In a friendly tone, do you know that the LS6 beats the M5 and S54 engines in pretty much all engineering credentials? I.E. less weight, lower CoG, better MPG, etc... Low tech it certainly is, agreed.
except in a key figure. one thats a good measure of effieciency,
horsepower per liter.
Z06. 5.7 liters, 405 horses= 71.05
M5. 5.0 liters, 394 horses= 78.80
M3. 3.2 liters, 321 horses= 100.31 horseys. big ones.
we could also compare such mundane things as redlines, turning radius and so on just to skew the data another way.
when you compare DOHC engines to OHV engines, especially in light of things like center of gravity, you really skew the comparison to make it appear your way. by nature, specifically the twin cams in each head and multiple valves for each cylinder, DOHC engines are much more top heavy than OHV engines. when you factor in such goodies as double VANOS which the BMW engines have (VANOS is variable valve timing and lift in BMW speak) you also add weight to the head. if i recall correctly the system uses oil pressure and requires a separate oil pump for its operation. additionally the corvettes cam is in the vee between the banks, much lower than the BMWs and only operates two valves per cylinder. which is a considerable achievement when you consider how powerful it is.
the more efficient and more complex DOHC units also always weigh more than comparable OHV units of the same displacement and material. they generally have twice as many valves, four times as many camshafts in the case of the M5, the requisite timing chain to keep that symphony working, bigger heads that contain andother paraphenalia that make them heavier. that siad they generally spin higher and breathe better, a function of the ease of use of hemispherical chambers and cross flow combustion.
the OHV engines typically have pushrods in the place where you'd place the intake port. this usually results in the port coming in from an angle making a near 90 degree turn into the chamber and at exiting executing another near 90 angle. this achieves the cross flow characteristic required for good evacutation and filling of the combustion chamber but those two turns just before and after the cylinder prevent good flow characteristics compared to an OHC engine which can have the mixture basically go straight in and out.
mpg is dependent on many different factors. like how tall a car is. or how heavy. or how aerodynamically efficient. or its gearing. etc etc etc. the corvettes great fuel economy is a result of many of these things. its lighter than an M5 by almost 1000 lbs. 3116 lbs vs 3781 lbs for the M3 and 4024 lbs for the M5. yet the M3 has figures that are only 2mpg worse than the corvette even though it has a smaller engine and a heavier curb weight, taller profile and worse Cd. the corvette also has a ridiculously long overdrive sixth. something like 0.50 compared to most cars that have an overdrive of about 0.70 or so. for height, the corvette is 47.8 vs 53.7 for the M3 and 56.6 for the M5. corvette seats two while the M3 seats 4 and the M5 can seat 5. as for aerodynamics, we wont even compare an out and out
sports car to two sports
sedans that are ultimately derived from luxury cars.
not really a fair comparison i think.
figures taken from edmunds.com.
Who said anything about what car is better? 
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