[uucdigest] Tuesday, February 15 2000 Volume 03 : Number 267 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | For all available Digest commands including unsubscribe/subscribe, | visit the BMW UUC Digest page: http://www.uucdigest.com | Send SUBMISSIONS to [EMAIL PROTECTED] | Complaints? Send 'em to [EMAIL PROTECTED] if you must. | Visit http://www.bubbaclub.com | www.bimmers.com - "serving enthusiasts on the 'net" | Visit http://www.bimmer.org - ultimate BMW bulletin boards! | Subscribe to the Zionsville Autosport Parts Digest: | http://www.zionsvilleautosport.com/majordomo.htm ����������������������������������������� In this BMW UUC Digest: [uuc] Pads for M5 Re: [uuc] <WOB/Tech> Active Noise Suppression (long) [uuc] <WOB> How to identify where a driver is from: Re: [uuc] Re: <E28 M5> my weekend - long [uuc] Re: <E28 M5> my weekend - long Re: [uuc] simple OBC question Re: [uuc] <OT> Tech Info Request RE: [uuc] '84 533i or '85 535i - Does it matter? [uuc] Speeding joke... [uuc] <E28> Removing Rear Emblems Re: [uuc] simple OBC question Re: [uuc] <WOB/Tech> Active Noise Suppression (long) ---------------------------------------------------------------------- Date: Tue, 15 Feb 2000 09:41:11 -0800 (PST) From: kjk <[EMAIL PROTECTED]> Subject: [uuc] Pads for M5 I had my pre-driving school inspection yesterday and learned that I have 4mm left in my front pads. I put Perf. Friction Z rated pads on last summer and did 2 track days, 2 autocrosses and maybe 12k miles since then. I thought they would last a bit longer than that. Anyway, can't seem to get my hands on a new set soon enough and I don't think 4mm is enough for a weekend of hard driving. Any recommendations for a similar street/track pad? I will leave the PF's in the back, they have quite a bit of pad left--looks like twice the front or approx. 8mm. Kevin Kelly 91 M5 Golden Gate Chapter __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com ------------------------------ Date: Tue, 15 Feb 2000 12:52:49 -0500 From: albert jenab <[EMAIL PROTECTED]> Subject: Re: [uuc] <WOB/Tech> Active Noise Suppression (long) I'll toss in my two cents here. Yes ANC works, and works very well in certain applications. The early enthusiasm for wide ranging sci-fi applications like zones of silence has dimmed though, as real-world constraints narrow down what can and can't be done economically or physically. The dust has settled now as the hype faded in the face of an enormous amount of military and private sector money spent on unsuccessful research projects. What can be done very well is to canc*l noise in a 1-dimesional sound field. Like fan noise inside a duct, say for a big HVAC system. In this case the source is far away from the speakers. This also includes active mufflers where the speaker is making sound inside the exhaust pipe. The frequency range for which this is successful has a practical upper limit; the wavelength needs to be long compared to duct width, basically more than 4 times the diameter of the duct. Sound speed in air is roughly 1100 ft/sec, so for a duct that is 1 foot wide you can get good results up to 275 Hertz or so. A decent system will get you 20 dB reduction broad band, and that includes sound fields with single tones, multiple harmonics, and white noise. A key for making this work is having a signal present, time-wise upstream from where you want to canc*l, that is highly correlated (in a mathematical sense) to the sound field you wish to eliminate. For HVAC noise, it may be a tach sensor on the fan motor. This would allow you to nail that frequency and all its harmonics. Or it could be a microphone in the duct, near the HVAC unit. This would get you the tones and harmonics, but also the flow noise. For an active muffler, it might be a microphone in the exhaust, closer to the engine. A tach sensor picking up the firing of one cylinder works better. You can canc*l all harmonics of engine firing that way, up to the 1/4-wave limit mentioned earlier. A basic 1-D system consist of two sensors, one or more speakers, and a processor. The "upstream" sensor (called the reference sensor), a sensor near the speaker to measure how well you are doing (called the error sensor). The processor receives data from the reference sensor and predicts what the sound field will look like at the error sensor. Based on this it calculates what to tell the speaker to do and sends the signal to the speaker which than makes the sound. The error sensor measures how far off the processor was in predicting & producing the anti-noise, and adjusts the internal models and algorithms in real time. These algorithms are collectively known as "feedforward" as opposed to feedback, because of the time-wise upstream-ed-ess of the reference sensor. Typically they are all variations on what is called the Filtered-X algorithm. For FX you construct a digital model of the propagation path (transfer function) between the reference sensor input and system output at the error sensor, and invert it. Making and storing these models relieves the processor from having to re-compute them over and over in real-time as part of its job. Point here is being time-wise upstream allows you do a lot of computation prior to needing to output a signal. These approaches are "smart" in the sense that they are adaptive, able to make changes in what they are doing in order to compensate for variations in the intervening dynamics and the input/output signal paths, adjusting parameters to place all the processing power where is needed. This is opposed to storing a giant table of coefficients for every possible I/O scenario. What can also be done well is cancel 3-D sound fields, but only when the speaker can be placed close to either the source of the noise, or close to the place you want the noise canc*lled. Example here are headphones and active mufflers with the speakers outside the pipe but near the opening. The 1/4 wave rule applies here too. For a 3" diameter exhaust pipe, this means wavelengths no bigger than 1 foot. So the effective canc*llation bandwidth theoretically goes up to about 1100 Hertz. Provided you can get speakers close to the pipe, they are efficient, and you have the power to drive them. This is still a 1-D system in terms of algorithm structure and system design. The resulting canc*llation is 3-D. You can do an easy home experiment with your stereo and a tone or function generator. Hook up the tone generator output to one of the line-level inputs of your amp. Place the speakers right next to each other, but switch the phase on one. You'll hear no sound, or little sound, at low frequencies, al over the room. Then move the speakers farther apart and you can hear patterns of amplification and canellation around the room. You can also raise the frequency with them close together and see where the cancellation effect peters out. I have built a number of these systems over the years, as part of a large research program funded by DARPA back in the early '90's. Part of my job was to evaluate the whole ANC area and build stuff that looked promising, for military apps. One system was for an un-muffled 350 small block Chevy with race headers. We ended up getting 20 dB reduction broadband, from 20 Hz to 1200 Hz. Knocked out as many as 40 harmonics of the fundamental firing rate by 60 dB each. However we needed a bank of speakers, ranging from two 15" subs to 6 smaller mids in a cabinet surrounding the two exhaust pipes. We needed a lot of acoustic power. Oh, and four Texas Instruments C40 DSP chips. No chance of production. It was very cool though. Another system was to coat a large nuclear powered underwater vehicle with speakers and make it invisible to sonar, by forcing a local impedance match of the hull to water. An acoustic cloaking device. That didn't get built, because it turned out to need so many processors and speakers that it would go to sea once, and sink forever. If anyone at DARPA or ONR is reading this, that program was declassified a long time ago. Anyway, considering the interior sound field in a moving car. It is broadband, containing both white noise and tonals plus harmonics. All from different sources, engine, drivetrain, road, wind, etc. Some may be useful as reference sources, some not. You want to create a zone of silence around the head of each passenger, more precisely at the ear of each passenger. So this turns into a much more complicated system with perhaps many reference inputs and at least 4 error sensors, possibly 8, one for each ear of each passenger. The processing power needed is staggering to do it well. For lower frequency sounds, say under 100 Hz, this isn't so hard. Wavelength here is 11 feet, so you need to get within 2.75 feet or so. This could be done passably well for everyone with an in-car stereo system, an add-on processor box, and error mic's on each headrest. Still very complicated. As you move up in frequency, say to 1100 Hz, the wavelength is now 1 foot, so speakers and sensors need to be no more than 3" away from each passenger's ear, across the entire range of movement of their heads. Hopefully it is obvious by now why ANC headphones work well and other systems don't. This hasn't stopped some people from still trying to do cabin noise. I believe Colin Ross in the UK successfully did something for aircraft cabins (Saab) years ago and it went to production. This was probably single-tone for prop/engine noise. Low-frequency, single reference sensor (or more, one for each engine) could be done for multiple harmonics on say a turbo prop. Like a Dash-8, which are noisy as hell. Still would require lots of speakers and error mics, basically at least one for each passenger. There are some very unscrupulous types in this business. I know of one military aircraft parts manufacturer (who shall remain nameless) who was developing a system for helicopter cabin noise suppression. They couldn't get the system to work, but had a big trade show coming up. They had an actual helo cabin at the show, with the system installed and people could sit in it. They had large speakers playing loud simulated rotor noise. They'd switch on the ANC and voila! 20 dB reduction. Wow. Except the switch didn't activate the system, it merely lowered the volume of the simulated rotor noise. There have been worse. BTW, a lot of same math, engineering and physics principles apply to active and semi-active suspensions. These work quite well and many are in or near to production. This is what I spend pretty much all my time doing now, for military aerospace applications. Hope this helps explain the ANC field a bit. - -Al 95 M3 ------------------------------ Date: Tue, 15 Feb 2000 09:55:02 -0800 (PST) From: Chester Wong <[EMAIL PROTECTED]> Subject: [uuc] <WOB> How to identify where a driver is from: 1. One hand on wheel, one hand on horn: CHICAGO 2. One hand on wheel, one finger out window: NEW YORK 3. One hand on wheel, one finger out window, cutting across all lanes of traffic: NEW JERSEY 4. One hand on wheel, one hand on newspaper, foot solidly on accelerator: BOSTON 5. One hand on wheel, one hand on nonfat double decaf cappuccino, cradling cell phone, brick on accelerator, gun in lap: LOS ANGELES 6. Both hands on wheel, eyes shut, both feet on brake, quivering in terror: OHIO, but driving in CALIFORNIA 7. Both hands in air, gesturing, both feet on accelerator, head turned to talk to someone in back seat: ITALY 8. One hand on 12 oz. double shot latte, one knee on wheel, cradling cell phone, foot on brake, mind on radio game, banging head on steering wheel while stuck in traffic: SEATTLE 9. One hand on wheel, one hand on hunting rifle, alternating between both feet being on the accelerator and both feet on brake, throwing McDonald's bag out the window: TEXAS 10. Four-wheel drive pick-up truck, shotgun mounted in rear window, beer cans on floor, squirrel tails attached to antenna: ALABAMA 11. Two hands gripping wheel, blue hair barely visible above windshield, driving 35 on the Interstate in the left lane with the left blinker on: FLORIDA ===== __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com ------------------------------ Date: Tue, 15 Feb 2000 12:55:40 -0500 From: "Pat Donahue" <[EMAIL PROTECTED]> Subject: Re: [uuc] Re: <E28 M5> my weekend - long ...so you're sayin' that it's because Matt's too dumb to know he can't do that?? Works for me! Geeeze '95 Honda ST1100 ABS for sale $8k - ----- Original Message ----- From: Erick Baumeister <[EMAIL PROTECTED]> > I've noticed this as well with my non-motorcycling friends. I came to > the conclusion that I've got defensive driving skills (from riding a > bike for so long) ingrained in my head to the point it carries over to > the games. My oblivious friends don't have that problem > > Erick > > "Pat Donahue" <[EMAIL PROTECTED]> wrote: > > We had fun kickin' your butt there > > but someone please tell me how Matt, who has never driven a motorcycle, > > could kick both our butts so decisively on that stupid motorcycle game? I > > don't know about you but the last time I was on a bike was .. today. > ------------------------------ Date: Tue, 15 Feb 2000 10:01:36 -0800 From: Tom Childers <[EMAIL PROTECTED]> Subject: [uuc] Re: <E28 M5> my weekend - long I have Eibach springs and Bilstien sport shocks in my E28 M5, and I love the combination. It feels nice and tight, but not jarring. The springs and front shocks were already installed when I got the car, but it had KYB rear shocks, which were horrible - brutally stiff. The Bilstien rears made the car very comfortable for me. I find that this suspension setup is great for zipping around town, and is even okay for long highway trips. The car is uncomfortable to drive on a dirt road. It is not stiff enough for sustained 140 mph driving across the desert however :-) Once upon a time, I got to drive an E28 M535i Euro with Dinan stage 3 suspension. It was too stiff for my taste. - -tdc At 08:06 PM 2/14/00 -0500, Ned wrote: >So, what needs to be fixed? Some small things but mostly, the suspension >needs a little help. The Self Leveling system appers to be working but the >car is pretty "floaty" at speed on irregular pavement. Feels like the >dampers are shot. I know that one choice is to replace the self-leveling >system with the Bilstien solution. I don't plan to track the car. It's just >for spirited street driving. So...I'm trolling for options. ------------------------------ Date: Tue, 15 Feb 2000 13:00:29 -0500 From: "Pat Donahue" <[EMAIL PROTECTED]> Subject: Re: [uuc] simple OBC question I've got the OBC still in my race car and it gets shut off (resets to Deutsch) frequently. With the key on punch the display to fuel economy, poke a pen or something into that little reset point on the lower right until it reads English. Geeeze '88 325is SCCA ITS #88 - ----- Original Message ----- From: <[EMAIL PROTECTED]> > I just purchased a 1987 325IS in great condition, but it did not come with an > owner's manual. Can anyone tell me how to switch the OBC to miles rather > than km or is this not possible? I like my '02 but I'm really enjoying the > smooth 6 of my new toy. > TIA > Mike > '87 325IS-soon to be sharked > '71 2002 > ------------------------------ Date: Tue, 15 Feb 2000 12:07:43 -0600 From: "-A." <[EMAIL PROTECTED]> Subject: Re: [uuc] <OT> Tech Info Request Thanks to the two digesters who replied with the following: <http://www.sae.org> and >I suggest "Internal Combustion Engine Fundamentals" by John Heywood. It is an >excellent text which is used in many ME engine courses. The sae.org bookstore and this text seem to be just what I was looking for. Thanks again! Cheers, - -A. `87 325is ------------------------------ Date: Tue, 15 Feb 2000 13:14:42 -0500 From: "Cagann, Alexander" <[EMAIL PROTECTED]> Subject: RE: [uuc] '84 533i or '85 535i - Does it matter? 533i (83-85) ENGINE cylinders: 3210cc six bore&stroke: 89mm x 86mm overhead cam compression: 8:8:1 carburetor: Bosch L-Jetronic EFI max power: 181bhp @ 6000 max torque: 195 lb/ft @ 4000 OTHER axle ratio: 2.63:1 tires: 200/60/VR 390 wheels: 65 TR 390 alloy curb weight: 3,125lbs 535i (85-87) ENGINE cylinders: 3430cc six bore&stroke: 92mm x 86mm overhead cam compression: 8.0:1 carburetor: Bosch ME Motronic EFI max power: 182bhp @ 5400 max torque: 214 lb/ft @ 4000 OTHER axle ratio: 2.63:1 tires: 220/55/VR 390 TRX wheels: 165 TR 390 alloy curb weight: 3,230lbs from: BMW 5 SERIES: The complete story James Taylor Alex Cagann 88///M5 ------------------------------ Date: Tue, 15 Feb 2000 13:15:38 EST From: [EMAIL PROTECTED] Subject: [uuc] Speeding joke... A young woman was pulled over for speeding. As the motorcycle officer walked to her car window, flipping open his ticket book, she said "I'll bet you're going to sell me a ticket for the Highway Patrolman's Ball". He stiffly replied "Highway Patolmen don't have balls". There was a moment of silence while she smiled and he realized what he'd just said. Then he closed his book, got back on his motorcycle and left. She was laughing so hard, she couldn't start her car. ------------------------------ Date: Tue, 15 Feb 2000 10:19:15 -0800 From: "Darrel & Kalmia" <[EMAIL PROTECTED]> Subject: [uuc] <E28> Removing Rear Emblems Greetings, Has anyone had experience with removing the 535i emblem from the trunk? If so, how is it attached? It is glued on, or attached with studs like the front and rear Roundel? Thanks, Darrel 85 535i 95 Olds 88 LSS ------------------------------ Date: Tue, 15 Feb 2000 13:25:05 -0500 From: Chip Baines <[EMAIL PROTECTED]> Subject: Re: [uuc] simple OBC question Regarding an '87 325iS, it was asked: > Can anyone tell me how to switch the OBC to miles rather > than km or is this not possible? The following works on an '86 e28 -- I bet it works on your OBC as well: Press the "AVG MPG" button, so that your mileage is displayed. It defaults to liters per hundred kilometers ("L:00" in the display). Then press the little button in the lower right hand corner (the one that you press using a ballpoint pen or a safety pin - this is the same button you have to press to set the time or date). Each time you press this little button the display should cycle from "L:00" to "MPG" to "M/G". MPG is miles per gallon using US gallons, "M/G" is in imperial gallons (imperial gallons are 20% bigger than US gallons). Once you get it to read "MPG", press SET/RES, and it sets. Outside temp will now be displayed in degrees F, and the clock will be in 12 hour format (AM and PM) versus 24-hour. Complete instructions for all OBC functions for this vintage are on my web site at: http://ebaines.home.att.net/obc.htm Good luck. As an aside, I am a bit puzzled by how often this question comes up. It seems quite common that people end up buying a used car without the owner's manual. How does this happen? Do the original owner's lose them? Doesn't everyone keep the owner's manual in the glove compartment (which makes it pretty hard to misplace)? If so, how does it get lost? Maybe there's a lucrative market for old manuals, and that's why they walk away? Just wondering... - -Chip Baines BMW CCA '86 528e '97 328iC ------------------------------ Date: Tue, 15 Feb 2000 13:27:06 -0500 From: "James Sheridan-Peters" <[EMAIL PROTECTED]> Subject: Re: [uuc] <WOB/Tech> Active Noise Suppression (long) > I'll toss in my two cents here. <snip> > Hope this helps explain the ANC field a bit. Hot DAMN! That's a hell of a lot more than two cents and worth it. Thanks for a very lucid explanation, Albert. I love the range of expertise on this list... :) - -- James Sheridan-Peters [EMAIL PROTECTED] '98 323is National Capital Chapter '85 SCCA Spec RX-7 #00 ------------------------------ End of [uucdigest] V3 #267 ************************** _________________________________________ | Please visit these UUC-approved BMW parts vendors/service providers: | (listed alphabetically) | Bonneville Motorwerks . http://www.bonnevillemotorwerks.com | Circle Tire Co. 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