Cool Air And Noise Reduction

My last winter project, this time for the DHC. I have actually been toying with this idea for a few years now, especially after a few longer trips abroad ... So with the preparations for this year's edition of Club Triumph's 10 Countries Run about to start, I thought it a good idea to give it a go. The plan is to get rid of the open K&N filters currently fitted to the engine and replace them with an original air filter box. Well sort of !

The outlines for this little project are to fit a more or less standard air box, but instead of an air filter it will have ram pipes inside. Actually the box is only fitted to reduce noise levels on longer trips, and to help get cool air from the front of the car to the carburettors. 

Here I encountered a few small problems, because I wanted an early box with the two round funnels, as these make fitting the air hoses so much easier. But I also wanted the later type lid with the alignment tabs, instead of the earlier design, as it works much better in aligning the cover and keeping it in place. Here's a picture of the lower edge of the early box ...

Luckily both variants have the same dimensions and have a strip spot welded to their lower edge that acts as locating strip. And this was rather straight forward to swap with a decent drill and a welder. The finished box looks like this, with the alignment tabs clearly visible ...

Also took the opportunity to remove the sensor from the base plate and blank of the hole. Looks much cleaner and the sensor won't be used anyway.

With the air box sorted it was time to focus on the most important part of the exercise, filtering the air and routing it to the air box. I based the design on the original cardboard blanking plates that are mounted to both sides of the radiator. The RH one will be replaced with a steel one. I choose steel as this enables me to weld in two tubes from an old filter box. To the front of these tubes I will fit two universal K&N filters. This way they will sit in front of the radiator and above the oil cooler. This should give them plenty of nice cool air. And to get that air to the carburettors the rear of the two tubes will be connected to the air-box using universal ø44mm air hose. Sadly still waiting for the base plate to be cut, so I can only show how it should look ...