Drilled Airbox
11-20-2003, 09:36 PM
#1
Intermediate
Thread Starter
Join Date: Oct 2003
Location: Dayton OH
Posts: 46
Likes: 0
Received 0 Likes
on
0 Posts
Drilled Airbox
Drilled out the airbox with 4 large holes. My car has an Autothority chip. Well took it out tonight and well not all that impressive till I merged onto the highway and gave it full throttle ------WOW! It sounds awesome! Not sure if it is actually faster but it feels faster and it sounds freaking unbelievable. The airbox howls.
11-20-2003, 10:08 PM
#2
Addict
Rennlist Member
Rennlist Member
Join Date: Jan 2003
Location: Tampa, FL
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
Yes, I drilled mine, 5 holes. When it calls for power at around 4,000 RPM it drops a couple of octaves and growls. It's "Rice Repellant" for those occassional Civics that try to close in for a peak at a Porsche.
11-20-2003, 10:36 PM
#3
Three Wheelin'
Don't want to drill my airbox since car is totally stock otherwise...my christmas list has a fabspeed air filter cover so I can get the sound too & keep the stock part...can't wait!
Trending Topics
11-21-2003, 07:27 AM
#8
Remarkable
Rennlist Member
Rennlist Member
Join Date: Jul 2003
Location: Currently living the dream
Posts: 1,648
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTE]Originally posted by Phil Raby
The operator (who knew Porsches) said the drilled box was worth 4-5bhp! [/B]
Phil,
Doesn't 4-5= minus 1?
The operator (who knew Porsches) said the drilled box was worth 4-5bhp! [/B]
Phil,
Doesn't 4-5= minus 1?
11-21-2003, 08:12 AM
#9
Technical Specialist
Rennlist
Lifetime Member
Rennlist
Lifetime Member
Has it ever been proven anywhere whether or not drilling the air box really helps performance?
When they first hit the track, cutting away the airbox was said to gain around 7hp. Don't recall whether that was attributed to Porsche or Rohr as the source. Recent dyno tests have shown that the gain is a bit optimistic.
11-21-2003, 09:58 AM
#10
Burning Brakes
Join Date: May 2001
Location: London (England)
Posts: 1,037
Likes: 0
Received 0 Likes
on
0 Posts
On my 93 C2 it sounded bad, just made it seem like something was not quite right with the engine. At high revs it just sounded higher.
Went in my friend's 91 C4 and it sounded much nicer... How weird!
I have a theory that the holey airbox works best together with the aluminium intakes (present in the earlier models) than it does with the plastic intakes.
Went in my friend's 91 C4 and it sounded much nicer... How weird!
I have a theory that the holey airbox works best together with the aluminium intakes (present in the earlier models) than it does with the plastic intakes.
11-21-2003, 10:45 AM
#11
Drifting
There is a official Porsche bulletin for drilling the holes and how many. The air flow is better towards the engine, so more air means more measured air on the air flow meter, so more fuel will be injected which means a 3 till 5 more horse power [depending what air filter you use.
I drilled mine also and use a K&N cotton filter.
Awesome sound. For the Nurburgring I have a foam special made in the air filter cover size to use if the sound measure is going on [DB'S]
I drilled mine also and use a K&N cotton filter.
Awesome sound. For the Nurburgring I have a foam special made in the air filter cover size to use if the sound measure is going on [DB'S]
11-21-2003, 12:10 PM
#12
Instructor
Join Date: Nov 2001
Location: Kentucky
Posts: 105
Likes: 0
Received 0 Likes
on
0 Posts
Does anyone know what a typical sound level is, at WOT with a drilled airbox? I'm still trying to decide whether I should drill or not.
For our local SCCA autocross events, we have a limit of 98 dBA, when measured at 100 ft.
Ron
91 C2 Cab
85.5 944 NA
For our local SCCA autocross events, we have a limit of 98 dBA, when measured at 100 ft.
Ron
91 C2 Cab
85.5 944 NA
11-21-2003, 12:20 PM
#13
Rennlist Member
Join Date: Feb 2003
Location: Albuquerque, New Mexico, USA
Posts: 1,004
Received 109 Likes
on
64 Posts
There is a official Porsche bulletin for drilling the holes and how many.
Do you have a link or reprint of that? Was it a Euro TSB?
I subscribe to ALLDATA, and if it is a USA TSB, I surely missed it.
BGL
11-21-2003, 12:22 PM
#14
Racer
Join Date: Mar 2002
Location: Farnham, Surrey
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
I drilled my airbox, love the sound and don't worry too much whether it gives a few more horsepower or not.
BTW I have decided I'm going to keep it as is so if there is anyone out there who doesn't like the sound of their drilled box, I will gladly forward the plastic circles I removed to fill the holes in yours.
BTW I have decided I'm going to keep it as is so if there is anyone out there who doesn't like the sound of their drilled box, I will gladly forward the plastic circles I removed to fill the holes in yours.
11-21-2003, 12:44 PM
#15
Drifting
I have to ask my Porsche Specialist, He told me about the many holes and the size of it. I will ask him asap, he is now somwhere for race activities...
I heard from people in England, I think it was John Miles, he had a 104 DB coming out a creb.
Andrew911, Make it yourself, buying one is a complete waste of money!!!
A Fabspeed one is one big square hole....... nothing else.
Find a used one for spare for a 25% of the price!
I heard from people in England, I think it was John Miles, he had a 104 DB coming out a creb.
Andrew911, Make it yourself, buying one is a complete waste of money!!!
A Fabspeed one is one big square hole....... nothing else.
Find a used one for spare for a 25% of the price!