335i driver does test-drive with M3

[Keto]

Originally Posted by coaster

A BIG "thank you" to the OP for his comparo. This is what I have also been waiting to do here in the US. Test-drive the M3 and compare the experience to a Vishnu-tuned 335 (which I have recently driven). I was already suspecting that the tuned-35 is the better daily driver of the two cars modulo 20 thousand bucks. The OP's driving experience is confirming.

The M3's tiny torque requiring the driver to rev the heck out of the engine every time you need to move is not my idea of a well performing daily driver. Feeling "slow" around town, paying the gas guzzler tax, and getting bad gas-milage for everafter isn't helping either.

But the badge, ooohh that badge ... makes up for everything.

Onward ...

Reduced to arguing which car is better for hauling groceries? I fail to understand how low-end torque linearly correlates with "daily drivability." For me, the M3 will be the better daily driver because of its better ride. The torque is plenty, at any rpm, in both cars, to cut off that soccer mom on her cellphone in the Odyssey.

I am sure the Vishnu folks had daily driving in mind when they made their software. "Vishnu -- Now you'll get that space in front!"

The elephant in the room is, of course, that both cars, and even the stock 335i, have more power than anyone needs for daily driving. Thus, the ridiculousness of all of these posts.

[bruce.augenstein@comcast.]

Originally Posted by hwelvaar

I currently drive a E92 335i (since 8 months) and I recently did a 1-hour test-drive with the E92 M3.

My opinion:
- I prefer the torque of 335i for daily driving (and my 335i is still stock) - it makes your car real fast in daily traffic
- when you're not revving, the M3 feels slow ; I was *really* disappointed. I was *hoping* that the M3 would blow me away, so I could convince my own brain to drop the extra bucks to get an M3. But it didn't. Not on normal roads.
..

OK, most of the fireworks are over, so time to rejoin, and sow a little whole truth.

The two camps represented in this debate represent the two classic sides of many such discussions, one saying you can't ignore experience and the other saying you can't ignore numbers. Each side needs to move a little more toward the middle.

I believe I more or less started the mild rancor by stating that lucid and Swamp didn't even know what they didn't know, and while completely true in that context, that was unfortunate phrasing on my part. I know that each of those gentlemen know a lot, and have mild pride in that fact, so my phrasing was guaranteed to produce some acrimony.

I apologize. You guys really do know a lot. However, in this case, while your truth (begun in note 17 with lucid's spreadsheet) is the truth and nothing but the truth, it isn't the whole truth.

Although it's clear that the OP was talking about everyday around-town driving (i.e. - not full throttle), there was some confusion about this early on, so I'll take a look at full throttle performance of the two vehicles at low rpm.

As has been mentioned, Car & Driver does 30-50 and 50-70 mph roll-ons in top gear whenever they can, and of course they do this in order to give the reader a feel for how the cars perform in low-rpm, everyday street driving - what they call engine "flexibility".

Note the cars have identical gearing except for the final drive, and their tested weights are essentially identical (3571 for the M3, 3557 for the 335), so those variables are essentially negated.

Looking at the results is interesting. I've attempted to do an average rpm (to deduce average wheel torque) for the individual cars in these runs, which isn't entirely accurate (since each car will spend more time at and around those speeds where wheel torque is reduced), but still, the results are more or less representative.

Car---Run---Begin RPM---End RPM---"Average" RPM---Average Torque--Time

M3---30-50----1327--------2212----------1770------------4587--------6.8
335------------1115--------1859----------1487------------4750--------6.5

The 335 is a little quicker (perhaps just a hair quicker than you'd expect it to be, given the difference in average wheel torque), but hey, think about these two cars. In this sort of test, every dynamic advantage goes to the M3. It has instant throttle response (eight throttles, no waiting), but more importantly, the 335 is sitting there with its turbos spinning at about the same rpm as a water wheel, so boost is nonexistent. You'd probably have to wait for something close to a full second to reach full boost, so in that context, the 335 definitely does better than expected.

The 50-70 test is more revealing, since it encompasses rpm already fully accounted for in lucid's chart:

Car---Run---Begin RPM---End RPM---"Average" RPM---Average Torque--Time

M3---50-70---2212------3097-----------2655-------------5179--------5.9
335-----------1859------2602-----------2231-------------4763--------6.0

Sure enough, the M3 is a little ahead, but since it makes around 9% more wheel torque in this test, so you'd expect it to run around 5.5 seconds, based on the 6.0 time turned in by the 335. Then there's the fact that the the M3 still has all the throttle-response advantage it had in the 30-50 run. Even though the 335's turbos are now spinning at the same rpm as a water wheel under flood conditions, it's still way off boost, so it still runs with a penalty. All things considered, the M3 should have turned in a comparitive time below 5.5 seconds, instead of the 5.9 second time it actually got.

Why would the M3 under perform in this sort of analysis?

I'll tell you why, but you'll have to bear with me since the dynamics involved in automotive rotational inertia are a little esoteric.

Rotational inertia is measured in slugs (swear to God), and if you look it up in an engineering text, you'll see that there's a square in the formula based on overall gearing - meaning rate of rotational change.

Why does that matter?

Because you dramatically increase the effect as you try and more rapidly accelerate rotational speed. On any automobile, rotational inertia (sometimes referred to as "flywheel effect") is highest in first gear, and drops off significantly as you go up through the gears. The effect is often expressed in terms of additional vehicle weight, so a car will have an apparent or dynamic weight (as far as the power plant is concerned) that is much greater than the actual weight measured as sitting on a scale. The added "weight" drops in value as the gears ascend, but there will always be some rotational inertia, as long as the vehicle is accelerating.

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%.

Although what you've just read is gospel, you don't have to take my word for it. For a bunch more on this and other topics, pick up a copy of "Fundamentals of Vehicle Dynamics" by Thomas W. Gillespie. It's available from Amazon for $80, and at that price, it's a steal. Swamp, I especially recommend this almost lengendary text for you. You will absolutely revel in the math, and learn a ton.

Bruce

PS - The commentary in this string in regard to how fast an M3 engine will lose revs compared to a 335 is immaterial. Nowadays, no car loses revs except under direct factory supervision (for emissions puposes). In fact, some cars just sort of annoyingly hang there while you sit around waiting to shift. The fact that an M3 seems less unfettered in this regard is a definite plus for the engine, but you can bet it's not related to rotational inertia. The eight pistons and rods on four double-width throws will probably contribute as much or more to rotational inertia as the six rods on six single-width throws inside the 335 motor.

PPS - This is in no way an attack on the new M3 or its engine. It's especially not intended in any way to compare the attributes of either car except in this narrow fashion. In fact, in a drag race, the M3 will simply walk away from the 335 from pretty much any speed to any other speed.

As mentioned before, I believe hwelvaar, footie and termigni are still correct in their comparitive assessment of street "liveliness" under part throttle conditions, for the reasons outlined in note 42. This endless treatise only addresses full throttle parameters.

[footie]

Bruce,

Thanks for those enlightening comments but you have explained why the 335i might feel quicker on part throttle but it doesn't explain why the S5 should also feel quicker as it too has the same number of moving parts as the M3 and more besides when you include it's awd system.

Explain this beauty.

[southlight]

Originally Posted by bruce.augenstein@comcast.

As has been mentioned, Car & Driver does 30-50 and 50-70 mph roll-ons in top gear whenever they can, and of course they do this in order to give the reader a feel for how the cars perform in low-rpm, everyday street driving - what they call engine "flexibility".

Note the cars have identical gearing except for the final drive, and their tested weights are essentially identical (3571 for the M3, 3557 for the 335), so those variables are essentially negated.

Looking at the results is interesting. I've attempted to do an average rpm (to deduce average wheel torque) for the individual cars in these runs, which isn't entirely accurate (since each car will spend more time at and around those speeds where wheel torque is reduced), but still, the results are more or less representative.

Car---Run---Begin RPM---End RPM---"Average" RPM---Average Torque--Time

M3---30-50----1327--------2212----------1770------------4587--------6.8
335------------1115--------1859----------1487------------4750--------6.5

The 335 is a little quicker (perhaps just a hair quicker than you'd expect it to be, given the difference in average wheel torque), but hey, think about these two cars. In this sort of test, every dynamic advantage goes to the M3. It has instant throttle response (eight throttles, no waiting), but more importantly, the 335 is sitting there with its turbos spinning at about the same rpm as a water wheel, so boost is nonexistent. You'd probably have to wait for something close to a full second to reach full boost, so in that context, the 335 definitely does better than expected.

The 50-70 test is more revealing, since it encompasses rpm already fully accounted for in lucid's chart:

Car---Run---Begin RPM---End RPM---"Average" RPM---Average Torque--Time

M3---50-70---2212------3097-----------2655-------------5179--------5.9
335-----------1859------2602-----------2231-------------4763--------6.0

Nice work. Only the torque numbers are wrong since the tests are done in 6th gear. Doesn't change the relation between the cars, though.


Best regards, south

[sdiver68]

Originally Posted by Keto

I am sure the Vishnu folks had daily driving in mind when they made their software. "Vishnu -- Now you'll get that space in front!"

As a matter of fact, they did. But don't let facts get in the way of your argument!

[13eastie]

Originally Posted by bruce.augenstein@comcast.

A load of largely sensible, well-explained stuff - thanks.

Hopefully this thread can continue in a sensible vein. I've turned down every chance so far (i.e. dealer trying to make be buy a car RIGHT NOW) to test the 335i. I want to change this ASAP. I think we all know the M3 will win out on any track situation. I'm going to try a find out what the subjective "town driving" differences are, but in the mean time it's interesting to keep on with the theoretical stuff.

I'm sorry to winge, but you are still not really recognising the fact that driving at 30mph (or 50mph, for that matter) in 6th gear in an M3 is just ridiculous. I will take a photo that will show you even the BMW dashboard, trying to maximise your fuel eficiency thinks this is stupid.

Secondly, differences in the final drive are pretty fundamental if they affect the overall gearing.

The above two points are likely intertwined, I admit.

Finally, regarding the moment of inertia, while I appreciate that the effective mass of the car changes with gear, (of course, the moment of inertia is actually a constant over the rpm range, it's only the fraction of total kinetic energy it steals that changes), I think this part of the discussion can only be furthered with real numbers. Be grateful if anyone could help with a comparison of this.

[lucid]

Bruce, I appreciate your response. It is always good to read your posts, and as always, I'm glad you are on board.

For the record, let's treat this topic as an intellectual discussion we can all learn from at this point as opposed to a M3 vs. 335 pissing contest since that is pointless and results in unnecessary tension. I really mean the learning part.

Originally Posted by lucid

As a side note, for dyno runs with acceleration, the Tq output should be lower, and the two engines might respond slightly differently than each other to those conditions, but the output drops should be fairly consistent. I don't have that data.

Please allow me to reiterate that almost everyone who has participated in this discussion so far is aware that rotational inertia related loses of the drivetrain will reduce the torque at the wheels for both cars under acceleration. As you can see above, I have acknowledged that before, so I am not sure that there was really a need for a detailed explanation. The issue is if the rotational inertia for the two drivetrains are significantly different from each other—to the extent that they would factor into the relative acceleration performance of the cars above 2000 rpm.

Originally Posted by bruce.augenstein@comcast.

Rotational inertia is measured in slugs (swear to God), and if you look it up in an engineering text, you'll see that there's a square in the formula based on overall gearing

This is incorrect. Rotational, or, moment of inertia is simply:

I=m * r^2 m

In other words, mass times the square of perpendicular distance to the rotation axis.

There is nothing about gearing or angular velocity in that expression.

If the book you are referring to gets this wrong, I would not treat it as a credible source.

What you really are referring to is rotational kinetic energy, which is:

Angular KE = 1/2 * I * w^2

In other words, 1/2 times the moment of inertia times the square of angular velocity.

What we are really interested in is how the avaliable torque at the wheels is reduced at different angular accelerations. That is dictated by:

T = I * alpha, where alpha is angular acceleration.

Yes, at lower gears, the angular accelerations will be higher, therefore the torque loss will be higher as well. However, that relationship, as can be seen above, scales up linearly. So, there is no square term there.

Originally Posted by bruce.augenstein@comcast.

The 50-70 test is more revealing, since it encompasses rpm already fully accounted for in lucid's chart:

Car---Run---Begin RPM---End RPM---"Average" RPM---Average Torque--Time

M3---50-70---2212------3097-----------2655-------------5179--------5.9
335-----------1859------2602-----------2231-------------4763--------6.0

Sure enough, the M3 is a little ahead, but since it makes around 9% more wheel torque in this test, so you'd expect it to run around 5.5 seconds, based on the 6.0 time turned in by the 335. Then there's the fact that the the M3 still has all the throttle-response advantage it had in the 30-50 run. Even though the 335's turbos are now spinning at the same rpm as a water wheel under flood conditions, it's still way off boost, so it still runs with a penalty. All things considered, the M3 should have turned in a comparitive time below 5.5 seconds, instead of the 5.9 second time it actually got.

Why would the M3 under perform in this sort of analysis?
PS - The commentary in this string in regard to how fast an M3 engine will lose revs compared to a 335 is immaterial. Nowadays, no car loses revs except under direct factory supervision (for emissions puposes). In fact, some cars just sort of annoyingly hang there while you sit around waiting to shift. The fact that an M3 seems less unfettered in this regard is a definite plus for the engine, but you can bet it's not related to rotational inertia. The eight pistons and rods on four double-width throws will probably contribute as much or more to rotational inertia as the six rods on six single-width throws inside the 335 motor.

First of all, please note that the measured vs. expected performance is somewhat small, so small differences in a variety of factors can be influential. That said, there are issues with this explanation and your conclusion:

1. You are operating under the assumption that the moment of inertia, “I”, for both cars are the same, or that it is more for the M3. That is a significant assumption. You say a few things about the engine layout, but that is far from being convincing. At this point, we don’t know anything about the mass of the rotating components, but one would think, given the M3 engine revs up to 8400rpms, BMW engineers would have busted their asses to bring those weights down by using different more expensive materials. We need the “I” numbers to be conclusive.

2. Regardless of all this, even if we assume the M3 has a higher “I” figure, the M3 still comes out to be faster in the 2000rpm+ comparison. This whole debate got kicked off because I started arguing against the 335 being faster above that range. I am ignoring the other comparison which starts around 1100rpms since, from the very beginning, I acknowledged that the 335 would have the upper hand there as that is what the data I posted also demonstrate. So, I am not sure about what your point is exactly. Are you saying that if the test was done in 2nd or 3rd gear instead of 6th gear, the rotational inertia related losses would be higher for the M3 because of the higher angular accelerations experienced in those gears (it will pick up even more revs per unit time than the 335 during that race), and the M3 would be slower? If that's what you are getting at, keep in mind that the M3 picking up more revs would also mean that its average torque would also go up significantly, whereas the average tq for the 335 would stay the same, relatively speaking.

3. Weight might be a significant factor. Let’s see what we have said about the weight difference between these cars so far on this thread:

Originally Posted by bruce.augenstein@comcast.

It's also a bit heavier than the 335, which is another factor that's with you at 100%, all the time.

You are saying the M3 is heavier than the 335 above.

Originally Posted by lucid

Yes, someone finally called me out on the weight difference, but that is like 5%. Not significant enough to give the 335 the upper hand.

I acknowledge that here and say the difference is about 5%.

Originally Posted by bruce.augenstein@comcast.

and their tested weights are essentially identical (3571 for the M3, 3557 for the 335), so those variables are essentially negated.

In your most recent post, you are now saying that the weight is almost identical.

I am not sure about what is going on with these numbers. Were these measurments obtained on the same day and issue, with exactly the same method? The M3 number is definitely unladen DIN.

This is where the waters get really murky, and the difference between the measured vs. expected performance you reported might actually be explained by the weight difference these cars have.

Check this out:
C&D 335i coupe 3366lb unladen DIN? (Jun or Jul 07; I don’t have access to this issue to verify what the OP is saying on this thread. He claims to have weighed his own car on a certified scale at 3360lbs)
http://www.e90post.com/forums/showth...unladen+weight

If the above C&D numbers are correct, the 335 might be about 7% lighter, and the weight difference alone can explain a significant portion of the difference between the measured vs. expected performance you reported.

Because of the several points I raised above, I stick to my original position.

EDIT: I read my post with a clear head this morning, and realized I was somewhat sloppy with rotational energy and angular acceleration, so I cleaned that up.

[Keto]

Originally Posted by sdiver68

As a matter of fact, they did. But don't let facts get in the way of your argument!

Clarification: Primary objective.

Is that your position?

EDIT: Saving you the effort -- "our products offer no-holds-barred performance while never sacrificing daily drivability or utility." -- sounds like they were made to enhance daily driving. /sarcasm.

[bruce.augenstein@comcast.]

Originally Posted by 13eastie

...I'm sorry to winge, but you are still not really recognising the fact that driving at 30mph (or 50mph, for that matter) in 6th gear in an M3 is just ridiculous. I will take a photo that will show you even the BMW dashboard, trying to maximise your fuel eficiency thinks this is stupid.

Secondly, differences in the final drive are pretty fundamental if they affect the overall gearing...

Of course I realize that whacking it in 6th at 30 (or even 50) mph is contraindicated, as they say. As mentioned, Car & Driver does that testing to give the reader some insight as to engine (and drivetrain) flexibility.

Pretty much the entire point of that lengthy treatise was about overall gearing, and the rotating inertia penalty that means no free lunch.

Bruce

[swamp2]

Originally Posted by coaster

I was already suspecting that the tuned-35 is the better daily driver of the two cars modulo 20 thousand bucks. The OP's driving experience is confirming.

It is totally amusing that you stick to this exaggerated figure to argue in favor of the 335i. How exactly is a base MSRP of $56.5k - base MSRP $40.8k = $20k. I'd say it is closer to $15k than to $20k. Oh yeah, I forgot you can get the 335i for $5k under MSRP. Yeah right.

[mkoesel]

Originally Posted by swamp2

It is totally amusing that you stick to this exaggerated figure to argue in favor of the 335i. How exactly is a base MSRP of $56.5k - base MSRP $40.8k = $20k. I'd say it is closer to $15k than to $20k. Oh yeah, I forgot you can get the 335i for $5k under MSRP. Yeah right.

Actually swamp you could via ED. That's what we did.

However, I agree with your points about MSRP. In fact, rightfully you need to add ZSP to the 335i to get the sport suspension, seats, steering wheel and 18" wheels that the M3 has standard. And the difference is actually less than $15k if you compare the sedans (making sure to add the moonroof to the M3).

Granted the 335i still has the better stereo.

[sdiver68]

Originally Posted by Keto

Clarification: Primary objective.

Is that your position?

EDIT: Saving you the effort -- "our products offer no-holds-barred performance while never sacrificing daily drivability or utility." -- sounds like they were made to enhance daily driving. /sarcasm.

The perfect combination of performance and comfort is what sells thousands of BMW 3 Series every month in the United States. Adding a little more performance without compromising comfort or durability is what Pathak set out to do with the 335i.

It works. A 100 pound-feet increase in torque over a stock 335i from 2,000-4,000 rpm makes the Vishnu 335i not only quicker but also immensely more drivable. It never falls out of the power band. Roll into the throttle from 80 mph in top gear and the improvement in acceleration is, at first, only "meaningful." It quickly builds to "substantial," reaching its zenith at "Holy crap, this thing means business!"

Outright speed hasn't been the primary goal with the Vishnu 335i and it also isn't the primary accomplishment.

From:

http://www.edmunds.com/insideline/do...ticleId=119485

So I guess I would put it that Vishnu's stated primary goal is for both performance AND everyday usability.

[sdiver68]

Originally Posted by mkoesel

Actually swamp you could via ED. That's what we did.

Exactly.

And even at US MSRP, you can make good deals on 335i's close to invoice...so that's at least $3K under MSRP. Can you do either ED or close to invoice on the M3?

[bruce.augenstein@comcast.]

Originally Posted by footie

Bruce,

Thanks for those enlightening comments but you have explained why the 335i might feel quicker on part throttle but it doesn't explain why the S5 should also feel quicker as it too has the same number of moving parts as the M3 and more besides when you include it's awd system.

Explain this beauty.

I can't comment with authority here, but can only assume that the same conditions apply as those commented on by a couple of European road testers when comparing the M3 and RS4. They said that in spite of the numbers, the RS4 engine felt a little meatier in everyday driving. The S5 will make more torque down low than the RS engine does, so it's even more willing under those conditions.

As an aside (but still on topic), there are a number of factors involved in a driver's analysis of how quick a car feels in everyday driving. I've already addressed a couple in note 42 ("throttle" response and overall rotational inertia values), but noise and vibration are also major factors. I can't speak directly to vibration issues, but going back to trusty Car & Driver tests, there are major differences in sound levels between these two cars, and these will directly affect the driver's perception of how hard the engine is working in order to give you your chosen rate of acceleration.

The 335 shows 69 dba at a 70 mph cruise, and livens up to 75 dba under full throttle conditions. By contrast, the M3 shows a palpably louder 74 dba at cruise, and perhaps more importantly, skies to 85 dba at full throttle.

85 dba is either cacophony or music, depending on the quality of the noise, but to put it in perspective, the M3's numbers are just slightly louder than a current Z51 Vette with the hot-damn exhaust option.

I don't know if you've tried such a Vette, but I can tell you that although it's clearly music to my ears, 84 dba is loud.

The major thing we can deduce from this is that when prodded, the M3 gets a lot louder, a lot more quickly than the 335 does (as you'd expect it to, given the differing missions). The difference between 75 dba and 85 dba at full chat is almost akin to a murmer vs a shout, so when you're just driving around, the 335 feels effortlessly fast, while the M3 feels effortfully fast. You need more revs with more noise in the M3, while the 335 more or less glides to speed, so that's another reason why the 335 simply feels faster.

Bruce

[coaster]

Originally Posted by swamp2

It is totally amusing that you stick to this exaggerated figure to argue in favor of the 335i. How exactly is a base MSRP of $56.5k - base MSRP $40.8k = $20k. I'd say it is closer to $15k than to $20k. Oh yeah, I forgot you can get the 335i for $5k under MSRP. Yeah right.

How many of you fans have driven a properly tuned-35? Go drive one and then try the M3. Then tell me if you are blown away by the DIFFERENCE of the M3 experience. The OP dared to compare the "stock" 35 and was underwhelmed by the difference. Had he compared the M3 to a car with nearly 100 ft-lb MORE torque than the sctock-35 he would really be disappointed.

Yes it is an extra ~20K, I'd like to see you negotiate M3 pricing the way you can 35 pricing. Don't forget guzzler tax, delta tax, and moonroof while you are it.

I am waiting patiently for the mighty M3 to reach our shores so that I too can do what the OP did and get a taste for this so called budget "supercar". (But the bar for impressing me has been set pretty high by the Vishnu-35 I drove last week.)

[gmund1948]

The suspension, transmission and diff improvements on the M3


You can add breast implants, modify some facial features, reduce the
hips put some make up on and she will look like the truly beautiful
woman that you desire. Its not the same you will always no its a
replica

I own a 335 and side by side its not an M3 but a great car.

A 335 with mods might make a good stunt double

BMW are not stupid people

[coaster]

Originally Posted by gmund1948

The suspension, transmission and diff improvements on the M3


You can add breast implants, modify some facial features, reduce the
hips put some make up on and she will look like the truly beautiful
woman that you desire. Its not the same you will always no its a
replica

I own a 335 and side by side its not an M3 but a great car.

A 335 with mods might make a good stunt double

BMW are not stupid people

No I didn't know about the suspension, trans. and diff. But thanks to wizards like you I now do.

BTW, you forgot to mention the "superior" badge ...

The OP's point of view is the same as mine. Go test drive the cars and form your own opinion (and ignore people like you). In about two months we'll now how good the car really is.

Onward ...

[swamp2]

Originally Posted by coaster

How many of you fans have driven a properly tuned-35?

Perhaps obviosuly I have not yet driven the M3, I have driven a MT 335i but not a Vishnu one. I would certainly like to.

[swamp2]

Bruce an interesting analysis above, but still quite a few flaws.

I have used and referred to "Fundamentals..." but don't own a copy myself. Lucid, +1 on the basic defintions of moment of interia, and energy. Those are correct and anything but those (or versions using alternate units) is incorrect. I absolutely would not discount the book even if they screwed the pooch on dirvetrain interia (is this the case Bruce?).

My comments/corrections on inertia are as follows.

1. Just like F=ma the rotational analogy is T=I alpha, where alpha is the angular acceleration or time derivative of rpm (with some constants of course). Acceleration at a point on the a rotating object is then radius x alpha. Just like a bodies mass does not change as you accelerate it in a linear motion an objects moment of inerita does not increase as you angularly accelerate it (increase its rpm). Drivetrain and flywheel inertia is important but it's effects are nowhere near the drivetrain parasitic losses. When you combine rotating and linearly moving masses the acceleration basically works out to be (of course this leaves out drivetrain loss and constants, etc., just for simplicity sake):

a = engine torque/(wheel radius x (vehicle mass + inertial terms))

Another key thing here is that the inertial components do not vary all that dramatically from car to car in loosely similar peak torque categories. The key reason the rotating components are still so important to keep light is that they do "double count" in the above formula their mass is included in the total vehicle mass and their mass and mass ditrubution then counts in the inertial terms.

2. I think one test does not cover the spectrum nor does it give a great idea of possible ranking errors. Simulations with CarTest show top gear 30-50 times for the M3/335i at 5.6s/6.4s respectively. Similarly sims show 5.1/5.4 for 50-70 in favor of the M3. Again these are the sims that match 0-60 and 1/4 mi times within 1-2 tenths for both cars.

3. Averaging results across a nearly 1000 rpm range is not meaningful nor accurate. This is why you need a simulation - torque/hp/losses all vary smoothly with rpm and vary a lot. This is key.

4. Look at a diagram of a MT. There is only two moments of intertia to consider the lay shaft and the output shaft. And BOTH are spinning all the time. Have a look here for a great cartoon or here if you want to see the real thing. Also consider the radii of the different gears on the different shafts, not all the great of a difference especially when you consider there are smaller and larger gears on BOTH shafts. So the conclusion here is that the transmission moment of inertia is nearly constant, it is relatively small and there is no hokie non-linear effects happening here.

5. What your analysis is missing Bruce is drag and drivetrain losses which depend on rpm. Have a look at the following "power balance" chart generated by CarTest. It shows all losses and how they vary with vehicle speed. Below about 50 mph drag losses are indeed negligible ans similarly below about 75 mph tire losses are also about nil. However, at 70 mph drag losses are absolutely not negligible. Transmission losses are very loosely speaking constant but then a saw tooth ramp up/step down is added through rpm in each gear primarily due to friction which just as in linear motion is speed dependent.

I would be quite a bit more restrained in your use of the term "gospel" when you have a lot of incorrect statements and misconcpetions. Again we really need a broader range of test values to know if the 335i really does out perform the M3 in top gear low speed accelerations runs.

[e36jakeo]

I've been driving a 335i with V2 around for the past 4 months. On 91 octane it makes about 350 WHP (about 400 at the wheels) and 375 WTQ. It is very fast and smooth anywhere in its powerband and is fuel efficient to boot (avg 23 MPG US in normal mixed driving). The I-6 also has very good throttle response and sounds great, although a bit too quiet for my tastes. The 335i also handles excellent for a normal 3-series, although the lack of LSD is annoying in slower corners, where I spin the unweighted wheel.

However, with the reasonable base price of the M3 sedan, and the amazing DKG with perfect gearing, making it that much quicker and faster than the 6-speed (which is already hella fast), the excellent LSD, the adjustible suspension, the instantaneous throttle response, and the unbelievable high-end power it is definitely the more exciting car.

I've said all along - those who choose the M3 must REALLY appreciate a performance vehicle, because to get your money's worth out of the M3 you will need to rev it A LOT, push it hard in corners, brake hard, and, for heaven's sake, bring it to its home: A good road course! If you drive it strictly as a daily driver and your idea of driving fun is to go fast on an on ramp and accelerate to 80 MPH before entering the freeway then JUST GET THE 335i. It, too, is an amazing ride (esp with V2 Procede), but just not quite as extreme as the M3.

[MikeHK]

Hi all,

My first post here but I have been reading this forum for quite awhile.

Yesterday, I conducted a 30 mins test drive an alpine white E92 M3 6speed. I drove my golf gti there and had my friend driving the 335i (both bone stock). We did some run with the M3 against the 335i, so I think I can share my experience.

I have a deposit on the DKT M3 (refundable but damn, BMW HK demand a HK$140k, ~ USD 18k deposit to hold the slot), I am still undecided on the purchase mainly due to the HK$1390000 (~ US$180k) asking price. Rumor says the price will drop to approx. HK$1080000 (~US$140k) due to the surprising low price of the C63 in HK. We shall wait and see.

Now to the test drive, below is my reply to your points from my experience after the test drive:

Originally Posted by hwelvaar

- I prefer the torque of 335i for daily driving (and my 335i is still stock) - it makes your car real fast in daily traffic

- when you're not revving, the M3 feels slow ; I was *really* disappointed. I was *hoping* that the M3 would blow me away, so I could convince my own brain to drop the extra bucks to get an M3. But it didn't. Not on normal roads.

I must agree that the 335i does "FEEL" faster as it gives more violent acceleration in comparison with the M3.

We did a short run (m3 vs 335i) from approx. 60kph up to 170kph, I didn't start in the most optimal gear (3rd) due to the terrible HK traffic. The 335i just could not keep up with the M3, I confirmed with my friend that he was at full thorttle at all time, where I started in only 3rd gear and changed gear at approx. 6500 rpm (sales man in car).

I rate of speed building up is extremely quick but it does not give you the "push to the seat" kinda grunt from the 335i which make you FEEL the 335i is sometimes faster without taking a look at the speedo.

I just think people who will be buying 6 speed M3 would lean more towards to the driving dynamics of the M3 more than the pure grunt from the 335i. For city driving (HK type of traffic), I think DKT would be the clear choice.

I think if it is all about city driving, or light to light racing, there is no reason to buy 6 speed and I believe all of us will switch to the MB camp, which I think is what the 335i is targeted for.

Originally Posted by hwelvaar

- the sound of M3 engine is fantastic in high revs, but not noticable in low and mid RPMs
- the sound of 335i is very nice in both mid and high RPMs

I agree, the M3 engine note is like music to ears, the roar just keep making you rev'ing higher and higher.

For the 335i, it also sound very nice but I believe it is more the exhaust note than the engine note where the M3 is the other way around.

Originally Posted by hwelvaar

- I prefer the suspension of the M3 for daily driving (with EDC in comfort) and the fact that you can switch to sport when needed;

The M3 is noticably more precise and agile in turns despite being more heavy than the 335i (I think so, correct me if I am wrong).

One thing I don't really like tho, is I believe BMW purposedly trying to lighten everything up in the M3, from steering, to clutch. The gearbox is perfect tho, love it.

Originally Posted by hwelvaar

- It felt good to drive around in a car labeled "M3"
- I prefer the looks of stock M3 over stock 335i (no-brainer)
- LSD is a must-have for occasional fun drifting !
- 1 hour-drive on normal roads, and 1/4th of the M3 fuel tank is empty -> M3 really drinks alot !

I didn't have the opportunity to go so wild that I can test out the LSD and I didn't monitored the fuel consumption, so I can't comment.

Originally Posted by hwelvaar

- the brakes on the M3 are definitely good (and noticably better than stock 335i)

Agree 100%

I think torque sometimes fool people on the actual speed. I drove the GTI immediately after the test drive, and it did FEEL faster than the M3 in lower rpm as well but we all know they aren't even close.


Just my 2 cents, peace!

Mike

[gmund1948]

After 2 days of driving the M3 at the Nurburgring, and also lapping in the 335
(convertable) It is obvious which car BMW has built for the upper end of performance driving.

Thanks for the complement but I am no wizard,

As far as the badges go I order all my cars without badges.

The 335 is a great car, with mods, even more potent.

If you find a way to test drive the M3 versus a modded
335 you might want to measure lap times, period.

The trolling, you are doing must be entertaining to you
it is almost like an M3 is out of your reach or you are in
a self jusification mode.

It is fun to see what you type, thats for sure. You have taken a position without a comparison, and keep shouting about badges as justification.

Drive the M on a track if you can and you will see the differences that cannot show up in a magazine.

Thanks for the compliment, however it is futile to argue any point unless
you have experienced both, which you have not.

We dont need a Badge patrolman or a trolman of any kind here.

Do you work for Proceed, Vishu (sp) ?

Originally Posted by coaster

No I didn't know about the suspension, trans. and diff. But thanks to wizards like you I now do.

BTW, you forgot to mention the "superior" badge ...

The OP's point of view is the same as mine. Go test drive the cars and form your own opinion (and ignore people like you). In about two months we'll now how good the car really is.

Onward ...