Alternative Airbox

Was talking to someone in the pitlane at Oulton yesterday and the topic of the Exige airbox came up. Apparently, someone has tried a different airbox that is open ended at the right as well as the left and thus has two lengths of ducting down to the left and right air intakes. This apparently improves breathing to the 2 right side cyliners…anyone heard/seen this or care to comment on the theory?

Didn’t the guy from Australia design one like this?
Or was it one fed from the top scoop (redesigned)?

Anyway, I’ve heard of this, but may be better to feed the intake from the roof scoop, as if you use both side scoops, what’s left to cool the engine bay?


…what’s left to cool the engine bay?

Um? The Air Conditioning!


The roof scoop ! - look carefully … ( thanks to Pesky and Steve.E )

I know, but you’re bringing the air intakes down from 3 to 1.
And I don’t know if that one alone can cope with all the work (unless you have it modified like mine )


NACA ducts in the tailgate ?

Its a fantasy of mine

I fancy putting a slimline Pacet fan (or 2!) in the undertray and set it to suck air into the engine bay, this should have the twofold benefit of:

  • increasing downforce
  • cooling engine

…or am I talking *&llocks???


In order to have a fan sucking air there you’d have to run it with such a powerful motor that you’d overload the whole electrical system.
Besides, there are already two NACA ducts in the undertray below the engine, in about the only place they’d work. Have you seen them?


Uldis - not sure i understand what you mean…the Pacet fans are designed for auto use and are rated to pull in x cubic feet of air per minute without overloading any normal electrical circuit

Would you not need a fan to get the air out as well? Then again, you could end up with a presurised engine bay which could in turn act as a sort of turbo…or am I just taking a mad concept too far?


as cool air enters the bottom of the engine bay hot air is drawn out of the top of the engine cover through the flat mesh section. In fact it is pulled out (to a degree) by the airflow over the roof. A fan pushing air in underneath will just help this process.

There is a 340r running a brush skirt mounted to the undertray in an attempt to obtain a little more ground effect

Deep waters, it’s not that easy but let’s start by saying that the way it is, i’t balanced.
If you increase the air in, you have to increase the air out proportionally, otherwise it might be effectless or problems could follow.

First, any fan is advertised as able to move XXX cu.ft/min, but that is with zero differential pressure or helping pressure (like the fan on our radiator, if it is not on, air is still moving, and in the same direction).
In the case of the pressures underneath the car and the engine bay they are very different, the one underneath being lower than the one inside the engine bay.
Air will not move naturally (except in some positions) so a fan will have to fight this differential pressure.
Now, the amount of air that can come out of the perspex section (low pressure zone) is about the same as the addition of the fluxes of: the 2 side scoops + the roof intake.
So you want more air in/out?
You can:

Incraese the hot air out:
open fake vents in exhaust area (the ones with the grille)
open the area behind the numberplate (huge)

Increase cool air in:
open the roof intake (almost like the motorsports one)

With only one mod to increase air in, and since more air is flowing out now, air has to come in on the existing places faster to compensate.

But I wouldn’t touch the undertray, as aerodynamically-wise it is such a critical component of our car (downforce).
Besides, (and you would need proper testing for this) I would think that the fan would need to cope with an air flow that is much bigger than what it can move, and if you get a fan that can move a lot of air, it won’t work with high differential pressures, for that you’d need a bigger DC motor.

In short, one of the proven ways to cool your engine bay (if you’re concerned about that) is te rear plate mod vent, and opening the fake vents at the sides of the exhaust.

Just my 2p.


Uldis - I guess we are all shooting the breeze here…but its good to have different opinions expressed in a sensible manner