Airbox - Yes Again!

The airbox on the Stylus has been an ongoing story - not a story of woe I hasten to add, just a story of ideas superseding ideas.

In the beginning the car had sock type filters over alloy trumpets, it works but it means the engine is breathing hot engine bay air, so I got some foam, cut it to make a male mould & made an airbox drawing from a cone filter next to the radiator.

To connect up the hose I used an alloy connector that came with the filter glued into the end of the airbox. It was fine, but after a few years the glue failed & the alloy connector was rattling about.

I hit upon the idea of 3D printing a circular seal which was basically N cross section so the outward facing groove would fit into the edge of the box & the inward groove would fit over the connector flange.

AND IT WORKED!

But (you knew there'd be a "but") the connector sticking out of the angled end of the airbox put the hose very close to the edge of the bonnet aperture & the underside of the bonnet - it looked awkward & I don't like awkward.

So then I thought If I re-designed my seal / retainer, I could have the connector angled downwards, which would make the hose route straighter & take it away from the bodywork.

It looked good, but then I thought - the alloy connector is now swinging off the end of a rubber thing just hooked into a flexible composite box, why am I using it at all?

Back to the drawing board.

The next iteration did away with the alloy connector & just put a bead on the end of the printed thing. I would be using the harder polyurethane, so the hose would still clamp on & yes, a little weight saving, less components, less airflow disruption - marginal improvements I'll grant you, but better is better.

But then I thought - why take the air in through a curved pipe? normally that would be good, aligning the airflow with the space I'm putting it into. However, the trumpets take up a lot of the depth of the airbox, a straight pipe would "aim" the airflow at the trumpet mouths, again marginal, but as I was printing something anyway, why not?

Back to the drawing board again.

So here is the final version, it's a simple shape, so I fired up the printer with shiny black 95 shore hardness TPU & just over six hours later I peeled this off the printer bed.........

I put a "break" in the bead as you can see so a/ the spiral wound hose screws on (ish) & b/ so there was no "support" required for the overhang & the print finished sooner.

Getting it into the end of the airbox was a bit of a trial, but warming it up made the flanges pliable enough to twist into place on the box end wall & it is a tight fit, so isn't going to wobble itself out.

It just remained to wrestle the airbox back over the trumpets (it has to be navigated round the trumpets, the bonnet hinge, the suspension rockers, the fuel pressure valve ......) & connect up the hose.

As you can see, the air hose now runs nicely along with plenty of clearance with the body work. It's tucked nicely out of the way, it could rotate to point a little further down, but I think where is is is the best place.