2 x Valves on intake manifold

[Boosted]

Hi All

Just wanting to see if anyone knows what exactly the 2 valves on the intake manifold do?

I just pulled it apart and found the whole manifold covered with 5mm of oily gunk. I also noticed that the butterfly valve on the split runners closes as soon as the cars is turned on and doesnt open at all during revs. Seeing as it is a major flow restriction and cant see any real benefit of the valve I disconnected it and hopefully should improve flow

 

[tweak'e]

see the egr butterfly mod threads.

 

[xtturbo]

Hi All

Just wanting to see if anyone knows what exactly the 2 valves on the intake manifold do?

I just pulled it apart and found the whole manifold covered with 5mm of oily gunk. I also noticed that the butterfly valve on the split runners closes as soon as the cars is turned on and doesnt open at all during revs. Seeing as it is a major flow restriction and cant see any real benefit of the valve I disconnected it and hopefully should improve flow

Put the valve back in - its a variable length intake manifold... the valve will only open under high rpm and load, just reving the car will not suffice.

The point of the valve is to allow the engine to make low down and up top torque.

 

[Boosted]

The valve has never opened. I put a video camera under the bonnet and tested it, i went through the whole rev range a few times and it didnt budge. After i disconnected it i personally think it made an improvement on down low power and at high revs it has gained a noticable amount of power. Plus i have a front mount and i dont think the little bit of extra length on the manifold runners would make much of a difference

 

[tweak'e]

Put the valve back in - its a variable length intake manifold... the valve will only open under high rpm and load, just reving the car will not suffice.

The point of the valve is to allow the engine to make low down and up top torque.

nope not even close.
manifold lengths are about the same anyway and diesels don't have high rpm.

valve closes when in gear and under ~1700 rpm. officially its meant to improve swirl. however as it used in conjunction with egr i think its more egr related. ie increase egr by blocking off half the air flow and the increase in air speed helps mix the egr/air mixture.

all the different vehicles that use that system, there is nothing bad mention if the valve fails. if its disabled it improves volumetric efficiency.
with egr blocked disabling that butterfly valve improves the low rpm pick up a bit.

 

[Krankin]

I think he is talking about the system as used by ford on their 6 cyl EF/EL period intake manifolds.

 

[tweak'e]

I think he is talking about the system as used by ford on their 6 cyl EF/EL period intake manifolds.

yeah and lot of other petrol engines that use similar setups.
yet to see a diesel with variable intake.