RustyRotors

I have been looking at changing the air filter housing on my 96 C2 for the Porsche OE motorsound upgrade. This upgrade looks like it is a modified outer half of the air filter box housing consisting of a chromed funnel that changes the appearance and sound. Perhaps there is more to it but that is what it looks like. Is there any real difference with this modification? I am only looking for some sound improvement. Perhaps a little more growl on accel. I do not think or expect that there will be any horsepower gain.

Then I found in Panorama a non Porsche upgrade for a little more money that essentially looks like the stock airbox with the entire back of the housing cut away fully exposing the actual air filter. Sound improvement over stock or OE sound kit?

Why can't I just cut away my stock unit to look like the aftermarket version and save the $$ ? If I cut it away or use this non-OE version is their a risk of water(rain) entering the filter?

Thanks
Ron

993polarsilver

I have the modified stock airbox that mimics the fabspeed version that you saw in Pano. I am not sure about a HP gain, but it sure sounds nicer than stock. As for water on the filter, I don't have a problem when I wash the car, but would probably swap back to the stock cover during a rainy period. Look for a stock cover in the classifieds or on e-bay, they are cheap, and keep your current one as a backup. Good luck.

kkim

https://rennlist.com/forums/showthre...ght=airbox+lid

https://rennlist.com/forums/showthre...t=airbox+cover

AOW162435

Ron,
You are correct, the Motorsound cover has a chromed lip for appearances. But to achieve the throatier sound, the actual cover has a series of drilled holes.

I've read that the stock cover already has the hole pattern molded into the backside of the cover. Take the stock cover off and see if there is a pattern visible on the inside. If so, go to town with a drill.

My 993 came with the Motorsound cover already installed - great sound! I sold the stock cover before I even had a chance to inspect it.

Andreas

97Targa

The standard cover does have a faint "shadow" of ths MS cover pattern on the inside of it. On mine it was kind of hard to see unless I held it just right in the light. You could mark the pattern with a pencil or sharp object and then drill it.

Bob Rouleau

Drill 7 one inch holes in the side of the airbox. This gets you the sound and the performance increase. Tech tactics with Bruce Anderson reported a 7 HP gain on the dyno. This was also published in Pano. Simple mod and you get free HP.

Rgds,

Crimson Nape Racing

don't waste your time drilling the little wimpy holes the motorsound box has. do what Bob says and drill a bunch of 1" holes - much better sound, especially at WOT.

96C4S

cut it right open like the fab speed sound differance is huge 5000rpm plus

Racer944

Ok Bob;

I'm diggin' out my drill now... I need all the help I can get next spring! ;-)

Eric

cmoss

Drill the holes in a "happy face" for an 8 - 10 hp gain.

RustyRotors

Mine is a '96 so I think the box is a little different than the earlier 93-95 versions. My real concern would be with water/rain. Anybody able to put my mind at ease if I take the large drill to it?

I live in the pacific northwest where it has been known to rain once in awhile. October to April. Should I be worried or go for it?

Thanks
Ron

Bruce SEA 993

I don't think the 1" holes will let any water in...I have had mine drilled for about 5 years now!

DO IT! The sound is very cool.

Cheers

Darrell E

I haven't done my 993 yet but I had both a 964 and a 3.2 Carrera with modified airboxes while I lived in Seattle. The 3.2 had the entire airbox cut away like the Fabspeed version and the RS America had the airbox drilled with 1" holes like the cup cars. Neither car experienced any problems driven in Seattle rain

AV8TR

I can understand how this makes the car sound better, but the claimed power doesn't make sense. I am a pilot and one of our protections from ice is an alternate air door. Essentially if the air filter (air intake) gets clogged with ice or whatever we can pull a handle and there is an alternate door inside the cowling the opens. When this happens you loose manifold pressure because your are sucking in hot air. The one difference is the normal air intake is essentially "ram" air and the inside one is not. Our cars aren't getting air in the same manner, but I would think the air would still be hotter and not as good for the engine as fresh cool air.

Thoughts?

Bob Rouleau

Rain is not an issue. The Motorsports cover has a ton of smaller holes, sort of like a speaker grill. Big enoough to let water in if it was a problem. Eric, sorry, I thought you knew this trick. Power and sound both improve. It works on all 993's froom earliest to the last. As I recall Bruce A's explanation, the 993 had trouble meeting Swiss sound regs. That's why they added the cover under the engine (which EVERY 993 owner should remove (hint to Eric)) and restricted the airbox. The Motorsound option was not made available in Swiss and similar markets. Bruce and Assoc tested the drilled airbox on a dyno and to their surprise, gained 7 HP. The seven x one inch holes trick was tested and yup, they saw from 6-10 HP on the several cars tested. Note to anyone who doesn't know, the holes are drilled in the side of the airbox, the flat part which faces the passenger side of the car when installed.

The rest of the story is also interesting. Having been surprised with a gift of about 7 HP they tested various high performance air cleaners on the dyno. No gain over the stock paper element. As a control, they re-tested with NO air-filter at all. No gain. So much for K and N etc. claims.

This was part of the Tech Tactics presentation back in spring 96 I think. Worth attending the meet in Springfield Mass. to learn little secrets like this.

Best,