Initially I needed to get an air filter organised quickly to test the setup, so I chose a good quality ITG foam filter - these are well made and come in a variety of sizes. In my opinion it's not worth going for some of the cheaper makes filter, the ITG units are very sturdily made and have dual layers of foam. As this was to be used on a road car, I wanted something with the best filtering ability possible for this type of filter.

Although eventually I intend to run a plenum on the rear of the bodies, the foam filter allowed me to run the setup straight away before I committed the time and money into making a plenum. The plenum will attach just as the air filter does to the same backing plate using quarter turn fasteners.

 

The finished filter plate!

 

I used a standard ITG backing plate as the base to hold my horns, and cut the base from the stock Fireblade air box to give me something to fix the horns to, and seal the plate to the bodies using the stock Honda seal, which is integrated into this piece. The air box base was glued to the filter back plate with a high strength engineering epoxy along with the horns.

The intake air temperature sensor was neatly fixed to hide under one of the throttle body pairs, and secured with nylock nuts. 

I sourced some air horns from Jenvey who just happend to make some off the shelf with the exact size to fit perfectly in the Fireblade bodies. They also kindly provided them to me without their mounting bosses attached, as I simply wanted the horns. The flutes were trimmed as required to sit beside each other.

 

The whole backing plate assembly simply bolts onto the the Fireblade bodies in the same way the original airbox was making it easily removable for access round the rear of the engine. Naturally the retaining bolts are fitted with thread locker to avoid any mishap.

 

The complete setup was calculated to give me as much runner length as possible, bearing in mind that a plenum had to be allowed for in the future. The CRX's engine bay presented a number of compromises, so I did what I could with the space available. The slight angle that's added by using the stock Honda throttle body couplers helps gain some extra space, kicking the bodies up slightly at the back.

I could have used a filter with a smaller profile, but this would have placed the trumpet mouths within 10mm of the structure & foam inside. With this filter on there is adequate room to remove it easily, and allow for movement of the engine, and also giving plenty of "breathing room" in the filter.

As always the dyno will reveal all, if changes are required at least they can be easily accomodated.