Air Induction Systems

[JMA -997]

Hey guys!!! I just have a question on this subject. I know that freeing up the intake on some cars can make some HP. On other cars (like a Subaru STi) messing with the intake actually makes LESS power. My question is this, will a high flow intake system like KNN or the like be good for the 997 S??? I also saw some kits that blank of the resonance chamber and replace it with a silicon hose and advertise 15 HP gains with this mod alone. Following this logic, simply fabricating a blocking plate to the resonance chamber will do the same trick. Also what exactly is the purpose of this chamber with thits sensor and vacuum fittings???

[RFM]

If you mean the resonance chamber in the air filter box, this is just for environmental reasons (noise) K & N filters and silicon hoses gives little or no advantage, only a special intake manifold and air filter box, chip, possibly with headers and exhaust is worth it IMHO.

[JMA -997]

If you mean the resonance chamber in the air filter box, this is just for environmental reasons (noise) K & N filters and silicon hoses gives little or no advantage, only a special intake manifold and air filter box, chip, possibly with headers and exhaust is worth it IMHO.

Thanks!!! So far what seems to work was redoing the exhaust to remove the large and restrictive stock mufflers and 400 cel cats and fabricate a free flowing exhaust with 200 cel cats per bank. It's a little louder but pulls like crazy :thankyou:

[berty987]

Its probably worth casting your eye over the parts catalogue at the X51 powerkit and how the parts differ to stock. You will notice the cams are different and the exhaust valves are bigger on the X51 kit , along with different headers. I dont think Porsche would invest in new heads if it wasnt required , so I would suggest though the inlet filter may help , its probably only a very small part of the modifications required to improving performance. A recent porsche magazine article suggested that the X51 powerkit induction kit actually isnt optimised and can be improved upon with an aftermarket kit , though you need to have the manifolds (headers) ECU remap and revised heads already in place to exploit this modification.

Since most Bhp improvment claims are made as a result of a rolling road measurement , its worth mentioning that the Bhp figures claimed on a rolling road are always lower than actual , as the ram air effect of the cars movement cannot be replicated when stationary. As a result , the air filter being replaced or de snorkelled gives a false sense of BHP improvement as the Bhp figure claimed by the performance filter is probably very similar with the standard element when there is a ram air efect. Ultimately in many cases its not the filter but the throttle body, exhaust valve or cam timing that is providing the restriction in the engine breathing. If you take the arguement to the extreme , with no filter , the engine can actually end up running lean , which causes it to overheat . In most cases the overfuelling and lambda sensors adjust the timing to protect the engine from these scenarios , though supplying too much air is in effect a waste , as its always as a result of poorer filtration and at the risk of contaminating the Mass Air Flow sensor (MAF). The standard paper element is pleated so its overall surface area is much larger than the oiled performance one, as a result it takes longer for the entire element to become dirty so the performance or pressure drop across the filter stays consistent for longer. Conversely an oiled element has a smaller area so the gains drop off quicker as the element becomes blocked due to a smaller surface area.

Performance filters have their place on track cars when they can be cleaned and replaced regularly and the engine is already modified in terms of exhaust , inlet , cam and timing. For road cars the beneifts are a different induction sound and a slightly quicker throttle response , though higher maintenance is required to ensure these gains are sustained.

[JMA -997]

Thanks for the input!!! :thankyou: :notworthy: Sooner or later (probably sooner) I will invest in some sort of ECU tuning and mapping with a good wideband. Car runs great now with simple exhaust upgrades. At least for a change I have a car that has performance built in so I guess with proper tuning and goo d parts selection I can hopefuly make 400 WHP....