More superchargered than turbocharged

[SuperchargedStealth]

Originally Posted by LOBBS

A top-mount positive displacement blower is universally accepted as being less efficient than a centri or turbo due to its location directly above the engine. Yes, you can intercool and/or shield them to help the keep the IATs more reasonable but they are less efficient.

A centrifugal, same as a PD, is a mechanically driven and is building boost from idle to redline relative to engine RPM. Yes, peak boost is at redline but they are spooling up throughout the curve. In situations where traction is at a premium the slower build of boost can be advantageous. Now, a centri like the Procharger i-1 with its CVT can give you a near-turbo like torque curve with instant, full boost at any RPM.

I don't disagree that a turbo, or a pair of turbos, can be selected to obtain max boost at 1500 rpm. But being small enough to be brought up to speed at that RPM poses a risk of being restrictive at higher RPMs. This, of course, does not take into account variable vane turbos or running a pair of big/small turbos in sequence which could help mitigate that issue. But, again it is generally accepted that turbos will not give much help below the RPM required to get them spinning.

It's all in the setup with a centri. Because of the way I'm setup, I can manage boost anywhere in the power band from having it run at 14lbs all the way up to 25lbs. In regards to turbos, yea, back then there was always the concern of turbo lag. Since then, you can use bigger turbos with little to no lag using twin scroll turbos.