Wednesday, January 5, 2011

Fiat Topolino - Saab V4 Powered?

The earliest version of the Topo was powered by a Saab V4. Since Jack has built a couple hundred of these little engines, it made perfect sense. It is an extremely compact design, and when it isn't hiding under the hood of a Sonett, it can house some respectable cross-ram Webers.

Cross-ram intake manifold featuring twin Weber DCOE carbs:

Saab V4 mated to Fiat 124 5-spd trans:

More details showing the cross-ram Weber setup:

And along came a twin cam. About this time, Jack took possession of a low-mileage Fiat 2000 Spider that had been smacked in the butt. So after a bit of measuring, deep introspection, Jack decided the little Topo should be powered by a hot rod 2L Twin Cam:

Ultimately, this setup has proven less costly, far easier to make work, and possibly even more powerful given similar carb setups.

Fiat Topolino Mechanical Details

These are a few of the various mechanical sketches Jack did for the Topolino project in Sketchbook #4.

Fiat 124 Spider front suspension and Saab 99 steering rack. This basic setup actually made it to the final product:

Jack ended up building a simple roll cage following much of this early design:

More cage details, including doors beams:

Window winding mechanism and handle/lock details:

Brake master cylinder mounting details:

The Topo came equipped with a 124 rear diff, setup with leaf springs, per this sketch. The final product uses coils and modified Saab 99 rear trailing arms:

Jack had grand visions of driving the Topo in 100-degree heat, so some of his earliest sketches included details for mounting air conditioning:

Highly detailed HVAC setup: