The spool down of the turbos Borg Warner EFR's (the ones we use in our deluxe kit) are a new technology design that address several issue with past designs, and the internal bypass allows the turbine wheel (made out of Gamma-Ti Titanium alloy) to continue spinning at speed for faster recovery and the Gamma-Ti allow cuts turbine inertia by app 50% dramatically improving response time & spool-up. They also have integrated adjustable wastegates (not the plate style of old) so external wastegates are not needed. They also have Stainless Steel turbine housings VS cast iron that allow for less weight & thermal inertia.
The problem right now is availability. With the IRL cars going to turbos this season the teams have bought up most any in existance (we were lucky to get the ones for Whiteside Customs when we did) so it will be Jan/Feb 2012 before we expect the next batch. In the mean time we are using ceramic ball bearing top quality units for the systems.
