I haven't ducted the back of the radiator. Because the gastank creates sort of a nice natural ramp. And it is open to the sides so air can find its way out of the front wheel wells, if it needs to. The placement and shape of the radiator exit air holes should be in a low pressure area ( I hope... )
The radiator is a Mk1 Fiesta piece that I had laying around, complete with its fan. I have no cooling issue's ( yet...)so there must be enough airflow through it.
I'd like to put a lot more downforce on it. But with only 65Hp, I can't go too far with putting on aerodynamic drag.
Another problem is that the Fiat 600 gearbox I'm using isn't geared right for the track. ( 3rd is about perfect, but 4th is way too tall and spaced too far from 3rd ) I can get a close ratio gearset for it, but there is also a strength issue...
And also, I'm using stock Fiat 126 rear stubaxles. And as with all rear engine Fiat & Simca designs, those can crack sometimes. ( and catastrophic failure, if you don't catch it in time )
BMW used these in a BWM spec racer formula race car. And they had them mated to a sequential 6 speed Hewland.
But they didn't have the space restrictions I have, and they were able to have a very long bellhousing so the stock BMW alt & starter wouldn't be in the way of the Hewland diff.
I need to have it all as short as possible, so that meant I had turn the gearbox over and run it in its OG VW configuration ( Hewlands Mk5 Mk9, etc were originally based on VW casings, and because of their VW lineage it turns out several stock off the shelf VW parts fit. Which has been a real bonus already...)
7.25" is really close to 180mm, so I got a 6 puck sintered plate made for a racing Porsche 356. It has the same splines as a VW bug, so it will fit a stock VW input shaft, and the other end of the VW input shaft fits the Hewland guts.
I cut down a Quartermaster pressureplate ( really close to Tilton, same 7.25 3 plate setup and boltpattern to the flywheel ), so it would have the right clamping force for the ( now single )friction plate.
The Hewland Mk9 usually uses a VW gearbox casing, which is a great piece. Very light mag/aluminum alloy, etc.
But the bell is cast in, so I was happy mine came with an aftermarket casing that had a bell that partially unbolted. ( it was meant to use a hydraulic clutch release bearing, which ( again ) adds to much length, so I'll make my own mechanical linkage later )
But making an adapter plate going from the BMW bell to the shortened Hewland still wasn't short enough. So it was time to make my own bellhousing.