etom

I think many of us would be curious to see what various people have done to their air boxes in the name of "drilling" them? Is there a method to this wonderful madness?

Any pics would be greatly appreciated by the non-drilled contingency.

fstockcarrera

Cut off the face and Horn leaving the frame to hold the filter = 4RWHP + Noise
Like this

etom

I am sounding kinda dumb here, but do you mean cut off the horn, leaving more or less a flush hole in the side of the box facing back? Sorry, but the pic does not make this clear. It also sounds like you cut off more or the whole of the face of box, rather than drilling holes. Correct?

Thanks again. The "drilling" has a bit of mystery surrounding it for us novices, perhaps because no two people have done it the same way . . . ?

Cupcar#12

here you go - maybe this will help


more shots here on the Cup registry site

did you dyno the 4rwhp gain? - interesting...
then with the Gizmo and the cut airbox i am +9 HP

etom

Thanks--I see that you cut out the whole of the front face, rather than just drilling holes. Also, in the link, you show that the horn is left on.

Thanks again....

SimonExtreme

OK. I am confused. I thought there was a general consensus that drilling or cutting the airbox didn't add to power! There have been so many threads on this, I am confused!

Andy Roe

I don't think I've read any confirmation that it adds any power at all. It does add a nice intake roar when accelerating hard though. If you're thinking of doing this though, try to have a ride in a car that's had it done before going ahead as not everyone likes it. Better still, buy a spare cover that's already been drilled so you can change back to stock.

boxsey911

Totally agree. My original is below but I've now bought a new one (thanks to a friendly 964RS owner who had a spare ). The response feels smoother with the stock set up (and no intrusive noise).

Red rooster

Cutting the Air box is a race mod with a little virtue .

For road use there will be an inlet temperature rise in slow city driving . If you have a Hammer/ Doug software system pull the lid off, use tape to hold the filter element in place and do some measurements . In the summer 10-20 C temp rise is common.
Hotter intake air makes LESS power . After a bit of faster driving the temp will go back to correct. The inlet temp sensor time loop is a farly slow response .
The choice is 1. Noise is the most important feature or 2. I want best performance !

Sorry to be a kill joy but this is a very simple technical decision !!

Geoff

SimonExtreme

Thanks, Geoff. That is how I understood it! I am about to put a standard cover on (when I source one) and in the mean time, I have stuck tank tape over the holes! I actually prefer the quieter sound

fstockcarrera

I'm just reporting the dyno results that Geoffery and I ran. Maybe he will chime in. Your logic is sound but I'll go with the dyno every time. Sorry why would the factory place a mod that looses power????????

jimq

Haven't we all had this discussion a 100 times at least. This is like the tray on tray off battle

SimonExtreme

Strange. However, I think Red Rooster has probably done as much dyno time on 964 as anybody, if not more. I also know of 3 attempts to prove this all of which were inconclusive.

As for using it on race cars, in that case you shouldn't lose as you aren't sitting in traffic with heat build up in the engine bay.

Red rooster

Bob,
Race is a different situation to road in air temp terms. The 911 rear motor situation adds complication to the whole scene !
In the end I guess your happy with what you are happy with !! and why not.

Geoff

AB-Oz

the PO of my 964 drilled the airbox, I'll take a pic and post it at a more sane hour...