Custom race spec build of a naturally aspirated 2.0 litre, 20v, 5-cylinder Fiat engine. Huge thanks to Paul of Exon Race Engines for the help, advice and workshop facilities and further huge thanks to Dennis of OD Engineering for letting me use his CNC machines, teaching me how to use them and machining the stuff I couldn't!
In order to optimise the timing of the camshafts, adjustable vernier pulleys are required.
One of the very few components of this build that has not had to be custom made is the ultralight flywheel.
Originally, the plan was to port the head, fit throttle bodies, re-profile the cams and use ARP con rod bolts to allow the engine to rev higher on the standard con rods.
The only people who seem to have camshafts off-the-shelf for the Fiat 5-cylinder engine are Italian firm, Colombo & Bariani. Unfortunately, nothing they had was anywhere near as aggressive as I wanted and their prices were quite high so I sent the camshafts from the 2.4 head to UK based Kent Cams.
There are only two downsides to the Fiat 5-cylinder engine; one is the weight and the other is the fact that nothing is available for it off the shelf!
A key method of extracting power from a naturally aspirated engine is the use of multiple throttle butterflies. In the old days, this meant carburetors but generally speaking, they are inefficient, thirsty and require maintenance. Throttle bodies, on the other hand, do not suffer these issues.
