rpm's S2

Not sure I understand the logic... what is the difference between the airbox in your car and an additional one you buy to drill holes in? If you do the mod and are unsatisfied with the result (an outcome I have never heard about, though possible I suppose), then buy another airbox and replace.

The airbox mod merely frees up airflow that Porsche originally restricted. When you examine the design of the snorkel and airbox it seems fairly certain that it was designed to keep horsepower down. With the 964 flat six putting out 250hp in 1992 it made sense that Porsche kept the 968 10-12 hp below that. This is also yet another example of what an amazing engine the 3.0 is.

RajDatta

While it will be impossible to ever come up with solid evidence of Porsche doing this to power down the 3.0, a lot of times snorkels are designed to keep induction sound down.
This snorkel could have been the best compromise they found for keeping decent power and induction sound levels.
Anyone who has done this mod can easily attest to the much increased induction sound from the airbox mod.
Raj

rpm's S2

True enough. But even with the mod the induction sound is significantly lower and less aggressive than the 964. The Cayman could outperform the Carrera with just a bit more engineering. Porsche will never never allow that on production vehicles. Fair enough, it is their design/engineering/marketing decision.

I think we are just lucky that such an easy and inexpensive modification has such a noticable result on the 968. We also owe some gratitude to Dave Greimann and Bob Larson for working through the details and doing such a good job of promoting the solution and providing easy to follow templates.

rdhayward

Seems to me, just from inspecting the airbox, that those holes could allow quite a bit of water to splash in, whereas the stock snorkel is bent and aimed to prevent water coming in. Has anyone played with the snorkel itself? (sounds funnier than I meant it to be)

odb812

if anyone needs a spare airbox i can help you out. i bought a spare with the same logic that i can undo the mod, but i can't ever see myself going back.

earossi

A lot of interesting comments on this topic. Yes, the air mod does increase induction noise....but, to a level no louder that the induction noice from my stock BMW 325. Most have described the sound as a good sound. That would include me.

I am struggling with the comment about water getting into the air box. The cavity in which the airbox resides is totally closed off to the world except for the lower grill below the front bumper. The airbox sits about that air path, so it is hard to believe that water will find its way into four 1-1/4 inch openings on the front wall of the airbox.

Actually, Porsche has done such a great job with this motor, that it is really difficult to get any noticeable bumps in torque or horsepower. Sport exhausts will not outperform the OEM exhaust (except for providing a "better" sound). So, other than chipping your car and doing the airbox mod, there really isn't a whole lot you can do without spending big bucks and going radical by doing cams or playing with head mods. And, though I have never driven one of the cars with these radical mods, I would bet that there is a sizeable tradeoff in driveability.

In fact, the engine is go good (except for the very few mods listed above), the only way to improve performance IMO is to begin taking weight out of the car.

rdhayward

Thanks for setting me straight on that. It was an observation but not based on experience.

Jfrahm

True, you can always try to find an airbox later on but if you got one first you'd know that you could undo the mod and how much that'd cost. Also if you can't sleep at night, overcome with shame you can always go out to the garage and put the proper airbox back in :-)

I do not think the airbox is designed to restrict HP. If Porsche wanted to keep HP down on the 968 they could have left off the piston squirters, not bothered with a MAF, skipped the variocam, or something that would also have saved them some money. The car was already too expensive, if they could have drilled a few speed holes and left the piston squirters off I think they would have done it.

One concern I have with the airbox mod is if the stock snorkel pokes out into high pressure air, the new holes will leak that pressure out into the engine bay rather than maintaining it in front of the filter.

-Joel.

SpeedBump

You remove the snorkel after drilling the holes.

Jfrahm

Oh. Hmmm. Doesn't sound like a good idea to me.

SpeedBump

Been done on both my cars for a long time now, but just because some of us do it certainly does not mean everyone should. If you are uncomfortable with it you certainly should not.

rpm's S2

Last year I had the opportunity to drive Bob Larson's heavily modified cab. With a performance chip, RS Barn exhaust, upgraded suspension and a lightweight flywheel (which certainly does technically 'remove weight') his car is the perfect example of the potential lurking within the 968 for quite amazing performance - for a 4 cylinder car without turbo. I was amazed at how much engine response the lightweight flywheel released. Simply stunning, the car revved like an S2000 with torque and had acceleration I never dreamed could come out of this engine without a turbo. Now of course there are tradeoffs. His car could barely clear the driveway and would probably be somewhat tiresome to commute in.

The airbox mod is a great first start. My wife, who occasionally drives the car, immediately noticed the difference in both seat of the pants feel and improved sound. (And just to clarify and debunk - after a year of commuting - including winter cold and rain - I have had no water problems in the airbox). Any one of the good chips is another quick and only slightly expensive upgrade. Beyond that, between suspension, exhaust, and flywheel upgrades, there is a lot of performance potential in this car just waiting to be unleashed.

PorscheDude1

I have no snorkel and have no problems in any weather conditions.

rpm's S2

[QUOTE][I have no snorkel/QUOTE]

It's like we are all suddenly U-boat commanders dealing with damage from an Allied depth charge attack.

RajDatta

Ralph, a 968 would never rev like an S2000 unless serioeusly modified internally. The crank itself on our cars weighs a ton. Just too much reciprocating mass. S2000 engines were 2.0 and later enlarged to 2.2 and their internals are a lot lighter. Just removing 15-18 lbs from our cars will not make them rev like an S2000. They will rev quicker than before but by no means they could light a cnadle under an S2000 or an M3 engine.
There is just too much mass and as you said, there are tradeoff. People are quick to discount turbo charging but a 968 turbo charged engine is a lot easier to live.
Raj