spf_lexus
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- Murrieta California
I have been doing a lot of reading on this and found it pretty interesting. The biggest downside of the centrifugal design? Not enough mid range and low end torque! What I have found is that you can have your cake and eat it too (with very little repercussions).. here's how it works in 2 easy steps:
http://www.musclemustangfastfords.c...l_supercharger_wastegate_install/viewall.html
First step is to number crunch pulley sizes, crank damper diameter, max engine RPM and the max RPM rating of the blower bearings. Once this max PSI rating is realized (and max pulley size), install a smaller blower pulley which will allow the blower to max out just below the maximum bearing rating.
Second, install a wastegate onto the charge pipe with a spring rated for the max boost you would like the engine to see. (pulley set for lets say 15psi and watse gate set for 6psi). And thats really it.
By "pulleying down" you are increasing the blower's step up ratio which in turn, causes the blower to move air at a much lower engine RPM (think positive displacement). In other words, max boost can be found a few thousand RPM lower resulting in huge torque gains.
Downsides:
-Some increased bearing wear (nothing too severe, as the bearings are still not being overspun).
-Slightly higher parasitic loss due to increased step up ratio.
-Supercharger will be maxed out so adding peak boost is as easy as changing a wastegate spring however no mid range torque gains will occur. If more mid range and top end is desired, the blower will be over spun so a larger unit would be required.
-Blower will be slightly louder.
Im waiting on my Procharger to be rebuild but I will be running this setup. Looking at a 12psi pulley and a 5 or 6psi wastegate spring. So instead of weak dyno torque results of: 360whp and 300wtq... I can maybe squeeze 360whp and 360wtq.
http://www.musclemustangfastfords.c...l_supercharger_wastegate_install/viewall.html
First step is to number crunch pulley sizes, crank damper diameter, max engine RPM and the max RPM rating of the blower bearings. Once this max PSI rating is realized (and max pulley size), install a smaller blower pulley which will allow the blower to max out just below the maximum bearing rating.
Second, install a wastegate onto the charge pipe with a spring rated for the max boost you would like the engine to see. (pulley set for lets say 15psi and watse gate set for 6psi). And thats really it.
By "pulleying down" you are increasing the blower's step up ratio which in turn, causes the blower to move air at a much lower engine RPM (think positive displacement). In other words, max boost can be found a few thousand RPM lower resulting in huge torque gains.
Downsides:
-Some increased bearing wear (nothing too severe, as the bearings are still not being overspun).
-Slightly higher parasitic loss due to increased step up ratio.
-Supercharger will be maxed out so adding peak boost is as easy as changing a wastegate spring however no mid range torque gains will occur. If more mid range and top end is desired, the blower will be over spun so a larger unit would be required.
-Blower will be slightly louder.
Im waiting on my Procharger to be rebuild but I will be running this setup. Looking at a 12psi pulley and a 5 or 6psi wastegate spring. So instead of weak dyno torque results of: 360whp and 300wtq... I can maybe squeeze 360whp and 360wtq.
