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01-20-2008, 03:44 AM | #155 |
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In the real world these numbers mean nothing!!!! I have a e46 M3 and I live in the Northern NJ. 15 mins away from NYC.. All I can say 0 to 35 is the new 0 to 60 these days. 1st and 2nd gear are used the most!!! The new M3 will not be such a great car near city limits. Dont get me wrong I like my M3 but with all this traffic I cannot reach its full potential as a DD. I drive my Jeep Cherokee more than my M3. Only time I enjoy my M3 is to drive 1 hour away on the weekends. The 335i with steptronic would be the better car for DD in my area anyway. Heck a 335xi will beat a 335i and E92 M3 from 0 to 35mph LOL. The M3 will always be a sports car and will be great on a track. The 335i will be a sporty 3 series and be great for daily driving.
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01-20-2008, 03:51 AM | #156 | |
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thanks for your review it was helpful to decide my next car from BMW! |
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01-20-2008, 01:13 PM | #157 | ||||||
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By the way, glad you cleaned up that section. I was preparing myself to be involved in a bunch of additional discussion about those details - something which I find unrewarding, both on general terms and because it's ancillary stuff. Quote:
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I later remembered about the C & D data, and typed that novelette. The major point there was that due to increased rotational inertia, you don't get what you think you're going to get from aggressive gearing. Quote:
Their number for the M3 seems to be a little light considering what I've read from BMW elsewhere, but the car was in fact a European version, and based on that it may in fact been a little heavy, since C & D weighs cars empty with all liquids topped off, American style. The difference between American and Euro standard weights seems to be in the neighborhood of 150 pounds or so, meaning the car would've come in at roughly 3500 pounds under U.S. terms. Why heavy? Options, maybe. As far as comparing cars based on road tests a year or so apart, C & D "zeroes" their test results to a C & D standard day, which seems to be roughly equivalent to the old SAE Gross Standard Day. Not perfect, but as close as they can manage. The gorilla in the room may be the supposed under rating of the 335 by BMW, but even if I assume 325 HP and a like amount of torque for the 335, the M3 still comes up a little short when you factor in turbo lag, which I think accounts for at least two or three tenths in such a low speed roll on. Figure around maybe 180 pound feet for the 335 the instant you mat the throttle, soaring to 300 (or possibly 325) pound feet after around a second or so - but not less than that. If you factor in, say, a 12% rotational inertia penalty for the M3 based on more aggressive gearing (per my novelette), the numbers start to work out pretty well. Bruce Edit: PS - Assuming the 335 really is under rated, that's yet another reason why it seems to be a killer car in everyday driving compared to the M3. |
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01-20-2008, 01:25 PM | #158 | |||
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It wasn't a complement but you knew that already. You obviously have not experienced both either. I suggest you do unless of course you have already made up your mind. I have nothing to do with Vishnu, I only test-drove a friend's car with the tune. |
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01-20-2008, 01:41 PM | #159 | ||
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Best regards, south |
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01-20-2008, 03:44 PM | #160 | |
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Signed, Someone whose has read about every 335i dyno put up on e90post.com |
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01-20-2008, 04:28 PM | #161 | |
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Actually you are correct
I have not driven the vishnu? car but I have driven the AC Schnitzer tuned 335 with about 350 HP, lowered, with exhaust and modded suspension, done by the Germans who have a lot more experience than the procede boys. but hey we have the autobahn over here and a few more open roads and tracks close by.
I own a 335 convert and an 08 Corvette C-6 and will be getting an M3 in March/April but I do track the car and we have areas of the Autobahn with no speed limit so It is a different world I reread your post(s) and since you do not drive the car at the track, and only need it for traffic, a 335 would be a fine car for you. The 328 would easily meet your needs as well. It really is not a badge thing, however the M-3 is not a car to weave in and out of traffic, it is snappy alright, but you will never use the car so you are right, no need to spend the extra bucks. I like you, dislike car buyers who buy performance only to be a poser. You say only need snappy. The vishu 335 will give you bragging rights and additional boost. The voiding of warranty is disconcerting, because most of the other more established tuners cover you. Glad to hear you dont work for them, I detest trolls good luck in your choice Quote:
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01-20-2008, 04:31 PM | #162 | |
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There is already a big discussion on this in the "M3 vs" forum. Go there and try to convert people.
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01-20-2008, 04:50 PM | #163 | |
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Human behaviour.... (as he puts on his flame retardant suit)
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Just thinking of something not so witty ///M3 E92 '09 Jerez Black | 6MT | Ext Fox Red | Tech | Prem | 19s |Heated Seats | iPod |Smartphone | Euro Deliv June 09 Sold: 540iT / 530i / 323i Last edited by Voltigeur; 01-20-2008 at 07:12 PM.. |
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01-20-2008, 07:10 PM | #165 |
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Seriously, the same issue keeps coming back. Remember when that V2 chipped 335 beat a M3 in a drag race and 100 posts were made in 4 different forums here.
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01-20-2008, 07:58 PM | #166 | ||
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Good luck to you as well ... I guess each of us has his own interests and it's good to be able share information without necessarily having to agree with each other's car opinions. |
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01-20-2008, 09:25 PM | #167 | ||||||||
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1. The rotational inertia of the two drivetrains can be different. 2. Even if the rotational inertia of the two driven trains are the same, it is true that since the M3 has a more aggressive final drive ratio, the rotating masses in front of its differential will experience higher angular accelerations (rpm gains per unit time) during WOT acceleration. Speaking to 1, we don’t really agree that there is a difference. You are saying 335’s I is lower. Swamp and I seem to be saying it is either the same as the M3’s or higher. We don’t have the numbers, and we most likely never will. Speaking to 2, we all seem to agree it is true, but we don’t seem to be able to agree on the magnitude of the effect. Also, if M3’s I happens to be lower than 335’s I, than the effect of 1 might cancel out the effect of 2. Quote:
If we look at the right side of the equation: 1/2 * I * w^2 and differentiate with respect to time, we get (by using the power rule): 1/2 * I * w^2 * d/dx = 1/2 * I * 2 * w * dw/dt = I * w * dw/dt since dw/dt is alpha, which is angular acceleration, we get: I * w * alpha When the left side of the equation is differentiated, you simply end up with power, which is T * w (the same way P = F * v in linear motion), so the whole thing becomes: T * w = I * w * alpha w cancels out, which brings us back to T = I * alpha So, one can consider the rotational inertia related loss either in terms of power or torque. Since we are dealing with the torque curve and acceleration in this discussion, we naturally stick to the torque equation. Quote:
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These posts are getting longer and not shorter, so maybe time to let it go unless one of us comes up with some definitive numbers? |
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01-20-2008, 10:52 PM | #168 | |
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In regard to 2, the magnitude of the effect is that you get between 81 and 88 percent of what you think you get (mechanically speaking) in terms of increased acceleration, with an average of about 85%. The data is from testing approximately thirty cars over the years - with German cars, on average, below 85%. Bruce |
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01-21-2008, 08:19 AM | #169 | |
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01-21-2008, 08:19 AM | #170 | |
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A 335i owner posted his impressions of the M3 and protests resulted. I have no dog in this fight, by the time the M3 is available my lease is up. But you don't want to hear that, you'd rather assume bias, justification, or any other ad hominem reason as opposed to talking about the cars. |
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01-21-2008, 08:46 AM | #171 |
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01-21-2008, 09:42 AM | #173 | |
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"...If you've stuck it out to this point, let me offer a single example. In three passes with a Vericom on board (same stretch of level road, same technique, within a few minutes of each other, etc.), my 3 liter M3 showed an average peak acceleration of .463 G in second gear (at peak torque, obviously). The G peaks were measured at .465, .462 and .463 G, first to last. In *first* gear (same stretch of road, same day and approximate time as the second gear runs, etc. etc.), the car pulled an average acceleration peak of .644 G, averaged from three runs at .649, .638 and .646 G. So what? OK, here's what. According to BMW, my car had a first gear ratio of 4.20:1, and a second gear ratio of 2.49:1. Assuming truth in BMW publishing , the car should've been able to pull .781 G in first gear, based on the .463 G average obtained in second. (The .781 figure is from multiplying the second gear results by a ratio of 4.20/2.49.) In fact, if I had tested the car on a chassis dyno at, say, a static 4250 rpm (peak torque), the car would've demonstrated a drive wheel force differential that would very closely approximate the difference in gear ratios between first and second gears. There would be slightly more wheel slip in first gear, and first gear is generally slightly less efficient than second gear (by generally less than a percent), but this is small potatoes. Furthermore, in my test out on the road, I was obviously contending with more rolling and wind resistance in second gear than in first gear, so these factors would tend to cancel out the tire slip and transmission efficiency differences. Drive wheel torque would vary, as I said, pretty much equal to the difference in gear ratios. So why the discrepancy in acceleration values? The shortfall of about 17.5% out on the road (.644 observed over .781theoretical) is due almost entirely to rotational inertia - "flywheel effect", which only comes about when you are accelerating (or, in fact, decelerating). In first gear, that M3 gained about 189 engine rpm for each mile per hour gained, while in second, it was down to 112 rpm. It takes energy to accelerate these rotating parts, and this energy is then unavailable to accelerate the car. The parts affected are basically every rotating thingy forward of the transmission tailshaft. This obviously includes the engine, flywheel and all engine driven accessories, as well as the clutch, pressure plate, transmission input shaft, various gear clusters, etc. In the gospel according to Sir Isaac, these parts don't like to change their speed, and the only thing that will make them do that is engine power - which is then not available to accelerate the car. Proportionally more power is lost in first gear than in second gear, etc, etc. The same effect occurs when you change final drive ratios. You'll get higher peak acceleration in each gear - but not proportionally as high as the difference between the ratios would suggest. I've done testing on many, many cars over the years, and the smallest shortfall I've ever measured was on an '85 stick Vette (with a lightweight Borg Warner Super T10 transmission and a fairly light flywheel at about 18 pounds). That shortfall was about 12%, but most cars had a shortfall typically around 15%. German cars (with flywheels apparently liberated from old U-boats) often were in the low 80s, meaning an acceleration loss getting uncomfortably close to 20%..." Moreover, my experience with cars over the decades leads me to believe that rotational inertia tends to have a very significant effect in terms of how lively a car feels in everyday driving. I don't know how to quantify this, but, starting way back when we hurled a set of 4.56s into a '57 Chevy to replace the "slow" 3.55s, I noticed that even though the car was quicker in a drag race, in everyday driving, it seemed to be noticeably slower. In that scenario, you needed to work a little harder to stay with traffic. That is to say, it felt as if it needed a little more effort. My belief is the difference was for two reasons. The first is that you'd shift earlier, interrupting power earlier, which we all know means something in terms of drag race ET. (Yeah, I know it's everyday driving, but the principle is exactly the same.) The second is rotational inertia, which grows with gearing, and is omnipresent regardless of throttle setting. My theory is that rotational inertia plays a bigger role in everyday driving than it does in a drag race simply because it's 100% with you all the time, and if you're at light power settings, it plays a bigger role. I admit I have no way to back this up, and some help would be wonderful. For this and other reasons I've documented (interminably) in this string, I believe the OP when he says the 335 feels quicker than the M3 in everyday driving. Furthermore, my belief is that not only does it feel quicker, it is quicker. I can't back that up in a quantifiable way, either, but this matches my firmly held belief that good automatics are measurably quicker than good sticks in everyday driving, even though most of them are slower on track. Bruce |
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01-21-2008, 09:49 AM | #174 |
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As a side note to the technical discussion on this thread, I think the choice between these cars entails more than a real-life performance per dollar consideration. I personally have a deep appreciation for well designed and built machinery. So, even if I'll get to drive the M3 on a track only 3-4 times a year, I would still would like to own one the way some people like to own fine works of art. There is no question that its engine and transmission are innovative, and its handling is special in its class. We can debate the meaning of that for daily driving, but that doesn’t change the fact that the artifact itself is superior in terms of the engineering rigor that created it; that is what the M division does.
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01-21-2008, 10:22 AM | #175 | |
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I don't have to assume anything. It is all over your posts and everyone knows it.
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01-21-2008, 11:46 AM | #176 |
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