Wachuko

I drilled mine just for the sweet sound it makes...

marc 1xx1

Don't drill your airbox like cheap swiss cheese.

Carefully cut your box Cupcar Style.

Same improved sound and 'alleged' HP increase, but it looks much nicer.

Agree to adding the secondary bypass. GREAT SOUND.

marc

PS: Has anyone fitted a cat test pipe with this confuguration? Looking for info to or not to.

rutz964C4

I think is also a waist of money I bought a used one and started drilling holes, at the end I just cut a big square hole.


ALEX

joey bagadonuts

Andrew911, Another alternative is to buy one of these (right, Alex?).


Marc 1xx1, I'm running a secondary and cat bypass along with cone. I love this configuation and I believe Jeff Curtiss (moderator/racer) runs virtually the same setup.

Flatsixer

Does anybody run the Fabspeed exhaust, cat bypass and cupstyle airbox combined ? This is what I endeavor to do but want to do wheels and suspension first. That combo must sound great plus you get rid of a reasonable amount of weight. Regards, Brady

rutz964C4

For the price of the Fabspeed you can buy a cone filter like the one joey shows, much better than the Fabspeed.


ALEX

Flatsixer

Is it really better though ?? My experiences with cone filters on previous cars are excessive noise. I would also be concerned that the cone filter on the 964 would absorb more heat being directly exposed to the hot airstream in the engine compartment. Regards, Brady

andrew911

Thanks for the input- maybe I'll try to find a used one & use that to drill the holes!

"KY-91C2", I know some people on the board have to measure the specific decible rating of their car for inspection (seems like a bunch of the European countries require this), but why on earth do your local SCCA (Sports Car Club of America) events measure the dBA level when racing on a prepared autocross or track event? Is it because they require the car to be "stock" or street legel for competitive events?

JoeW

Andrew,

SCCA has maximums for noise, but (at least in the NERegion) at a specific distance. When we race at NHIS, for example, a worker is sent w/equipment to stand between the track and a residential area to measure the noise and make sure it is less than 98 decibels, IIRC. As you can understand, in residential areas racers have to be careful for the neighbors. At Lime Rock this summer everything had to stop for "lunch" from 11:30 to 1:00 for a wedding in a nearby chapel! J

garrett376

Our local PCA runs at the stadium parking lot for their autocrosses, and 92DB is the max allowable there. At Laguna Seca, there are only a certain number of days they allow loud cars, so the "lesser" events like the POC, PCA, and NASA races we have to run full mufflers that are 92DB or less (or is it 98, I don't recall). Not too much fun, I like the noise of an open exhaust!

John Miles

I don't believe drilled airboxes have any effect on static noise tests. The great sound really only occurs when the engine is under load, pulling hard. With revs held at 4500 you don't get the great sound. Accelerate hard through 4500 and you do.
Seems to me as well that the sound is much more noticeable from inside the car than out.

Anyone any explanation for the above?

J

darkvoltage

4 hp out of the stock 250 hp is a +1.6% increase; is it really worth the trouble?

Jim Howley

People's opinions on this topic appear fairly mixed but I would not consider the power increase when deciding whether or not to do this mod. Find a 964 which has had it done and go for a drive. You'll either like the noise it makes or you won't, you certainly wont feel the power increase if there is one.

As for the trouble involved I reckon it was well worth the 15 mins of effort!

Greg_L

I wholeheartedly agree with Jim, only i'd add that 99% of people will like the noise
I'm going to ask santa for a K&N filter .

Arjan B.

Attention with the cone filters..... watch if no water drops in from the bonnet. Rain and car wash could give too much water which comes in the filter!!!!!!!!!

With a drilled air filter box, water stays out, but for sure, I drilled a extra 10mm hole in the bottem of the filter housing for evt waterdrain.