You can get the same amount of horse power from a kenne bell supercharger. They have a article on their site about the 700+ Hp Cobra.

 

For the driving that I will be doing, I am looking for a twin-screw. I don't need huge high-end power, and won't be up in the RPM range all that much, and I like the low-end torque of the twin screws.

However, if you were looking for pure power, it is really hard to ignore twin turbos. While I usually don't point to magazines, the current MM&FF (Dec.) has a great comparo of dyno sheets between the four types of boost (Roots, twin-screw, centifigul blowers and twin turbo). The bottom line: twin turbos kick major hiney. All at 11psi, the turbos made 83hp over the Vortech, and caught up to the roots at 3400rpm (vs. ~5400rpm). The final numbers were 750hp (turbo) v. 629hp (Vortech). But the dyno charts tell the story much better.

 

It also depends on where you're going to be driving your car. Sure, turbos can spin faster than a super charger because they're riding on an oil bearing. But, you won't get your power out of the turbo until you spool up.... and whoever said turbo lag is a thing of the past.... when's the last time you rode in a brand new turbo charged car? Lag is there and it will always be there unless you blet drive your turbine, which is exactly what a centrifigal blower is.... and STILL, there is lag for those waiting to spool up too. They have to build up their boost in the intake manifold and back to the blower before they start to force air. Now, as far as boost at idle, the only way you're going to get that is with a screw type or Lysolm type supercharger. That is NOT what is on the 03/04 Cobras. They have a roots type blower made by Eaton which happens to be the most inefficient type of super charger. They build boost in the manifold instead of the SC itself, and when they do finally build boost, they dump a large amount of it back into the SC and wind up heating the charged air. So, I can see why there are huge HP gains on the Cobras by removing the stock blower and putting on an aftermaket one. But yeah.... I wouldn't consider a turbo, especially w/o a top to bottom engine build because with this stock motor, you can't push more than 8 PSI anyways, and if that's the case, I'd much rather have that boost at idle. A turbo isn't going to be an advantage unless your motor can handle a lot of boost.... and even so, there are still race application screw type chargers that can give you up to 25 PSI ON TAP. Screw turbos, they blow (all puns intended)

 

http://forums.bradbarnett.net/index.php?showtopic=8634

Whipple and Procharger are cool, but I don't trust either of them as much as Kenne Bell. KB actually puts real dynos up on their site.

http://www.kennebell.net/techinfo/techinfo-ford.htm

 

... and since i want to go faster i say twin turbos

 

Turbo lag is good, when was the last time you had a mustang that you could take to 6k rpm and drop the clutch and not just sit in one place... never right... so turbo lag until 2500 rpm is good it allows you to gain traction before you get full boost. After 1st gear there is no lag cause you shift and you are already in your powerband. In addition to that a turbo is much more efficiant and if you plan on running 8lbs of boost on your 05 might as well get as much power as you can for that 8lbs.... why lose 15% of it to a belt drive?

 

Can't wait to see some real world tests on these prior to making a choice myself. Need a few guinea pigs to enlighten us all sometime soon....

 

HANDS DOWN in efficiency the Procharger is where it is at. I will be doing some testing over the next two weeks with the Procharger and will post results. The 2003 kit is in the $3500 range not the $5000 range and I expect the 2005 model to be similarly priced. It also only takes 6 hours or so to do the complete installation. Keep an eye on my websight for updates. I will be baselining the car tonight.

Michael Freedman
www.xlr8racing.net