I was wondering what everyone's opinions are about what effect a v-mount intercooler setup has on aerodynamics....most notably, how the air that goes through the radiator later goes under the car. I have some ideas about this, but I just wanted to throw it out there first to get other people's thoughts as well.

 

The same thing happens with a normal set up...

If anything a v-mount combined with a vented hood actually gives you more down-force since it ducts some of the air coming through the bumper up over the car.

 

This still can't be optimal though I wouldn't think.

I know that after I installed my HKS v-mount intercooler and before I installed my Knightsports hood, I could actually see my factory hood bowing up when doing 80+ mph, so a vented hood definitely reduces lift induced by v-mount intercooler airflow.

 

Vent everything through hood, close of underside of engine bay...

Riz.

 

I use a splitter under the front of the car. I have a pair of vents cut into the bottom of the splitter to ensure optimal cooling airflow. Most of the benefit of the splitter comes from the air hitting it and having nowhere to go but up. The under car benefits are substantially less. I've run a slight angle on the splitter to attempt to create a vaccum under the car with little no no effect. The splitter + air dam I currently use gives way more front down force.

I've also built a vented hood using a lightweight race hood and a buddy who does fiberglass work. The ariflow from the intercooler is 100% routed through the hood. with an additional vent slat to allow some rad airflow through as well.

Realistically, you have to be moving pretty fast to get a noticeable effect from the aero work. I think my wing + splitter is good for an additional 5 mph through a high speed corner at 90 mph.

-TrentO

 

That's why you don't want to introduce the air that has passed through the radiator in the under car airstream.

Riz.

 

Riz's thinking is right inline with my thinking and is why I posted this thread. I LOVE my vmount setup, but have been considering a more traditional radiator mounting solution with an air-to-water intecooler. This would also make it easier to duct air to my brakes and turbo inlet. I'm just trying to figure out if the aero benefits that are floating around on my head are accurate??

 

I posted this over at MotoIQ as well and got an interesting response with a link to a Nissan GT-R document showing airflow.

http://www.motoiq.com/forum/aff/15/a...afv/topic.aspx

 

i agree, in the stock configuration, ALL the air goes out the bottom. in theory, venting air to the top is better, but actually quantifying any changes is not easy.

 

Like I said, I would try to vent everything out the top and sides. Top will be easier... As was posted in the GTR article in the other thread, air passes through a radiator pretty slowly (the air velocity is about a quarter of the speed the car is travelling). The differential in air velocity when compaired to air moving over the top of the car, along with the pressure differential (hood (for the most part) is a low pressure area), makes it possible to route the airflow post-radiator through so pretty tight corners. Even more then 270* bends are possible with proper ducting. I have seen race cars where the post-radiator flow pretty much changes direction (controlled by ducting ofcoarse) to vent out the hood, and clear intake and suspension parts. Added benefit: The front of the hood is a lower pressure area.

Riz.

 

Dont forget venting out the wheel wells is an option as well. Make sure to louver the fenders...

 

With an FD I would run dual radiators that evacuate out the side of the front bumper, behind the dive planes, and wheel wells ala, porsche, and a fmic with traditional hood ducting. Where to put the oilcooler you say? I would use a oil/water heat exhanger...

 

This is what I was thinking as well.

 

I have also considered this. If you have the room you could vent behind the front wheels a la DTM. But you will need to place back the engine, and move your seating position back since your pedal assembly will need to be moved back aswell.

On my car I will try to vent everything out the hood after calculating how big the vents need to be. There are formulas, at at some point bigger vents don't have any advantage. IIRC the vent doesn't have to be larger then 2/3 of the cooler surface area. But don't take my word for it, study or consult your local aerodynamicist.

Riz.

 

v-mount is the best way to go

 

You base this on?

Riz.