Anybody know why?

 

Performance? Perhaps cost? Perhaps a little of both.

 

I think its both. Probably cost close to the same, with slightly better performance. Plus I believe whipple 'chargers acctually produce a tad less heat than an eaton.

 

Scothew is right. Twin Screws are a more efficient design than rootes blowers are. They generate less heat and they don't simply force air into the motor they actually compress they air too, which creates a denser air charge. More oxygen, bigger bang, more power.

A twin screw will also produce similar boost at far fewer rpms than will the older rootes, and even makes more hp at a given bar/lb of boost! They basically stomp on the older rootes design in every respect.

 

whipple has kits for the 3v 4.6 for 5600. thats a chunk of cash. that includes heat exchanger, reflash, etc though. course, then theres the internals...

 

Scott is right?
[1 BULLITT fuming and foaming at the mouth]

 

It will not be a twin screw because Lysholm can not make the twin scews fast enough. 10 preday for the twin vs 50 for the single screw

 

Without a twin screw, there is little point in using a 5.4L -- the Eaton M112 would just choke it. And I think that even if your number is correct, a production order from Ford for 7500 superchargers would inspire Lysholm to figure out how to make the screws faster.

Dave

 

Call up Whipple and ask them. It's a twin screw.