inlet manifold

4ndee · Post by **4ndee** » Mon Jan 31, 2011 7:48 pm

On the inlet manifold there is a vacuum controlled valve, which operates 4 butterflies. My question is what do they do and what are they receiving a vacuum from? BTW its an n.a 3sge

JDM-MAT · Post by **JDM-MAT** » Mon Jan 31, 2011 8:04 pm

Good question

ashley · Post by **ashley** » Mon Jan 31, 2011 9:25 pm

The valves close at higher rpm, decreasing the volume of the inlet manifold at higher rpm. This gives the benefit of increased low/ mid range torque, and increased power at higher rpm through 'inertial supercharging' once the butterfly valves close.

It's called ACIS - Acoustic Control Induction System, and is the main reason for the change in noise that your engine makes at higher rpms

http://en.wikipedia.org/wiki/Acoustic_C ... ion_System

EDITED cos I'm an idiot

4ndee · Post by **4ndee** » Mon Jan 31, 2011 9:29 pm

O ideal. So how do you set up? I have it so the flap is open all the time

ashley · Post by **ashley** » Mon Jan 31, 2011 9:31 pm

EDIT- I might have it the wrong way round, just going to check- the valves may be open at lower rpm and closed at higher rpm...

4ndee · Post by **4ndee** » Mon Jan 31, 2011 9:36 pm

There is a screw on the side to adjust how open they are. I had mine off yesterday and adjusted it so they were as open as possible thinking its letting more air pass. But now I'm thinking its wrong ha ha

ashley · Post by **ashley** » Mon Jan 31, 2011 9:45 pm

Yeah- sorry I'm an idiot- they are normally open, and close at higher rpm to shorten the volume of the inlet manifold

I think you want to set the adjustment so that they fully close once you have a vacum applied to the actuator

4ndee · Post by **4ndee** » Mon Jan 31, 2011 9:48 pm

Surely its needs to be closed? Because as it is it will never be sealed?

ashley · Post by **ashley** » Mon Jan 31, 2011 9:49 pm

When it's open all it does is open the inlet tract to the sealed box above the butterfly valves, so the whole manifold is still sealed from atmosphere, but just has a higher volume.

4ndee · Post by **4ndee** » Mon Jan 31, 2011 10:11 pm

When I say open I mean the flaps open

JDM-MAT · Post by **JDM-MAT** » Tue Feb 01, 2011 9:16 am

What are you hoping from adjusting this? More power/torque

pbmr2 · Post by **pbmr2** » Tue Feb 01, 2011 3:55 pm

you need to put a vacuum tester on the vsv to close the butterflys and then adjust it for a proper seal.

why are you playing with it in the first place? what are you hoping to improve?

spoofer · Post by **spoofer** » Tue Feb 01, 2011 6:51 pm

after head rebuild, my garage told me that half the butter flys in my have broken of the shaft. alsoa few aor leaks causing her to idle at 1600.

vac pipes have been replaced, but will buttler flys being duff hurt my MPG

what would this part be discribed as in an ebay search

www.imoc.co.uk

inlet manifold

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