Where did you come up with that? You are absolutely wrong on all counts.

 

+ 1 on the K&N
I love it.

 

I love their drop in filters. They make great products for car.

 

Like to explain exactly why I'm wrong? Do you suggest that the engines doesn't have electronically controlled throttle valves? Or that it is NOT a well known fact that oil filled airfilters can destroy the MAF? You can just read several posts in this very tread to see support on the last point.

My main source for "coming up" with this is Adrian Streathers book Porsche 996: The essential companion, but also other sources like a lot of web forums, magazines etc.

Do you really understand how the engine works with electronically controlled throttle valves??? Me don't think so....

 

Maybe you can explain why you think an electronically controlled throttle valve inhibits any more power from an improved intake? My understanding is that when the throttle valve is wide open (WOT), it does not make any difference how it is kept open. So, at WOT, if a new intake flows better it should provide more power.

The only way I can see that an electronically controlled throttle valve can inhibit this power increase would be if it for some reason did not keep WOT when flooring the pedal.

Or have I missed something???

 

Oh, you read it in a book. I guess it must be right then.

When you leave the classroom and come out into the real world, you'll find that the fact is, oil does NOT destroy the MAF. Additionally, changing to a freer flowing air filter or a more restrictive air fiter will change the way the engine performs, for several reason, with or without an electronically controlled throttlebody.

 

Well I have had the FVD (K&N) sw/intake on my car now for over a week. I just drove from washington DC to Orlando yesterday. The shop that did my instal is by far the best shop I have ever dealt with and will stay loyal to them and their recommendations as long as I own this car (AtSpeed Motorsports). I have only good things to say about the system. I was iffy as to which system to choose but eventually decided to take their suggestion as they spend a lot of their time on RSRs and ACTUAL race cars. The car has noticeably more power especially in the middle range. I drive a C4S and felt that the car was over engineered for the power it put down stock. This little extra bit makes a world of difference for me. I had an opportunity to open the throttle up for a good bit on the drive down and saw 180 on the digital speedo before having to slow down for a curve. I was skeptical of K&N at first because of all the stuff they sell at autozone and everywhere else but the owner of the shop i deal with reminded me that they have a gigantic budget for R&D and spend a lot of time figuring out ways to make their systems as good as possible. If anyone has any questions about my setup I would be more than happy to answer them. This is my first mod.

Also, I misspoke about the corner balance. The C4S does not have a height adjustable suspension stock so all they were able to do was realign the car to a more aggressive setup. I believe the front toe is as close to 0 as possible now.

 

Just installed the Schnell Cold Air Intake with OEM filter. It sounds great compared to stock for just over $100 at Vertex Auto. It took about 7 minutes. I've heard too many stories about the K&N filter fouling the air flow sensor and didn't want to take a chance. Worth every penny. It's not obnoxious, but provides just enough growl to let em know your coming.

 

I had CEL with K&N. Went through tons of R&D, K&N ended up refunding my money and taking it back, CEL went away. Go Evo.

 

Which SW did you have?

 

Well, if you say so I guess it HAS to be right, huh? Great arguments, thx.... I think I live in the real world: As I said, I did not ONLY read that one book - but it is a good one, and has a lot of references to Porsche and well-known Porsche experts. At least I give a reference, unlike most other people here... The arguments in the mentioned book is supported many places, which is a reason that I find them plausible.

On a more "seriuos" note, I actually hope that I'm wrong on this, as I'd like some ekstra HP for almost nothing just as much as anybody. But I have yet to see any valid data or arguments on the following points:

- That the original airbox on a 996 is restrictive (Porsche claims that it isn't), and the fact that remapping the ECU will provide more power suggests that the original airbox has a surplus of airflow in relations to the original mapping. And the original airbox is in fact a cold-air system, so I can't see the difference between that and all the others so-calld CAI.
- Isn't the part of the airbox system where the MAF is installed the limiting part on the whole system? No matter what you change before or after the MAF part, the air has to go through that bit if it isn't removed.
- That the MAF is not in danger of being destroid by oil? There are peolpe arguing the opposite all over the Porsche community, mostly based on their own experience. Can you document the fact that the MAF cannot be destroyed by oil?
- When it comes to the question about WOT like Bjarne asked, my understanding is that the ECU is mapped to give a specific performance, even with WOT, and thus the ECU is the "restricting" part in the whole power chain, and therefor the reason why a remapping is in order. For me it then looks like the throttle valve will only let in the air necessary to give the desired combustion, and no more even if there is more air available.
- Has anybody Dyno'd their car right before and after installing a new airbox, and have hard data on the effect?


BTW 1999Porsche911, I hope you can learn to have a discussion like an adult an give your own reasons for your arguments, and not just try to put down others on a personal level. Just like me, you really don't know anything about other people giving their opinions here....

As I said, I hope I'm proven wrong on this. Good luck on that.

 

I do not think the ECU can restrict the power at WOT if the airflow is higher than stock. This would cause the engine to run lean with the possible consequence of overheating!

Wether or not an aftermarket CAI is acually better than the stock system, is a completly different discussion.

 

That is true, let me refrase my point: Even with the throttle pedal depressed all the way down, the ECU can theoretically ajust the throttle valve to avoid WOT if it is mapped to do that. That is what I ment, sorry for the confusion.

One scenario where this could be likeliy (but I am speculating here, and are not aying that this is true for a M9602/03/04 engine) is if Porsche would like the car to have the same performance regardless of ambient air temperature and/or altitude. Lets say that a car is mapped to provide 300HP and a specific torque band up to 6500ft and up to 105 degrees fahrenheit (or ca. 2000m and 40C) - maybe not at the same time hehe, and that the car is programmed to retain the same performance at any given altitude and temperature below these tresholds. That means that at sea level and at 68F (20C) there will be a lot more oxygen available for the engine due to much denser air, and the throttle valve need not to be wide open even at full throttle to allow for maximum power (i.e. 300HP) under this mapping scheme.

My argument is that something like this is actually possible, and that this could be why the engine will not let more air in without a remap. It will not be true for the M96-01 for 98-99 cars or GT3 engines.

 

That the original airbox on a 996 is restrictive (Porsche claims that it isn't), and the fact that remapping the ECU will provide more power suggests that the original airbox has a surplus of airflow in relations to the original mapping. And the original airbox is in fact a cold-air system, so I can't see the difference between that and all the others so-calld CAI.

I have never seen Porsche’s “claim” that their air box is NOT restrictive. The fact is, the air box and the entire intake system are restrictive by the laws a physics. The remapping of the ECU on a stock intake system involves more than just adding fuel. It includes changes in timing which alone will alter the power delivered by the engine. I fail to see the point of your argument.

That the MAF is not in danger of being destroid by oil? There are peolpe arguing the opposite all over the Porsche community, mostly based on their own experience. Can you document the fact that the MAF cannot be destroyed by oil?


People argue all sorts of things on these boards that are wrong. The presence of oil on the MAF does no damage to the sensor. I have soaked a MAF in a jar of oil for a week, cleaned it off and it is currently running as designed in my SC’d, oil soaked intake filtered 996 and has for the past 70,000 miles. What oil can do to the MAF is to change the sensitivity of the sensors which is easily corrected by proper cleaning. The reason MAF’s fail is because of the increase in airflow past them which increases the current passing through the circuit. A very dirty MAF or a MAF that is running at or near peak limits, can be damaged by this increase in air flow which allows the MAF to produce current which is too high for too long and thereby burning it out. This problem is easily eliminated as I have stated numerous times on this forum.

Isn't the part of the air box system where the MAF is installed the limiting part on the whole system? No matter what you change before or after the MAF part, the air has to go through that bit if it isn't removed.

No, you are incorrect. The amount of airflow to the cylinders is not simply determined by the volume of air passing into the throttebody by also by its velocity. Often, the increase in restriction of the airflow at the throttle body and afterwards can dramatically increase engine performance depending on the particular intake design. Porsche does exactly this by using a variable length intake. Additionally, reducing the restriction to the intake air BEFORE the throttle body as many aftermarket filters attempt to do reduces the temperature of the air due to the restriction reduction. The frequency of the air is also changed as is the velocity of the air to the throttle body.

It is a common misconception that all restrictions or an increase in pressure in a closed system automatically translates to less flow. Many people use this argument to justify using Mobil Water in their crankcase rather than a proper viscosity oil, thinking their abnormally low oil pressure readings means there is more oil flow when in fact the volume of oil flow is the same.

Even with NO increase in the volume of air getting past the throttle body, a change in frequency and velocity of the air can translate into better volumetric efficiency which translates into better engine performance.



Has anybody Dyno'd their car right before and after installing a new airbox, and have hard data on the effect?


If you hope to properly learn about engine performance, you need to first accept the fact that 99.9% of dyno results are bogus and do not translate into real world performance. There are too many variables that are not controlled. I won’t get into all the problems with dyno racing as it has been covered here before.

 

Upgrading your intake is like shaving your body to swim faster.
It will sound like you're really going fast though

1999P911, way to sneak in the oil into the air wars..lol