Induction modifications

[7MAT]

As I had today off work I decided to modify the air-intake system on my Trophy by removing the air-valve located near the horn to see what would happen as most after-market CAI on the market (ITG Maxogen & Viper etc) recommend removing the valve on installation.

To my surprise the cars feels so much better without it, after several test runs I found that the car performed best with the valve and pipe totally removed, I also took out my front fog light so that there was lots of cool air getting in.

This set-up is pretty much identical to a Clio fitted with a Maxogen I saw yesterday evening at Brands that was prepared by Mark Fish Motorsport.

Pick up at low revs is so much better even in fourth gear and there’s a real surge of power at 5200 revs and beyond. I’m extremely pleased with the result especially as it was a sunny 28 degrees here in Croydon this afternoon.

This is what I removed from the car;


Original Renault airbox still in place;


Fog light removed;


Fog light removed with some race mesh;

 

[hyb]

You could enter the clio cup races soon Looks smart

 

[oliie]

Looks good!!!

Just 2 questions...

1) Do you think it would do any damage? I mean why is all this stuff there in the first place? I can't see it adding to lower emissions etc.

2) Where did you get the mesh from?

O.

 

[TrophyDan]

As Oliie said.......

Why the valve in the first place if the engine performs better when taken out?

Try it for a week and see wot happens

(Quite brave taking your car to bits? :shock: )

 

[OliS]

Interesting post Matt, any plans to run a cold feed from the foggy to the airbox?

 

[7MAT]

Oliie
No I don’t think it would do any damage, and not 100% sure why the valve is there in the first place, after all other brands and the few race Clio’s I’ve seen use a less complicated system perfectly well?

The RGA race mesh was purchased from Halfords, bit of a bargin as it was reduced from 21.99 to a fiver.

TrophyDan
Got no idea why Renault put the valve there in the first place – anyone?

Yes I do plan to fully test the changes over the next week to sure as I’ve been fooled like this in the past thinking a change has performed better just because it feels different.

Brave? Not sure about that just a bit bored and fancied having a play. All the removed parts are carefully stored away in my garage and the car can be put back to standard again very easily.

OilS
I’ve been thinking about this one. I’m not 100% sure that a long feed is the answer? Now that the fog light has been removed, there is no shortage of cooler air available. Plus the original factory setup sucks in air from there anyway (2nd feed) so can't be that bad? Perhaps I might try a small pipe about 5inch's long to replicate the neck of the Maxogen system?

 

[Steve]

I thought I remebered reading on here that the valve in the longer air feed was to improve low-end torque. I have absloutely no idea why restricting the air available for induction would improve torque!

Any chance of a rolling road test, before and after? I don't think I would remove the fog, but if the longer feed + valve proves to be just for smoothness/acoustics/emissions - It'll be going. :twisted:

 

[oliie]

Had a quick look today.. it seems thaere are two holes going into the airbox - one has the tube you show above and one has nothing at all (just in front of the one with the tube).

Wasn't easy to remove the tube so left it there for the time being...

O.

 

[big_peaches]

al ready done it and found cold air intake wort it!!!!!!!!!!!!! www.cardomain.com/id/garzo


check it out

 

[son of solo]

i'm always of the opinion that "everythings there for a reason"
theres no sense for renault to fit parts not needed for cost and weight reasons...
maybe on a mk1 golf gti with no modern day electronics,EFI,ECUs and the like throwing out the induction pipes will produce a definate change...we even used to pepper the bottom of the air box with holes untill it resembled a sieve...i wouldnt do this on my trophy now though...

 

[7MAT]

i'm always of the opinion that "everythings there for a reason"

I agree, but the reason probably has nothing to do with performance - more likely to meet emision targets?

 

[son of solo]

i had another think about this...if the pulg that you unpluged in to remove the valve was a closed circuit then the CPU will now think the valve is always open when it shouldnt be and may change something else on the management side due to this...or think there is a fault....or maybe not
its not like reanult sport would spend all that dosh on the engine only for someone to come along and say "hey if you take that pipe of it goes better"...

 

[big_peaches]

CAN VE HAVE SOME PICS OF THE ACTUAL BORE, SHOWING THE VALVE???

 

[George K]

I had always wondered how the valve could help mid-range torque, because it is the 'wrong' side of the airfilter panel to be able to affect any resonant pulses. It is also intriguing that Renault have gone to the trouble of fitting two air inlets to the airbox, both quite reasonably sized (about the same diameter as the throttle butterfly valve), but only fitted the 'valve' to one of them.

As it is popularly known as an accoustic valve perhaps it is to deal with some drive-by noise level issues. This begs the question of whether the egine has been mapped to suit, and that the real benefits would come from removing it and re-mapping. All expensive to find out and would involve quite a lot of back to back rolling road testing.

Perhpas one day someone fron Renault provide the definitive answer.

In the meantime Matt will be interested to hear how you feel about it in a week's times

 

[big_peaches]

oh yeah....the other inlet under the box is alwayso open

 

[7MAT]

CAN VE HAVE SOME PICS OF THE ACTUAL BORE, SHOWING THE VALVE???

Here you go, the valve pipe diameter is only 58mm.

 

[7MAT]

As it is popularly known as an accoustic valve perhaps it is to deal with some drive-by noise level issues. This begs the question of whether the egine has been mapped to suit, and that the real benefits would come from removing it and re-mapping. All expensive to find out and would involve quite a lot of back to back rolling road testing.

I think you are right that the engine will need some re-mapping to make the most out of the changes.

I have been recommended to use Superchips by quite a few people now including Mark Fish and will probably use Sanspeed in Bexleyheath, Surrey.

For £350 they will use the off the shelf Superchips re-map as a base and then map on a rolling road to get the best out of my current set-up.

I was very tempted to go for an ITG Maxogen but think I will stick with the original Renault air-box with the accoutsic valve removed and possibly add a Hill Power bend and some cool air piping?

I've got a de-cat pipe on order with GDI and plan to try this out before I go for a re-map. Will be interesting to see how much the difference is to my sports cat.

 

[Cue]

will keep an eye on this thread to see the results :idea:

 

[7MAT]

It’s been a full week since I took out the acoustic valve and can report no negative effects from removing it. The car has been used everyday on both normal roads and motorways on my journey to and from work. I’ve also had it confirmed and George K is correct the job of the valve is to reduce noise levels.

To try and improve things before I go and have a re-map, I have installed a Venair Sport 85mm air feed pipe (the Renault pipe was 58mm) from the fog light to just in front of the main air-box opening and a Hill Power silicon bend.

Last week I noticed that the Trophy only comes with one single tone horn, so today while I had the arch liner off I fitted some PIAA twin sports horns (very loud).

Here are some pics - enjoy;

 

[OliS]

Good work, nice little mod. Will be interested to hear what the figures are after the re-map.