EKaru

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http://images.330i.net/media/m3be.mpg

SiLvaC32

wow! look at it GO!

cliverman

That was beautiful! I'll need a few minutes by myself......okay...I'm better. :v

EKaru

It's amazing how the acceleration doesn't let up at all...
Eric...

Vomit

"290 kilometer/hour = 180.1976457 mile/hour (mph)"

Maybe my download/viewing of the video was incomplete, but "all" I saw on this CSL video was 266 KMPH (equal to just about 165 MPH). Given that there have been videos taken of C32 drivers exceeding 180 MPH, I find this video somewhat less than orgasmic. (Edit: Upon further review, I note that the the speedo needle is nearing 290 KMPH, but that the digital display reads 266 KMPH. Which one was correct? If the needle is correct, then this was a very impressive run! If the digital readout was accurate, I remain tepid).

In any case, the 0-200 KMPH run of the CSL was impressive. Based on the traction control warning, the CSL was smoking the tires all the way through second gear! However, after the last shift (at about 260 KMPH on the digital display), it really seemed to hit a wall. Is the high speed problem the result of the CSL's relatively low torque, or is it aerodynamics?

It would be very interesting to see a race between a CSL and a C32 starting from 200 KMPH or so. I have a feeling that the C32 would meet it or beat it (with the C32 top speed limiter deprogrammed, of course).

M&M

What? BOy are you brand blind. I have 2 buddies with CSL's. They trap 110 stock. Over 1km , they trap 6mph more than me.

Vomit

M&M: Maybe you missed the point of my post. It had nothing to do with 0-1/4 mile or 0-1KM trap speeds. I have little doubt that, with talented drivers, the CSL would beat a stock C32 in either of these races.

My post dealt only with (1) trying to determine if NKaru's video showed a CSL going 165 MPH, or 180 MPH, and (2) speculating about the outcome of a high-speed (200 KM to the "aerodynamic wall") race between a CSL and a C32.

M&M

When my E36 M3 was normally aspirated it was tuned to about 350hp. Here's what sped it could do:

It ran off the clock to where 300km/h (188mph) would be. True speed at that point was verified by GPS to be 285 km/h (178mph).

THe CSL has more top end power, better aerodynamics & better gearing.




IT helps when you approach your power peak as you hit 180mph. If your power drops off at high rpm, you might struggle to overcome air resistance.

Psychoburn

i don't get how M&M's posts have any relevance to what vomit was asking... and i'd like to know the answers to this too..

Also how does csl compare to a c55 in terms of straight-line speed?

EKaru

C55 has about the same straight-line speed as a stock E46 M3 and the CSL weighs 440 lbs less... In other words, I wouldn't want to race one..
Eric...

M&M

Well trap speeds are important because it shows that the CSL pulls away from a stock M3 at high speeds. Therefore, a C32 has no chance at any speed. It has more hp than a C32 & is 440lb lighter. You do the math.

Vomit

M&M: Maybe I should make the question simpler: Which vehicle (C32 or CSL) has a higher top speed (assuming no electronic intervention to spoil the fun )?

Weight and HP are not the only factors in a "top-speed death run." I can put 400 HP in a 2800 lb. Suzuki Samurai and probably not hit 150 MPH (scary thought!)

In fact, you appear to have omitted two very crucial elements from your analysis: (1) coefficient of drag and (2) gearing. Anyone know how the c/d compares between the C32, C55, and E46? (I assume that the stock M3 c/d is the same as the CSL, but have little doubt that you will correct me if I am wrong.)

It is my understanding that a stock C32 will top out just about right at 180 MPH. What will the CSL do?

M&M

The formula for horsepower includes power, drag co-efficient, frontal area & air density. CSL has same cD as a stock M3 or a C32. However, as you approach 180mph, CSL will be putting more power to the wheels than a C32. Can anyone tell me why?

reggid

becasue it has more.............lol :p

Vomit

The M3/CSL has the same c/d as the C32? I thought that the C32 c/d was .27 and the M3 was .33? Where do you get your data supporting your contention that the c/d of the M3 is the same as the C32?

As for your question: "However, as you approach 180mph, CSL will be putting more power to the wheels than a C32. Can anyone tell me why?"

My Answer: "Who Cares?" My 400 HP, 2800 lb. Samurai has more HP at 150 MPH than both the C32 and the CSL, yet it will not further accelerate. Both the C32 and the CSL will walk away from it at high speed. Please stop avoiding the question. . . If your vaunted CSL has a higher top speed than the C32, just say so (and cite to your source of proof).

You know what my position is: In a flat out top speed run, the C32 and CSL will run very close to each other. Prove me wrong

doofoo

Everyone keeps saying the C32 top speed is near 180. I did a little run and didn't have much RPM's left when I hit 159. Here is the video, you cant really see the tach on it, but right around 155-159 you can see I only have maybe 600-700rpm's left. I don't think it'll do 180.

Video:
http://www.ods.org/~doofoo/c32/morning/C32159MPH.MPG

-Mike

blando

More info on C32 Top Speed (unlimited):

175 stock, 190 with modified gearing

http://www.caranddriver.com/article....&page_number=1

Aerodynamic Drag:

C32 0.27
http://www.mbusa.com/amg/specs.jsp?p...technical_data

M3/CSL 0.33
http://www.bmwusa.com/vehicles/M/M3Coupe/techdata.htm
http://www.globalcar.com/datasheet/BMW/2003BMWM3CSL.htm

That is a HUGE difference. Bottom line, it takes a significant amount of horsepower to overcome drag as speeds increase. For more information, refer to the following: http://autozine.kyul.net/technical_s.../tech_aero.htm

Key points:

"You can see a car travelling at 120 mph has to fight with 4 times the drag of a car travelling at 60 mph. You can also see the influence of drag to top speed. If we need to raise the top speed of Ferrari Testarossa from 180 mph to 200 mph like Lamborghini Diablo, without altering its shape, we need to raise its power from 390 hp to 535 hp. If we would rather spend time and money in wind tunnel research, decreasing its Cd from 0.36 to 0.29 can do the same thing."

"Cd World Records: 0.27 Mercedes C-Class"

derAMG

vomit is right...
co drag has more important values on high speed run than weight...
plus momentums will take away the weight, the faster you go, the lesser concerns is pay to weight.

btw, identically, stock M3, C32 and C55 has the same gear ratio, so our top speed is pretty much the same...and i think the M3 CSL has the identical SMGII semi matic box...

base on my thinking... i think torque and co-drag is what you need for high end speed if gearing is not a problem. C32 and especially the new C55's torque is much stronger and with the much lower co-drag #s...

wait... the M3 CSL has a different front spoiler with fewer vent and 1 extra circular intake hole i thought? wouldn't M3 CSL has different co-drag # then?

hey guys... we are just disgussing here... don't get it flamed

Improviz

M&M comes here, and to the Audiworld S4 forum, for one reason and one reason only: to troll. Look at the following post, where I catalogued no fewer than ten instances of his trolling (and could easily have posted more)...he does one of two things here (and on Audiworld, where he's been trolling, first under username "321ponies", then as "M3x2" and now as "343bhp" for over three years now--note that the first post I linked to above is from June 2001):

1) post flamebait to demonstrate the "superiority" of the M3, and argue incessantly with anyone to challenge it;

2) argue incessantly with anyone here who dares to post that they like the AMG cars better than the M cars. Same MO as Gabri343, who also trolls here incessantly.

Apparently, this is pretty much his life: trolling Internet car forums trying to annoy people and stir up trouble. Sad, really...these guys must not have gotten enough attention from mommy and daddy when they were kids to have turned out like this!!

M&M

Improviz, here's the formula for top speed. LEt's discuss it:



OR for power to reach a certain speed:



Where p = rho = air density (1.3 at sea-level)
cD = drag co-efficient
A = frontal area
v = velocity

Hell, where's torque. Guess what? Sir Isaac Newton decided to leave it out of the equation for top speed. Where's the power peak for the C32 & I can work it out for you guys?

reggid

if density is 1.3 then you must be using SI units so don't forget power is Rear Wheel power (watts) and other measurements are in metres (m), kilogram (kg), Newton (N) and seconds.

Its worth noting that Cd is not really constant its a function of velocity so is different at 30mph than 180mph.

if you want torque then:

V = (2.T/p.R.Cd.A)^0.5
T = 0.5.p.Cd.R.A.V^2

T = RWTQ = Engine torque X gear ratio x diff ratio x efficiency of transmission in Nm
R = Rolling Radius of Driven Tyre(s)

M&M

OK so according to all the dyno's on this forum, the power peak on a stock C32 is between 5900-6000. Power seems to really die after 6100.

http://dynoperformance.com/search_details.php?ID=756

Loses 14rwhp from 6050 to 6100rpm. But that's fine. The typical Merc customer doesn't want to rev to the stratosphere. A roots type s/c has parasitic losses at high rpm & in some applications the s/c actually decouples at high rpm due to the high power requirements of the s/c at high revs.

So once you pass 6000rpm you aren't going to be able to overcome the massive air resistance at those speeds if your power is dropping off at 14whp every 50rpm. So can a C32 reach 180mph?

According to my calculations in order for a C32 to reach 175mph it needs:

Cd = 0.27
frontal area A = 2.21 square metres
V = 175 mph = 280 km/h = 77.7777 m/s

P = 0.5 * (rho) * Cd * A * v^3
= 0.5 * 1.3 * 0.27 * 2.21 * (77.7777) ^ 3
= 182488.70 W
= 182.488 KW
= 248.184 RWHP

Shouldn't be a problem for the C32 to reach 175. But remember that's rwhp in 5th gear. What gear do you guys use to dyno?

So we have calculated that a C32 has enough hp to to 175mph. How about 180?

Well doing the same calculation it needs 270 rwhp to do 180. However, at 180, it will be past 6200rpm in 5th.

At 6000 rpm in 5th he C32 is doing 175.6 mph.
At 6100 its doing 176.8 mph.

Power is dropping off rapidly. At 6200 rpm C32 has around 250rwhp. SO it will not go past 175-176 unless you change the final drive.

bverotti

My C32 is quite modded and I tell you the CSL is a tough cookie to beat. Forget taking on a CSL in a stock C32, you will be embarrased.
Even with about 440 HP a CSL is very hard to shake, these cars are simply very fast indeed !

steve s

don't forget environmental factors... one of the important considerations for high speed test is headwind.. so if on a certain day u can't reach a certain speed..don't be too discouraged... i can assure u, that even if u r going downhill..if the headwind is too strong, u can see 20 mph lower or even more than what u expected..


anyway...so is this 180 mph actually tested or theoretical on u guy's c32 (modded or stock?)?


btw, i counted roughly in this vid..the m3 csl did:
80-180 kmph ~9 sec

for comparison 80-180 kmph..
McLaren F1 : 6.7s
Lamborghini Diablo VS : 6.9s
Ferrari 550 : 7.0s
Porsche 911 GT1 : 7.5s
Corvette (year unknown) : 11.4s
Merc E60 AMG : 11.5s

Vomit

So it sounds like a stock C32 will top out at 175. 180 would seem to be unlikely with the stock gearing/unmodified car, as it is true that the stock C32 power takes a nosedive around 6000 RPMs. I stand corrected.

Which brings us back to the question of the CSL top speed. . . The video shows the speedo needle at 180 MPH, but the digital speedo display at 165 MPH. Given the less efficient aerodynamics of the CSL, I suspect that the digital display is closer to what the actual speed was at the time that the driver shut down. In all fairness, it really did not look like he really topped the car out (it was still accelerating, albeit slowly, when the vid stopped).

My prediction of the C32 vs. CSL top speed run: Just about dead even.