Worthless post but: Save me from the IS-F!

[bruce.augenstein@comcast.]

Originally Posted by swamp2

• The largest expansion due to CTE of an exhaust is along its length and this is the one that must be designed for fairly carefully.
• Fake is fake, most folks agree.
• Lucid intial impressions are here and I think you misread them. Actually I think you did dream it as you mentioned. Do keep us all posted (not just lucid) on this re-engineering of the M3 for better low rpm throttle response. We are all very anxious for a "fix".
• Autos more reliable than sticks? I'll take your data to back up that claim and I am not interested in anecdotal nor preferences from drag racers. I mean real evidence about regular production vehicles. I seriously doubt your claim.

I'll not discuss the exhaust anymore. We disagree on whether or not this is good engineering, and agree that the tips are bling. Of course, I think the M tips are bling as well.

OK, I PM'd lucid, and he remembers posting somehting to the effect that his M3 has a significant disparity between just driving it and chasing after it modes, but I can't find it, and won't chase after it any more. (Of course, he loves the car.) In any event, unless you're a fanboy, there are records all over the net pointing to a comparative shortfall in the mid range, the latest of which was recently posted in this forum wherein the testers said the car was short of torque compared to the RS4.

Of course, it really isn't short of torque compared to the RS4, and we know that in high gear the car pulls really well from low speeds when you boot it. Better than the RS4, in fact - but it just feels less lively when you're not booting it.

I have no tested, off the shelf fix, but remembered corresponding with Mark Kibort a few years back in regard to an in-line fan he had developed, so a cursory net check came up with this.

This isn't the answer, because it's designed to activate at full (or at least major) throttle, and therefore rapid spinup is mandatory. The device thus has a more powerful fan motor than you need (more than one HP), providing a semi-instant one psi of boost. Under those conditions, a temporary 62 amp drain on the battery is fine, but obviously not supportable as a full-time amp draw.

I think a 150 to 200 watt unit would supply that additional one psi of boost at part throttle and low to medium rpm, fading to something considerably less than that at full throttle and high rpm. But of course nobody is complaining about how the M3 runs when you're banging on it, are they?

A device such as this would provide sharpened throttle response, but also more torque at part throttle, just driving around. If it were me, I'd probably start with the as-delivered unit, but seek to replace the electric motor with one of a more suitable reduced capacity.

In regard to automatic transmission reliability, it's common knowledge. Enough so that nobody is writing about it any more. I read about this more than 20 years ago in some SAE papers by Ford and GM guys.

Generally speaking, an auto is good for at least 150 to 200 thousand miles with normal fluid and filter changes. You can get more than 100K miles out of a clutch, but you're on borrowed time - especially in a high-performance car. The other bogey with a stick car (especially a high performance model) is the synchros. Not that I've ever missed a shift in my life, but I hear other people have.

That old saw about more parts (and more moving parts) leads to less reliability turns out not to be the case (he said, diplomatically). If that were true, a dohc V8 would have perhaps a third of the MTBF enjoyed by an ohv four cylinder.

Bruce

[lucid]

Originally Posted by bruce.augenstein@comcast.

I personally love the idea of that unbelieveable torque curve, but the damned thing is a half-liter short of greatness, in my opinion - at least when installed in something that weighs as much as the M3. Everybody and his brother Sammy has made mention of the part-throttle, everyday driving phenomenon wherein the car comes up a little lacking. This started way back when early drivers found the 335i to be notably more assertive when not really going after it. You and lucid beat them up a bit, but now lucid understands. It's far from fatal, but it's an issue. I'm personally trying to research an off-the-shelf solution that won't cost $10k.

Originally Posted by bruce.augenstein@comcast.

Funny, I could swear I read a post by lucid in regard to his car being willing when pushed, but a little lethargic otherwise. In it, he referred to looking for ways to reduce the vehicle's weight - then opened a separate note on the topic. Can't find it, though. Maybe I dreamed it?

Bruce,

Allow me to clarify: the M3 by no means feels "lethargic". Sorry, but that is your attribution, but mine.

The issue around weight that I have been trying to express is not easy to get across, and that is why I recommended you to drive the car. In my previous posts, I tried to qualify that comment by repeatedly stating that "although it feels a bit heavy, the weight does not get in the way of performance." It's super agile and quick. No issues there as the numbers indicate.

The only time it becomes somewhat of an issue is when you are rolling off from a dead stop. I am really talking about an rpm range of 0-2500 or so. In this car, that does not qualify as "mid-range" as you put it. It is more like the low-range. I seldomly find myself in that range even when driving around town--again, the only exception being a dead stop. Mid-range in this car is more like 3000-5250 rpms, and there are absolutely no issues there regarding torque/power. It just pulls.

Coming back to the stock 335 vs M3 debate. I stick to my position after having driven both. Above 2500 or so, the M3 has more torque at the wheels, and will out accelerate the 335. From a dead stop, the 335 will most likely have the advantage--assuming it has traction and is driven properly--but it will then be caught up and chewed on (again, I am talking stock vs. stock as we were on that other thread).

The part-throttle issue: yes, the 335 most likely has more torque at the wheels than the M3 through the mid-range at part throttle because of how the boost is mapped and all that. Is this an issue? Not at all. Again, my point has been that if you want to go fast, you press the damn pedal. When you do that in the M3, the engine respond instantaneously, and you're off. Even at part throttle, I wouldn't characterize the car as lethargic or anything like that. It's responsiveness makes up for the extra boost that is mapped onto the 335 part-throttle in my opinion. I see absolutely no reason to improve the throttle response in the M3 as it is already excellent.

See article posted by Malter2.0 on some relevant discussion about design for responsiveness here (it obviously is talking about the M3 engine only, so it doesn't serve a comparative role, but still useful):

http://www.m3post.com/forums/showthread.php?t=126071

Having said all this, would I like my M3 to weigh 200lbs less? Yes, of course. If I owned a 335, would I have had the same desire (considering the two cars weigh about exactly the same)? Yes, of course. That's more in the lines of the E9X series should weigh closer to what the E46 series weighed, and not specific to the M3.

Finally, it is true that the M3 becomes the beast that it is under WOT. There is some kind of a discrete affect there, and I think it was intentional--by design. But that doesn't mean that it is problematic. It is not problematic because the transition happens instantly if you want it. You don't have to press the pedal and wait for it, and that is the real beauty of this car/engine.

P.S. I haven't driven the RS4, so I can't comment on that comparison, but I bet RS4 owners would like their cars to weigh 200 lbs less as well. Also, I can produce another chart that would most likely result in another civil war of some kind.

[sayemthree]

I've driven the RS4 - its awesome, but the RS4 owners wish it weighed 400 lbs less!!!!!

[bruce.augenstein@comcast.]

Originally Posted by lucid

Bruce,

Allow me to clarify: the M3 by no means feels "lethargic". Sorry, but that is your attribution, but mine...

...The only time it becomes somewhat of an issue is when you are rolling off from a dead stop. I am really talking about an rpm range of 0-2500 or so.

So what do you think of something along the lines of Kibort's in-line fan?

Bruce

[lucid]

Originally Posted by bruce.augenstein@comcast.

So what do you think of something along the lines of Kibort's in-line fan?

Bruce

Well, sure a blower is a blower, and anything you can do to increase intake pressure is good in general within certain limits.

They claim the blades do not restrict airflow when the device is inactive. This is simply not possible. There will always be additional resistance at the blades and friction at the fan bearings, etc, since this thing has to be mounted in series with the main intake airflow. How much impedence would that result in at different engine speeds, I have no idea, but it's not 0.

Having said that, one can say it will never be inactive, and that it would always be running. I don't know that that means it won't restrict airflow at high engine speeds when the M3 engine is sucking in massive amounts of air. Saying fan blades spin at 23000 rpm doesn't mean anything. Just becauase the fan is spinning fast doesn't mean that it is keeping up with airflow. Meaning, does this thing have enough power to act as a compressor at high engine speeds, or is it simply going to become a load? At low engine speeds, I can see how it could be beneficial IF it has enough power to act as a compressor (we are talking about only 684 Watts).

I am not an electrical engineer, but I wonder if constantly drawing 57 amps would be problematic. How many amps is the alternator putting out? And what is demand from other systems?

[bruce.augenstein@comcast.]

Originally Posted by lucid

Well, sure a blower is a blower, and anything you can do to increase intake pressure is good in general within certain limits.

They claim the blades do not restrict airflow when the device is inactive. This is simply not possible. There will always be additional resistance at the blades and friction at the fan bearings, etc, since this thing has to be mounted in series with the main intake airflow. How much impedence would that result in at different engine speeds, I have no idea, but it's not 0.

Having said that, one can say it will never be inactive, and that it would always be running. I don't know that that means it won't restrict airflow at high engine speeds when the M3 engine is sucking in massive amounts of air. Saying fan blades spin at 23000 rpm doesn't mean anything. Just becauase the fan is spinning fast doesn't mean that it is keeping up with airflow. Meaning, does this thing have enough power to act as a compressor at high engine speeds, or is it simply going to become a load? At low engine speeds, I can see how it could be beneficial IF it has enough power to act as a compressor (we are talking about only 684 Watts).

I am not an electrical engineer, but I wonder if constantly drawing 57 amps would be problematic. How many amps is the alternator putting out? And what is demand from other systems?

Apparently you missed my post #67 in this string. I believe the device would work better with a lower power electric motor (say, 150-200 watts) designed to run continously. The device would then be effective only at lower engine speeds (and especially at part throttle), but would not be an impediment at higher speeds since total airflow of 800 cfm would be affected only moderately (or even not at all) at redline. This is because the device wouldn't have the capacity at max rpm to actually compress air with that reduced wattage, so max rpm (25000) shouldn't change much, or perhaps not at all.

I can't see the M3 engine needing more than 500 cfm, assuming 85% volumetric efficiency at 8300 rpm.

With the lower powered electric motor, you'd be drawing a max of 15 amps, which is doable with the standard alternator.

Again, the goal would be to liven up the zero to 2500 rpm window where the engine could absolutely use some help, in my opinion. I've now driven one for about 45 minutes, and will write that up shortly.

Bruce

[sayemthree]

this thread is getting more worthless all the time!!!!

[Hans Delbruck]

Originally Posted by sayemthree

this thread is getting more worthless all the time!!!!

[swamp2]

I am not ready to chime in fully on the topic of electric blowers. However, I would offer this small point. If they are that good, that simple and without any major comprimises why wouldn't they be widely integrated and installed at the OEM level on sporty cars or perhaps on cars lacking low rpm torque (like the poor M3 ).

[lucid]

Originally Posted by bruce.augenstein@comcast.

Apparently you missed my post #67 in this string. I believe the device would work better with a lower power electric motor (say, 150-200 watts) designed to run continously. The device would then be effective only at lower engine speeds (and especially at part throttle), but would not be an impediment at higher speeds since total airflow of 800 cfm would be affected only moderately (or even not at all) at redline. This is because the device wouldn't have the capacity at max rpm to actually compress air with that reduced wattage, so max rpm (25000) shouldn't change much, or perhaps not at all.

I can't see the M3 engine needing more than 500 cfm, assuming 85% volumetric efficiency at 8300 rpm.

With the lower powered electric motor, you'd be drawing a max of 15 amps, which is doable with the standard alternator.

Again, the goal would be to liven up the zero to 2500 rpm window where the engine could absolutely use some help, in my opinion. I've now driven one for about 45 minutes, and will write that up shortly.

Bruce

Yes, I forgot about your earlier comment.

Maybe you have dealt with compressors all your life and have internalized some basic relationships between pressure, air flow, and power, but I haven't. To answer the question of, "does this thing have enough power to act as a compressor", I would need to pull out some books and calculate how much energy is required to compress a specific volume of air, and than relate that to flow rate and power.

If it won't have enough power at high engine speeds, then I still don't see how it won't impede flow when it stops acting as a compressor. One can argue that it is negligible, but one can't argue that its impedance would be 0.

Looking forward to hearing about your test. Did you install it in your Acura?

[bruce.augenstein@comcast.]

Originally Posted by swamp2

I am not ready to chime in fully on the topic of electric blowers. However, I would offer this small point. If they are that good, that simple and without any major comprimises why wouldn't they be widely integrated and installed at the OEM level on sporty cars or perhaps on cars lacking low rpm torque (like the poor M3 ).

C'mon, guy. You already know the answer. But for those who may not:

Because this "solution" is a complete and total engineering Bandaid (especially in the form which I've suggested), and it makes up for that by being hideously expensive for limited results.

For about five bucks per car in extra (machined) metal, BMW could build a 4.5 liter version of the wonder motor, and reap benefits everywhere. "Problem" solved.

Bruce

PS - Now that I've spent some quality time behind the wheel, I tend to agree with lucid's commentary. You can feel the weight, and the softness in the torque department below about 2500 at part throttle is noticeable, but it's not annoying. Therefore, "my" engineering Bandaid answers a question that won't be asked by most folks. It's really an issue only when you do comparisons (for instance to the RS4, which I've sampled), and after all, once you buy the car, why bother with comparisons? You bought the car instead of the RS4 (or whatever) because it appealed to you more. End of story.

[lucid]

Bruce, since you brought up perceived RS4 vs. M3 torque differences at the low-end several times, I couldn't resist thinking about the numbers. Here they are for both cars in 2nd gear. Obviosly, the RS4 will have more traction below 2500, but how much more and is that enought to offset the weight difference? (I assume we can agree that rotational intertia issues are pretty much a wash here.)

On the part throttle issue: what throttle mapping did you drive the M3 at?





Values adjusted for temp and hum. http://www.rri.se/index.php?DN=29

[swamp2]

Originally Posted by lucid

Bruce, since you brought up perceived RS4 vs. M3 torque differences at the low-end several times, I couldn't resist thinking about the numbers.
...

Don't forget the KEY additional factor you can not really feel torque but you sure can feel torque/lb! It all comes back to the accuracy of the butt-ometer and I think many folks think there butt is better than a real accelerometer.

[swamp2]

Originally Posted by bruce.augenstein@comcast.

For about five bucks per car in extra (machined) metal, BMW could build a 4.5 liter version of the wonder motor, and reap benefits everywhere. "Problem" solved.

As well you know darn well why the car is 4 liters. Well 3.999 to be exact... For those that don't the answer is taxes.

[Krueger///M3]

Mercedes must have lost their butt in taxes on the C63, they seemed to take the American muscle car approach on that engine.

[hellrotm]

Originally Posted by Krueger///M3

Mercedes must have lost their butt in taxes on the C63, they seemed to take the American muscle car approach on that engine.

C63 is a freakin BEAST.

6.2 powerplants in the x63 cars are one of Mercedes best.

[Krueger///M3]

+1, just commenting on the aforementioned engine taxation.

[lucid]

Originally Posted by swamp2

Don't forget the KEY additional factor you can not really feel torque but you sure can feel torque/lb! It all comes back to the accuracy of the butt-ometer and I think many folks think there butt is better than a real accelerometer.

Sure. That's why I mentioned that the benefits of the additional traction RS4 has with 4WD are most likely evened out by the weight difference between the two cars.

[footie]

I remember posting some time ago that the S5 felt have more go on part throttle then the M3. I would like to readdress this opinion after re-testing the M3, only this time I tested the M3 with SportPlus engaged and this time the M3 feels every bit as quick. Maybe more so in fact.

The only problem I found with SportPlus throttle mapping was that on a bumpy surface in a low gear it's hard to be accurate with your inputs. For me Sport is much better.

[ideliver]

Originally Posted by swamp2

As well you know darn well why the car is 4 liters. Well 3.999 to be exact... For those that don't the answer is taxes.

Can you please elaborate?

I was not aware that a cars engine size has a bearing on taxes. I was only aware of GGT based on MPG.

Seems like another way for government to get in our pockets.

[bruce.augenstein@comcast.]

Originally Posted by swamp2

As well you know darn well why the car is 4 liters. Well 3.999 to be exact... For those that don't the answer is taxes.

I didn't know that. Actually, I still don't know that. Has BMW made an announcement on this?

If not, Audi and Mercedes must feel pretty dumb by now, having missed that obvious advantage, so important to this area of the market.

Bruce

[sayemthree]

Originally Posted by swamp2

As well you know darn well why the car is 4 liters. Well 3.999 to be exact... For those that don't the answer is taxes.

rumors are that in some parts of Europe taxes and insurance is based on discplacement and HP. thats the tory on why BMW rates the HP very conservatively. my folks 540it rated at 282 hp dynoed at about 320 hp.