[shlim8]

violametallic-s, what did you do with the air vent hose that goes to the rubber intake pipe between the airfilter and the throttle body on the original, after installing the ipd plenum ?

The equivalent ipd intake pipe does not have a vent hole for the pipe to plug in, so my mechanic just capped the vent pipe and said that it's ok. In fact it's just dangling there now... will go in later to fix that.

I had the ipd plenum, a bmc airfilter and the aos changed at the same time and my reaction was.... in order of how much of a surprise...

1. The intake roar when flooring it was surprising (from a bmc filter, and NOT de-snorkelled) - it's LOUD ! Did not expect this at all.
2. The engine is now creamier and smooth... I would presume this is from the aos ?? I did not have excessive pressure from the oil filler cap but changed the aos anyway as with the plenum and tb off, access to the aos was slightly easier. I did have oil in the intake pipes.
3. Pull from the engine is definitely improved.... It used to be less willing to rev up (like internal resistance) but now pulls cleanly. Going from 110km/h to 200km/h is now a breeze
4. Improved fuel economy ??? Seems odd, but that's what my last run showed and quite significantly too, but then again perhaps its due to a lower avg speed due to traffic. Need to monitor.

Overall, there's significant improvement in the engine's pull and eargerness... Probably more effective on a 986 as there is also an increase in the TB size, improving the throttle response (mine's a tip).