JonT

OK, that's funny right there.....

richard glickel.

D,

Other mods wouldn't matter since we: 1. dyno'd car (that's the baseline, regardless of any existing mods); 2. changed airbox for the modified box; then 3. dyno'd car.

rgs944

I have not done the mod yet but plan to this weekend. If it only gains 4 HP that is great. If it gains 10 that would be incredible for something so easy. I already went to a test pipe and I really believe that opened the car up some as well as getting rid of some weightl. It feels like it pulls real strong to me and plenty strong enough to enjoy as a weekend street car. If I get bored Supercharging may come later in the year or next year. As of now it is so much fun it should be a while before I need the added boost of the SC.

RajDatta

I saw 3rwhp increase on a dyno. It's barely noticeable. What you get is a placebo effect of increased intake growl. Makes you think the car is quicker . Good luck.
Raj

Fox944

a 3-4HP gain still makes this arguably the best bang for the buck modification one can do. Even if your car only see's a 4HP gain, thats 4HP more then you had before. Coupled with a much nicer intake growl, and there really isn't any reason not to do it....unless of course you have a bone stock pristine low mileage car which you don't wish to mod. Such as Jeff's Mint Cab, i would not touch a thing on that car outside of restoration.

For the guys seeing an increase of only 4HP, did you replace the stock air filter with a K&N or just simply drill holes in your box with the stock filter in place?

rgs944

Anyone have any thoughts on running the KN with no oil if it was always driven on pavment. Increased flow either going in or coming out seems to be the easiest way for performance gains. I am hopefull that the combination of straight pipe and airbox mod might ad up to 10 to 15HP which should be a noticable difference. Does anyone know of any Dyno test that compared with or without cat?

Damian in NJ

I don't know about other states, but in NJ if you get caught running without a cat you get fined $1,000/year since your last state inspection.

Fox944

Upstate, NY they no longer perform emissions tests on OBD 1 cars. Unless a tropper pulls you over and looks under the car, you will be fine. The odds of that happening are slim to none (especially in a Porsche, they would typically check lowered VW's or Honda's, etc).

However, i would not go catless in my car because it harms the environment and makes the car 2 loud for my tastes. The gains by going catless on a 968 are also very minimal, about half of what some of you claim to be seeing with the airbox mod.

PorscheDude1

You need to oil the filter. Oil is what traps the particles.
Only oil the far side (bottom) of the filter.
If too much oil is used, you run the chance of fouling up the MAF.

rgs944

Just drilled my 4 2 1/8 in. holes. I will take it out for a spin late this evening. I know just by sitting in the car it felt like it is at least 6 HP faster. LOL

rgs944

First test drive with airbox mod. The car feels a little stronger. More air going in and less restricted air going out has got to make a difference. I wish I would have done the test pipe and the air box mod at the same time to feel the entire difference that has been done. Better yet I wish I could have done pre and after dyno's.

midblue

Haven't been on here in a while but this thread caught my eye when I saw it.

I was present and part of the original testing at the dyno shop when this mod was being researched and developed. I saw an increase of a bit over 10 hp on the dyno results with my own eyes. I am not discounting or debating what results anyone else has achieved but I know what I saw on the dyno read out and it was certainly enough of a gain for me to do the mod. I believe that the rings should be used as they help "smooth" the air as it is sucked throught the mod holes and help achieve the max results for this mod (I know this only because the airbox was tested with and without the rings installed).

There were many variations of the mod and several chips tested that day. I was surprised to see any gains in hp/torque after years of being told there were no possibilties of getting anything out of the engine without MAJOR mods being done.

This mod is a no brainer....

Ron
94 coupe/6 speed

Damian in NJ

Nice to see you back Ron!

smshirk

Where can you get rings to fit the holes. I did the mod a long time ago, but never have run across anything the right size. It did feel stronger to me at the time.

Jfrahm

I'm a big skeptic regarding this mod. I have not bothered to try it myself and if I ever do I will try to measure any differences pretty carefully.

Be aware that you cannot really test this mod on a dyno as the ram air effect feeding the stock airbox is negated on a dyno. The stock setup pokes the snorkel into what I believe is a high pressure area while this mod opens the airbox up to a low (or lower) pressure area. Fans on the dyno are not moving that much air, you'd really need to test it on the road and with the lower covers on and the like.

There might be an HP or two on the table due to noise abatement design considerations of the OEM setup, but I dunno. Whatever. Speed holes. Makes the car faster.

If anyone in the front range has a modded airbox we could test it sometime. I have a dead stock one. I also have a K&N and a paper filter. I think you'd have to measure acceleration on a steep hill or something to see if there is any gain.

-Joel.