The 458 Ferrari is a 4.5 litre flat plane engine with no balance shafts ... ? I'm yet to hear somebody complaining of smoothness issues, but it could all be part of the Ferrari vibe Pee
My wife always says I am bad at explaining. Generally a 4cyl above 2litres has balance shafts. Some do not, and some cars also employ active motor mounts and other hardware to quell harmonics and vibes. The porche 944 had if memory seems a 2.5 and then a 3 liter 4 which used balance shafts. I believe this motor was essenti half a 928 V8 a motor which had a bent crank and therefore no need for balance shafts. I don't think I said the Ferrari v8 uses balance shafts although my 4cyl comments may have implied that. Personally I found the 458 engine really smooth whereas the smaller 308 one Has lots of secondary vibes. I am speculating that on the458 Ferrari with its budget unlimited can use really light pistons rods and crank meaning the counterweights to quell vibes are Similarity light. Light everything is a virtuous circle, less vibes less stress and easier to balance plus then smoother at revs. There is also probably a good rod ratio and it's a short stroke? all of which is good for snappy revs and smoother operation. As I said the 458 seems far smoother tha. The 308, motor mounts may also have something to do with this. Flatbplanes as I understand it are not inherrany smooth which is why most v8s are bent crank.the firing pulses on a flat plane are supposed to provide better combustion/exhaust efficiency and therefore more power and the setup also leads to snappier revs. The Ford is a bigger motor than the Ferrari, built on a more Limited budget. There is a reason no one has made a hipo flat plane in that displacement, from what I understand the counterweights needed negate a lot of the benefit of snappy revs. According to the Ford engineer the solution at 5.2 liters with the pieces used was really heavy counterweights and that the voodo block aftermarket motor with bent crank has the same hp, revs just as nicely and is far smoother. This implies to me that the voodo is more marketing than real benefit. I have not been in a voodo powered mustang, but media reports definitely talk of lots of vibes at high revs which apparently ypu just have to get used to. None of which is meant to dis the 350R which appears to be a great car for those of us who go to the track. Great to see the USA being the home of true performance cars these days. Hopefully Brian or someone with far more knowledge can weigh in where I am wrong.
Yeah sounds like marketing hype, pity ... but marketing sells. Interestingly the Alfa Romeo GTA (real, not moderner one) has a heavier crankshaft than the standard GT engine. Pete
