Air intake.. front or back?

Level 1 User Joined: 10 Aug 2004 Posts: 28

Since I've not got an original airbox, and a BMC CDA came my way for the right money, I've got one of these puppies sat on the desk.

Now supposedly the best way to have it set up is so that the intake is connected up to a pipe which runs to the front of the car, typically in the grill or replacing a foglight. The "ram" effect is supposed to help air get into the system and the intake works more efficiently (apparently).

Now, I've been doing a bit of looking around, and some cars run an intake up to the front of the windscreen, around where the scuttle area is. Supposedly the air is nice and cool here and is also at a low pressure, so the engine can suck air in easily. Renault themselves did this with the Clio Maxi - have a look at this pic:

Gruppe M do an induction kit for the CTR which is very similar:

Other reading suggests the intake on the front of a car isn't all it's cracked up to be, and only gives you an extra 1.2% at high speed (~100mph).

So guys, front or back? I could get an intake scoop made up a bit like that Maxi one....

Site Subscriber Joined: 02 Oct 2004 Posts: 1575

imo the fresh air intake should be at the front ie by the side of the rad, fox light etc. and from what I understand of ram air it don't work until 100-120mph anyway.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

Well Lowe you are mistaken. The area in front of the screen is a high pressure area.

Thats why with the interior fan off you still get air flow into the car.

Air intakes depend very much on the car itself. Some are better near the screen, wheel arch or the front.

But I would say if you can go either way then try it or settle for th eone where the distance is the shortest.

Level 1 User Joined: 10 Aug 2004 Posts: 28

Shortest distance is probably to the front of the car. It'll be probably the coolest as well, since going backwards to the windscreen would mean the airbox sat directly over the turbo, not to mention putting a huge 180 degree kink in the intake. I'll go to the front.

Cheers Chris Smile

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

maybe the rally car has its intake up at the screen area as this is the least likeliest area to get plunged into water...ie large puddles that rally cars usually charge thru....at frt it may have a nasty mouthful of water

Level 1 User Joined: 10 Aug 2004 Posts: 28

I'd imagine so. Last thing they want is hydralic lock Very Happy

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

Well rally cars go through some rather deep puddles.

Cars like the focus WRX have holes in the bonnet above the airbox so any water on the bonnet pours in, obviously theres drainage in the air box.

Its a case of aerodynamics and airflow.

I am goign to eventually do a tech article on it all.