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      02-08-2016, 03:51 PM   #17
pokeybritches
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Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

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Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Quote:
Originally Posted by Westersund View Post
Running high comp and high boost on pump gas will be very risky. Increasing the comp while adding boost makes no sense, rather leave the comp were it is stock and add more boost.
Why do you think it makes no sense? The supercharger will be very nearly maxed out at 15-16 psi. Raising compression increases both efficiency and power. If you increase the base engine's power, you don't have to run as much boost to make good power. Or, you can run the same boost and make even more power. Lowering compression would be a last resort to ensure a margin of safety. Based on the supercharger discharge temperatures, this would be necessary with the TS3 kit. I don't know that the Vortech necessitates lower compression.

I will have both an intercooler and water/meth injection to control temperatures. My car is currently tuned for 8-9 psi, and the trunk-mounted water/meth kicks in at 4 psi.

One other point - water/meth is more feasible on a centrifugally supercharged car. I've used maybe 1/2 of a tank in a year. With a twin screw car, I would have to base it on something other than boost pressure (like rpm), unless I wanted to fill the tank up every few weeks. There's also the issue of finding a way to inject it post-supercharger for maximum effect.
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