Thursday, March 09, 2006

Model differences; 750 cc Senna, 2002 EVO2, 2003+ EVO3, SPR

Let me paste the words of Andrea Goggi outlining EXACTLY the differences between the Senna, EVO2 and EVO 3. Please find an easy reference summary at the bottom.

For background, let me first post the question that generated the response from Andrea Goggi at MV:

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Here are the contents of msg 13573 from someone asking the initial question on yahoogroups:

My guess is the factory was not able to complete their work on the SPR motor for the 2002 model year and ended up just making some simple modifications to the already improved Evo2 engine. Result…the F4 Senna. More specifically, I believe MV took the redesigned Evo2 motor (which included [for all versions] new Malhe forged pistons, a Malhe cylinder block, a lighter crankshaft, a redesigned combustion chamber, different exhaust valves and valve springs, jets for cooling the underside of the pistons, a modified clutch hub, and a fix for the self-removing oil filter) and made a few more changes to distinguish the Senna from both the "vapor"-SPR and the cooking version. When the dust settles on this issue, I think we'll find the Senna had the following engine improvements:

1) slightly different cams (not F4S, not SPR); **FALSE
2) a different fuel injection control unit (possibly off the SPR); **FALSE
3) a different gear box; (ratios) **TRUE
4) three rear sprocket options; **TRUE
5) the SPR exhaust manifold; and **TRUE + RG3 included
6) two new e-proms unique to the Senna and matched to the Senna's cams and SPR headers (one for the stock silences and one for the included RG3 silences). **TRUE

I believe the Senna also has a different alternator and a sturdier clutch disc material to provide a stronger platform for the higher revs (13,900 rpm) allowed with the RG3 chip. ===============================

And here is Goggi's response to the questions raised:

Basically almost everything written in msg. 13573 is somewhat right, but You need to learn some history more.
In 2000 R&D was already working on the upgrade of F4 S engine, and on SPR engine; at that time they were different projects, with different engine specs. Then, due to all the production retards caused by our financial troubles it was decided to make F4S same as the SPR of that time, calling it EV 02. This is shortly the story of F4 EV02. As a consequence the SPR evolution project began again starting from EV02. Differences between first series of engine and EV02 are quite precisely listed in msg. 13573 (pistons, valves, crancksshaft, etc. etc.), so I don't repeat them.
Senna engine is very similar to EV02 engine; differences are gearbox, clutch disks, Eprom (basically rev limiter from 13300 to 13900), and a special care in selecting production heads (better porting casting) in order to obtain a more restricted production tolerance in engine performance.
SPR engine (which is finally going in production right now for the first time), as a result of a further developement step, has many parts new and different than EV02, i.e. increased compression ratio, both in-ex ports, combustion chamber, 100% hand polished inlet ports, cam profiles, tappets, springs, pistons, trumpets, other than same clutch and close ratio gearbox as Senna.
F4 EV03 engine is same as EV02, only with painted pick-up, clutch and sproket covers (same color as Brutale).

I'm sorry to hear about troubles in getting the right informations, but in this moment of re-start of all our activities communication is for sure suffering; It will get better because as we always did we are working hard to make it happen. Anyway the informations about differences between basic engine and EV02/Senna have been communicated to press in a precise way, so it is strange that so many doubts still exist. I hope everything is more clear now. Ciao - AG =============================

EVO3 talking point from the engine designer: "F4 EV03 engine is same as EV02, only with painted pick-up, clutch and sproket covers (same color as Brutale)."

Senna talking points: "Senna engine is very similar to EV02 engine; differences are gearbox, clutch disks, Eprom (basically rev limiter from 13300 to 13900), and a special care in selecting production heads (better porting casting) in order to obtain a more restricted production tolerance in engine performance."

SPR talking points: "SPR engine (which is finally going in production right now for the first time), as a result of a further developement step, has many parts new and different than EV02, i.e. increased compression ratio, both in-ex ports, combustion chamber, 100% hand polished inlet ports, cam profiles, tappets, springs, pistons, trumpets, other than same clutch and close ratio gearbox as Senna."

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