Driiling airbox

[Guest]

Hi,
I've heard that some people drill holes in their airboxes for a better sound and more HP.
Is this true?, has anyone done this?
If so can I see a picture pls?

thanks
Amolak

 

[Guest]

You seem to be keen on these 'simple' modifications, what with the cone air filter, etc.

 

[Guest]

Just reading other forums in US, and wanna know what ppl do here.

Sorry if it sounds trival.

Amolak

 

[Guest]

Sorry if it sounds trival.

I did not mean to imply that anything was trivial, just an observation or two, with a view to wondering where the ideas came from, which you have already answered.

 

[Guest]

Sounds good, zero horsepower, no pictures !

Its pretty self explanatory once you remove the airbox cover. You simply take a holesaw and drill some holes. Alternatively cut the whole side panel off. Search for Fabspeed and cup airbox to get an idea of what I am talking about. I also have a recollection that one of the 964 sites (PCGB member, John Miles/Mills???) has info on the drilling and pictures of the finished product.

RB

 

[Guest]

Hi,
Thats funny, it is stated that a 964 would get a few more bhp.

http://www.porsche964.co.uk/technical/airbox_mod.htm

rgds

Amolak

 

[Melv]

Ruf's recomendations: four equal sized holes on the bottom of the airbox;

Porsche chief engineer's (Roland Kussmaul) recomendations: cut out whole airbox, leaving 30mm around the sides to keep the filter in.

Rgds
Mel

 

[Yoda]

I went for the cut away option and am very pleased with the results. I was at Donington on Friday and the car didn't feel any slower (hard to say of there was an increase) but the sound under acceleration, especially beyond 4000rpm was fantastic.

What is particularly good is that on the drive there/back ie on the motorway at 3000rpm the was no additional noise in the car so at a cruise it was not at all intrusive and when you nail it you get the induction roar.

 

[Melv]

"......the car didn't feel any slower ......."

Are you sure?

Mel

 

[Guest]

What is the difference between cutting whole lot and drilling holes?

Would u also recommend a K&N filter ?

I dont plan to use the track (yet)

thanks
Amolak

 

[Guest]

ORIGINAL: Amolak911

Hi,
Thats funny, it is stated that a 964 would get a few more bhp.

http://www.porsche964.co.uk/technical/airbox_mod.htm

rgds

Amolak

Yes, but is there a dyno test or any other evidence to prove that it increases hp? And if it works on a 964, does that mean it has the same effect on a 3.2, which is a smaller capacity with less appetite for air?

Once you have the airbox cover and filter off you can see into the AFM. IMHO you will see that the airbox and snorkel are unlikely to be the cause any restriction compared with the AFM.

In any case, a couple of horsepower is much less than you can feel thru the seat of your pants. I would suggest you take the airbox cover off and duct tape the filter in then go for a drive. You will hear the difference and you can see if you feel any difference. Then you can decide if you want to start drilling or sawing. I cut mine up like the Cup airboxs but I don't expect anything but a nice noise at WOT.

I would use a new paper filter element rather than K&N - I have never seen any independent tests that show they flow better and I have seen tests that show they do not filter as well. Just in case you didn't get the hint in my reply to your other post, many folks are not big fans of K&N - based on the independent evidence, they do not do anything worthwhile and they may hurt your engine. YMMV []

ciao
Richard

 

[Beaky]

I did the latter, easy to do, great sound, but no noticable difference in performance

 

[Andy Tims]

Yes, but is there a dyno test or any other evidence to prove that it increases hp?

Whilst you might see a power increase on a dyno, that will be with fans blowing cool air into the engine bay. This will obviously not be the case when on the move when holes in the airbox result in hot air being "consumed"

 

[Guest]

Just drilled the holes and gave it a rev standing still didnt notice any difference in noise.

going for a spin..............

Amolak

 

[Guest]

HMMM... Didn't notice any difference in noise.

Amolak

 

[Yoda]

Hi Amolak

What you should get is increased induction roar, usually over above 3500 - 4000 revs. I cut mine away and the noise was very good, noticeable but not intrusive. Drilling the holes should have a similar effect.

 

[Guest]

Maybe because I got a sports exhaust, I can't notice it.

Amolak

 

[Guest]

You will only hear a difference in sound at full throttle and at high rpms - like 5000+rpm. Did you test it under these conditions? Even my wife could hear the difference with mine and she has no interest in cars at all, so I can assure you it is quite obvious. Just yesterday, I had another 3.2 owner comment on how loud my car was after a few laps in the passenger seat.

I don't agree with Andy's comment regarding ingesting hot air. Where is the hot air coming from? The engine cooling fan moves so much air thru the engine bay that I simply can't see how hot air can accumulate in an area that is so close to the engine bay grill.

Richard

 

[Guest]

Yes I did notice a growl at high revs.
Sounded a bit like a Ferrari (ouch!)

I remember fitting a cone filter on a Ford COrtina yrs ago, that produced an overall roar throughout the rev range.

tx

Amolak

 

[Guest]

I wish someone would come up with a way to make a noise like a turbo charger on a subaru WRX... I just love that whoooosht between gear changes... then I could drive around deliberatly changing gears just to hear that whistle......?
Maybe I could just fit a whistle next to the drivers seat and when I change gears I could blow in this whistle...?
Do you think anyone would notice...?
what a kcuf bag?[&:]
where's the little blue lights?[&:]
maybe I could tie ten pound notes to the car and listen to them flap as I drive?
Or... put a rare 200 year old scotch in the fuel tank?
Or... stick a coat hanger on the front wing?
maybe fit a towbar?