[Boss330]

Originally Posted by swamp2

I disagree. With significant changes to redline, intake system, exhaust system and block one can radically alter the sound of any engine. Yes there is still something essential the crank type and firing order contribute, but it is NOT the single factor.

I really expected a better reply. You're obviously astute on engines in general. However, it seems you want to rest your argument solely on crankshaft configuration. I don't disagree that is important but it is only roughly as important as power delivery - i.e. torque/power curve shapes and redline.

All of my previous replies was posted on an iPhone, not the best tool to type long replies on

Obviously revs and exhaust change the pitch of the exhaust. But let's say that you put the M3 intake and exhaust on a Mustang V8 and rev it over the same rev range as the S65. You would not be able to tell any difference in sound. Try to put the same exhaust on a 458 Italia (intake is allready similar). VERY different sound! What's the main difference? (hint: Crankshaft layout )

Originally Posted by swamp2

A bedplate design is significantly more stiff than a traditional design. Although overall noise is dominated by intake and exhaust noise there is also a significant content to overall sound level and sound quality directly from the engine block and engine itself. The stiffness of the block greatly affects this component of the sound.

It's fine for you to state this but you've not provided any evidence. My evidence was (again):

• Bedplate design (a major design decision by the way)
• Individual throttle bodies
• Highly efficient/engineered heads leading to very high flow at high rpm and providing
• High rpm linear power delivery (shape of torque and power curves)

Even though the S65 might have a bedplate bottom end, the Modular Ford has a similarly stronger bottom end block design unlike traditional small block V8's:



The differences in block strength here are highly unlikely to be detectable on the soundtrack IMHO.

Individual throttle bodies do make a difference, but is really not part of the engines basic design. Just like exhaust, it's added on parts to enhance the efficiency of the basic engine design. Individual throttle bodies are mainly there to get super sharp throttle response. Regardless, a Boss Mustang Laguna Seca (or any other Mustang V8) would sound even more similar to the S65 (as regards intake sound), still won't sound like a 458 Italia.

The S65 isn't the only engine that has high flowing heads...

The result is an intake port that outflows the Ford GT intake port by 4 percent and the Yates D3 (NASCAR) intake port.

The Boss 302 receives CNC ported heads cast in 356 aluminum providing additional airflow and strength, and a higher lift exhaust camshaft profile is used. Valvetrain components were lightened as much as possible, including the use of sodium filled exhaust valves, while strengthened powdered metal rods and forged aluminum pistons were added. Piston-cooling jets were also deleted, which are standard in the 5.0 model. Exterior changes include a high-mount intake plenum (as opposed to the standard engine's low-mounted one) with shorter runners to improve high-rpm power. Power is increased from 412 hp (307 kW) to 444 hp (331 kW), and torque drops from 390 lb·ft (530 N·m) to 380 lb·ft (520 N·m) due to the upgrades. The Boss's redline is increased to 7500 rpm, but has been verified stable up to 8400.

And this is only from a cheap main stream Ford, not even an exotic manufacturer...

The Boss 302 Power curve isn't all that bad either:



And, the Maserati Granturismo Sport has a engine that isn't half bad either. It's not like the S65 is something so special that BMW must have discovered some secret ingredient no one knows about...

Originally Posted by swamp2

Furthermore the bold part above about ability to make power at high revs is simply completely false. The S65 and F430 have very similar power curves at the upper rpms (nearly linear). However, I've not been able to locate a proper factory dyno for the F430. From some of the regular old "garage" dynos the S65's ability to maintain flat torque and linear power right up to redline appears to be even superior to the F430!

Not true. Heads, valve system and the entire intake system are as highly engineered for flow across a extremely wide rpm range as many other parts of an engine. Which leads me to your next statement. Please find a V8 (or any production) car engine with as broad and flat of a torque curve as the S65. it has 90% of peak torque from 2500 rpm to 8200 rpm (98% of redline). The thing is - you can't! Also, you are now even talking aftermarket compared to stock with is really grasping at straws...

Factory BMW S65 M3 Dyno

Again, my argument isn't that the S65 is a bad engine. It's definitely a highly tuned V8, just like so many other V8's. Some from the factory, some with aftermarket parts. But, those V8's share the same basic architecture of a cross plane crank, 90 deg V, multi valve cylinder heads and DOHC. Where the Ferrari engines differ from this concept is in their crankshaft layout. All else is the same (or you might care to elaborate on vital architectural differences here?).

No matter how you try to argue about how much the heads flow, bedplate engine block etc. The factor that makes a Ferrari V8's sound stand out from other V8's is down to the fact that it uses a flat plane crank!

One other issue is the huge weight saving on a flat plane crank, making the throttle response much better.

I suggest you read these articles/threads to learn a bit more about why there IS a big difference between cross plane and flat plane crank designs:

http://www.m3post.com/forums/showthread.php?t=283826

http://www.autozine.org/technical_sc...ne/smooth4.htm

http://www.ferrari.com/English/GT_Sp...raftshaft.aspx

And some videos of a Chevy with flat plane crank, notice how different it sounds...

And notice how the M3 GTR sounds so different from the std M3 (with the P65 engine which actually is a S65 engine, but only with a, YES, flat plane crankshaft).

http://www.youtube.com/watch?feature...&v=LeiA9vyi7YM


I'll finish off by quoting Ferrari:

Whether a flat or cross-plane crankshaft is chosen depends on what kind of performance is required. To get maximum performance from the engine, the flat-plane must be used but for all-round functioning the cross-plane is best.

The advantages of the flat-plane crankshaft over the cross-plane one can be summarised as follows:

A flat-plane crankshaft is lighter than a 90-degree, or cross-plane crankshaft, and, having a lower rotating mass than the latter, provides sharper response as well as allowing higher maximum revs, useful when seeking higher power outputs. Another advantage of the flat-plane crank is that it allows more efficient exhaust manifold design.