BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

eggz, the Cayman is a daily driver and it got much more excitement at 50 kmh compared to R8. For me that's not perfection.

And the automotive sensation of the year is definitely GTR lah.... bro.... bro... GTR rulez leh...

 

[acupunch]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

simple 2 reasons:

1) the 6.2L v8 on the AMG is almost a race engine. The weight is lower than the already light 4.0L V8 on the M3.

2) The 6.2L v8 is optimized for V8, that's why everything could be built for output and weight, while the 4L V8 on the M3 is compromised for modularity between V8 and V10.

I've watch F1 and their V8 is only 2.4L, why are you saying 6.2L V8 is better than 4.0L V8 le?

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Race engine is not street engine lah. As Shaun say, if races don't put capacity limit, people will build higher and higher capacity because (according to Nismo) given the same power output, natural aspiration is better than forced induction.

F1 is 2.4L not because it is the best, but because the rules say so.

You see pre-war Grandprix, some engine even reach 10K cc I think.

 

[acupunch]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Race engine is not street engine lah. As Shaun say, if races don't put capacity limit, people will build higher and higher capacity because (according to Nismo) given the same power output, natural aspiration is better than forced induction.

F1 is 2.4L not because it is the best, but because the rules say so.

You see pre-war Grandprix, some engine even reach 10K cc I think.

I know F1 2.4L V8 is a rules. I asked because I like to know what mean by optimum...

 

[kenntona]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Besides GTR, there are the C-class, Cadillac CTS, Lexus LS460/600, Jaguar Super V8, Maser Gran Turismo, Audi A5/S5.........

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

I know F1 2.4L V8 is a rules. I asked because I like to know what mean by optimum...

optimum for NA RACE seems to be 350cc per cylinder (debate going on in some forum)

optimum for NA Street seem to be 500cc per cylinder (many authorities)

 

[Shaun]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

tell me how MB managed to stick in a monster 6.2 litre V8 and still allow the car to dance like Michael Jackson? I would have thought that a humungous lump like that would have turned the car into a front heavy understeerer. A sumo wrestler on ice skates comes to mind.

Handling is a function of much more than engine weight.

Engine weight is a significant but far from dominant factor. If you can pay a little more for the right materials and proper engineering, you can gain a lot of displacement and actually lose weight. Even if you keep materials and engineering the same, in most cases engine weight grows in small and non-linear proportion to displacement because required engine speed for a given power comes down and engine speed is the hardest thing to deal with in any engine. There are E36s that lose weight, move weight distribution rearward, reduce MOI in all 3 axes, increase engine reliability, all while more than doubling stock power (250+ hp gain). Going from a cast iron I-6 to aluminium V8.

Going beyond engine weight there is engine placement, wheelbase, track, suspension type and kinematics, roll stiffness distribution, overall vehicle weight, wheel and tire type, F-R stagger etc. that all play major roles in determining handling.

Then the next question - why would a 6.2 litre be "optimised" for a V8 configuration? I would have thought that anything over 5 litres would be pushing the design envelope to remain in a V8 shell. Surely you would have lower reciprocating masses and better revability if the same displacement was spread over say 10 cylinders

optimum for NA RACE seems to be 350cc per cylinder (debate going on in some forum)

optimum for NA Street seem to be 500cc per cylinder (many authorities)

I know F1 2.4L V8 is a rules. I asked because I like to know what mean by optimum...

When you guys come across the word "optimum", always realize that it falls within only certain context and is never a rule unless explicitly stated so and successfully explained. The cc/cyl, cyl no. , induction type ideals, optimums and superiorities all are refer to different applications and even within those applications there are different targets.

What are one or two things that an engine is designed to do.. as in what quantities are typically assigned to it? What specs are typically published? How are they related to revability and why should it be a target if objectives are met? Can you list two different engines that fulfill roughly same nominals but have very different rev range? Which of the two is more cheaper, which more practical for everyday driving, yet better for racing in almost all cases seeing as engine speed has an inverse relation to longevity, and remembering that what gets the car off the corner and down the straight is power.

What happens to individual cylinder surface area to volume ratios as you increase bore and retain stroke, or increase stroke and bore equal amounts, or keep dimensions square, or retain bore but increase stroke? What has to happen to the block to accommodate large bores or large strokes? And how does that affect valve area, compression, shake forces? When you take a set displacement and divide it by 4 cylinders vs 12 cylinders, whats happening to overall surface area to volume ratio? Emissions? What about overall engine length? And as that grows.. effect on block and crank stiffness?

 

[axl]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Hey mountain-fish.. you're supposed to share with us your knowledge, but yr last para was full of questions instead!

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

he point out we understand the word `optimize' wrongly, because to `optimize' means need rules. Life's no fun without rules. very incisive, curse my cotton brain.

 

[Shaun]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Hey mountain-fish.. you're supposed to share with us your knowledge, but yr last para was full of questions instead!

hahahh.. because if you seek the answers to one question, you'll find a page of them, but 5 more questions that accompany it. Chase down the answers to those 5, and you'll have 5 pages of answer and 25 new questions.. and it just keeps repeating and growing, going from macro to micro, but sometimes the reverse.

So instead of writing pages, I write a few questions and then from working it out yourself, you'll remember it forever. Also am quite sure I wrote a fair chunk on this stuff some months ago on this forum.. if in slightly different form.

 

[Shaun]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

he point out we understand the word `optimize' wrongly, because to `optimize' means need rules.

Yes and going beyond hard rules and a singular objective as in racing; in near zero restriction environments like production cars, there are still many soft limits across a wide spectrum of purpose - many of which overlap. This multi-factor subjective mix makes it near impossible to lock a car down to an exact class or determine winner of a class, or "optimum" - whether applied to engine, chassis, or car as a whole. One can use the word optimum, but in order to be accurate, it will have to be followed by a sentence or two describing in fair detail what it applies to.

Life's no fun without rules.

You could build anything you wanted with no rules. It might not be responsible, safe, or cost effective, and there'd be no objective competition or comparison, but it'd be load of fun I think
But if I understand you right, I agree it is more fun winning in objective arenas.

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

without rules there is no clear victory for cars and things which have subjectivity, Shaun.

Even in business, financial victory with allegations of immorality screw up the glory part.

 

[PerverTT]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Thanks to Shaun and centurion, I think we have a little more clarity on this matter.

I also did a bit more research and found an interesting table comparing engine weights and outputs for a number of well known performance cars. The author is a clever chap called cxcheng and the link is: Wheel Talk » Engine Weights Compared

Vehicle Engine Configuration Power
hp Weight
lbs
1989 Porsche 964C4 Porsche M64/01
3.6L SOHC H6 247 525
1992 BMW 740i BMW M60B40
4.0L DOHC V8 282 463
1992 Chevy Corvette GM LT1
5.7L OHV V8 300 620 manual
562 auto
1993 Cadillac Seville STS GM L37
4.6L DOHC V8 295 470
1996 Porsche 993 Porsche M64/05
3.6L SOHC H6 270 511
1997 Porsche Boxster Porsche M96/20
2.5L DOHC H6 201 402
2000 BMW 330i BMW M54
3.0L DOHC I6 231 375
2001 Chevy Corvette GM LS1
5.7L OHV V8 350 497 manual
458 auto
2003 Porsche 996 Porsche M96/05
3.6L DOHC H6 315 449
2003 Porsche Carrera GT Porsche M80
5.7L DOHC V10 604 472
2004 Audi S4 Audi
4.2L DOHC V8 340 430
2005 BMW 330i BMW N52
3.0L DOHC I6 258 357
2005 Chevy Corvette GM LS2
6.0L OHV V8 400 443 auto
2005 Porsche 997 Porsche M97/01
3.6L DOHC H6 321 444
2005.5 Audi A4 3.2 Audi
3.2L DOHC FSI V6 255 374
2006 BMW M5 BMW S85
5.0L DOHC V10 500 529
2006 Chevy Corvette Z06 GM LS7
7.0L OHV V8 505 490
458 dry
2007 BMW 335i BMW N54
3.0L DOHC I6 Biturbo 300 419
2008 Audi S3 Audi
2.0L DOHC FSI I4 Turbo 265 335


OK, the table came out all funny but here are 2 interesting conclusions that I drew:

1) Higher displacement does not necessarily equate to higher engine weight (as pointed out by centurion and Shaun). The LS7 engine used in the 2006 Corvette (7 litre v8) for example weighs about the same as the 5 litre V10 used in the current M5. Outputs of the 2 engines are also very similar. All the more interesting because the LS7 uses prehistoric push rods rather than modern overhead cams. Two different routes to the same destination.

2) Engine weights have dropped dramatically in the last 2 decades. And their outputs have shot up just as dramatically. Again, the same 5 litre V10 in the current M5 weighs about the same as the 3.6 litre flat 6 used in the Porsche 964 of 1989 - but the M5 engine has double the output.

I couldn't find the engine weight of the 6.2 litre V8 used in the C63 but I suspect it is a very light engine for the size, as mentioned by centurion. Not surprising given it has been described by others as a detuned race engine. It would be an interesting exercise to compare engine weights for the C63, M3 and Cayman S.

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

aircool heatsink make 993 engine heavy tho ...

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

super nice link!!!

 

[PerverTT]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

Yah, I'm surprised at the comparatively heavy weight of the some of the non-turbo Porsche engines. Take a look at the 2.5 litre flat 6 used in the early Boxster - it's quite porky for its output (sorry about the pun, couldn't help myself). The author attributes this to an engine block shared with other Porsches that run a larger displacement. But could things like a gargantuan oil sump also play a role?

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

dry sump got all kind of additional pump.

but the engine is down low, so the heavy weight not as prejudicial as say, I6, where balance is concerned.

Obviously a H6 use more metal than I6, but got balance advantages especially in MR form.

 

[Darth Vader]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

m3 coupe will be a flog.
m3 sedan may sell better.

if i got money i would rather buy porsche cayman s.
unless i got money to buy both.

 

[centurion]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

m3 coupe will be a flog.
m3 sedan may sell better.

if i got money i would rather buy porsche cayman s.
unless i got money to buy both.

darth what a thing to say esp with your 335 coming. You are disloyal to your car!

 

[Darth Vader]

Re: BMW M3 vs AMG C63 and Cayman S : Topgear Magazine head to head

darth what a thing to say esp with your 335 coming. You are disloyal to your car!

my 335 here already.i am not being disloyal.just felt that bmw messed up m3.at $333k its hardly a best buy compared to porsche cayman s.

the porsche cayman s is my dream car now.