Anyone know just how functional the vents/scoop on our cars are? I am trying to bring down the "lets race" look a bit after being pulled over numerous times because police thought i was going fast and have a really nice offer on a trade+cash lancer hood from a friend.

Thoughts?

 

I'm pretty sure on the Ralliart's that it is as useful on my evo IX.
On a cool wet day you'll see quite a bit of heat escaping the vents. Remember that turbos create alot of heat. More than a N/A car.

I'd say keep the hood and get a good radar detector. The cops will get used to seeing you eventually.

 

Yeah, I've unbolted the plates to make them all functional (or even more functional).

You don't want to keep that much heat under there. It gets pretty hot...

 

The back vent on the Ralliart hood is for cooling the turbo down, you'll notice that it's pretty much pointed that way. The front scoop on the right (when looking at the front) is for the air box and the one for the left is for....well not quite sure but it would look weird missing.

 

You guys are close, but a little off; yes it's to reduce under the hood temps. Air comes in through the center scoop, pulling heat away from the turbo and engine, and then pulled out the front vents; but its a system of convection. You see how the hood makes a sharp angle right at the leading edge of those vents? That's a brilliant design of using the air moving across the outside of the hood to pull out air from under the hood

 

I disagree.

The fronts 'vent' the radiator/FMIC heat away from the engine/bay while the rear (NACA-style) vent pulls in cool air (boundary layer pressurized) to flow in over the turbo. Need to see a CFD and thermograph to be sure- but i am pretty confident.

 

Actually, with the heat shield in place, it would seem the NACA duct is designed to keep the heat from the turbo from rising up and affecting the rest of the engine. The turbo itself does not have any air from the duct blowing directly on it.

 

So, in short, yes you need it. lol.

 

lol. I kinda figured such. Im usually not actually speeding, but rather they get someone on radar and see my car and assume its me and not one of the millions of BMWs around me.

 

I think we agree. Blowing cool outside air down = keeping hot air from turbo going up. The entire bay (aft portion of engine) behind the NACA duct gets cool air which exits under the car.

 

It works with the undertray for the car to vent hot air down and out.
The drivers side vent is used by the I take and the passenger side vents overall front of block. You will notice in the winter the passenger side snow melts before the others.

 

The RA hood is so much lighter too. Would be a bad choice to swap!

 

Not sure how useful it is since I saw a review where the 2011 RA in australia has the naca duct basically plugged.

 

symmetry my friend

 

Not quite it... You are right for the middle one bringing cold air around the turbo...

But the ones one the sides are to take out hot air from the intercooler and radiator... If you look how the vent are oriented, the only way they could get air inside the engine would be if you were driving backward...