Quote:
Originally Posted by Sportsguy83
Ok, you make good points and its true, but it is kind of "off" the point I'm trying to make. The TQ dip in between 3.5-4.5K is gone.
Going with your point (that they are still not full boost at those RPMs and that's why they don't show the TQ dip) then SC kits are also not full boost at those RPM's but still have the TQ dip.
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Unknown with the twin screw, but I would bet it is close to full boost by 3k. Twin screws have a tendency to be at full boost or near it early in the RPM range. It is the nature of a positive displacement supercharger. Therefore it will show the natural tendency of the engine at that point.
The Vortech kit won't be any where near full boost until the top of the rev range. It will only make a few psi at most lower in the rev range. The rising in boost pressure during the torque dip isn't enough to overcome the dip itself. Notice the preliminary Vortech curve smooths out the dip, but doesn't eliminate it. If boost pressure was increasing at a faster rate (smaller pulley), you may see it eliminated. Hard to say at this point though.
With turbos it will depend a lot on the size of the turbo, but their boost curve will be nothing until a certain point and within 500-1000 RPMs there will be full boost. When this happens during the torque dip, the torque dip disappears because you go from 0-5+ psi in a short time, or if the turbo spools before the torque dip it will shot the same tendency as the twin screw.
The point is that the rising boost pressure masks the torque dip, it doesn't eliminate it.