Acoustic valve...

[r8byb]

been searching for the last two hours so please dont say search,..>

Ive read how to do it etc so im ok with all of that...

I have an ITG panel filter in my air box, will removing the acoustic valve aid me in any way with out the addition of a new cold air feed or is it more likely to loose me abit of low down power..

Also is it worth removing the top cold air feed slightly away as in theory hot air is dense so it travel's quicker, so would that be the best of both worlds as well as getting a bit of induction roar as my car is totally standard and i want a little grunt

Thanks Rob.

 

[graham_172]

take the valve out but leave the feeds unless you change to an induction kit

 

[mattih5]

What is an acoustic valve and what is its purpose?

 

[Christophe]

I've heard its just to reduce induction noise. I could be wrong but im sure someone will clarify

 

[*Clare*]

I have a ITG panel filter on mine also.. I had the acoustic valve removed, but havent done anything else to the air feed at all..

As said before unless you are getting an induction kit then change the feeds.

 

[ben_p]

they do f all, not worth the hasstle to remove it!

 

[Johnc172]

Also is it worth removing the top cold air feed slightly away as in theory hot air is dense so it travel's quicker

Isn't cold air more dense, hence the point of a CAF?

 

[mattjk]

The above applies for outward gases not for inward. Hence people heatwrapping there manifolds. The difference is negligable at best though.

 

[24Seven]

Removed mine and left the standard feeds there for now, too lazy to uprate them but havent lost any power, gained a bit more induction noise and torque seems to have improved ever so slightly lower down in the range. Not really worth the hassle to remove it though I would put mine back on if I could be bothered.

 

[realnumber 1]

I think I read its easier to just disconnect it? I think I also read the MPG can go down slightly when I was looking at doing it. I might well be wrong with that to though?

 

[fil_b]

there is a pipe that connects to it

put a screw in the end else ya car will run weird or not start

 

[JonC]

I've removed the said valve, car drives better at low revs when in a high gear. Pick up from 1.5k rpm is better as the engine no longer what I can only describe as "grumbling". I have replaced AV and hoses and attached a 60mm alloy hose of a similar length to the AV and "furry" hose to the standard air box. I have also replaced the squashed "furry" hose with a 50mm alloy hose under the air box so it all still pretty much as standard as the hoses are the same length.

As an experiment, I also re-attached the AV as before except in a location that I can observe the valve when the engine is under load. And what did it do you ask? Squat diddly doo!! The valve didn't do anything, from idle to the rev limit, no movement! just stayed in the open position. I'll post a video of it in a mo! So all in all the AV did nothing but cause an obstruction the intake!!

 

[JonC]

Heres the valve all connected up doing sweat FA. The engine was warm at the time so perhaps it only works on a cold engine.
http://www.youtube.com/watch?v=w4XWOpLIm3E

Heres a run before the removal of the AV on a cold evening:
http://www.youtube.com/watch?v=QrC01R3Rw9c

Heres a run after removal of the AV on a sunny afternoon, sorry for the poor lighting, it hits a ton at around 16 seconds.
http://www.youtube.com/watch?v=X008U7Ea71s

Overall its about a second quicker through the gears to the ton.

 

[maupineda]

JonC, do you have an image of the hoses you used? I guess you kept the standard plastic fittings to the airbox and just put alloy hoses attached to them. Can you share a pic or two of your mod?

 

[FeelX]

JonC,

Did you have the electrics on the valve? Can't see it not working when warm or cold.

BTW I removed mine a while ago and lost it somewhere

Mauricio,

I'll take a pic of mine in the weekend. gives you an idea.

 

[maupineda]

Mauricio,

I'll take a pic of mine in the weekend. gives you an idea.

Thanks Felix!!! I also have a new custom map Henk sent to fully take adavantage of my ported manifolds. Thanks for all the help with the latter, the car feels eager mid and upper the rev band! This hose thing may help a tiny bit to breathing

 

[JonC]

JonC, do you have an image of the hoses you used? I guess you kept the standard plastic fittings to the airbox and just put alloy hoses attached to them. Can you share a pic or two of your mod?

I used 60mm dia BMC alloy hose for the side intake (a tight fit connecting to the fitting) and a 50mm dia pipercross hose for the bottom intake. The lengh of the side hose is around 40cm, slightly longer than the standard lengh of the hose plus valve. The end of this hose is attached to the bracket for horn and just points down to keep the pipe straight as possible.

Side intake:
http://cliotrophy.co.uk/forum/files/dsc00113_195.jpg

Lower intake:
http://cliotrophy.co.uk/forum/files/dsc00114_161.jpg

When I tested the valve it was connected up as standard, ie, the vaccum pipe to the plenum and with the electrical plug connected.

 

[FeelX]

Ok JonC,

Strange it did not react then. However when the engine is under load it makes another sound (air pressure) and then the valve might be actuated.

Like when you rev the car in neutral you never get the low down grunt as when driving it, and flooring from 2000rpm.

ECU measures pressure inside the inletmanifold and might use that info to operate the valve.

 

[JonC]

I have no idea as to why it didn't do anything. Perhaps someone else has some more insight into how it's supposed to work.

However, for me, the results of removing it speaks for itself.

 

[Neil G]

they do f all, not worth the hasstle to remove it!

+1

 

[mattjk]

It's just opinion really. I think its better without, but could just be all the crack I smoke it could just be my midn playing games with me!

 

[Sir_Dave]

According to Renaultsport themselves, it's there to limit induction noise for EU noise regs. The flap seems to open at 4.5-5k rpm, you then seem to get the '5k kick' .... with a flap closed in an air feed you will get less air. Common sense dictates that if a flap is open and you are getting more cold air, you will get marginally more power.

When i fitted my espace airbox (with ITG filter), I removed mine & replaced it with 100mm ducting, ive subsequently lost the 'kick', but the power curve seems smoother. Not sure on power, but the noise is good MPG has dropped by 2mpg, which would also suggest that the more plentiful, colder air is creating a larger spark, making more power and using more fuel?

I could be talking b****cks though as im no engineer :rasp:

 

[mattjk]

Nope what you have said makes sense but it wouldnt be a bigger spark it be a bigger bang lol

 

[Sir_Dave]

Pah, i was close :rasp:

 

[JonC]

For me since the removal of the AV, the 5K kick is even more pronounced, especially in 2nd gear! It's running so much better with it removed, thought induction noise has increased ever so slightly.

 

[Yellow Dave]

According to Renaultsport themselves, it's there to limit induction noise for EU noise regs. The flap seems to open at 4.5-5k rpm, you then seem to get the '5k kick' .... with a flap closed in an air feed you will get less air. Common sense dictates that if a flap is open and you are getting more cold air, you will get marginally more power.

When i fitted my espace airbox (with ITG filter), I removed mine & replaced it with 100mm ducting, ive subsequently lost the 'kick', but the power curve seems smoother. Not sure on power, but the noise is good MPG has dropped by 2mpg, which would also suggest that the more plentiful, colder air is creating a larger spark, making more power and using more fuel?

I could be talking b****cks though as im no engineer :rasp:

What was the ITG filter for? as i guess they don't make one for the v6 Espace, is it the same as fitted on the Ph-1 172 cylinder style airbox, are they the same airboxes but with different sized feeds on them?
I'm considoring using the v6 Espace airbox but not sure what filter to order

 

[Neil G]

Nonsense

CR designed/mapped to run with it on so leave it in situ

 

[JonC]

Nonsense

CR designed/mapped to run with it on so leave it in situ

Doesn't mean the design cannot be improved upon! If you want save your ears and keep it EU noise compliant, then by all means keep it on. I'm willing to sacrafice a slight increase in noise for a bit more performance for a little effort and for little or no cost.

 

[franx]

According to Renaultsport themselves, it's there to limit induction noise for EU noise regs. The flap seems to open at 4.5-5k rpm, you then seem to get the '5k kick' .... with a flap closed in an air feed you will get less air. Common sense dictates that if a flap is open and you are getting more cold air, you will get marginally more power.

When i fitted my espace airbox (with ITG filter), I removed mine & replaced it with 100mm ducting, ive subsequently lost the 'kick', but the power curve seems smoother. Not sure on power, but the noise is good MPG has dropped by 2mpg, which would also suggest that the more plentiful, colder air is creating a larger spark, making more power and using more fuel?

I could be talking b****cks though as im no engineer :rasp:

What was the ITG filter for? as i guess they don't make one for the v6 Espace, is it the same as fitted on the Ph-1 172 cylinder style airbox, are they the same airboxes but with different sized feeds on them?
I'm considoring using the v6 Espace airbox but not sure what filter to order

Yeah i've also read there are no ITG's for the V6...
i had a look at the pic of his V6 airbox, it seems just the feed is different, the box looks to have the same dimensions as the phase 1 box so you can fit the ITG. He's got a giant 10cm Caf to it, nice one that. I have changed to a phase 1 box, put two 65 mm feeds to it after removing the acoustic valve. Actually having 13cm CAF there then i reckon (2* 6,5cm)..Anything bigger than the pphase 1 box would definately not fit the bay without removing battery+bracket.

Powercurve is more linear, do'nt know if i won anything. Going for a Henk Fastchip special (custom map) to suit the mods soon... Decat and larger feeds, there's gotr to be a gain there... but as said in one of the reactions (Neil) ; you need the map for it to gain benefit i'm also thinking

 

[FeelX]

I spoke to dave (d4ve) about this Ph-1 / Clio cup airbox once before and he fitted the standard ITG filter for a Clio Ph1 if I remember correctly.

Also I thought the airbox of the Ph-1 has 2x 70mm holes where the CAF should be fitted on. The Clio cup airbox has a 100mm hole which has a larger area then the 2x70mm

Also Franx if you fitted 2x65mm feeds I guess the holes are 60mm which is significantly smaller then the 1x100mm

http://www.cliosport.net/forum/showthread.php?t=291218&highlight=cup+racer+airbox

Anyway I still have no idea why the valve did not move

 

[JonC]

Also Franx if you fitted 2x65mm feeds I guess the holes are 60mm which is significantly smaller then the 1x100mm

Area= PI x radius x radius

100mm Feed: 3.14159 x 50 x 50 = 7854mm2

2x65mm Feed: 2 x (3.14159 x 32.5 x32.5) = 6637mm2 - 15.5% smaller

 

[FeelX]

Nice maths JonC

I was too lazy to calculate again.

I know the filters are the same, only a different box...if the inlets of the box aren't restricting airflow there might not be any benefit to fit a clio cup racer airbox.

Anyway bin the valve

 

[Lagerlout]

they do f all, not worth the hasstle to remove it!

+1

Done it. Back to back. No discernable difference whatsoever.

 

[FeelX]

Just for mauricio and everybody who is intrested

My CAF (pikey solution...as always)

Anyway I removed the complete hose including the hard-plastic part that ducts from the original hose to the airbox.

The hole on the airbox is oval and I used a 76mm hose which has a metal band in it. I made it oval and fitted it to the airbox. (here's the pikey part) I used the smallest drill and made an extra hole to use tie-reps to hold the caf to the airbox.

If you look closely you can see it even in this bad picture.

I binned the acoustic valve and routed this CAF to the same place and it's hold tight by the horn and pointed at the grill-type hatch in the bottom plastic cover which is mounted in the bumper.

It gave my car a bit more low down grunt but not real preformance change.

 

[mattjk]

Your engine bay is a bloody mess!! You should be ashamed!

 

[FeelX]

hmmm I know mate...but unfortunately I am not really concerned with it

However it could use a fast wipe down....in Holland most people don't care much about their cars, I do, but not really the clean-ness of my engine bay.

 

[MarkCup]

Your engine bay is a bloody mess!! You should be ashamed!

- I thought that was very clean!

I took my AV out...only worthwhile gain from it is the weight removal

 

[franx]

Also Franx if you fitted 2x65mm feeds I guess the holes are 60mm which is significantly smaller then the 1x100mm

Area= PI x radius x radius

100mm Feed: 3.14159 x 50 x 50 = 7854mm2

2x65mm Feed: 2 x (3.14159 x 32.5 x32.5) = 6637mm2 - 15.5% smaller

I knew that.... :quiet:

After driving around a coupe of weeks i can say i'm happy with the mod.. But also think the most benefit will be after a new map to suit this mod. Still waiting for the decat from K-tec, as soon as that comes in i will be doing a custom Henk job (Fastchip) .

Seeing the thread Dave wrote i can see how much a pain the 10cm feed would be to route down below, it's giant !! With my two 65mm Cafs i will be having to remove them when changing a lightbulb...

Oh, FeelX ; your engine bay looks like mine. Protected under a layer of dust

 

[FeelX]

Yeah Frank, that just the way we Dutch people are. Protecting our stuff under a thick layer of dust

Anyway when you have your decat, we should talk I know you need a cat for APK (MOT) but if the sport cat is good enough for APK you can have my normal CAT for the APK-time and ofcourse we have to talk money by that time.

 

[maupineda]

Just for mauricio and everybody who is intrested

My CAF (pikey solution...as always)

Anyway I removed the complete hose including the hard-plastic part that ducts from the original hose to the airbox.

The hole on the airbox is oval and I used a 76mm hose which has a metal band in it. I made it oval and fitted it to the airbox. (here's the pikey part) I used the smallest drill and made an extra hole to use tie-reps to hold the caf to the airbox.

If you look closely you can see it even in this bad picture.

I binned the acoustic valve and routed this CAF to the same place and it's hold tight by the horn and pointed at the grill-type hatch in the bottom plastic cover which is mounted in the bumper.

It gave my car a bit more low down grunt but not real preformance change.

Thank you Felix!!!!! That is exactly what I was thinking, you seem to be one step furhter all the time

I also plan to do something alike for the bottom duct, Did you do this too? By the way, I currently run the car without the lateral duct at all (the one in your picture) and the car has that induction noise most of us like, many say I am sucking hot air, I say not as much really as that part does not get too hot, what you think? I have tried putting the OEM duct and hose back again but feel the car less responsive. Henk has mapped the car to run as it is, may be this is why as the car is mapped for a bit more air (even if a bit hotter) then with the ducts. Do you know if I put this two large cafs in place I will keep the induction noise but more importantly the amount of air the car has been mapped to? I will give it a try as the the overall volume will be increased with the larger ducts plus a bit colder air!