Hi everybody! It's been a while since I've been to Fchat and am just getting accustomed to the new looks and ways (and I don't know if my former post counts have already been added)... Anyway... My question is this, Being a BIG aficionado of Ferrari, specially the road cars, I eagerly devoured the R&T pages that took the Enzo to a 1500m test. I was stunned about everything, and savored every word they wrote as if it was I who was behind the wheel... There's one thing that got me thinking... Being the Enzo the High Revving, BIG POWER street machine that we all know and love, I, for one, always thought that it was a 5 valve per cylinder. Or so I assumed... By reading R&T I found out it wasn't (I've seen about a dozen tests and videos of it, but it seems like I've never really paid much attention...). Why is that? Isn't there advantages on providing the engine with a 5v cylinder heads? Won't it get a better admission? Pardon my ignorance and all, I'm just hoping those of you who are more technically inclined might take a few moments to explain it to me, and If it is a more advanced solution why it hasn't been adopted yet. Thank you all! Ferrari RULES!! P.S. Here's a pic of the 550 engine in exhibit on the Ferrari museum in Modena! Hope you enjoy it!!
welcome back! stellar picture, dude!!!! do you have a better snap of it? or other snaps of it? tia, doody.
Man, do I ever!?! I was in Italy for nearly a month and took more pics at Ferrari than at the entire country... Here's another... I'll try to post them every once in a while (it's nearly 50 of them). Glad you liked it... any thoughts on the 5valve 12 cyl engines?? Later, Miguel
5-valve design doesnt guarantee covering more head area than 4-valver. Nevertheless, if the combustion chamber is in irregular shape like the picture shown, the valves may cover a larger area. The Ferrari F355 makes use of this to enhance high-speed breathing. Is there any disadvantage? Yes, faster breathing also harms low-speed torque if no counter measure is taken. Therefore it is really more suitable to sports cars. All existing 5-valve engines have 3 intake valves and 2 exhaust valves per cylinder, still arranged as cross-flow. The exhaust valves are larger, but in terms of total area the intake valves are larger. In the F355, by arranging the outer intake valves opening 10° earlier than the center valve, it gets the swirl needed for better air / fuel mixture, hence more efficient burning and cleaner emission. The advantage of 5-valve engine is still under question. Even the Ferrari F1 cars which was once famous for its 5V engine switched back to 4v design.
One way to get around the off idle response and low end torque issues with a 5 valve head is to go with variable cam timing or have 2 of the valves running the hydralic lash adjusters on different oil passages. doing this the engine can use just one valve at idle giving the engine more than ample air. Once the engine comes off idle to about 1750 RPM then open up a valve that let oil to Valve #2 then at about 3500-4000 RPM Open up valve #3. With modern engine fuel and ignition systems, this method would not be hard to acheive. Other than getting the additional oil galleys in place, That could be done on the outside of the engine.
