[Streaker]

I have read through a lot of the threads before joining this forum and maybe I am wrong, but once in my third year of school I heard a theory that a man named Benolli (if I remember right from 28 years ago) stated: With speed pressure drops and vise verse.

Now I know it is fluids he is refering too, but since computational fluid dynamics and aerodynamics go hand in hand doesn't this explain why all our fancy aftermarket air intakes don't deliver the goods? Ram air creates speed and therefore pressure drops! ( To explain, I live at 5600ft altitude so I make 90hp on the wheels, but at sea level I make a 100hp. )

What I learnt with racing bikes (BMW included) was it wasn't the ram air but taking the air from a high pressure source that really makes a diffrence. Before you jump on me for the bike reference, I am a national racer with 4 wheels and I work as an advanced driving instructor for a german manufacturer. Bikes are my hobby!

My idea is create a high pressure zone behind the kidneys, easily done, which doesn't obstruct the radiators yet gives our engines lots of slow moving (high pressure air) which is also cold and not heated. As I am very new to E90's, but have been driving BMW ever since I started working for them in 2001......oops that slipped out.

It won't cost $50 dollars but using simple physics should see a healthy increase in cold air (sort of like the BM performance intake taking air from the windscreen idea). Must admit, it worked on my K12's everytime but I still need to install a similar idea on my 320. Will do soon and keep everyone posted of the results.

P.S: The best counter you can throw at me is ram air forces more air into the intake, but lets think logically, how much will those little scoops in front of the radiators really supply and at what pressure? Also how much radiator surface area you loose through less area and wake turbulance disrubting the air?

Pm me if you curious about my idea!

[Haywood]

I am no scientist and people claim that custom intakes don't make a difference. But, I can definitely feel an increase in throttle response with my Stage 1-3 Riss Racing intake. It doesn't give you the 20-30hp that some companies claim. The biggest gains come from adding DP's and a more free flowing exhaust. I'm happy with my purchase.

[Andrew@ET]

not following instead of scoops your going to use?

[Citizen Z]

The temperature of the intake charge does not impact power in a turbocharged system; only the turbocharger duty cycle. The only case where this is not correct is when you've maxed out your turbocharger. [edit] Ok, never mind, you're talking about NA engines. FWIW, I don't think its possible to create a high pressure zone without experiencing prohibitive cancellation issues from heat. Additionally, the volume of air a vehicle will ingest at its peak power producing RPM won't create a need for a low pressure zone; the air flowing in won't have a much different density than the air moving through the intake due to engine demand.

[josephr25]

I think you meant Bernoulli.

There was a good argument about the ram air effect on a F1 forum I used to go to. Something along the lines of whether the engine is built w/ the ram air effect in mind, as opposed to trying to force the effect on a production engine (which will never see 200 MPH on a constant basis). An intake at that speed isn't necessarily going to work at 60 mph.