very nice. Be careful with the fiberglass, I've seen one which was probably a bit old , but clearly mangled/crushed. I don't know if the heat or what can weaken it, but as I view it... when you DIY you should over engineer to some extent to try to get ahead of murphy's law or you can try the KISS (keep it simple, Stupid) approach which is what I did...

Looks good, but are you going to seal up the edges of your duct? Otherwise the air will just take the easiest path, which will be out the edges and around your IC.

I did seal the edges pretty well. I am also rather unclear as to the % of inefficiency that occurs by not forcing 100% of the air through the IC. Obviously forcing all air is best, but with the stock duct air is also re-routed to the intake and the battery which provide alternate "outs".

In the future, I may use some rubber matting to replace the Al. to get a better seal.

Hey...I'm certainly not going to hate on it.

Great job on the fabrication, lord knows if I knew how to do that stuff, I'd be making carbon fiber toilet bowl lids or something. :smoker:

I'm sure you know this, but that's why Mazda relocated the stock intake for the later year models, because at high speed/rpm, the intake was "stealing" airflow from the IC. On my car, the battery is butted up pretty close to the opening, so there's not a whole lot of airflow that can go through there. I was worried about battery life due to heat, but it's still the same battery that was in there when I bought the car four years ago, so I guess it's doing OK. And since I did a somewhat ghetto mod to the stock airbox, I got rid of the stock intake crossover duct; had to anyway because I had to cut the stock duct to work with the SMIC.

I went the rubber mat route, but it was a PIA to get everything to fit and seal up properly. One of these years I'll either just fork out for a Pettit duct, or fabricate one like forcefed.

Where did you find the rubber matting? Any temp issues with it? Thanks.

Hate to admit this, but I got the rubber mat down at the local OSH hardware store. It's the stuff they used for outdoor steps, so it's thick enough to withstand the heat, but thin enough to be pliable so that you can form it a bit to your requirements. You have to cut out some areas carefully so that it doesn't crease up excessively when you fold and form it to both the IC and the stock duct (I cut mine just like yours; there are some sections that are pop-riveted on that I took off). The good part about the stuff is that it's easy to get it to seal up pretty effectively by zip-tie-ing it to the the IC, and pop-riveting it to the stock duct. Yeah, it sounds "fugly", but you can't even see it since it's hidden beneath the top sheet metal bracket that braces the top of the IC to the front body. Plus the stuff doesn't cause interference with the radiator fans, bracket, etc.

Yes, totally ghetto, but it works. I've driven the car hard, then pulled over to check the IC for any signs of heat soak; it was literally cold to the touch.