The Acura Legend & Acura RL Forum - View Single Post

Henyaman · 01-19-03, 01:49 PM

Basically is changes the resonnant frequency of the incoming air so that it about matches the speed that the intake valves are opening up. That way it lets the engine "breath" a little easier.
By changing the area of the intake manifold, it changes that frequency to match higher RPM's.

I dont think it makes a HUGE difference, but my main questions is once you are pulling in as much power as DV8, for example, so much more air is coming in that it may be starving the engine at lower RPMs until the other butterflys open. So it may benifit to remove it and polish the entire manifold, on the other hand it may always still match the RPM's/Frequency since when you are making that much more power you rev quicker so it still may be in tune.

Theres only one way to find out. Any other input is welcome. I have my intake manifold sitting here as well and I was trying to figure out if that would be better or what.

This is from an NSX page-
VVIS stands for "Variable Volume Induction System," and is explained in the second NSX book on pages 26-29. The VVIS optimizes the air intake for different rpm ranges. For more low- and mid-range power, these butterfly valves remain closed (they look like paddles in the intake system, one paddle per runner). The book says the VVIS is activated by manifold vacuum above 4,800 rpm. By opening the valves, the intake air has acess to a second plenum which provides more "space" for the air- sort of like the Porsche Varioram system.

A note about the NSX variable induction butterfly valves: You can make it run at max volume all the time by disconnecting the hose to the solenoid and capping it, however I didn't notice any difference in performance when I did this (supposedly I should get less low end torque). Makes you wonder if the variable induction is of any real use or if they included it as a techno-gimmick.

01-19-03, 01:49 PM	#8 (permalink)
Henyaman Registered User Join Date: Mar 2002 Location: Canton OH Posts: 250 Car 1: 1994 Acura Legend iTrader: (0)	Basically is changes the resonnant frequency of the incoming air so that it about matches the speed that the intake valves are opening up. That way it lets the engine "breath" a little easier. By changing the area of the intake manifold, it changes that frequency to match higher RPM's. I dont think it makes a HUGE difference, but my main questions is once you are pulling in as much power as DV8, for example, so much more air is coming in that it may be starving the engine at lower RPMs until the other butterflys open. So it may benifit to remove it and polish the entire manifold, on the other hand it may always still match the RPM's/Frequency since when you are making that much more power you rev quicker so it still may be in tune. Theres only one way to find out. Any other input is welcome. I have my intake manifold sitting here as well and I was trying to figure out if that would be better or what. This is from an NSX page- VVIS stands for "Variable Volume Induction System," and is explained in the second NSX book on pages 26-29. The VVIS optimizes the air intake for different rpm ranges. For more low- and mid-range power, these butterfly valves remain closed (they look like paddles in the intake system, one paddle per runner). The book says the VVIS is activated by manifold vacuum above 4,800 rpm. By opening the valves, the intake air has acess to a second plenum which provides more "space" for the air- sort of like the Porsche Varioram system. A note about the NSX variable induction butterfly valves: You can make it run at max volume all the time by disconnecting the hose to the solenoid and capping it, however I didn't notice any difference in performance when I did this (supposedly I should get less low end torque). Makes you wonder if the variable induction is of any real use or if they included it as a techno-gimmick. __________________ 1994 Acura Legend Sedan <img border="0" src="http://pages.sssnet.com/delanier/legend.jpg" width="516" height="251"> Custom Greddy Cat-Back Exhaust Full Gound Wire Upgrade HKS Intake w/ Breathers Bypassed TB Coolant passage Clarion Audio Epic Arnage 17" Chrome Wheels 3 Layers of Dynamat (Entire Car) Brand New Paint job