Why vent your hood?
This is a key element to improving the cooling system, and is well documented in the Miata community. Reducing the pressure behind the radiator creates a larger differential between the front and rear of the radiator. The larger the differential, the greater the airflow. Reducing underhood pressure also cuts down on lift under the front of the car – thus improving downforce.
The problem was we didn’t have any well designed vent options available. There are very few aftermarket hoods, and most of them weigh more than the stock hood. We’ve all seen the DIY vent options out there, including grafting on vents from other cars. Most of these are less than ideal and run into problems as they aren’t intended for our hoods.
Developed through Testing
We started by investigating the pressure and airflow of the stock hood and then tested a number of existing venting options that we had access to. We used the best performing vent we found (Garage Vary Hood) as our benchmark and set out to beat it with a new design from the ground up.
We started with a general design based around what should work well, then tweaked and tested until we arrived at the final version. The result is a louver system including gurney flaps that reduces the pressure under the hood by a staggering 50% and fits NA and NB hoods. Our louvers work in the lightweight factory aluminum hood to minimize cost and you don’t have to deal with poor fitment of aftermarket hoods, and doesn’t sacrifice hood rigidity so that even the stock hood latch can still be used.
Features of the kit
Our Miata louver kits feature an integrated gurney flap design: a vertical fin at the front that creates a low pressure pocket above the length of the vent. Other vents on the market are not designed around actual airflow testing on the car and do not include this feature.
This is a DIY part. That said, we’ve thought about ease of install from the beginning and you get a full vinyl cutting template specific to the NA or NB. The cut template removes all of the guesswork from your install – just stick it on and it shows you where to cut. Also included is rubber trim that fits around the circumference of the holes, making it easy to achieve a clean and finished look.
The louvers ship flat (unbent), you bend the fins when you receive them.
VERSION 2 UPDATE: All of our Miata louver kits now come anodized black. You’re free to finish them in another color if you like; powdercoat, automotive paint, and spray paint will all adhere over the anodize. Another great tip is to go down to your local NAPA and they can paint match to your car’s color and mix it up in a spray can for under $10.