SteveW@stig

Found out some hard info on drilled air boxes. This comes from a very experienced race engineer who has worked for Porsche racing teams for a long time.

It makes no difference to the air flow, the standard box has plenty of air flow. It is down to heat, the standard box tends to store heat and when the DME sees more than 25C air intake temp it starts to wind back the ignition, reducing power. So improvements in the summer and not worth it in the winter.

Olli Snellman

I suppose nobody has done this to get more air.It's just that "better" sound.

Olli

Roygarth

Someone should start a poll:

'Have you drilled your air box?'

I don't know how to / don't think I'm allowed to?

BR
Piers

Flying Finn

Terve Olli! (hello Olli),

Just wanted to say hi to a fellow countryman, not many Finns around here.

Airbox,

I think Stewe is right, it's the temp that might give you a slight andvantage.

But in 964 or 993 (maybe 996 too?), if you have fixed wing, you need a snorkel and maybe then, drilling isn't so good (except for the sound, which is always a nice improvement!)

John Miles

Don't tell me that any of you on this list actual believed my tales of HP improvement, optimum hole size etc.
Perhaps we need a wind up graemlin.
J

John Henry

Very good John. You had me going for a while there.
My results are as follows.
Drilled 5/8th holes in each of the ribbing squares, so that means about 20 or so holes altogether. I couldn't tell the difference power wise. The sound is another matter. I initially removed the trumpet section attached to the airbox & the sound is completely different. I real rasp when revved right out, but no difference on part throttle or when cruising. When I washed the car I noticed some water around the airbox so put the trumpet back on & then the sound was the same as with the undrilled airbox, so I assume that most of the difference in the sound is attributed to the removal of the trumpet & not the actual holes in the airbox. Anyone else done a similar experiment

krish

Yup, did the drilled airbox thing and did notice a marked difference in intake roar (sheer music!) but the removal of the trumpet took that tone to another level! Like the latter definitely!! Have just picked up a MAF from another Rennlist member c/w later ECU and chip. This comes with a K&N cone so don't know what acoustic accompaniment I'll end up with but looking forward to the experience!

cheers,
Krish

Wachuko

Yup! Did it just for the awesome sound when flooring the gas pedal, nice howl!! I have the drilled air box cover with a K&N filter.

horst

Last Indy 500, I had a garage & pit pass. I palled around with a mechanic in the tire section of the garage area. He slipped me a set of 8 genuine steel Indy car valve stem covers. Since putting one set on my 964 I am getting at least 5-10 more HP.

John Henry

Yes Horst, I agree, those valve stem covers really do work. Here's another good tip. Polishing the inside of the exhaust tip is good for at least 5 HP!

Richard 92 C2

Just some advise on a technical question please if I may,

I have been told and read on another super car forum that If I chromed (or highly polished) the oil tank filler pipe that I could get better oil movement through to the heat exchangers so that the air into the dryer would be smoother, anyone else heard this and would it cost me an arm and a leg to change?

Only Porsche HP junkies need reply as this is a very technical question!

Christer

I think if this does indeed have any effect whatsoever, that it will not have a good 'bang per buck' rating. Personally, it sounds a bit like shaving your arm so that there is minimum air resistance when cruising with the window down...

This is one 'upgrade' that I have never heard of. Interesting to see what comes back.

DaveK

[quote] Personally, it sounds a bit like shaving your arm so that there is minimum air resistance when cruising with the window down... <hr></blockquote>

You mean I'm the only one? I thought everybody did this.....

RSAErick

Does anyone out there actually understand why (physically/mechanically) drilling your airbox actually changes the sound of the engine? I haven't done the drilling yet, because I just can't understand why it would improve/change the acoustics - not to mention fail to give any performance advantage.

Now shaving my arm and polishing the inside lip of my tail pipe is completely understandable - even by me.

tonytaylor

Richard C2 92

Sorry, and I will come across as being completely thick here, but what is the `dryer` you refer to?