crash said:
I drove my Procharged vehicles everyday, and my Procharged F-150 would SPANK a HEMI 1500 RAM with my boat on the back of the truck.
www.trixtersracing.com/project02.htm
I gained 198 RWHP on it (2 valve 4.6), and have owned two (Started with the Allen Roots type, and got WAXED by an extended cab with a Procharger. BAD. I hate to lose, and I hate it when people call me saying they want more power.
Previous blown F-150s...
www.trixtersracing.com/project98.htm
www.trixtersracing.com/project00.htm
Yes, a 4300 LB truck, but still a 4.6 5-speed. NO LAG, PERIOD. The Roots made more power in only the LOWEST 500-700 RPM, after superimposing the graphs. I will never go back to positive displacement.
To the day I sold the truck to get the 05 GT, I always had traction problems, Roots, Procharger, and TURBO (Especially the turbo, like in 3rd)
Besides, is there another system for our cars that has proven an 11.60-11.70 ET with nothing but drag radials???
not disagreeing with you just curious, but have you ever driven a twin screw powered car of the same spec on a like for like basis as it would be good to speak to someone who has, the mojority of people I've spoken to only seem to have experiance with one or the other, and as they will make A LOT more power than stock they are all impressive.
As for lag, well a centrifugal doesn't have lag like a turbo because MOST poeple do not know what lag is, they are under the delusion that it is where in the rpms the turbo makes boost and 'kicks in', whereas lag is more concerned with 'stall' periods when the throttle is closed (ie an off boost situation) lowering the exhaust gas presure which then can cause the impellor to stall, there is then a LAG before it will build up speed again and produce boost.
Being belt driven the centrifugal does not suffer this to the same extreme, although similar inertia forces are acting on it. What it does suffer is problems due to its inherant design. This being that high impellor rpms are required to compress the air, thus they do not make much or any boost at low rpms, and no boost will mean no power gain. As these engines are not low CR engines it doesn't matter so much as they will still produce regular power but it will be all n/a until the blower has built the boost.
Another inherant problem with centrifugals are the sluggish repsonse to throttle variations, the science behind this is very similar to TURBO LAG, but it isn't lag just mearly sluggish.
If you look at the most successful centrifigal blowers it will be the aviation industry, esp the WWII fighters such as the Spitfire with its Rolls Royce supercharged Merlin V12. Centrifugals work very well here because of relatively constant engine speeds, aero engines do not have a very broad rpm range so this allows the blower to produce a very constant amount of boost and produce some very impressive BHP numbers.
Remeber all of this is fact and physics, if you disagree please find research to the contray as I would like to read it.
On the plus side centrifugal blowers can and do produce lots of power, potentially more than any of the other types out there. But PEAK bhp numbers really don't mean anything, when driving hard you will use the entire rpm range not hold it at peak power. One day with the advent of CVT (constant velocity drive) gear boxes this may be the case but not yet.
And remeber even though a centrifugal can produce lots of power it still takes power to run it. A turbo will always produce more on a like for like basis.
Basically in automotive terms the centrifugal blower bridges the gap between the positive displacement blower (twin screw) and the turbo. Whether its the best or the worse of both worlds is for each to decide.
The only other points for consideration is the fact that the centrigual blower has been around longer than the twin screw, yet it to my knowledge has never been used on a production car, nor has it had any success at top level compitition either. Top Fuelers run twin screw blowers and race cars (GT and such) use turbo's - THERE MUST BE A REASON FOR THIS.
11.60 ET is very impressive, but that is hardly every day driving, which is where the biggest difference between all of the FI types will show up.
Also, I haven't yet seen any times for the other blowers out there, but I guess like for like they will be very similar. KB rate their 9psi kit on the 2v GT at over 400rwhp with proven 12.2 @113mph on DR's so pretty close considering its about 60rwhp down on PEAK power, ultimatley their 9psi kit has the potential to push the car to 11.6 ET's but I guess
suspension work would probably be needed and a VERY VERY good driver. So the new forthcoming kit for the 3v unit should be very exciting, as the s197 platform is much better than the sn95.
.I chose procharger because of the power gains. The Kenne is easier to install for an average guy. I guess it comes down to personal preference, but roots or screw type is better for daily driver. No auto manufacturer has ever installed a centrifugal blower on a car or truck from the factory, to my knowledge. There are reasons why.
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