Fender vents/garnishes

[mike the snake]

Next week my turbo kit's going in along with all the other parts and accessories.

In trying to keep my costs down, and also to keep the under-hood temps down, I'm planning on cutting my fender garnishes and the area behind them, turning them into vents, to hopefully help vent the hot air out.

In reading about air pressures, and that removing the plastic at the back of the hood/bottom of windscreen doesn't work because the high pressure at that spot causes air to go IN, not out, I'm wondering about how functional the fender vents might be.

Will they vent hot air at speed, or will they just allow air to be pushed in?

That spot on the fenders being smooth, my guess is Yes, it will pull air out, but I'd like to hear from someone who knows more about this.

Trying to explore things i can do myself before springing for a vented hood.

Thanks for any help.

Mike

[rx3]

Cutting your fender garnishes spray water/dirt in your engine compartment and if it doesn't work you would need to fix your fender garnishes (I'm not sure about the existence of any low pressure region in the wheel wells).

If you want to try a cheaper route you could install such a lip on your spoiler (this would guide more air towards the radiator and provoke a lower pressure region underneath the bumper/engine) and then remove one or both panels underneath the engine (without cutting them up).
[ame="http://www.amazon.com/EZ-Lip-Universal-Bumper-Spoiler/dp/B009F10RVC/ref=sr_1_1?s=automotive&ie=UTF8&qid=1385583827&sr= 1-1&keywords=spoiler+lip"]EZ Lip Universal Front Bumper Spoiler 7.5 Feet : Amazon.com : Automotive[/ame]


3 and/or 2




Are you installing an oil cooler? (As this will work for sure).

But the most important thing is to get an ODBII reader so you know your temperatures and can figure out what works and what doesn't.

[andrew20195]

Originally Posted by mike the snake

In reading about air pressures, and that removing the plastic at the back of the hood/bottom of windscreen doesn't work because the high pressure at that spot causes air to go IN, not out, I'm wondering about how functional the fender vents might be.

Correct on high pressure at the cowl area. Not sure about the fender garnish, also not sure how well the air would flow from the engine bay into that area.

Originally Posted by rx3

Cutting your fender garnishes spray water/dirt in your engine compartment and if it doesn't work you would need to fix your fender garnishes (I'm not sure about the existence of any low pressure region in the wheel wells).

I think he's talking about the exterior "fake vent" fender trim, not the inner fender liner.

[mike the snake]

Looking under the hood, it's a clean shot to the backside of the fender garnish, so air definitely has a clean path to the outside if the garnishes were converted to vents.

This does not affect the inner fenderwell, so no water/debris would be thrown up into the engine bay, although water/rain could get into behind the fender, but it's on a near vertical surface, so not sure how much would actually get back in there in any case.

I know for performance at least I don't want to vent hot air out under the car, but this would be fine for my car as it's 99% street and may see an AX or track day possibly.

[s2d4]

Paging @CSG Mike

[CSG Mike]

I'm not an aerodynamicist, but I'm pretty sure they were left closed on purpose. This car was very carefully designed in terms of aerodynamics, and there are a lot of design cues that show it was made to be slippery.

Stock, all of the air is vented downwards, keeping heat away from the upper components. If you vent the fenders, you'll hurt your aero a bit, and have heat travelling to places it didn't originally, e.g. over your brake master, over your battery, etc.

That's why we chose to have a center vent closest to the front on ImperiousRex's build.

[mike the snake]

When you say center vent closest to the front, is this vent on the hood, or underneath the car?

I'll check, but I think everything under the hood gets hot with no vents at all.

My car will be 99% street, and will spend time stopped in traffic, along with spirited driving on winding roads. Eventually I'll probably go with a vented hood.

[DC2R]

Any developments here? How bad would it be to make a path from engine bay to vents for a daily driver?