rotor displaces 11.2 liters of air per revolution, compared to the "D", which displaces 10.8 liters per revolution. In simple terms, the C rotor makes between 8-10lbs of boost more, at the same overdrive as the D rotor. This boost difference was measured when the blowers are in the mid 90% overdrive range. Walt Austin has done these tests numorous times. If you have a choice, no rules, are buying new, and don't really care about resale, then go with the C rotor.

 

You guys are great the info is much appreciated! Thanks sean