Yesterday we did a before and after dyno on a Soarer, specifically testing a set of intake pipes(imported from Kurt Atzmuller in australia). The
theory is that the small diameter pipes leading to the turbos are a restriction. several cars in australia had reported earlier spool up, and boost increases, which showed that they were restricted. But we needed dyno proof.
the car was a Wellington based Jzz30 , with twin dump pipes(a dump off each turbo) a large diameter exhaust system, a Front mount intercooler, with a shift kitted auto trans. The base run was 236 hub kW on The STM dyno at 16psi boost, with no boost controller.
The intake pipes are 3 inch in diameter, narrowing down to 2" just prior to the turbos(not much room between the firewall and the compressor cover on that rear turbo).
After the pipes were installed, Evan-the owner, noted the turbos spooled up earlier. The car gained 2psi boost , to 18psi, and experienced 'missing', so the new plugs were replaced with one range colder and gapped down to accommodate the increased boost. final power was 252 hub kW, an increase of 16kW.
2JZGTE owners in the States have experienced similar results.
There are images available on the "Kurt's intake pipes" thread on
www.soarercentral.com