Lancer Evo VIII hood vent

[Hermie]

It's to reduce front-end lift by reducing underhood pressure, as well as increase cooling from greater ammounts of airflow. I installed some hood vents on my own car.

[jtbo]

This is rather old topic, but I think this link will provide some answers, however not all of them:

Evo 8 (very little aero, mostly marketing, but shows some pics from underside):
http://www.myevo.com/ecms/Lancer%20evo%20VIII.pdf

Current model:
http://www.mitsubishi-motors.com/cor...008/20e_08.pdf

Of course one must remember that this vehicle is not designed for low cd, but for downforce and good cooling when driven hard, so while some elements are designed reduce cd those are mostly meant to reduce increase that comes when making downforce and as such may not apply to lowering cd purpose as they are.

I would think that with hood vent one could get away with smaller front opening for radiator and it might make possible to cover underside of engine bay better.

But what it do for air that goes to wheel wells, will it cause some issues there?

Also I have no idea how vent would affect topside aero, I would imagine that it might increase pressure at windshield and perhaps increase air that goes to sides and the top, where it might cause effect of mirrors and rear top and sides being larger than without vent, but it can be whole lot different from what I think as aero sometimes is not quite so what you think it would be.

[jime57]

According to Hucho, venting out the hood surface is the lowest Cd of all the ways to get warm air out of the engine compartment. So not only does it work from a cooling viewpoint, is is also good aero.

[aerohead]

Originally Posted by NeilBlanchard

Hi,

I see that the (newest?) Mitsubishi Lancer Evo VIII has what appears to be a radiator heat vent in the top of the hood:


While it is not ducted, do you think this either helps the cooling and/or helps the aerodynamics?

Kamm's lowest drag car had the radiator extractor at the base of the windshield.While this cowl area is at a relatively high static pressure,it is lower than the forward stagnation point,so the air does flow out,and Kamm used this flow to help energize the flow which might be prone to stall over the windshield header.This allowed his roofline to work better.He's remembered for the 'Kamm-back' but the accomplishment was the energetic flow which made the roof work.
Mitsubishi has positioned their vent forward,in a higher velocity/lower pressure area and it will provide an outlet.And it should cancel some lift,although most of that is produced just forward of the windshield header.
In a four-season climate,snow might enter,as well as rain.They may have internal guttering to carry precip away,it's hard to tell from the photo.
If the outlet was 'tuned' in the wind tunnel,it might have some potential for drag reduction but as others have mentioned,it may be more of a boy racer sort of thing.If it was tuned,then folks better leave the entire grille area alone.
Mitsubishi remains a player in aerospace.You may remember their products from December 7th,1941,at Pearl Harbor.
Mitsubishi also manufactures submarines for the Japanese navy.So they're not unacquainted with fluid mechanics and I would give them the benefit of the doubt when it came to aerodynamic prowess.
My opinion about cooling system efficiency is that Alberto Morreli(sp?) has set the standard in 1978 with the CNR 'banana' car.

[jtbo]

Originally Posted by aerohead

In a four-season climate,snow might enter,as well as rain.They may have internal guttering to carry precip away,it's hard to tell from the photo.

It has some kind of mesh on top and below that there are air guides, bit like half open blinds (note, photographer has not understood vent being outlet as he claims it being intake):
2006 Mitsubishi Lancer Evolution IX hood | Flickr - Photo Sharing!

Bulge at front of vent is to increase low pressure area at hood vent from my understanding, which might help extract air bit better out.

Self made versions that mimic shaping of EVO hood scoop have been shown to be very effective in throwing snow upwards at speeds of 25mph and above, so it is not very problematic in terms of snow.

Those 'blinds' are probably important part when there is no tunnel, one can also do working vent by simply doing few cuts and pushing leading edge down, to make this kind of shape, but it is important that rear of each fin is not rising above hood level:


If there is small bulge added to leading edge side of vent (that is front) it will work more efficiently.

From my memory, rule was that half way of hood is where one should no longer add exhaust vents, from there to windshield it should be intake area, but of course exceptions may apply.

That is something I wish to experiment, just IC ducting comes on way that runs in hood.

[Mario_Marques]

In a mitsubishi lancer evo, everything you see works, it's not for show off.
I work with rally cars and believe me, lan evo is the closest thing to a wrc a "small amount of money" can buy(compared to a true wrc).
It's almost perfect for his kind of car.