S55 vs. S65

[Killerfish2012]

Originally Posted by Sedan_Clan

You make great points, but it just really felt anemic. Even my 2002 BMW 330ci felt better through the rev range. I suppose it didn't help that I went straight from a 2003 M3 into the 2004 G35 (..how I managed to stay objective was beyond me). Boy was I glad when somebody wanted it more than me and decided to take it off of my hands while I was out of town. I was in a 2005 M3 before the insurance even sent the payoff check. Good riddance!

With BMW it's all about very aggressive gear ratios. They have Fast down to a science.

[swamp2]

One does need some care with time to speed vs. time to distance vs. speed at distance. Ignore the 1' rollout for simplicity sake. Then imagine the fellow who uses (a very effective) line lock to sit and spin for a significant amount of time at the start of a drag race. His times to speed will all have an offset for how long he sat stationary. However, his speed at distance (trap speed in the 1/4) will remain mostly unaffected.

The proper way to judge the (distance) gap at 1000m is one of two ways. Record the lagging distance of the slower of the two cars when the first to cross the 1000m lines does so. That's my preferred way since the "race" is over at that point. One could alternatively track the lead of the winning car when the loser crosses the 1000m mark. The results will generally be close with close competitors but certainly not the same.

Using the first definition and a graph of time to distance gives the results required. Again using these three particular cars my simulations for the gaps are (all automated manuals):

F82 M4: Winner
E92 M3: 68m, 15 car lengths
E46 M3: 141m (an additional 73m behind E92 M3), 31 car length total or an additional 16 car lengths

The times for each to get to precisely the 1000m mark are:

F82 M4: 21.5 s
E92 M3: 22.5 s
E46 M3: 23.8 s

By the time the E92 M3 crosses the 1000m mark the E46 M3 is then behind by (basically ignoring the winner as if the race was between these two):

77m or 17 car lengths (gap widened by ~1 car length)

The reason we can approximate distances moved in a short time interval at high speeds is because the acceleration is like 1/10th of peak acceleration and not much velocity is gained in these short durations of time. One can very roughly approximate this at zero acceleration.

This discussion has again shown the power of simulation. One can find video or published results showing a (way) too small of a difference or too large of a difference among cars. Simulation is a way to make a test as "apples to apples" as possible.

So in conclusion although many performance metrics show a naturally smaller gains with the new generation, some metrics show very similar gains. This is a natural consequence of the reasonably accurate constant power approximation which yields both time to a given distance as well as speed at that distance varying as (weight/hp)^(1/3) and (hp/weight)^(1/3) respectively. In simple English it is just that power gains (or weight losses or improvements in those ratios) follows a law of decreasing marginal returns. Anyone who has spent any time drag racing certainly is painfully aware of this.

[swamp2]

Originally Posted by tightie

Yeah but do they last?

Well, perhaps obviously, lifespans will be greatly reduced. There are some post/histories right here on the forum of surprisingly resilient E92 M3s at those power levels.

[swamp2]

Originally Posted by ruff

My concern for the F8x is it seems to be unknowingly following in the footsteps of AMG and Japanese performance cars, while in the process distancing itself from its M lineage.

Indeed, nice to see you here after some time!

[CanAutM3]

Originally Posted by swamp2

The times for each to get to precisely the 1000m mark are:

F82 M4: 21.5 s
E92 M3: 22.5 s
E46 M3: 23.8 s

...

Great analysis, as usual Swamp

For this particular metric (0-1000m), it seems the F8X will provide a similar leap from the E9X as the E9X did with the E46 (77m vs 68m).

I am guessing you used around 455hp for the F8X .

[swamp2]

Originally Posted by CanAutM3

Great analysis, as usual Swamp

For this particular metric (0-1000m), it seems the F8X will provide a similar leap from the E9X as the E9X did with the E46 (77m vs 68m).

I am guessing you used around 455hp for the F8X .

Correct, 455 hp. Seems a bit aggressively underrated even for BMW but as noted here it matches the official 21.9 second figure from BMW.

Unfortunately, though I just noticed an inconsistency. I reread the graphs posted there and 21.9 seconds appears to be accurate. However for the exact same inputs CarTest reports 21.5 seconds in its tabular format. I verified the difference to be rollout. The quicker times in the tabular view include a US standard 1 foot rollout. The graphs do not include these (more the EU reporting method). Either way all comparison numbers I have reported use rollout consistently again insuring a more apples to apples comparison.

[mPlasticDesign]

I'd be interested in the respective speeds @ 1000m.

E46: ~135-137mph
E92: ~145-147mph
F82: ~155-157mph

Close?

If Swamps earlier E46-E92-F82 0-150mph models are accurate (which I believe they are) it really shows what happens to the E46 above 135mph and beyond 1000m.

0-150mph:
E46 = 31.46sec
E92 = 23.72sec
F82 = 21.04sec

[swamp2]

Originally Posted by Mr.Metak2you

I'd be interested in the respective speeds @ 1000m.

E46: ~135-137mph
E92: ~145-147mph
F82: ~155-157mph

Close?

You might have missed them, already posted in km/hr here. Converted they are:

E46: 138 mph
E92: 148 mph
F82: 151 mph

Originally Posted by Mr.Metak2you

If Swamps earlier E46-E92-F82 0-150mph models are accurate (which I believe they are) it really shows what happens to the E46 above 135mph and beyond 1000m.

0-150mph:
E46 = 31.46sec
E92 = 23.72sec
F82 = 21.04sec

I do prefer looking at distance ahead at a given distance rather than time to speed. The time to speed metrics do show significantly different gaps between the generations that is not shown in the trailing distance type of analysis. Obviously because the closer one gets to the maximum speed the larger the times are going to take to get there until they take an infinite amount of time... However, with a time to a distance, everyone at any speed will still get there.

[Boss330]

Originally Posted by swamp2

One does need some care with time to speed vs. time to distance vs. speed at distance. Ignore the 1' rollout for simplicity sake. Then imagine the fellow who uses (a very effective) line lock to sit and spin for a significant amount of time at the start of a drag race. His times to speed will all have an offset for how long he sat stationary. However, his speed at distance (trap speed in the 1/4) will remain mostly unaffected.

The proper way to judge the (distance) gap at 1000m is one of two ways. Record the lagging distance of the slower of the two cars when the first to cross the 1000m lines does so. That's my preferred way since the "race" is over at that point. One could alternatively track the lead of the winning car when the loser crosses the 1000m mark. The results will generally be close with close competitors but certainly not the same.

Using the first definition and a graph of time to distance gives the results required. Again using these three particular cars my simulations for the gaps are (all automated manuals):

F82 M4: Winner
E92 M3: 68m, 15 car lengths
E46 M3: 141m (an additional 73m behind E92 M3), 31 car length total or an additional 16 car lengths

The times for each to get to precisely the 1000m mark are:

F82 M4: 21.5 s
E92 M3: 22.5 s
E46 M3: 23.8 s

By the time the E92 M3 crosses the 1000m mark the E46 M3 is then behind by (basically ignoring the winner as if the race was between these two):

77m or 17 car lengths (gap widened by ~1 car length)

The reason we can approximate distances moved in a short time interval at high speeds is because the acceleration is like 1/10th of peak acceleration and not much velocity is gained in these short durations of time. One can very roughly approximate this at zero acceleration.

This discussion has again shown the power of simulation. One can find video or published results showing a (way) too small of a difference or too large of a difference among cars. Simulation is a way to make a test as "apples to apples" as possible.

So in conclusion although many performance metrics show a naturally smaller gains with the new generation, some metrics show very similar gains. This is a natural consequence of the reasonably accurate constant power approximation which yields both time to a given distance as well as speed at that distance varying as (weight/hp)^(1/3) and (hp/weight)^(1/3) respectively. In simple English it is just that power gains (or weight losses or improvements in those ratios) follows a law of decreasing marginal returns. Anyone who has spent any time drag racing certainly is painfully aware of this.

Thanks

Don't remember what we discussed re simulations, but these seem spot on with what I also believe are the relation between the E46-E92-F82

The gap between the E9x and E46 at 73m is also interesting as that is closer to my illustration of a "1 sec gap at a steady 150 MPH" than what I thought it would be. The gap here is a bit more than one sec and the gap increases from 0m at start to 73m at 1000m, due to the rate of acceleration and speed difference between the two cars.

To avoid confusion on the part of certain people: The 1 sec gap was ONLY used to illustrate how large the distance between two cars travelling 1 sec apart at 150 MPH would be (67m).

[Boss330]

Originally Posted by Killerfish2012

FYI, caranddriver together with most magazines, were really really cooking their accelerations times last decade. Especially in the early part of the decade that you are citing. For instance they were all reporting 0-60 times using rollout, without disclosing this.

I was using C&D times as that was what the other guy used as a basis for his claims. I searched C&D and found several better E46 times then the one he had used. Apparently those C&D times wasn't of interest to him though

Regardless, we have established that on most metrics such as 0-1000m (not 0-1000 feet as someone read that as ) the degree of decimation seems to be on a fairly similar level between the three generations. On the last 10 MPH from 140-150 MPH I agree that there will be a larger gap between the E46 than between the E9x and F8x

[e46e92love]

Originally Posted by swamp2

I'm siding with the opposition here. Your source doesn't really even address the key point of contention here. Journalists often give praise to an OEM for some outsourced component (steering, tranny, diff, electronics, etc.).

Now although I would give the vast majority of the design/engineering/manufacturing credit to Getrag for the M-DCT in the E9X M3, BMW and Getrag almost for sure cooperated on the unit. After all software for the transmission must cooperate with the engine software (further cooperation/integration has been discussed for the DCT in the M4). This tight knitting clearly requires some co-development and this is very typical as the supplier engineering team becomes a bit intermingled with the OEMs team during the development phase.

If I were to speculate on the customizations for BMW software is one obvious one as is the overall external packaging. The M-DCT unit advertised on Getrags website (right around and prior to the launch time of the E9X M3) looked ENTIRELY different than the actual unit. I'm sure those pics can easily be dug up. However, the internals both in their advertised unit and those for the other BMW models offering a nearly identical spec, are likely very close to identical. They probably offer very slight internal revisions and updates here and there but are going to be largely identical. There is plenty of documentation both external and I believe straight from the horses mouth (from BMW) stating this as the case.

Guys, not saying it's not a Getrag unit.....I'm fully aware that BMW does not build it's own transmissions (or many other parts such as fuel pumps) but that was not my point.

My point was simply that it was the first M-DCT rated to 9k rpms, something 5+ yrs later is still special as it's the only non-exotic to lay claim to such a feet.

I see that the part numbers are the same for DCT in BMW, but no chance this stat which was reported in 1000 places, as info provided by BMW, that it's false. Technically, series 3er and ///M3 have the same basic chassis designator, but the ///M does have chassis mods via increased support.

We are probably both right in our arguments.

Cheers,
e46e92

[e46e92love]

Originally Posted by swamp2

Is this fairly contradictory or am I missing something, especially the bold parts?

Is it the chassis or engine which wasn't visceral enough? I've never heard the S65 being described as anything but frenetic and visceral.

We've also beat the "not enough torque" think to death in about 100 threads. The car has more torque at the wheels than a 400 ft lb Z06 Vette at most rpms in most gears. Torque at the crank is largely a meaningless. It is torque with the gear/FD multiplication which gives wheel torque which is then something directly related to instantaneous acceleration.

Thanks for highlighting a point that most of the world seems to forget. But, I have stopped using this argument with friends as the torque at the engine vs wheels is meaningless if you shift the car properly, but if you prefer the tq to be there without having to drive the car, it means something, and unfortunately that is what most people want in today's world.

I think the two sides of the argument is better understand when we first understand the level of involvement people want and the amount of work people want to put in.

Cheers,
e46e92

[e46e92love]

Originally Posted by ruff

My concern for the F8x is it seems to be unknowingly following in the footsteps of AMG and Japanese performance cars, while in the process distancing itself from its M lineage. Even Corvette has successfully remained true to its small block lineage, despite stringent fuel standards and new technologies, which fuels its mystique among young and old enthusiasts alike. What set M cars and to a greater extent Porsche and Ferrari apart from every other manufacture was their race car inspired NA engines, stratospheric red line, Valhalla exhaust note and scalpel like steering response and handling. With M3's moving to FI, it becomes another FI car in a sea of FI powered cars now distanced by the GTR and Porsche Turbo. Duckworth said, "turbochargers are for people who can't build engines." A bit harsh but the same argument made from the inception of this forum against Japanese sports cars, AMG and later, BMW's own turbo charged engines. I am certain the F8x will be a fine sports car. I just think in the process, the M division will continue lose a bit of luster and prestige among true sports car enthusiasts.

PERFECTLY SAID RUFF. Explained EXACTLY how I and I think others feel but in a much more clear and concise way

Cheers,
e46e92

[Robin_NL]

1973 2002 Turbo had a turbo, way before M GmbH even existed.

The 1983 F1 Brabham BT52 had a 1.5 litre BMW turbo engine:World Champion.
E30 M3 had a 4 cylinder and had its max HP @ 6750rpm...
E36/46 M3 were both 6 cylinders.

Some heritage huh?

Happy holidays to all of you.

Cheers
Robin

[Boss330]

Originally Posted by e46e92love

Wow..... famous 335i vs M3 has leaked over!!!

Can't say the OP is right or wrong. A bit brash, yes. I will say that the M-DCT was the first dual clutch trans in the world rated to 9k....beat the 458 by I think 6-months, and only those two, new R8 and new GT3 have them. Pretty cool, great job by ///M division.

So for me, I don't care about power, torque. I focus on the uniqueness of the way it's accomplished and thrill of the drive. Always felt that the S65 was the culmination of the S54, S85, S65 line of REALLY high revving engines and exciting transmissions and power delivery to the rear wheels. Maybe not the most reliable, or fastest, but cars with engines and trans that have you a special experience.

Sorry for the long opinion.

Cheers,
e46e92

Originally Posted by e46e92love

Incorrect......some basic design may be the same, but internals are different, even from other BMW DCTs like on the 335is.

Best source I could find: http://www.caranddriver.com/reviews/...take-road-test


Cheers,
e46e92

Originally Posted by e46e92love

Guys, not saying it's not a Getrag unit.....I'm fully aware that BMW does not build it's own transmissions (or many other parts such as fuel pumps) but that was not my point.

My point was simply that it was the first M-DCT rated to 9k rpms, something 5+ yrs later is still special as it's the only non-exotic to lay claim to such a feet.

I see that the part numbers are the same for DCT in BMW, but no chance this stat which was reported in 1000 places, as info provided by BMW, that it's false. Technically, series 3er and ///M3 have the same basic chassis designator, but the ///M does have chassis mods via increased support.

We are probably both right in our arguments.

Cheers,
e46e92

Your link references the Getrag DCT transmission. They compare it with BMW's SMG transmissions, which are NOT DCT transmissions...

The DCT in the E9x M3 is the 7DCI600 transmission, also used in the 335i (and in numerous other RWD Applications). The difference between a 335i and M3 DCT being software and output flange etc, see attachment of BMW tech info for the M-DCT. Also of difference is the OD ratio, meaning that the normal versions are Limited to 7500rpm, or else the driveshaft would rotate at up to 10.000rpm...

http://wardsauto.com/news-amp-analys...y-number-seven

Here it says that Getrag developed the DCT for Ferrari and BMW simultaneously. There is no indications that BMW has developed the DCT. They, just like Ferrari, have asked Getrag to develop a gearbox that suits their needs. That is what BMW gets (and Ferrari).

The M3 is just the first of many high-performance, front-engine/rear-drive cars to use the new 7DCI600 transmission, called M-DCT by BMW.

Getrag's factory, 31 miles (50 km) north of Stuttgart, which produces the new gearbox, is set up to allow a “flexible concept on volumes,” Rinderknecht says, noting the factory architecture allows for a production of 100,000 units per year.

Because the M3 only is expected to absorb about 15,000 units annually, and the addition of a DCT option for certain '09 3-Series models won't take up the remaining capacty, that leaves plenty of room for other programs.

However, the BMW M5 and M6, which currently are saddled with the oft-criticized single-clutch SMG automated manual, will have to wait until their next iterations to sport a DCT, despite the new gearbox's ability to cope with the 5.0L V-10's 384 lb.-ft. (520 Nm) of torque.

Getrag's dual-clutch transaxle unit for the Ferrari California is more robust than the BMW version and capable of absorbing 553 lb.-ft. (750 Nm) of torque. This is far beyond the maximum torque of Ferrari's latest V-8 powertrain, which is expected to produce in the California slightly more than the F430's 343 lb.-ft. (465 Nm).

It, too, is capable of extreme revs — 9,000-plus rpm, which is well above the 7,500-rpm maximum permitted by even the best conventional automatic — yet manages a range of ratio spreads from 4.7 to 6.1.

The Ferrari gearbox is built in much lower numbers of between 5,000 and 10,000 annually.

“We expect further customers, because it offers important advantages over an automatic at high revs,” says Rinderknecht.

As such, it's not hard to imagine the gearbox becoming standard on all Ferrari road cars, much like how carbon-ceramic disc brakes have proliferated through the auto maker's lineup.

http://www.heise.de/autos/artikel/Va...artikelseite=4

In die Länge gezogen

Noch höhere Drehmomente überträgt das 7DCI600, welches Getrag für BMW baut. Es wird für die Modelle M3, 335i, Z4 und 135i angeboten. Das "I" steht für Inline, also Hinterradantrieb, wie er bei BMW üblich ist. Optisch erinnert das 7DCI600 an einen Wandlerautomaten, was auch kein Zufall ist:

Today the 7DCI600 is replaced with the 7DCI700, found in the F10 M5 and F8x range:

http://www.getrag.com/media/products...00/7DCI700.pdf

The Getrag DCL750 has a rpm limit of 9500 RPM:

http://www.getrag.com/media/products...50/7DCL750.pdf

[Boss330]

Originally Posted by ruff

My concern for the F8x is it seems to be unknowingly following in the footsteps of AMG and Japanese performance cars, while in the process distancing itself from its M lineage. Even Corvette has successfully remained true to its small block lineage, despite stringent fuel standards and new technologies, which fuels its mystique among young and old enthusiasts alike. What set M cars and to a greater extent Porsche and Ferrari apart from every other manufacture was their race car inspired NA engines, stratospheric red line, Valhalla exhaust note and scalpel like steering response and handling. With M3's moving to FI, it becomes another FI car in a sea of FI powered cars now distanced by the GTR and Porsche Turbo. Duckworth said, "turbochargers are for people who can't build engines." A bit harsh but the same argument made from the inception of this forum against Japanese sports cars, AMG and later, BMW's own turbo charged engines. I am certain the F8x will be a fine sports car. I just think in the process, the M division will continue lose a bit of luster and prestige among true sports car enthusiasts.

Originally Posted by e46e92love

PERFECTLY SAID RUFF. Explained EXACTLY how I and I think others feel but in a much more clear and concise way

Cheers,
e46e92

Have you driven a '70ies or 80'ies Ferrari or 911?

Razor sharp steering and handling isn't the best way to describe their handling characteristics...

The sound and induction noise of a NA engine is hard to beat, agree on that

But, much of Porsche 911 heritage is from the 930 Turbo and later iterations of that. Including the RUF CTR Yellowbird And the 959 as well as the 911 GT1, probably the most exclusive 911 versions ever...

http://en.wikipedia.org/wiki/Porsche_911_GT1








Ferrari had the 288 GTO, one of the most valuable Ferrari's there is today, and not least the F40. Both of those where turbocharged...

http://www.ferrari.com/english/gt_sp...Pages/GTO.aspx

http://www.ferrari.com/english/gt_sp...Pages/F40.aspx







You also have the 208 GTB/GTS and 328 GTB/GTS turbo versions:

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

http://www.ferrari.com/english/gt_sp...GTB_Turbo.aspx







So, even though high rpm NA engines are a part of Ferrari and Porsche DNA, so is turbocharging. Both in "mundane" street versions and in their supercar range!

And as a European, I'm sorry but the Corvette engine with it's cam in block, pushrod, design doesn't really have a mystique to me When Ford came with it's DOHC V8's, that was a step in the right direction. And engines like in the Boss 302 Laguna Seca, or other DOHC iterations available from Ford Racing Performance Parts, those have much more of a modern NA V8 engine "mystique" to it (to me). The Koenigsegg had a Ford DOHC engine in the beginning, now they call it their own design. But just look at the design of the Koenigsegg engine and you can clearly see it's relation with the Ford Romeo V8

The Corvette Z06 with it's 7l engine making 505hp is still only at 72 hp/l. A 3l NA engine would only make 216hp at that level of tune (the BMW N53 3l made 272hp in the generic 3- and 5-series and could be had in software detuned versions at 258hp and 204hp). The S65 would have had a power output of 288hp at the Z06 engine's state of tune... Hardly any mystique or pushing of boundaries to get a 7l engine to make 72 hp/l.

The Boss 302 engine is slightly better with 444hp from 5l, equalling 89 hp/l (the Z06 would be at 622hp with the same output per litre).

And the C6 ZR1 was supercharged...

I'm a big fan of NA engines, and even drive the only NA I6 engine that was available in the F10 in Europe (N53 3l) which has a 7200rpm redline. My son's first car that he will use as a learner driver car has a 2l NA engine that redlines at 7400rpm (Focus ST170/SVT). So, I do enjoy the thrill of a high revving NA engine. and even more a NA engine that revs to 8000+ rpm

But I also enjoy driving a good turbocharged engine. There is something about surfing on that crest of power that a turbo engine delivers when it just thrusts you forward I have a Ford Sierra RS Cosworth (haven't been on the road for nearly 10 years now...) and the thrill of driving that when the turbo kicks in is something special. It also makes quite a spectacular noise, different from a NA engine, but still thouroughly enjoyable That engine is old school and with it's homologation style exhaust manifold and large(ish) turbo there is plenty of lag...

BTW, that 2l turbo RS Cosworth engine was made by the company Duckworth founded together with Costin, namely Cosworth. (the name Cosworth taken from Costin and Duckworth), So even Duckworth made turbo engines in the end (including a 1,5 l 120 degree V6 Formula 1 engine)


--

[Robin_NL]

@ Boss exactly. 959, CTR, 288GTO & F40LM ftw!

The world's fastest car ever @ the Nordschleife had a 6 cylinder turbo engine as well



Back to the future

Cheers
Robin

[CanAutM3]

Originally Posted by swamp2

Correct, 455 hp. Seems a bit aggressively underrated even for BMW but as noted here it matches the official 21.9 second figure from BMW.

Unfortunately, though I just noticed an inconsistency. I reread the graphs posted there and 21.9 seconds appears to be accurate. However for the exact same inputs CarTest reports 21.5 seconds in its tabular format. I verified the difference to be rollout. The quicker times in the tabular view include a US standard 1 foot rollout. The graphs do not include these (more the EU reporting method). Either way all comparison numbers I have reported use rollout consistently again insuring a more apples to apples comparison.

The acceleration times from 0-40km/h and 0-60km/h in post #164 also seem over-optimistic for the F8X. It would mean average acceleration of 1.5g and 1.25g respectively. I am not sure street tires would support this on a RWD car.

Could this be explained by some sort of roll-out?

[swamp2]

Originally Posted by Boss330

And as a European, I'm sorry but the Corvette engine with it's cam in block, pushrod, design doesn't really have a mystique to me When Ford came with it's DOHC V8's, that was a step in the right direction. And engines like in the Boss 302 Laguna Seca, or other DOHC iterations available from Ford Racing Performance Parts, those have much more of a modern NA V8 engine "mystique" to it (to me). The Koenigsegg had a Ford DOHC engine in the beginning, now they call it their own design. But just look at the design of the Koenigsegg engine and you can clearly see it's relation with the Ford Romeo V8

The Corvette Z06 with it's 7l engine making 505hp is still only at 72 hp/l. A 3l NA engine would only make 216hp at that level of tune (the BMW N53 3l made 272hp in the generic 3- and 5-series and could be had in software detuned versions at 258hp and 204hp). The S65 would have had a power output of 288hp at the Z06 engine's state of tune... Hardly any mystique or pushing of boundaries to get a 7l engine to make 72 hp/l.

The Boss 302 engine is slightly better with 444hp from 5l, equalling 89 hp/l (the Z06 would be at 622hp with the same output per litre).

Although I certainly appreciate (understatement) both the character of and engineering excellence required to bring about high redline, flat torque, high specific output engines, specific output arguments fall almost completely flat in the real world. What are the specific advantages for the customer outside of character?

Maybe the advantage is fuel efficiency? Oops the giant 7l engine trounces the S65 (perhaps through shifting trickery and/or cylinder deactivation - not something inherent to the pushrod design nor displacement). I suppose there is the argument about taxes when based on displacement but for us in NA that too is irrelevant. Other advantages of the pushrod engine are a lower center of gravity and less weight (not sure about the actual 7l Z06 vs. 4l S65, but at a given displacement there will certainly be a weight advantage). Pushrod engines also offer a lower cost (again at fixed displacement for sure, otherwise maybe not for sure).

The Z06 and M3 clearly represent a different philosophy and approach. Each has advantages and disadvantages but specific output remains largely something of academic interest (or certainly for racing when displacement limits exist).

[Ezio]

Originally Posted by Boss330

So, even though high rpm NA engines are a part of Ferrari and Porsche DNA, so is turbocharging. Both in "mundane" street versions and in their supercar range!

And as a European, I'm sorry but the Corvette engine with it's cam in block, pushrod, design doesn't really have a mystique to me When Ford came with it's DOHC V8's, that was a step in the right direction. And engines like in the Boss 302 Laguna Seca, or other DOHC iterations available from Ford Racing Performance Parts, those have much more of a modern NA V8 engine "mystique" to it (to me). The Koenigsegg had a Ford DOHC engine in the beginning, now they call it their own design. But just look at the design of the Koenigsegg engine and you can clearly see it's relation with the Ford Romeo V8

The Corvette Z06 with it's 7l engine making 505hp is still only at 72 hp/l. A 3l NA engine would only make 216hp at that level of tune (the BMW N53 3l made 272hp in the generic 3- and 5-series and could be had in software detuned versions at 258hp and 204hp). The S65 would have had a power output of 288hp at the Z06 engine's state of tune... Hardly any mystique or pushing of boundaries to get a 7l engine to make 72 hp/l.

The Boss 302 engine is slightly better with 444hp from 5l, equalling 89 hp/l (the Z06 would be at 622hp with the same output per litre).

And the C6 ZR1 was supercharged...


--

i think you are messing what makes the Z06 engine so great (LS7 engine). all those other European engines are maxed out from factory. those GM LS engines have a insane amount of power to be gain n/a. not to mention the engine is way easier to work on or fix. the engine is not high strung like a BMW S65. its a very reliable setup. the engine does not work hard for its power, where the S65 does. if that makes sense . that LS7 engine is a loved engine here in the US. people love modding the crap out of them.

i think LS7s are pretty cool engines, although you don't see me driving one. i find European engines like the S65 to have more "style" to them. which i like. but i still do respect and understand why the Zo6 has a huge engine.

[swamp2]

Originally Posted by CanAutM3

The acceleration times from 0-40km/h and 0-60km/h in post #164 also seem over-optimistic for the F8X. It would mean average acceleration of 1.5g and 1.25g respectively. I am not sure street tires would support this on a RWD car.

Could this be explained by some sort of roll-out?

Rollout has nothing to do with graph based outputs from CarTest, again rollout is just "bookkeeping" used for tabular data. Rollout simply starts all timers when the car has traveled 1'. I agree that the acceleration numbers are large and impressive and only possible through both weight transfer and good tires. I have not modified the tire parameters compared to any of the other sims I've presented.

Comparing the times to speed from CarTest for the F10 M5 vs. Fastestlaps (last table) does indicate some pretty substantial overprediction of the very initial (1st gear) acceleration by CarTest (0-40 km/hr results). Here I have disabled the 1 foot rollout, using 0 feet (more in keeping with the way anyone reporting km/hr figures would most likely be testing).

The second set of results in US customary units turns the 1' rollout back on and shows a much better correspondence with most test results. Perfect nope, a bit slow on the 1/4 trap, a bit quick on the time. Of course bear in mind this is just one data set, and it is typical for CarTest to more calculate a best possible sort of time. Also note I have used 580 hp and 520 ft lb torque, substantially underrated and loosely consistent with dyno and actual test results (esp for a car this heavy).

Some quick changes with the tire parameters in CarTest did not effectively lower the peak acceleration in first gear (puzzling - it is as if the simulation is using a fixed friction coefficient during the case of spinning tires which is also inaccessible to the user). I'm open to suggestions for improvements. Heck buy the tool yourself, it is inexpensive and the author offers basic email tech support. Good support for the basics but unwilling or unable to dive as deep as you and I have in some discussions (like losses).

Simulation certainly ain't perfect but it does always beg the (hopefully) obvious question as to what THE test based time is for any metric. There is no one "correct" single time.

[Boss330]

Originally Posted by swamp2

Although I certainly appreciate (understatement) both the character of and engineering excellence required to bring about high redline, flat torque, high specific output engines, specific output arguments fall almost completely flat in the real world. What are the specific advantages for the customer outside of character?

Maybe the advantage is fuel efficiency? Oops the giant 7l engine trounces the S65 (perhaps through shifting trickery and/or cylinder deactivation - not something inherent to the pushrod design nor displacement). I suppose there is the argument about taxes when based on displacement but for us in NA that too is irrelevant. Other advantages of the pushrod engine are a lower center of gravity and less weight (not sure about the actual 7l Z06 vs. 4l S65, but at a given displacement there will certainly be a weight advantage). Pushrod engines also offer a lower cost (again at fixed displacement for sure, otherwise maybe not for sure).

The Z06 and M3 clearly represent a different philosophy and approach. Each has advantages and disadvantages but specific output remains largely something of academic interest (or certainly for racing when displacement limits exist).

Originally Posted by Ezio

i think you are messing what makes the Z06 engine so great (LS7 engine). all those other European engines are maxed out from factory. those GM LS engines have a insane amount of power to be gain n/a. not to mention the engine is way easier to work on or fix. the engine is not high strung like a BMW S65. its a very reliable setup. the engine does not work hard for its power, where the S65 does. if that makes sense . that LS7 engine is a loved engine here in the US. people love modding the crap out of them.

i think LS7s are pretty cool engines, although you don't see me driving one. i find European engines like the S65 to have more "style" to them. which i like. but i still do respect and understand why the Zo6 has a huge engine.

I appreciate both of your statements and "affection" for a big pushrod V8 engine. That's why I said "as a European I...". To me it's kinda like NASCAR vs F1. Both offer racing and sound etc. But I much prefer the high strung pitch and tech of a F1 engine over a "lazy" pushrod V8 (I know that some of the tech in NASCAR actually is pretty high end, like piston speeds close to F1 engines). It's not that I don't respect US V8 engines, but I prefer the Ford V8's over the Chevrolet V8, because it actually seems to have evolved more since 1955

Stuff like VVT is also something of a tradeoff with a single cam in block engine. GM decided to go the easiest route that gave 80% of the benefit at low cost (no "cam in cam" tech as far as I understand).

Even though the 6,2 GM V8 is using modern tech, like cylinder cut off and DI, to save fuel. It still will pretty much be considered pretty low tech and dinosaur with it's pushrod engine over here in Europe. It goes like stink and get's respect for that though Even German Magazines has declared the C7 a winner in a 911 vs C7 test...

It has accessible power, unlike the S65 (don't get me wrong here ). But just like the S55... So anyone that appreciates the useable powerband of the Corvette engine, should also appreciate the S55 for it's power

So, yes I appreciate the power of the Corvette engine. But my comment was with regards to a "mystique" surrounding that engine. Yes it has plenty of power, but it's not a engine that pushes the envelope in any way or creates a mystique (IMHO), like a Ferrari V8/V12 or the S65/S85 etc.

Even the S55, even though it will be a great engine (I hope), will have a hard time creating the same "mystique" that the high revving S65 and S85 has done.