Intake pipe wtf?

[A2ON]

Once the flap is fully closed and fixed closed do you remoe the vacum hose or can it be left on as the flap is sealed shut ?

 

[Foxspeed]

Once the flap is fully closed and fixed closed do you remoe the vacum hose or can it be left on as the flap is sealed shut ?

leave it on - looks original and also will stop it just sucking air from the control valve and the sensor will thinks its working

 

[jaxx]

Can anyone give me a quick explanation to what this thing is/does exactly?

I kind of get the jist...

 

[Foxspeed]

Can anyone give me a quick explanation to what this thing is/does exactly?

I kind of get the jist...

simply - reduces induction noise to pass drive past noise regulations - think its tied in with euro4 emission regs

 

[mradam87]

So does jamming the flap closed not cause any damage then? Surely the ECU still tries to move it?

 

[Ozi]

So does jamming the flap closed not cause any damage then? Surely the ECU still tries to move it?

The ECU doesn't move it iirc it's moved by the vacuum that the engine creates under load. That's why I think it's there for a reason - under heavy load, hot intake air temperature, low revs ie not much speed,...it opens due to the vacuum created under load and "helps" the engine with enough air to accelerate as quickly as possible. After certain revs have been reached it closes.

The thing that convinces me of this is simple. Ever tried to take the resonator of an airbox from a standard car? If you have the chance try it on a 1.2, 1.4,....actually doesn't matter which car just that there is no pipe going to the airbox and you'll hear what I mean. It's almost the same if you put a fairly straight and short pipe (like the secondary one on the 197) on the airbox - the sound is still louder due to the fact no resonator is in front it. Look at some resonator designs and you'll see what I mean.

The second thing is this - driving in summer with my window down I heard a very loud and distinguished induction noise (like the ones I heard on my cars with CAI etc.) but it was only present in between 2k prm - 3k rpm +/- a few revs and only under almost full throttle.

My 2 cents :tongue_smilie:

 

[ben_r1]

Im sure this pipe, as stated above, is an auxillary air inlet, hence why it works off manifold pressure.

 

[simoxmino]

Im sure this pipe, as stated above, is an auxillary air inlet, hence why it works off manifold pressure.

:thumbup1: also for me..

 

[Ozi]

Im sure this pipe, as stated above, is an auxillary air inlet, hence why it works off manifold pressure.

Exactly. Nothing to do with noise regulation :biggrin: in low-revs the car due to it's slow speed needs all the air it can get and that's why it's probably made like this.

 

[Foxspeed]

Im sure this pipe, as stated above, is an auxillary air inlet, hence why it works off manifold pressure.

the opening and closing of the valve is controlled by the ecu - the vacuum is controlled by a seperate valve under influence from the ecu

 

[Ozi]

Still there is no logic in this...

that thing was installed by Renault to pass the European noise standards. its open at low revs and closes above 5k rpm

If it where open then the induction sound would be louder (described above) so no "noise standards". If it's open between low revs till 5k rpm I still don't see a reason why there would be any gains if you would close it. Obviously Renault put it there for a reason - for a NA engine the lenght of the induction pipe, shape of the runners (lenght, width), plenum size, resonance,...everything plays a role and surely Renault put a lot of effort into this. Obviously the engine benefits from this setup at low revs so why close it if it automaticly closes when it's not needed anymore? :001_unsure:

 

[ben_r1]

Its pretty safe to assume that almost anything induction wise on the 197 is best left alone as it seems to be the optimum setup. Unless you want to spend loads on a kevo setup.

 

[ryan197]

its nothing to do with noise as ive been told the box below the radiators expansion tank is the resonator box, i think thats its like what most people have said opens up at certain speed/rpm and probably opens up on cold start as it got an electrical connector on it aswel.

 

[Jib197cup]

its nothing to do with noise as ive been told the box below the radiators expansion tank is the resonator box, i think thats its like what most people have said opens up at certain speed/rpm and probably opens up on cold start as it got an electrical connector on it aswel.

the resonator box does not have a electrical connector

 

[ryan197]

the valve next to the air box does, the resonator box is below expasion tank, wasnt talking about that.

 

[Arun]

for a NA engine the lenght of the induction pipe, shape of the runners (lenght, width), plenum size, resonance,...everything plays a role and surely Renault put a lot of effort into this.

all these things don't matter after the air filter as the filter will surely cancel all effects

there was an official Renault answer on the renaultsport forum refering to the acoustic valve and they admitted that by removing it, you might get marginal gains at the cost of increased induction sound

 

[Ozi]

all these things don't matter after the air filter as the filter will surely cancel all effects

there was an official Renault answer on the renaultsport forum refering to the acoustic valve and they admitted that by removing it, you might get marginal gains at the cost of increased induction sound

Ouh but it does matter how long the induction pipe is. Everything after the air filter has something to do with air flow - steps from rubber hoses, the shape of the end of the pipe, the box of the filter, how many bends the induction pipe has, the interior of hoses, position...etc. All this effect airflow and by that the whole setup of the engine's intake.

Anybody who's closed this pipe - has the induction noise increased at low revs?

 

[rg197r27]

ask foxspeed m8 he should be able to help you

rich

 

[carlo_sg]

Question:
I had my car mapped, and the Tuner removed this pipe completely when fitting a performance filter - see picture below.



Does this increase or decrease performance?
I think the theory was that it allows more air to the airbox.

 

[Ozi]

It's an auxiliary intake for low revs/low speeds so the engine gets as much air as possible when accelerating hard. It closes after certain rpm/speed has been reached cause then the primary intake supplies enough air (colder then from the auxiliary intake) for the stock engine setup.