Standard airbox versus aftermarket

[frank]

Thanks again chaps. As said in the comments in the guide, the thought of it all seems very complicated but he made that rather easy to follow.

Could I leave the flap in? I actually quite like the change of noise when it opens.

[PetrolDave]

The argument that manufacturers have designed and tested all parts of a vehicle in a utopian vacuum before it hits the forecourt just doesn't make sense. There are plenty of reasons why development and manufacturing costs are impinged upon and lead to a less than perfect solution.

+1

My daily drive is definitely at the "budget" end of the market (a Citroen C1) and the air intake on that is in about the most stupid possible place - only a few inches away from and right above the pre-cat, so it doesn't take much imagination to work out that on hot days performance is seriously affected as the intake sucks in hot less dense air. All in the name of saving a few cents/pennies...

In most car companies "the bean counters" have to cost reduce something to prove they're worth their jobs, fortunately the RS4 airbox wasn't afflicted in that way!

[adsgreen]

The problem is oem ' s have many various conflicting rules and objectives.

- quiet
- cheap
- easy to mass produce
- effective
- physically fits in the engine bay

Manufacturers like Ferrari who charge a colossal premium can afford to focus on pure performance and be dammed the rest.
Like it or not the RS cars are essentially mass produced and share many components like the air box across many models. As such it is not the 'best' for the car as I'm sure it could be improved. However that being said, in the rs4 ' s case either by luck or design the standard box is more then enough for most applications including forced induction.

[Surrey Sam]

I bought the RS4 because of it's naturally aspirated V8 engine that revs beyond 8200 rpm , if something can then enhance that noise with no loss in power then I'm game.

Can't wait to fit my GruppeM.

[Rick_RS4]

before my exhaust the revolution filter sounded amazing, even the missus noticed the noise and liked it,

there isnt a problem with the revo filter itself then, like it not being able to pass enough air? the problem is the heat soak when sat in traffic etc? also the revo filter is like a cone so it funnels the air into the engine?

these are just my thoughts on the system

[adsgreen]

Funnel effect is nothing. A lot of cone type filters say that they cause a vortex effect to accelerate and reduce turbulent air. But if you look where it needs to go you can see that's not going to do anything magic.
Most of the problems are down to the material - ironically carbon may look good but it absorbs more heat than plastic.

[frank]

Is it ok to leave the flap in the airbox? Does it affect performance at all once the cold air feed is fitted?

[Rick_RS4]

I'd remove the flap and blank off the vac pipe Frank.


Should I take it off for the RR day then? Looking at the surface area the OEM filter is larger too

[MikeFish]

Should I take it off for the RR day then? Looking at the surface area the OEM filter is larger too

Depends whether you want to hit as high a number as possible or want to see what you are getting in the daily configuration.

Or do 2 runs? If you get in early then you will have time to swap the mover and do a 2nd run.
To be honest I doubt there will be much difference on a cold engine. Only once that engine compartment heats up will you see any difference.

[Rick_RS4]

im hoping they will do 2 runs and let me swap in between,

ill go standard and wip out the carbon, hopefully that will make their eyes light up and let me fit it. will post results on sunday

[Noyjatat]

Which rolling road are you heading to Rick?

[Rick_RS4]

Which rolling road are you heading to Rick?

corten miller near skegness, its a local car club im tagging along too, had it on their rollers when i first got it and made 392 i think, now its a little different, hopefully faster

[TonyHayers]

The problem is that the open intake which allows you to hear more induction noise than the standard airbox also allows more hot air in than the standard airbox.

I kinda like the idea of heavily modifying the standard airbox by putting a huge cold air feed in. Basically, making a rectangular trumpet shape which fits almost the entire aux rad position so giving you plenty of cool air but also acting a bit like a loudspeaker for induction noise. SAI would need to come out to make space though.

[frank]

Yes I agree Tony. From what I have read on here I will just be going for a decent cold air feed to standard airbox with some nice heat insulating material around the box.

I still can't see the gains in removing the flap though?

[Covkiller]

I've left my engine as standard, ie, inlet manifold induction flaps in place, both aux rads left in place and got 442ps after a carbon clean & custom MRC Doug map. Which is healthy in anyones book. The thing that made the big difference was installing my Milltek cat bypass pipes. The car now does 447.9ps.