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Old 05-20-2011, 06:17 PM   #37 (permalink)
dal1307
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Join Date: Jan 2011
Location: Colorado
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Drives: 08 G37S 5AT
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Quote:
Originally Posted by RCZ View Post
I was told the V3 is good for 18psi on an otherwise stock z... I could be totally wrong with this guesstimate, but I guess its only an approximation. Assuming that you will lose a few psi with other high flowing supporting mods...lets call that 15-16psi on a VQ37...would it be fair to say that that is our ceiling for power on this supercharger?

The stock block is probably good for ~11PSI at the limit...

Not only does the 928 impeller produce more power at the same impeller speed...but it also has a higher ceiling as Mr. Squeeze described. I don't know if the top RPM of the SC is limited strictly by the impeller or not, but all in all, this SC + the 928 Motorsports impeller has the potential to go well into the 500whp range with some internals. Hell, it can probably be enough to push those upgraded internals to the limit too.

The other advantage is that you can get the same power with less wear and tear on the SC unit since it will be spinning slower than the stock impeller would be.
Thats all true and the 928 Impeller is definitely a must to max ot the V3 but I am only wanting to get to a full 8PSI at altitude and use the 928 BLV set to 8 PSI to ensure that I stay at no more than 8 PSI even if I take the car to lower altitudes. I don't want to amp it up to the point that I worry about trashing the AT. Now if I had the MT, I would be tempted to explore the 10 PSI range but then you start getting into worrying about the engine internals.

BTW RCZ, the Vortech site lists the specs on the V3 in our kit as 53K RPM and 17 PSI max boost. Here is the link to their specs page:

V-3 SCi-Trim Supercharger | Vortech Superchargers

A quick, rough calculation gets you approximately 3117 RPM per PSI based on the 53k/17PSI max numbers. So that means the 9 PSI pulley should be turning somewhere around 28,058 RPM if you assume 100% efficiency. If you roughly factor in their peak efficiency of 75% listed in their specs then it should be turning around 35,073 RPM. Either way, there should still be a lot of headroom left and you get even more headroom using the 928 impeller.

By the way Mr. Squeeze, nice job on your build! Do you still have the slotted pulley off the SC itself? If so, could you measure it for me? I don't want to take the belt off mine just to make a measurement.

I don't know if I will actually make any changes as the car drives great and has good power but it is alwasys fun to explore the options.
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2008 G37s 5AT, Stillen SC, Stillen CBE, Stillen tranny cooler, DBA 5000 front/4000 rear, Stillen sways, Tein SS-P coilovers, SPC front & rear control arms, Goodridge lines
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