[uucdigest] Friday, June 20 2003 Volume 03 : Number 6491
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Send 'em to [EMAIL PROTECTED] |__________________________________________________________________ In this BMW UUC Digest: Re: [uuc] Brake upgrades for E34 525 [uuc] Magnecor spark plug wires for M20 Re: [uuc] Brake upgrades for E34 525 Re: [uuc] DME question Re: [uuc] Magnecor spark plug wires for M20 [uuc] 1985 524td for sale ---------------------------------------------------------------------- Date: Fri, 20 Jun 2003 14:04:28 -0400 From: "Michael McCoy" <[EMAIL PROTECTED]> Subject: Re: [uuc] Brake upgrades for E34 525 - ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, June 20, 2003 8:46 AM Subject: Re: [uuc] Brake upgrades for E34 525 > Michael wrote: > >problem that i am trying to overcome is mostly the balance issue. i want > to > >stop faster. stopping faster will require using all 4 tires to their > limit. > >not just the fronts to their limit with the rears kinda just *along for > the > >ride*. next aspect will be brake cooling. > > Out of curiosity what brake pads are you currently using and what tires? > Not that > altering the brake bias/rotor size/caliper/piston size isn't going to work > but I've > rarely seen where brake pad choice/tire choice and as you mentioned cooling > doesn't > solve all braking problems. If you're having problems on the street you > must > be a mad man behind that wheel! :-) > when there is traffic around I'm quite tame. the wheels are 16" Mille Miglia MM11-2 sports. very open 5 spoke design. the rotors are ATE powerslots front (cause I knew i'd have a pad gassing problem) and balo rotors rear (stock, non vented, non slotted, etc...). Calipers are stock, and pads are Metal Master's all around. (not the best pads for agressive stuff, so better pads would take the heat better, but that does little for the bias issue. and if I moved more bias to the rear on the stock rotor, it would become unhappy very quickly.) > From experience though I followed an E34 M5 at Mid-Ohio and I don't know > what he's > using for brakes but he was honking along for such a big car. Perhaps he > was a > horsepower mods type of person though, he would pull away from me on the > back straight. > > >*I guess in general I'm more of a "small brakes with big ducts" kind of > >guy. > > I think we're all in that boat unless you're Powell. <g> > > Carlos > 91 M3 using Bimmerworld backing plates, ducting, Goodridge ss lines, > Hawk HT-10s up front and Hawk Blues in the rear, Castrol SRF brake fluid, > calipers rebuilt often. > > you don't use those pads on the street, do you? - -Michael McCoy ------------------------------ Date: Fri, 20 Jun 2003 14:44:55 -0400 From: "Michael McCoy" <[EMAIL PROTECTED]> Subject: [uuc] Magnecor spark plug wires for M20 anyone have any experience with magnecor wires on an M20? specifically an i motor, in terms of dealing with the inductive pickup. would anyone happen to have a picture of the wires installed? I'm curious as to how close they stay to the head and how far the boots stick out. thanks - -Michael McCoy ------------------------------ Date: Fri, 20 Jun 2003 14:50:28 -0400 From: "Michael McCoy" <[EMAIL PROTECTED]> Subject: Re: [uuc] Brake upgrades for E34 525 - ----- Original Message ----- From: "Money, Jack (J.J.)" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, June 20, 2003 8:21 AM Subject: RE: [uuc] Brake upgrades for E34 525 > <<oh? different temps? cause the pad compound is generally the same front > and > rear. so you'd want it to be the same temp front and rear. probably > something you'd want to consider when designing a braking system for > something like track use.>> > > Unless you're using a proportioning valve or can change calipers/brake set > ups over stock, I still find it odd to use the same pads front and rear > because of temp/usage differences. I have never run the same pad front and > rear on my race car (formerly a stock class E30 M3). Well, I tried it > once....very bad results, horrible balance, terrible push, no ability to > trail brake, very touchy under tap and go situations. Not good. And the > ONLY variable during this "testing" was pads. Once I went back to a biased > set up (higher torque/heat range pad on the front) the car was instantly > back to neutral balance. > > I can certainly see that with a fully adjustable suspension one could > "adjust" out any handling issues but I can't see why one would use the > suspension adjustment to correct for brake imbalance. And in my case I have > absolutely no reason to use more of a rear pad, just not necessary. If the > car was perfectly balanced under braking I can see optimizing the pad usage > but I just can't believe that people do this. Perfectly balanced under max > braking means a compromise when off the brakes....such as acceleration! I > don't claim to be a vehicle dynamics expert but I certainly have training > and work related experience. It has been awhile since I've done all the > math though....might have to revisit this. > you don't change suspension setup to adjust for braking. suspension setup is to optimize cornering speed. (and sometimes straight line speed in some cars, based on ride height.) and balancing brake bias isn't for better pad wear. so in your situation the brake bias was too rearward. if the calipers were smaller in the rear than what you were using, then perhaps the pads would not have been so problematic? no? or perhaps the pads and forces generated were ok, but the rotor temp was not right in comparaison to the fronts. coefficient of friction changes with temp a little with most pads. they all have their *happy range* and if you go above or below that, their not so happy in one way or another. also, based on you saying it had a terrible push, that makes me think the rears were doing less than they should have, and when you went to the more agressive fronts, it put the rear pads back in their happy place. cars with too much rear brake bias tend to be *twitchy* and want to swap ends. cars with too much front brake bias push. currently BMW seems to like the 70% front bias for my car. this is indeed the "safe" approach as the car will lock the fronts first in a panic and thus go straight. same reason that FWD's are marketed as safer cars... people don't like it when cars swap ends. even if it is driver error. apparently people think that hitting things head on is better or something... I dunno. (how many skid marks do you see go straight into concrete walls along interstate on ramps and off ramps? lots.) less front bias means more rear brake usage, which in turns means more total braking force. think of it this way, if the fronts were on the edge of lockup, thus contributing maximum braking force, and the rears were at 50% utilization in terms of grip... you're quite far from the car's max potential braking force. if instead when the fronts were in that situation again, the rears were closer to 90% utilization of grip, then the car is stopping much faster. that to me is safer. to repeat, if given the choice between stoping quickly, or not stoping quite as quickly but guaranteed to be still pointed perfectly straight, I'll take stopping quickly... > Regarding all this discussion of brake bias and possible solutions, I did > not see you mention it specifically but I assume in all your calculations > you have determined what your weight transfer is under braking - especially > if you have altered the suspension. And of course it will be different > under different braking conditions as well as different road conditions as > Gary noted. I suppose you have calculated it using max braking and will > settle for the compromise at less that max. Care to discuss it further? > I did the math based around G forces of braking, as it made things easier. (weight transfer becomes extremely easy to calculate.) the big wild card in the brake calculations was maximum adhesion between the tire and the road. Gotta try to find that piece of paper now... I think I assumed *max* would be somewhere between 1.1G and 1.2G, and then *normal* braking to be closer to 0.6G. (0.7G also happens to be the decelerative contribution of sliding tires. so even a locked tire could generate this.) then kinda averaged the data. (biased the data torwards the upper end of the specturm though, but I did look at lower numbers for consideration to make sure it wouldn't be too tail happy. tail happy is what the long thin pedal on the right is for.) anything less than 0.6G, and balance isn't too important as none of the tires will be near the limit of adhesion. (yes even in the wet.) wet stopping distances on modern street tires are disturbingly close to their dry stopping distances. the 60-0 stopping distance of my 525 according to the literature is around 130 feet. which equates to ~0.9G. for reference 0.6G would be stopping around 200 feet from 60 mph. for center of gravity, something around 20 inches seemed like a reasonable number for a street car. (H&R springs with bilstein sport shocks, so the car is ~0.75 inches lower than stock. supposedly.) 108 inch wheelbase. so +- a couple inches in CG won't make the weight transfer numbers that horribly different. couple percent here or there is probably less than the difference the tire temps or pressures as well as brake temps would make.... or say the 0 to 4 extra people in the car with stuff in the trunk... :o) - -Michael McCoy > Jack Money > '89 325iX > #86 JP M3 > Elephant Motorsports ------------------------------ Date: Fri, 20 Jun 2003 15:09:43 -0400 (EDT) From: [EMAIL PROTECTED] Subject: Re: [uuc] DME question >From Brian Daley > >If you want a "reconditioned" DME try http://www.programainc.com Not >much savings vs. a new one from the dealer though. If you're looking to >save a few bucks try http://www.car-part.com/ It lists iventory from a >number of salvage yards across the country. You should be able to find >one for significantly less. Pick 1988, BMW 325i and "Engine Computer" >from the dropdowns. A quick search shows a 173 available at Bodyline >Auto Recyclers in Canada for $92.59 ($125 CDN) Not all the listings >show part numbers so a few calls might save you even more than that. > >Brian Daley >'94 325ic >Standard disclaimer: No affiliation, etc. > Not DME related, but car-part.com is how I got my replacement cam, rockers, and rocker arms for $125. Neat service. It does pay to know what you need and what else is similar and to talk to the individual companies to see who knows their stuff. - -- Joe - -- Joseph M. Krzeszewski Network Operations [EMAIL PROTECTED] Jack of All Trades, Master of None... Yet ------------------------------ Date: Fri, 20 Jun 2003 15:24:56 -0400 (EDT) From: [EMAIL PROTECTED] Subject: Re: [uuc] Magnecor spark plug wires for M20 >From Michael McCoy > >anyone have any experience with magnecor wires on an M20? specifically an i >motor, in terms of dealing with the inductive pickup. would anyone happen to >have a picture of the wires installed? I'm curious as to how close they stay >to the head and how far the boots stick out. > >thanks > >-Michael McCoy > > I have them on my M20 powered 325i. I bought them when I couldn't see spending $250 for the hand-twisted-by-german-gnomes Bosch wires. If you order the propper set of standard wires from Magnecor (7mm I think) they ship with the boot for the number six wire in the box instead of on the wire. This is so you can slip the pick up on the new wire. My pick up wouldn't fit over the crimped on connector, so I took a drill bit (might be 5/16) and carefully reamed out the pickup until it fit. I couldn't get all the wires back into the stock BMW loom as I didn't pay close enough attention to how the old ones came out. I am planning on building a custom loom to hold the wires and keep them a little away from each other, but in the mean time I have them zipper tied to the old loom. I would take pictures, but mine isn't real pretty... They do work fine though, and are a good bit cheaper than stock. - -- Joe - -- Joseph M. Krzeszewski Network Operations [EMAIL PROTECTED] Jack of All Trades, Master of None... Yet ------------------------------ Date: Fri, 20 Jun 2003 15:37:02 -0400 From: Michael Lawrence <[EMAIL PROTECTED]> Subject: [uuc] 1985 524td for sale I have a 1985 euro model 524td for sale Runs good, but is hard to start. Either needs injection pump timing adjustment or glow plugs. Once warmed, fires on first revolution. Been repainted burgandy, clear coat is coming off. Power sunroof but manual windows. AC worked great when we stopped driving it. I just had the driveshaft rebuilt by DLS here in atlanta. Both front and rear bumpers have been removed. Has US headlights, clear and clean title. Just dont have room or time to mess with it. I am going to put it in the paper here locally for $1000obo. It runs and drives fine, just needs some routine maintance. But I figured someone might want to buy it and use the forged crank, sell the turbo, injection pump and like new driveshaft to recoup the costs and then some. I dont have a place to part it out, so it must go as a whole driving away car, lol. I have owned it for the last 5 years I believe and it was driven daily for a long time until the driveshaft broke. Then it was parked, then replaced by much more modern BMW machinery Let me know Mike ------------------------------ End of [uucdigest] V3 #6491 *************************** | | In memory of Michel Potheau - friend, enthusiast, founder of the BMW CCA. |________________________________________ | Please visit these UUC-approved BMW parts vendors/service providers: | (listed alphabetically) | | Autoscope-Motorsports - http://www.autoscope-motorsports.com | |==================================================== | | Koala MotorSport . BMW technical information, special tool sales/rental | http://www.koalamotorsport.com | |==================================================== | | Taylor BMW - http://www.taylorbmw.com - Doc Bimmer! | |==================================================== | Turner Motorsport Inc . The Ultra-High Performance BMW Specialist | 207 Elm Street, Amesbury, MA 01950 | 978-388-7769 / fax 978-388-4202 | http://www.turnermotorsport.com | |==================================================== | | UUC Motorwerks - BMW Performance Fine-tuning | and home of the Ultimate Short Shifter - accept no substitutes! | 908-874-9092 . http://www.uucmotorwerks.com |__________________________________________________________
