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      04-17-2008, 03:02 AM   #23
swamp2
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Can some of your guys add all the performance figures for the various Vette models to our nice database here. It would be nice to see all the numbers and variation as well as all of the different models posted. Remember that new stuff goes in blue and you should provide a source and link if possible. I guess we don't need to add late model Z06 results and that compared to the M3 is not much of a performance competition.
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      04-17-2008, 07:22 PM   #24
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Quote:
Originally Posted by sayemthree View Post
Nordschleife, Germany

ONLY 6 seconds faster? pretty close. I am sure someone can get the M3 closer to 8:00

40. Chevrolet Corvette C6 7:59 04 400 / 1470 Motortrend...
I believe the M3 was on hot-damn sneakers at the time, with motorsports brake pads as well. Sporting stock rubber and pads and with a really hot cockpit assassin aboard, figure a tad slower than 8:05. Close enough, from my point of view, especially considering the M3's weight problem.

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      04-17-2008, 07:59 PM   #25
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Quote:
Originally Posted by malter2.0 View Post
No, it would not pull on M3. C5 Z06 has slower time 0-150mph than E92 M3. It would very close with edge on M3. C5 Z06 is quick in 1/4 because it has excellent low-end and mid range torque.

C5 Z06 0-150mph 25.5 sec
E90 M3 0-150mph 24.9 sec
The C5 Z06 has lousy aerodynamics compared to the coupe, which explains how and why it comparatively tails off a bit at speed, compared to the M3 (and the current C6, at 23.5 seconds), At, say, a 75 mph cruise based on the OP, aerodynamics is nothing.

Quote:
Originally Posted by malter2.0 View Post
It is also incorrect that power to weight matters from those speeds. It matters from a dig and becomes less of a factor as vehicle picks up momentum. At those speeds gearing and aerodynamics are everything. Power to weight will matter at high speeds if difference is significant.
So, you're saying that at 75 mph, power to weight is unimportant, and aerodynamics and gearing rule? OK, first things first: I agree that power to weight matters most at a stop, and least when you're approaching top speed.

But, 75 mph? At that speed, the M3 probably needs about 40 hp to cruise, and the Vette, maybe 45? Everything you're making over that is available for acceleration.

Gearing? I don't get it. How does gearing affect all this in the slightest? I get that, at 75 mph, the M3 is at around 6000 rpm in third, making around 320 hp. The Vette is at around 4700, making around 350 hp.

How does gearing trump hp?

Bruce
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      04-17-2008, 11:31 PM   #26
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
I believe the M3 was on hot-damn sneakers at the time, with motorsports brake pads as well. Sporting stock rubber and pads and with a really hot cockpit assassin aboard, figure a tad slower than 8:05. Close enough, from my point of view, especially considering the M3's weight problem.

Bruce
I think the 8:05 is on stock tires. track tires would be good for 25 sec on the ring. this test was by the same mag?

10. BMW M3 Sedan (E90) 1:38.7 07 420 / 1680 Autozeitung
11. Lamborghini Gallardo Spyder 1:39.0 06 520 / 1720 Autozeitung
12. Chevrolet Corvette Z06 1:39.4 05 513 / 1420 Autozeitung
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      04-18-2008, 12:17 AM   #27
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
The C5 Z06 has lousy aerodynamics compared to the coupe, which explains how and why it comparatively tails off a bit at speed, compared to the M3 (and the current C6, at 23.5 seconds), At, say, a 75 mph cruise based on the OP, aerodynamics is nothing.



So, you're saying that at 75 mph, power to weight is unimportant, and aerodynamics and gearing rule? OK, first things first: I agree that power to weight matters most at a stop, and least when you're approaching top speed.

But, 75 mph? At that speed, the M3 probably needs about 40 hp to cruise, and the Vette, maybe 45? Everything you're making over that is available for acceleration.

Gearing? I don't get it. How does gearing affect all this in the slightest? I get that, at 75 mph, the M3 is at around 6000 rpm in third, making around 320 hp. The Vette is at around 4700, making around 350 hp.

How does gearing trump hp?

Bruce
No to split hairs but I think the power needed to cruise at 75 in the M3 is closer to 60 hp. 75 mph is close to the point at which the drivetrain and aero losses are about equal.

On the gearing point if you convert hp tp torque and multiply by the gear ratios you will find that at that speed the M3 is putting down about 10% more torque to the wheels which determined instantaneous acceleration.
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      04-18-2008, 03:50 AM   #28
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
The C5 Z06 has lousy aerodynamics compared to the coupe, which explains how and why it comparatively tails off a bit at speed, compared to the M3 (and the current C6, at 23.5 seconds), At, say, a 75 mph cruise based on the OP, aerodynamics is nothing.
I doubt at 75mph it is significant, but if they ran up to 100-120mph (like typical highway pull), drag increases with square of speed, so any drag differences become evident very fast past normal cruising speeds.


Quote:
So, you're saying that at 75 mph, power to weight is unimportant, and aerodynamics and gearing rule? OK, first things first: I agree that power to weight matters most at a stop, and least when you're approaching top speed.

But, 75 mph? At that speed, the M3 probably needs about 40 hp to cruise, and the Vette, maybe 45? Everything you're making over that is available for acceleration.
I did not say it is unimportant, just that it does not become a determining factor, unless difference is staggering, which in this case it isn't. I have no clue what M3 or vette put down at 75mph or if that information is relevant on highway....maybe more significant when powering out of a tight bend on the track.

Quote:
Gearing? I don't get it. How does gearing affect all this in the slightest? I get that, at 75 mph, the M3 is at around 6000 rpm in third, making around 320 hp. The Vette is at around 4700, making around 350 hp.

How does gearing trump hp?
It matters heavily. Longer gears tend to be an advantage on highway pulls. Just an example, my old, stockish '95 M3 with factory 3.15 LSD had incredibly long 4th gear. It could often stay even on highway pulls with much more powerful car simply because it would continue to build speed in very linear matter, as other car has to shift, engine has to get back into momentum etc. To actually get the full advantage of it, you have to do a pull long enough to land you in jail...but thats another story.

Gearing does not trump hp in any way, but it affects how torque is distributed in rev range, something that is important during long pulls on highway.
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      04-18-2008, 08:34 AM   #29
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Quote:
Originally Posted by swamp2 View Post
No to split hairs but I think the power needed to cruise at 75 in the M3 is closer to 60 hp. 75 mph is close to the point at which the drivetrain and aero losses are about equal.
Seems high, but I admit my estimate was a complete guess, based on the old "25 hp at 60" rule of thumb.

Quote:
Originally Posted by swamp2 View Post
On the gearing point if you convert hp tp torque and multiply by the gear ratios you will find that at that speed the M3 is putting down about 10% more torque to the wheels which determined instantaneous acceleration.
OK, I'll do the arithmetic, instead of "Kentucky windage" estimating, which I admit I'm guilty of.

Assuming the M3 is making about 285 lb/ft of torque at 6000 rpm (at 75 mph), let's see, 285, times the third gear ratio of 1.58, times the 3.85 final drive ratio gives me 1734 pound feet at the rear wheels.

OK, the Vette makes 400 pound feet at 4800 rpm, so I'll be conservative and say 390 pound feet at 4700 (at 75 mph), times the third gear ratio of 1.43, times the final drive ratio of 3.42 gives me 1907 pound feet at the wheels.

So the Vette has around another ten percent of thrust available, but shorten that up by about two percent because the M3 has shorter sneakers.

In my opinion, torque at the drive wheels is merely a reasonable hint at acceleration ability. Other factors such as wind resistance, overall internal friction, rolling resistance and rotating inertia are all in the M3's favor.

As I said though, from 75 mph advantage C5 Z06 Vette. At higher speeds, the M3's closer gear spacing and better aerodynamics give it the advantage.

Bruce

PS - Swamp, I know you know this, but I'll remind you again. Once you get power figures, you don't have to bother with torque at the drive wheels. Horsepower is the great short cut in this context.
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      04-18-2008, 09:33 AM   #30
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Quote:
Originally Posted by malter2.0 View Post
I doubt at 75mph it is significant, but if they ran up to 100-120mph (like typical highway pull), drag increases with square of speed, so any drag differences become evident very fast past normal cruising speeds.
Yeah. Vette wins early, loses late (by a minor amount, based on your posted 0-150 times). Therefore, the likely result is that the Vette wins this impromptu matchup, unless both drivers stay involved for far longer than the typical street bash.

Quote:
Originally Posted by malter2.0 View Post
I did not say it is unimportant, just that it does not become a determining factor, unless difference is staggering, which in this case it isn't. I have no clue what M3 or vette put down at 75mph or if that information is relevant on highway....maybe more significant when powering out of a tight bend on the track.
See my just-previous post back to Swamp.

Quote:
Originally Posted by malter2.0 View Post
It matters heavily. Longer gears tend to be an advantage on highway pulls. Just an example, my old, stockish '95 M3 with factory 3.15 LSD had incredibly long 4th gear. It could often stay even on highway pulls with much more powerful car simply because it would continue to build speed in very linear matter, as other car has to shift, engine has to get back into momentum etc. To actually get the full advantage of it, you have to do a pull long enough to land you in jail...but thats another story.
This anecdotal evidence has nothing to do with effective racing from medium speeds. That said, the fact is the cars each have similar speeds in gears, with the M3 at 69, 104 and 138 mph in second, third and fourth, while the Vette comes in at about 71, 102 and 147 mph.

Bruce
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      04-18-2008, 11:58 AM   #31
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
.So the Vette has around another ten percent of thrust available, but shorten that up by about two percent because the M3 has shorter sneakers.
I agree with these numbers I totally botched mine using 1st gear and final drive instead of 3rd gear and final drive, ugh....
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      04-18-2008, 01:11 PM   #32
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This anecdotal evidence has nothing to do with effective racing from medium speeds. That said, the fact is the cars each have similar speeds in gears, with the M3 at 69, 104 and 138 mph in second, third and fourth, while the Vette comes in at about 71, 102 and 147 mph.

Bruce
If C5 Z06 has same shift speeds as M3, then we can take gearing out of the equation, at least in the scope of M3 vs vette case.
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      04-18-2008, 04:00 PM   #33
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Interesting debate, and a lot of good points from a scientific stand point, but I still believe it's a close enough race where it's driver determined.
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      04-18-2008, 04:22 PM   #34
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Quote:
Originally Posted by spearfisher View Post
Interesting debate, and a lot of good points from a scientific stand point, but I still believe it's a close enough race where it's driver determined.
From a poster I used to keep in my office: "The race doesn't always go to the swift, nor the battle to the mighty - but that's the way to bet."

In this case, I'd bet on the Vette, drivers be damned. There's one shift involved, a straight back pull from third to fourth, so it's going to take a really bad driver against, say, powershifting Malter to change the outcome.

From 100 in fourth? Hmm. Maybe I put my money on the Powerkraut.

Against a Z51 C6? I'd bet on the Bow Tie Brigade, except in a very short race. The M3 will have better traction and more effective gearing while both cars make their way up into the meat of the power.

Bruce
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      04-18-2008, 07:34 PM   #35
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lots of variables - even from car to car - you could get avette with a weak motor and anM3 with a ringer.

RandT tested both and using a professional driver the M3 was faster. with the M differential I would bet on the M3. from what I hear the Vette is hard to get traction off the line.

enough with all the science guys - dont you know by now that BMW magic M cars always outperform what the formulas say they should?
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      04-18-2008, 10:48 PM   #36
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Depending on the year the HP varies from 385 to 405 for the C5 Z06
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      04-18-2008, 11:38 PM   #37
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2001 was the only year with 385 i think
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      04-19-2008, 12:29 AM   #38
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Quote:
Originally Posted by sayemthree View Post
lots of variables - even from car to car - you could get avette with a weak motor and anM3 with a ringer.

RandT tested both and using a professional driver the M3 was faster. with the M differential I would bet on the M3. from what I hear the Vette is hard to get traction off the line.

enough with all the science guys - dont you know by now that BMW magic M cars always outperform what the formulas say they should?
I believe in M magic - but I also believe in Vette magic. (As I've mentioned before, I'm a badge whore for just about anybody - meaning I'm a really promiscuous badge whore.)

That R & T test was very interesting. They're the one major magazine I know of that still doesn't bother to adjust their observed figures to standard day conditions. Their standard test venue is in Southern California, which typically doesn't have weather extremes, but in this case, they tested the M3 in Germany, at 57 degrees, and the Vette in the U.S. at about 90 degrees. Result? M3 gets best ever results, and the 436 HP Vette goes just about as quick as the previous LS2 400 hp model. They said that the Vette would likely do a little better than the previous model on a cooler day. Gee, ya think?

Bruce
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      04-19-2008, 12:35 AM   #39
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
That R & T test was very interesting. They're the one major magazine I know of that still doesn't bother to adjust their observed figures to standard day conditions. Their standard test venue is in Southern California, which typically doesn't have weather extremes, but in this case, they tested the M3 in Germany, at 57 degrees, and the Vette in the U.S. at about 90 degrees. Result? M3 gets best ever results, and the 436 HP Vette goes just about as quick as the previous LS2 400 hp model. They said that the Vette would likely do a little better than the previous model on a cooler day. Gee, ya think?
Bruce
OH PLEASE!!!!!! If RT mentions 90F and high humidity I'll shut up, but 90F in southern california is rare. It is micro-climate with 70F weather for most of the year. I would bet my life that humidity was higher in Germany than in dry ass california. Humid air is significantly less dense than dry air, and will kill performance.
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      04-19-2008, 02:22 AM   #40
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Originally Posted by malter2.0 View Post
...but 90F in southern california is rare.
Says the not so educated and far distantly located New Englander. Ugh. 90 is common in the summer anywhere more than 5 miles off the coast (due to the very micro climate phenomena you mentioned). It was above 90 here all around San Diego last weekend and it ain't even really summer yet. Further of the coast in the 20+ mile range 90 is the norm in the summer.
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      04-19-2008, 11:55 AM   #41
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
I believe in M magic - but I also believe in Vette magic. (As I've mentioned before, I'm a badge whore for just about anybody - meaning I'm a really promiscuous badge whore.)

That R & T test was very interesting. They're the one major magazine I know of that still doesn't bother to adjust their observed figures to standard day conditions. Their standard test venue is in Southern California, which typically doesn't have weather extremes, but in this case, they tested the M3 in Germany, at 57 degrees, and the Vette in the U.S. at about 90 degrees. Result? M3 gets best ever results, and the 436 HP Vette goes just about as quick as the previous LS2 400 hp model. They said that the Vette would likely do a little better than the previous model on a cooler day. Gee, ya think?

Bruce
I beleive all the major US car mags adjust thier number for climate and elevation.
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      04-19-2008, 01:34 PM   #42
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Originally Posted by malter2.0 View Post
OH PLEASE!!!!!! If RT mentions 90F and high humidity I'll shut up, but 90F in southern california is rare. It is micro-climate with 70F weather for most of the year. I would bet my life that humidity was higher in Germany than in dry ass california. Humid air is significantly less dense than dry air, and will kill performance.
Well sure enough, I checked, and the humidity in Germany was 59%. I don't know what the humidity was in the Vette test, but it typically runs in the 40% range in their typical test venue - which by the way is at an altitude of 350 feet rather than the 650 foot test altitude in germany. At a guess, the humidity in the Vette test was probably even lower than the norm, because of the heat. (Note: figures not given for this becasue it was an "update" test, without full data panel.) In any event, figure a couple of tenths and another 1 1/2 mph coming the Vette's way, correcting for weather.

Meanwhile, I hadn't realized that there was a Vette in a later comparision test, where, near as I can tell, the temperature was at only 81 degrees, with 41% humidity. (These are about the norm for their test venue.) Sure enough, the car was quicker than in the earlier, hotter test, just as they predicted.

Still, it was a tenth off the benchmark M3 time (12.6 vs 12.5), although mph was up a skoche, at 115.7 vs 114.8 for the bimmer. Weather correction would show the Vette picking up a fat tenth and another mph, meaning that except for trap speed, they're right on top of one another.

My net of all this anal analysis is that from a dig, the M3 is a better performer than the Vette, and the Vette's better power to weight has to overcome the deficit before catching up and passing by - in this case, somewhere past the quarter mile.

All in all, I think the new M3 is a bit of an overacheiver in the acceleration department. It can make full use of the power right from rest, and the close gear spacing up top means, as with most Euro cars, it'll run hard when the speedo gets well over on the right hand side of the dial.

I'm still pondering lucid's problem, though. Pretty much all concerned (road testers, users) have said that the car runs really hard when you boot it, but tends to fall a little short of expectations just driving around - thus the interminable M3 vs 335 posts, wherein Swamp and I have traded pleasantries in at least one of those strings.

There ought to be a quick fix, but I need to check something.

Bruce
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      04-19-2008, 01:34 PM   #43
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Quote:
Originally Posted by sayemthree View Post
I beleive all the major US car mags adjust thier number for climate and elevation.
All but R & T. Ask them.

Bruce
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      04-19-2008, 04:47 PM   #44
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Originally Posted by swamp2 View Post
Says the not so educated and far distantly located New Englander. Ugh. 90 is common in the summer anywhere more than 5 miles off the coast (due to the very micro climate phenomena you mentioned). It was above 90 here all around San Diego last weekend and it ain't even really summer yet. Further of the coast in the 20+ mile range 90 is the norm in the summer.
http://www.wunderground.com/cgi-bin/...an+diego%2C+ca

There are extreme weather days and weeks anywhere. We had 86 F yesterday, which is unheard of for CT at this time of the year. I don't have to live in Southern California to see what kind of weather it is over there.
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