I noticed this over the past few days (Dale KSU1998 noticed it too), that my intake (HKS hybrid) isn't as loud as it was with the stock manifold. It sounds pretty much the same as it did from 3000-5000rpms, but after that it stays about the same volume as 5000rpms. Don't get me wrong, it's still loud and you something changed under the hood, but it doesn't have that loud snorty and resonating sound anymore. Instead, the sound is just smooth straight to redline. I think the intake might be quieter because it isn't choking in the upper rpms anymore. At first I thought it might be a vacumm leak, but my idle and overall driveability wouldn't be as smooth as it is right now. Have you guys experienced this?


Dave

 

Yep, mine does the same thing, it almost sounds more agressive. I like the way it sounds. I have the PRCAI. I'm going to try and hook up the vacuum system tonight and get it all working. If you keep the butterflies open for the entire range the sound is a lot quieter than the old manifold.

 

I agree somewhat that it's quieter, but I only drove my car for 3 days before I got hit so I can't go test it now. The rpms definitely go faster, and you can tell the resonance of the intake sound changes after the VI opens up. I would say that since the VI is resonance tuned that's why it sounds different/quieter.
-hype

 

maybe this is not the place to ask, but why do you need a vacuum system to install this intake?

 

Vacuum is what controls the valves opening. At WOT there is no vacuum so it is stored in a canister until it is needed.

 

i guess i am more confused now than before...

 

Yes my intake is quieter with the variable intake manifold.

 

I cant wait to get this mod next year all of a sudden I see lost of you guys posting alot about this MEVI. Heck Ill be helping on the install of one tomorrow so that should help me with my own installation!!

 

Yes I'd say mine is quieter and smoother sounding. Not as harsh at high RPM as before.