Jörgen

Hi there

I read about drilled airbox, what is the beefit ?, do yio drill holes in the airbiox before the filter ?, then there will be more warm / hot air into the engine, that is something that you want to avoid, or ?

What cams is the best for my 3.0 turbo, the SC or the 964 group B, or ......

Best Regards Jörgen U

Face15

Jorgen,
The drilled holes go on the right side of the air box (looking into the engine compartment), and Steve Wiener recommeds 5-6 1.5" holes. The mod adds a little more bass to your exhaust above 3K RPMs and anytime under full throttle. As far as HP increases, I've heard a few to actually losing 1 with a K&N filter installed. Hope this helps.

andycan

Hey Jorgen. I cut off the top of the lid on my 930 then put in the K/N, complete free flow. [img]C:\airbox2.JPG[/img]

Jörgen

Thanks for you replies !

Ok, I understand, one doesn´t want to loose hp......
I thing I will keep my airbox and try to bring fresh air into it, from the turbowing or elsewhere.Maybe its necessary to enlarge the hole in the box, to secure the flow.

Is it common to install a coneshaped airfilter ?

Best regards Jörgen U, Sweden

ron mcatee

Jorgen, I drilled 2" holes in an airbox I bought from a salvage lot, instead of the 1.5" ones. It improved the performance greatly. As stated above, there is a noise associated with the extra air as you increase the RPM's. It reminds me of my old 66 Pontiac GTO with 2 four barrel carbs without the air cleaner assembly on it. I notice that my 88 Carrera breathes much better and requires less pedal pressure at mid to high ranges to get the same speed.

Robert Henriksen

I cut out two rectangles, in the same place/size/orientation as the pattern the factory uses for the Motorsports Sound package. You can see the placement on a standard lid -- look at the inner surface & you'll see the hole pattern lightly cast into the surface!

Not sure if a bunch of round holes would have a different performance or aural impact as compared w. my two gaping rectangles. I can certainly vouch for a BUNCH more noise!

Full throttle passing through 5,000 rpm is very interesting. When the Varioram changes the intake runner length, you HEAR it!

JGriff

[quote]Originally posted by Robert Henriksen:
<strong>Not sure if a bunch of round holes would have a different performance or aural impact as compared w. my two gaping rectangles. I can certainly vouch for a BUNCH more noise!

Full throttle passing through 5,000 rpm is very interesting.</strong><hr></blockquote>

I went with a bunch of small round holes in my S2's airbox. I too have noticed a performance difference, and the intake and exhaust note has improved as well. So far, I'm happy with it.

Oh, I also have a fiberglass slotted nose panel on the car. (The previous owner included it with the purchase.)

Here are some pics:







Details and a few more pics are on my website (in my sig).

Hope that helps.

Jim

930 Turbo

Guys,

I have a Euro 930, and intend to cut off the fron face of the airbox. I will also try and create some sort of ducting to guide air from the grills to the airbos area.

I will let you know what the results are.

Regards,
Narinder

930 Turbo

Guys,

I have a Euro 930, and intend to cut off the fron face of the airbox. I will also try and create some sort of ducting to guide air from the grills to the airbos area.

I will let you know what the results are.

Regards,
Narinder

1988CarreraCab

Does this drilling/opening process help more than a K&N cone filter? What are the thoughts on the Mass Airflow Kit with computer chip - its kinda pricy at $1700 bucks!

Mongo

Jim I'd leave the airbox cover off your car, keep the filter element. Considering that you have the vented nose panel you will have RAM-Air intake on that S2. Do a cone filter conversion and then you will have both Cold Air and RAM-Air intake. My 2 cents to another 944 owner coming from one..

JGriff

[quote]Originally posted by EuroSpec944:
<strong>Jim I'd leave the airbox cover off your car, keep the filter element. Considering that you have the vented nose panel you will have RAM-Air intake on that S2. Do a cone filter conversion and then you will have both Cold Air and RAM-Air intake. My 2 cents to another 944 owner coming from one.. </strong><hr></blockquote>

The only concern that I have with that (which I have even with the small holes) is water ingestion. I'd certainly hate to grenade the motor due to a hydrolock, be it from heavy rain or splash from a puddle.

I may be a bit too conserative, but I'd rather play it safe than sorry.

Thanks for the feedback.

Jim

Oxford_Hippo

hi,.
has anyone modified the airbox on their 911sc

also wondered how to direct more cold air to it - maybe down from the rear spoiler vents?

thnks

Club Sport 911

Thought...Drilling airbox's is all fine for high RPM / high speed, but correct cylinder charge filling is more about airspeed than airflow. So, perversely a smaller inlet area works best for high torque / low-mid RPM regions.

all this "fresh air" stuff is great for wide open throttle, but actually loses torque when the engine is off cam

FYI - hence Varioram....variable inlet theory etc. Short inlet length = good for high RPM, and long inlet tract = good for low rpm / high torque

Be careful with those holes...

steve