Caterham 7 – Air Box Filter – Rear Plate Modification

Caterham 7 air box filter box modification

A local neighbor contacted me to inquire if I was able to help him with a modification to his Caterham 7 racing car.  Local, racing car for sure I can help.  He required the back plate of the air filter box modifying to allow the air filter to sit level with the bonnet opening.

As the Client was local I went and collect the existing aluminium slightly bent back plate, and had a quick look at where the new part was going to be fitting and a leaned about the modification.

So nice to meet somebody and see the project up close, makes a nice change from just receiving an email with a drawing just asking for a quotation.

I scanned the old plate and imported the scan in to CAD and used the scan as a template.

Once i started to draw the part, what I was not expecting was there was little symmetry in the hole pattern up to 3mm difference.

Once I had the basic design in CAD I printed it off and over-laid the old back plate over the print.  I then adjusted the holes to match the back plate.  This had to be done several times.

Time for the modification

Now for the clever bit.  The throttle opening were required to be raised by around 30mm and angled at 2.45 degrees.

The holes for the throttle opening were enlarged by 2mm to avoid any restrictions.

My concern was would it fit the car.  I produced a cheap CNC routed part made out of light weight stiff foam card.  This was offered up to the 4 carburetors and eight studs.  Minor tweaks to the design were required to align the stud holes in a couple of places.  These were required due to the small amount of free play around the bolt holes, and nothing being symmetrical.

With the new positions altered in CAD it was time to cut the 2mm black FR4.