Quote:
Originally Posted by BRZCory
I was under the impression that the stock manifold makes it's power via intake resonance tuning (IRIS valve). And that boost of any type would cancel out the effects of such (hence why turbocharged/supercharged cars don't have variable length intakes, because the pressure wave is a minimal factor compared to the charged intake air).
Processengr, it's an M90. I'd need twin M62's on an EG! which would allow you to retain the stock manifold if you could find room for all of that, but then you'd probably need a 12" cowl hood!  |
First off Cory, the standard manifold does not have “variable length intakes”. It uses two systems, an Inertia system till 4000rpm then a Resonate system from 4000rpm up. Both of these run on a inlet pressure of 14.74psi. It will do the same on an inlet pressure of 21psi. The inlet pressure does not change the way Inertia or Resonate pulsing works. The higher inlet pressure only increases the mass airflow delivered to the engine. It does not change the physics.
About 6 years ago we talked about this, when the ECU tune blower was being used. It was maintained by some that the Svx IRIS would not work when boost was applied, and that the engine power would keep increasing, regardless of the engines inlet system, and because the blower was going to keep pumping air, the power would keep increasing.
In the build the inertia system was removed and the Resonate system had its plenum removed. So that the engines standard power was reduced to a normal 3.3lt engine with no inlet systems.
As time has shown, the end result was that the engine didn't produced the power it was supposed to give with the boost pressure it received, and the torque/power peaks were produced at the same rpm as the standard engine. If the blower had been mounted else were, and the inlet manifold kept as it was, the power would have been produced.
If you want to read this thread about it, ignoring the intrusions, and sidetracking.
http://www.subaru-svx.net/forum/showthread.php?t=32065
Harvey.