Have you thought about fitting the plastic US spec inlet manifold. It acts like a schrick one but requires a few extra things to work. I was speaking to Martyn Culley a while ago about it, when i was looking into getting morw power in from race car. Seemed to make a big difference.
you sharing my secrets mike? It does make big difference as the design is a like the r32 but to fit the 12v VR6 engine. problem is you need another ecu to have an additional signal to drive the switching of the intake track. Helps improve power and torque.
Read this somewhere else, unfortunately my vr6 is more of a weekend 'sl@g' so won't be spending much money as doing it up on a budget. Someone recently was selling the US plastic intake on ebay for 120 stating it was an upgrade but I just dismissed it, but nice to see there was some truth after all
to get it to work well we also changed the cams to get more overlap to get the intake tracks to work at their optimum. have to also make your own throttle cable holder. We also had to change the throttle body and I think we put on a 1.8 turbo one but cant be sure. If we need more power we would upgrade this and bore out to fit r32 butterfly but we have no need at present. It not the easiest change to make for a trackday or weekday driver.
Just for ref. DIY throttle bodie. There are two humps to grind down. The obvious one at the bottom and the more inconspicous one at the top. It should end up pretty much straight through. Id personally remove the butterfly to do it properly lads.
if the 2.9 inlet manifold is bigger, can the 2.8 obd2 Throttle body fit onto that and grind a few bits out of the TB ? Thnak Joe
