View Single Post
      09-28-2008, 09:07 AM   #5
lucid
Major General
lucid's Avatar
United_States
374
Rep
8,033
Posts

Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

iTrader: (0)

Quote:
Originally Posted by BimmerRob08 View Post
I'd guess it would be best if a BMW engineer that designed the air box could comment on why they designed it as such. But I think and this is comming from my turbine technical back ground. Massive airflow injested will create high pressure as we all know. But for example, when the turbine engines are starting up, decelerating, and at lower rpm's the compressors have to "bleed" off some of the air that is originally injested from the intake. Only at higher rpm % do the bleed off valves close to allow full consumption of the airflow. So I'm thinking that the concept is the same here where at lower speeds/rpm's the air is allowed to flow without being backed up in a closed airbox. at high speed/rpm's where the engine needs all the air it can get, the airbox probebly allows the max air flow by creating a vacuum at the hood opening by suction. I don't think the M3 airbox was designed to gather air and compress it but to allow the maximum airflow across the filter. Just my technical guess but I cold be wrong. Maybe on a dyno one should seal it off and see what happens.

I do wonder why BMW built to inlet scoops and two opening at the hood although one is functional. I know there is a V10 M5 kit and the engine uses both air scoops/hood outlets but I wonder if BMW have another idea down the road??
This is a plausable explanation. But with the turbine design you are referencing, there are valves that control flow. Are there any valves in the M3 intake system? To the best of my knowledge, there aren't. It could be that flow at the hood opening simply reverses direction when the engine demands more air and the cylinders suck/pump more air in. I've been meaning to stick sensors in the intakes and driver around collecting data, but haven't gotten around to it. Maybe during Thanksgiving break...

I sounds like for whatever reason the single functional hood opening gave them what they were after. Making the other one functional as well might have produced undesired results.
__________________
Appreciate 0