I have been looking at different designs for this on other cars on the web, but haven't seen much in the line of Miata's. If anyone else have seen good designs, please post them up. I want a open discussion and ideas on the subject.

So after doing some measurements this is what I came up with for the front half of the duct. I will be going turbo eventually, so this design will be changing down the road.

If you have specific build questions on the car and not on the subject, please don't post them on here. Go to my build https://www.miataturbo.net/build-thr...2/#post1088581

I cut the steel bumper, toe hooks and top radiator support to lean the radiator from a 7 deg angle to a 13 deg angle.



After some test fitting







I'm not done mounting but you get what it looks like





More pics to come on part 2 I hope this help some other people with their race cars, I hope to see some more.

 

that seems so much easier without an intercooler in the way

 

Ducting looks great. Im a bit curious what you are going to do with the naca ducts already in the hood if you are going to put a vent behind it.

 

The hood will be changed soon. This one is more or less a test cut hood. (NACA is from a previous project that didn't work)

 

This is the only picture I can find of my old hood. I just cut a rectangle the width of the radiator that stretched from the radiator to the valve cover, and then bolted a piece of 1/8" aluminum angle to the front edge to create a simple louver. It dropped IATs significantly and worked great on track, but I was still street driving the car at the time and it was terrible when it rained because the rain just dumped onto the alternator belt and it would slip like crazy at cruising RPMs. I should have just cut the front edge and the side edges and bent the cutout down into a nice radius, then riveted on some side panels. Whatever you do, just make sure the belts and any electrical connectors are covered.

 

nniiiiiiiicccccccccccccccccccccccccccccccccccccccc eeeeee !!

 

What kind of car is that?

 

Here are some designs that I had on my computer from my research with links

Viper

http://www.timeattackforums.com/foru...louvers-3.html











AMS Evo X Time Attack

http://www.timeattackforums.com/foru...x-build-3.html











GTX Eclipse

 

My new setup will look a lot like #2, but will seal to the hood more like #3.

 

180sx
Builds>> Drifting Not Enough? Add Some Time Attack | Speedhunters

 

Any concerns about rigidity after cutting that much of the cross bracing out?

 

No, due to its in front of the front suspension. The stuff in front of the front suspension and in rear of the rear suspension doesn't have much to do with the stiffness of the chassis.

 

Very good work. The only thing i would say is that the opening is way to big for a N/A miata. iirc measure the radiator and divide by 3 this should roughly be the size of your opening.

 

The Radiator is 12.5" x 25", my opening is 5" x 24" so it is 2.6 times smaller

 

hmm, still looks way big though. look at the 949racing cars and jprestons pic. iirc my car is a 18x6 or so and i could close it up more.

 

Yep, I somehow just noticed the last 2 pics in the first post and was about to say the same thing. Reducing the size of the radiator inlet is a big part of the drag reduction from an EP airdam. I just went out and measured my cutout- it's 4x18" with no mesh or ducting behind it, and my temp gauge stays pegged at 180 deg thermostat temp (I know, I need a 195... lack of research up front + begi spacer + lazy) while on track. The cutouts on the 949 cars appear to be around the same size or even smaller, plus they use different types of mesh to cut down airflow further based on track temp. With ducting, I wouldn't be surprised if 50 sq. in. or less were plenty.

 

I am going to be redoing my air dam and i think i can make it a bunch smaller by having the mouth radiused into the ducting. The radiused edge will be more aero than a 90 degree lip and should force more air in for that particular size.

how it currently sits.

 

Now how did you mount the duct? I like pics.

 

At 180 deg, is with stock power or turbo and whats the HP. At stock hp a CRX radiator could be used.

 

130hp. Factory internals, factory radiator, coolant reroute.