Getting confused. Sent an e-mail to a supercharger dealer, who recommended a Paxton centrifugal unit.

My understanding was that roots-type units give performance increases at all RPMs. Centrifugal units do not. In a truck, obviously I don't want to spin 3000 RPMs before I see an increase in performance.

Can someone 'splain this? Thanks.

-Mike

 

Positive displacement blowers (Roots or Whipple) produce a constant overpressure at all RPMs. Your 302 wil act, more or less like a 428. With a positive displacement blower you can easily overpower the tires at low RPMs

A centrifugal blower increases boost as RPMs increase. It gives some boost at all ranges, but off idle the boost is barely enough to overcome the load it takes to drive the blower. Centrifugal blowers are, on the whole, more efficient than positive displacement ones, so at max revs, they tend to produce more maximum horsepower. A lot of design effort has been spent by all the centrifugal manufacturers on lowering the point at which their blowers come "on stream" without sacrificing the top end advantages.

I don't know about Paxton, other than that they are quality units, but I'd check with the factory about boost and RPM ranges. Vortech developed their "S" trim blower specifically for better mid range performance, I'm sure Paxton has done the same, but I'd get the info directly from them, not the dealer.

 

Paxton and Vortech are both headquartered within 15 miles of here, and I have heard good things about both, but the general concensus around here is that Vortech is the best, dollar for dollar.

Take care,
~Chris

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Thanks. I will check into Vortech as well. What about the ATI procharger or Powerdyne's unit?

Powerdyne told me that if I decide to supercharge my 302 and eventually change over to a 351 the same unit will work. Other companies say I'd have to buy a completely new supercharger.

The other option is to go with a performance 302 from the folks at Ford-power.com. Has anyone heard about these guys? They offer a, supposedly emissions-legal, 370hp 302. Their performance 351 is about the same price, and these are looking like attractive options (wouldn't need a supercharger--and they cost $500 less!)

The engines are balanced and blueprinted.

-Mike

 

The Powerdyne is internally driven by a gilmer belt unlike the Vortech which uses gears and the Paxton which uses a unique kind of ball drive. The powerdyne is quieter as a result. The powerdyne is internally lubed so it doesn't share engine oil and in case of a blower failure won't contaminate the oilpan with it's debris. This is probably part of the reason Ford chose them to provide the SVO blower kits. The down side is that, as I understand it, the Powerdyne kits run "further from the edge" than the Vortech or Paxton, meaning less power added as a result. I don't know if they have mid-range boost like the Vortech "S" or not. Again, contact them directly to find out.

ATI features an intercooler to allow more boost and more HP without the risk of detonation. My impression from their ads is that they are more race-oriented, more into 400+ HP street/strip Mustangs than street driven pickups. They may make a truck specific package, but they sure don't advertise it much.

Don't know anything about ford-power, but 370 Green HP is actually fairly easy to do. Make sure that the power is where you can use it though, not at 5000+ RPM. Get a set of HP and torque curves from them. You may decide on a 320-350 HP engine with a fatter mid-range. If the 351 is the same price, why not??