It’s almost 20 years ago this thread is made. I just bumped into it and wonder if you all succeed to gain 65 bhp?
The Trofeo had many specs. No doubt. Reading this thread I must conclude the car was in Group N.
The deckt of the engine block was skimmed off by 0.5 mm. The minimum height of the head is 69.5 mm. accordingly official Trofeo documentation. But be aware! That’s not the maximum you can skimm off the head, At that time you can throw the head in the bin. The technical handbook named ‘Vraagbaak Seicento’ notes that the min. height 70.15 mm. is. See my point here?
The matter is that you eliminate the squish between the piston and the head. This increases the compression ratio to around 10.2:1. Very similar the Autobianchi/LANCIA A112 Abarth.
Measuring the compression on a standard Abarth 1050cc 70 hp engine gives a pressure of 12 bar (12-13 Kp/cm2).
The head has a set of double valve springs derived from the A112. Valves are standard. Head bolts are bigger in diameter. It has a 290° cam. Technical data is not exactly known to me but I presume a Abarth A112 70 hp cam will do the job here.
The flywheel is lightened. How light? Good question. The rule is not to exceed over 25% of the standard weight. Well, better save then sorry: skim it just 15% and see what it does. You can always decide later to skim off to 20%.
The car has a different gear ratio. Also, it comes with at least two ECU’s: one for straight ends, one for ‘slalom’.
The engine has Champion RC7BMC sparkplugs with double electrodes. Nowadays hard to find but using cross reference shows a Bosch FR 6 LDC sparkplug.
The Weber SPi throttle body is bored out to 34 mm. Take a 32 from a Punto. You can bore that one to 34. When doing so you need to machine the alu spacer and steel plate underneath the throttle body to 34 mm too. And also grind some material away on the intake manifold/engine cover.
The exhaust manifold is similar as the one from a A112 but not exactly. The diameter where the mid pipe comes onto the spaghetti is around 53 mm. The one from a A112 is the same as all other tubes.
Furthermore it sits just at a different angle under the car. That means you have to do some correction and weld it together again. There is a mid pipe with a sportcat. mounted. The muffler has the same diameter and it is of a straight through type à la Abarth (…or actually like a motorbike: perforated pipe inside with metal- and glass wool materials).
Suspension is a kit from Bilstein with ‘Abarth’ springs. I believe the first badge of Trofeo cars had B6 type of shockers. Later on the front shockers were adjustable.
The rims are from Speedline. Later on the same ones were made by Stilauto called ‘Starlet’ and were mounted with studs instead of bolts and a 16 mm spacer was used to compensate the off set.
Brakepads used came from Ferodo: type DS2500. On front sometimes type DS3000. Note: these are not for daily driving!
Inside: a tachometer, Abarth Momo steering wheel and hub, laptime computer, extra spotlights to read instructions, Sparco roll cage, 6 point harness, Sparco bucket seats, box or netting for helmets, spare tire, tools, fire extinguisher: a system in the car and one under the bonnet + manual operated one.
Hope this will help a next generation of Cinq drivers.