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 Air intake.. front or back?
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Lowe
Level 1 User

Joined: 10 Aug 2004
Posts: 28

Posted: Tue Feb 01, 2005 9:33 am

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:

Image

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

Image

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....
david3533
Site Subscriber

Joined: 02 Oct 2004
Posts: 1575

Posted: Tue Feb 01, 2005 10:03 am

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.
Chris H
Forum Moderator

Joined: 02 Mar 2004
Posts: 19978

Posted: Tue Feb 01, 2005 10:04 am

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.
Lowe
Level 1 User

Joined: 10 Aug 2004
Posts: 28

Posted: Wed Feb 02, 2005 2:17 am

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
JB
Mr Quoter-vator

Joined: 16 Feb 2004
Posts: 7405

Posted: Wed Feb 02, 2005 7:28 am

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
Lowe
Level 1 User

Joined: 10 Aug 2004
Posts: 28

Posted: Wed Feb 02, 2005 9:15 am

I'd imagine so. Last thing they want is hydralic lock Very Happy
Chris H
Forum Moderator

Joined: 02 Mar 2004
Posts: 19978

Posted: Wed Feb 02, 2005 9:21 am

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.
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