Drilled air-box?

[Bioshock]

A mate of mine has drilled the air-box on his rover 220 gti.
he swears he's noticed a difference in performance.is this wishfull thinking,or does it work??I seem to remember this was a mod on escorts?

[Rico.]

The filter should be getting a lot more cold air now so the car will probably feel more responsive.
I did the same think with my golf and I also felt it was a little quicker off the mark but nothing major.

[robmajorca]

The theory is good but in practice? The big problem will be ensuring that you are bringing cold air into the box as oposed to the hot air picked up off the engine. I don't reckon just cutting a hole will work without being sure of where the air feed is going to come from first, if that makes any sense!!
I cant believe that the increase in performance would be that noticeable, it might feel a bit more responsive and peppy but surely it isnt going to change a cars performance that much?

[Bioshock]

hi rob,thats what i thought,cold air surely needs to be drawn from outside,this thing is drilled like a swiss cheese!

[bryn]

The usual practice is to drill or remove the leading edge/side of the airbox to turn it into a scoop, but as you guys have quite rightly pointed out you need a dedicated cold air feed to maximise the effectiveness of this. Racers in regulated series use it, but in all honesty this mod alone won't be noticeable in performance... It's more a mind thing.

It'll tend to sound a bit better, but that's just because the induction noise is less baffled, I've been on rolling roads and tested this on a Mk1 Golf, so I know it doesn't generally work as a stand alone mod. The airflow of the standard box is often disturbed or disrupted to the point of having a detrimental effect, hmm, getting too heavy... What the hell if it feels faster, it probably is. Back of the net... ;D

[slater]

Depends how restrictive the box was to start with tbh! sometimes the air intake to the box is restrictive so drilling holes helps a bit. sometimes its the filter that is the most restrictive part so drilling the holes desent relly make a differance.

[PhoenixC]

If its thought out and done correctly it will help and as slater says a lot of standard systems can be too restrictive.
Ive never done it myself but have considered it on my S12 as supposedly it does make a big difference to these. The standard intake has a very small x-sectional area.
I did once by a renault clio from a salvage yard. The air box sat on the back of the engine there was no cold air feed and the air box had been turned into swiss cheese. No extra power but it was loud.

[BenzBoy]

Simplifying the intake can give good benefits - the original set-up on my Benz was designed more for quietness than performance, so there were all manner of 90 deg bends, restricted passageways and muffling devices. I lobbed all that in the bin and grafted on an MG Maestro airbox with a K&N for a Sh!troen Suxo inside it (It fits with a bit of coaxing!). I still had to put in a bend from the airbox to the carb as there isn't much space but it works a whole lot better - and sounds pretty good too!
A drilled airbox definitely makes the induction roar more prominent, but as for performance - it may or may not improve it. It all depends what set-up you have in the first place, and where the restrictions are.

[robmajorca]

I think the nails been hit on the head. IF the standard feed is strangled then "unrestricting" it is going to help. We know that manufacturers don't necessarily design components for maximum efficiency, the Merc scenario is a good example, designed to ensure that any noise is kept to the minimum, sod any restrictions on performance.
Probably a mod well worth doing if you have already carried out others and already increased the BHP.
Daz, the Swiss cheese method reminds me of when i was young and silly as opposed to now being old and silly i had a MK1 Escort van that i had dropped a 1600 lump into. Rather than buy a proper filter etc i decided to drill 30 million holes into the standard plastic one. It looked ridiculous, sounded better but gave no performance gains at all, at least i had fun doing it ;D
Anybody else done anything as ridiculous, come on don't be shy, we wont laugh................................

[t5]

I drilled some holes in the airbox on my old mini, definately made in pick up a bit better. I remember an article in one of the mini mags were they tried it out on a dyno. There was a small improvement, not bad for free. I think thay ran it along side a cone type filter which came out quite badly against a K&N replacement filter.

[Deleted]

Nah it just made it noisier so he's driving it with more beans ;D