Les spécificités du moteur de la 360 Challenge Stradale

[Franck 7 088]

Pour ceux que cela pourrait intéresser, comme moi, voici les spécificités du moteur de la Ferrari 360 Challenge Stradale par rapport à une Ferrari 360 Modena :

"For the real CS nerds among you here's some more detailed info I have been learning since starting to study the 360CS engine. I have been comparing the detailed technical revisions with that of the original Modena engine. Here are my findings so far.

Gearbox

The actual gearbox itself is a bone stock Modena one with the same exact gear ratio's.

Due to Ferrari adding software Launch Control to the car and also more aggressive shifting software speeds (gearbox ecu software) the engineers also chose to (as a precautionary measure) uprate the differential. I think this was so there was no chance of anyone ever snapping them from the torque off the line (which would be kind of embarrasing!).

The biggest real difference overall was the sotware and that Ferrari also beefed up the clutch too. In fact this uprated clutch should be a direct replacement for the Modena's drivers too since its uprated so should take more abuse - well worth investingating further if your looking a replacing your stock modena clutch!

Engine Internals.

Ferrari changed very little of the engine internals but they did concentrate on blue printing so engine tolerances where very close to the design specs. They did however increase the compression ratio a little bit, they achieved this by simply adding new pistons (using the same head gasket, crankshaft, connecting rods, intake and exhaust valves, camshafts, all the bearings, etc. - basically they where all stock modena parts), they also changed the crankcase (uprated by any chance?) for which I havent got an explaination.

ECU programming was altered to take into account the better gas expulsion speeds from the uprated free flowing racing exhaust and better breathing intake. This helps to keep those valves open that little bit longer to make that glorious soundtrack that the cs is renouned for (and that tiny bit more power!).

Surprisingly to me they left the pair of camshafts bone stock. Had they increased the slope angle and made them a little bit more aggressive (lumpy) they could have gained at least another 10-20 BHP more and got closer to the performance of the 360 GT cars.

Maybe uprating the cams was seen as too aggressive as to make the engine seem a bit rough at idling? No variable timing in this engine, just good old fashioned cams so not as advanced as I was expecting in this respect.

Air Intake Optimizations

Another interesting point is that the basic paper filters themselves where retained from the Modena but the covers (now in carbon) had been improved by removing the resistance to flow areas inside them. There was a horrible velocity stack which would slow down the ram air affect in the original Modena boxes (due to their cheap construction method, would have been better to make them from plastic than aluminium!!).

This refinement improved airflow speeds into the intake improving power slightly (probably 5 BHP - 10BHP gained). Sadly they did not removed the corrugated piping connecting the airflow to the engine intake which again slows down the airflow which is a shame. This change would have optimised flow by yet another 5 BHP.

The often overlooked change when comparing the air intakes on the 360cs with the Modena (and a main difference actuall) was that the air conveyer box was optimized and enlarged (from the experience gained in the Challenge cars which also uprated this part). This probably contributes just as much to engine output as the airboxes themselves.

Exhaust Flow Out Optimizations

The thing that suprised me here was the decision to retain the original CAT's and the original manifolds. An optimized solution of 100CEL flow cats, tuned manifolds and a lightly baffled backbox can add 20BHP on its own. I'm sure another 5-10 BHP over the gains Ferrari did was entirely possible here with some more effort.

Summary

Considering the small number of changes done Ferrari did a great job. I feel its a bit of a shame that they decided not to go much further but I guess with the weight reduction and the instructions to improve lap times by only 3 seconds over a modena the engineering teams where stuck.

Also its probably a good thing for costs too as it has kept the number of different parts between the Modena engine and the CS engine low.

All in all the main difference is software, pistons (For compression ratio tuning) and intake/exhaust optimizations. Small things really. At least another 25-40BHP could have been gained still bringing the engine power up to 440-460 BHP from the normally aspirated 3.6!

Havent looked at the differences to sensors (heard Mass Air Flow sensor was uprated) and also the head yet. As I study more I'll provide more updates."

Source : http://clubscuderia.co.uk/