Tuesday, March 18, 2008

Ferrari F355 Engine Discussion Part 1




I began my search for information regarding the engineering underlying the F355s engine by typing “Ferrari F355 Engine” into Google. What I found was a short description and an even shorter description of the engine. Different web sites had taken the originals and changed words here and there but essentially there were two totally inadequate descriptions of the cars motor available on line. Even Wikipedia produced nothing interesting. Once I have completed my version I will post it on Wikipedia just for grins.


With more than just a few words changed here is what I learned.


Ferrari developed an aluminum block, with Nikasil-coated wet steel liners, for a short stroke engine with a bore and stroke of 85 x 77mm. Total engine displacement is 3496cc or about 3 ½ of those big soda bottles. Ferrari used five valves per cylinder, two for exhaust and three for intake or according to the owner’s manual “itake”. To keep weight down the engineers made use of titanium connecting rods and light aluminum alloy forged alloy pistons. I am not sure but I think this was the first use of titanium rods in a road car. These advanced when coupled with the engine management systems and four overhead cams allow the motor to rev freely to 8500. Compression is 11.1:1 which is almost exactly the same as our 3.6 litre 911’s 11.3:1.


Ferrari utilized variable rigidity dual valve springs and the valves are actuated by hydraulic tappets, this was a first for engines revving over 8000rpm. I am not sure how you make a variable rigidity valve spring. The engine is controlled by a Bosch Motronic system, M2.7 in earlier cars or M5.2 in my car, with twin hot wire electronic injection-static ignition system. Lubrication is provided by a dry sump engine oil circuit.


When they were done Ferrari had a motor capable of producing 375bhp at 8,250 rpm. The new engine’s maximum torque capability was 268 lb/ft at 6,000rpm, with a specific output of 109bhp per litre. Imagine stuffing 109 horses in one of those soda bottles.


So that's nice but not super illuminating, I will work on learning more. The owner’s manual has some information about checking oil levels and belt tension and some pictures but not as much detail about engineering as included above. Check back later.

1 comment:

Psychois said...

The Honda NSX (1990) had titanium connecting rods. This is the only engine right off hand that I could think of. According to wikipedia, it was the first.