This page contains information about the installation of some bonnet vents into my Honda Civic SiR to reduce the underhood temperatures. The new headers that were installed during the B16A Engine Swap generate a lot more heat than the stock exhaust manifold (which also has a heatshield). To remove some of the excess heat, I tried to find some suitable bonnet vents for my Honda Civic SiR.
For more information and photos of the bonnet vents installation, see the Bonnet Vents Installation web page.
Choosing Bonnet Vents - Installation
Finding some good bonnet vents that would suit the Honda Civic SiR turned out be more difficult than I would have thought given the increasing import scene in New Zealand. Most local places only sold cheap fiberglass Mazda GTR lookalike bonnet vents. I found some other bonnet vents that were similar in design to the Mazda GTR ones, but most of them required a large hole to be cut in the bonnet, which is then covered with a cheap looking fiberglass surround and some aluminium mesh. That seemed a bit silly because you might as well just have cut a hole in the bonnet. The gaping hole probably wouldn't help the aerodynamics and the would allow all sorts of stuff (like rain) to get directly into the engine bay.
With my lack of luck finding some good bonnet vents, I toyed with the idea of using a bonnet scoop and reversing it so it would face backwards instead of forwards. It would probably be functional by pushing in cold air (rather than sucking out hot air) and may even look nice. However, the reversed bonnet scoop would have to be put near the center of the hood (which is miles away from source of the excess heat), be flared into the hood and resprayed. After some thought, I decided the idea was a bad one and started to look on the internet to see what I could find in the way of bonnet vents overseas.
I found heaps of overseas sites that sold really good looking functional bonnet vents, mostly in the UK. Of the companies I emailed for prices and shipping charges, not a single one replied (probably because they couldn't be bothered shipping to New Zealand). However, I did spy the vents that I wanted - some cut in vents designed for a Sierra Cosworth as shown below.
Once I knew what I wanted, I asked around some more of the local body shops to see if they could het hold of the Sierra Cosworth bonnet vents for me. I eventually found one shop that could get them (albeit at a price). It took a couple of weeks but I eventually got what I wanted in black with a carbon fibre finish. The carbon fibre finish is a bit ricey, but it saved me the task of having to paint them because the plain black ones were simply the molded black plastic finish and looked really cheap.
Installation was a piece of cake given that I have access to a bunch of great sheet metal tools. The whole ordeal on only took about an hour and was really straightforward.
Of course if I had wrapped the Custom B16A Headers before installing them in the car, I might not have even needed bonnet vents. So, if you are going to put some new headers on your car I recommend wrapping them, or putting in some form of heat shield if you have room to.
For more information and photos of the bonnet vents installation, see the Bonnet Vents Installation web page.
