[uucdigest] Thursday, June 19 2003 Volume 03 : Number 6484
_________________________________________________________________ | | Search the ARCHIVES: | http://www.mail-archive.com/[EMAIL PROTECTED] | | Visit Richard Nott's Ultimate BMW Database: | http://www.bmwdatabase.com | | 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. | Technical Problems? Send 'em to [EMAIL PROTECTED] |__________________________________________________________________ In this BMW UUC Digest: [uuc] re: swapping airbag steering wheel for non-airbag wheel [uuc] Brake upgrades for E34 525 Re: [uuc] Brake upgrades for E34 525 RE: [uuc] Brake upgrades for E34 525 Re: [uuc] Brake upgrades for E34 525 RE: [uuc] Brake upgrades for E34 525 ---------------------------------------------------------------------- Date: Thu, 19 Jun 2003 08:40:42 -0700 From: [EMAIL PROTECTED] Subject: [uuc] re: swapping airbag steering wheel for non-airbag wheel Also, the airbag steering column mounts higher under the dash to position the airbag where it is more likely to decapitate a short driver, but maybe provide better protection for taller ones. Scott Miller GGC BMW CCA >Date: Wed, 18 Jun 2003 08:38:54 -0400 >From: Ed MacVaugh <[EMAIL PROTECTED]> >Subject: Re: [uuc] re: swapping airbag steering wheel for non-airbag wheel > >The difference in the columns is to reduce noise vibration and >harshness, the column had to be changed when the added weight of an >air-bag equipped wheel was added. The rack changed also. In each case, >the replacements from the parts bin are all of the later (airbag) variety. > >Ed > >Neil wrote: > >>FYI, >>The steering columns on the airbag-equipped cars are different than >>those in the non-airbag cars. I don't remember exactly what that >>difference is, other than that they collapse at a different rate or >>manner (the airbag column doesn't compress as much or as quickly, or >>whatever). There may be a safety issue in a frontal collision, i.e., a >>slight case of death. However, you put your body behind that wheel, not >>mine, so take the above with a grain of salt if you like. Just thought >>you should know. >> >>Neil >>'91 318is >>'86 M535i >>'89 325iX parts car ------------------------------ Date: Thu, 19 Jun 2003 08:49:42 -0700 (PDT) From: kjk <[EMAIL PROTECTED]> Subject: [uuc] Brake upgrades for E34 525 I am running the 345mm brakes on the front with stock pad and running a very aggressive compound in the rear with stock brakes on my M5 (rotors are cheap). It works pretty well under track conditions but the front pads do get bit overheated and leave a bit of residue on the rotors on tough tracks like Laguna Seca. I am going to get a bit more capable compound for the front (custom made by Carbotech because they aren't any for those brakes) for some more heat capability. Despite their weaknesses I have never had much fade to speak of on track. I just get a bit of a soft pedal. I was told by Carbotech that the new Subaru Sti/Evo Brembos have the same backing plate as the 345mm calipers. So at least the backing plates will be readily available. The problem is that the specs for the U.S. pad are about 1/3" short of the edge of the rotor (which is what I got when I ordered some from the UK from Mintex). They can make it in the proper pattern but I thought that was interesting. Rotor wear on the big floaters is an issue because they are about $190 each. I get about 10 track days plus street driving out of a set of stock Textars which are only $59 from Pacific. The best solution is better pad compounds and cooling. It is also much cheaper than Brembos. Kevin Kelly '91 M5 __________________________________ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com ------------------------------ Date: Thu, 19 Jun 2003 12:03:57 -0400 From: [EMAIL PROTECTED] Subject: Re: [uuc] Brake upgrades for E34 525 Michael wrote: >go look at a go cart. (non-shifter cart, cause shifter carts are allowed brakes at 4 wheels.) >100% brake bias to the rear. not too problematic. yes you could stop faster with brakes on all >4 corners, but for one thats illegal in these classes We have some of those here in Detroit, ~5-6hp Honda motors, real kart chassis and only rear brakes. I'm not terribly fond of the rear only brakes, for one you can't just stand on the brake pedal or you may spin, you definitely have to be really careful trailbraking into a corner. I've also driven an '89 Carrera on the track and also practiced trailbraking, I looped it a few times (this was an exercise not a lapping event) but it definitely is doable it just requires more skill than the average driver can handle. My E30 M3 on the other hand is really easy to trailbrake with. Carlos 91 M3 <--stockish brakes that work pretty well 88 iS ------------------------------ Date: Thu, 19 Jun 2003 09:21:18 -0700 From: "Marco Romani" <[EMAIL PROTECTED]> Subject: RE: [uuc] Brake upgrades for E34 525 Absolutely. Marco - -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Gary Derian Sent: Thursday, June 19, 2003 3:24 AM To: [EMAIL PROTECTED] Subject: Re: [uuc] Brake upgrades for E34 525 Also, peak weight transfer depends on the road surface. If the road is slick, you can't stop as fast which limits weight transfer to the front. Gary Derian > Michael, > > Do I understand what you're saying correctly? Do you want to put > smaller calipers in the front to move brake bias to the rear? > > I also think that if you really want to as you write > > " I'm really looking for a system that is truly balanced. as in the > limit of adhesion in braking is attained at all 4 wheels at the same time." > > I hope you're not forgetting that weight transfers forward as you jump > on the binders, so by making your bias move more to the rear without > addressing forward weight transfer you're going to lock the rears up > sooner and make the car pretty loopy. Or are you also putting some > really fast computer controlled bias valve that compensates for the > weight transfer. > > I'm obviously a bit puzzled as to what you're trying to do. > > BTW you can buy a cockpit adjustable brake bias valve that allows you to > play with bias to your hearts content. Just don't test it on the highway. > > Marco > > Michael McCoy wrote: > > ----- Original Message ----- > > From: "Rob Levinson * UUC Motorwerks" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Wednesday, June 18, 2003 7:26 PM > > Subject: Re: [uuc] Brake upgrades for E34 525 > > > > > > > >>The E23 calipers are not compatible with the E34. > >> > > > > > > hmm. now you tell me. :oP > > they have the same pistons as the M5/M6 so I was hoping that maybe they were > > just a cheaper version made by ATE. > > they are quite small. so that would definately have served my purpose in > > moving lots of the brake bias to the rear. > > oh well. they are on their way... less than $16 including shipping. maybe > > I'll find a place for them to sit and look pretty. > > > > > >>As posted previously, almost your entire menu of BMW factory-sourced > > > > options > > > >>is found right here: > >> > >>http://www.bmwe34.net/e34main/upgrade/brakes.htm > >> > >>(There's a rare E32 tiny 4-piston setup I left out of the list). > >> > >>How crazy do you want to go with the brakes? In about a week or two, UUC > >>will have the 355mm 4-piston front and 328mm 4-piston rear available for > > > > the > > > >>E34. They fit under 17" wheels and will be very reasonably priced for > > > > this > > > >>level of braking capability. > >> > > > > > > you done the math yet on brake balance/bias/dynamics yet? and if so, you > > care to share those numbers? > > > > I'm really looking for a system that is truly balanced. as in the limit of > > adhesion in braking is attained at all 4 wheels at the same time. also, for > > a balanced braking system, the thermal load at all 4 corners would be > > similar. as in the % utilization of the heat sink capacity is equal front to > > rear, so all the brakes would overheat at the same time. so not cooking the > > fronts and the rears only warm to hot (which is what the car does now). > > > > also, why such big rotors in the front? seems a bit excessive. 330mm was > > more than enough for most LMP cars (granted they are only 1500lbs, but they > > do more repetetive stopping from higher speeds than a 5 will ever see.) > > > > > >>Big brakes are not an option on the E34 - they are a _requirement_. I've > >>had 5-series for quite a few years now, and have experienced virtually > > > > every > > > >>setup listed on the BMWE34.net website. Frankly, all of the factory parts > >>(even the Nurburgring calipers) are insufficient, especially if you're > >>building a big-power car. > >> > > > > > > i don't know if bigger is always better. granted the E34 needs better > > brakes, but I think sizing the calipers to match the balance and maximum > > grip of the car is best. and then size the rotor to accomodate the heat > > characteristics of the system. > > > > i've been trying to work the math backwards, but keep finding things wrong > > with my approach. I want the math to be perfect before I figure out what > > calipers/rotors match the needs. the trial and error methodology would be an > > expensive way to approach this problem. > > > > -Michael McCoy > > > > > > > > > >>- Rob > >> > >> > >>----- Original Message ----- > >>From: "Michael McCoy" <[EMAIL PROTECTED]> > >>Subject: Re: [uuc] Brake upgrades for E34 525 > >> > >> > >> > >>>ok, so those are the fronts. what about the rears? > >>> > >>>I'm trying to get rid of the excessive front bias. (getting rid of heat > >>>faster too would also be a plus.) > >>> > >>>what can people tell me about the E23 7 series front brakes? they look > >> > > to > > > >>be > >> > >>>very similar to the front brakes on the M5/M6 of the early 80's. they > >> > > use > > > >>>the same rebuilt kit... but don't have the same caliper PN and such. > >>>any info on rotor size and the likes? > >>> > >>>thanks > >>> > >>>-Michael McCoy > >> > > > > > > > ------------------------------ Date: Thu, 19 Jun 2003 12:23:46 -0400 From: ben keyes <[EMAIL PROTECTED]> Subject: Re: [uuc] Brake upgrades for E34 525 kjk wrote: > I was told by Carbotech that the new Subaru Sti/Evo > Brembos have the same backing plate as the 345mm > calipers. So at least the backing plates will be > readily available. interesting. I've read that the list price for the STi stock pads is ~$380, with a good dealer price being ~$300. that seems pretty pricey given that most of the track pads I've gotten in the past are more like $180-$200/axle. one would expect there to be quite a few pad choices available relatively soon for the Evo/STi brakes, so that would be a good cross-over advantage for the M5 4-pots. I'd like for there to be Hawk Blues available for the STi but I'm not going to track it much, so I'll stick with stock I suspect... Ben STi coming sometime next month, E34 M5 brakes in garage (for E28 M5) more on the way... ------------------------------ Date: Thu, 19 Jun 2003 09:27:43 -0700 From: "Marco Romani" <[EMAIL PROTECTED]> Subject: RE: [uuc] Brake upgrades for E34 525 If you're first sentence was meant to say "the idea is indeed to move bias to the REAR" then the rest of the paragraph makes sense. Now another kludge to your problem would be to put racing pads on the rear and crap pads up front. But I wouldn't drive a car like that. Marco ps my suggestion for a bias valve may not work on your E34 if it has ABS. I haven't seen a bias valve installed on an ABS 3 or 4 channel system. I'm not saying it isn't possible, I just don't know how to do it. I thought you had an E23 for some reason, which I assumed did not have ABS - -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Michael McCoy Sent: Thursday, June 19, 2003 4:00 AM To: [EMAIL PROTECTED] Subject: Re: [uuc] Brake upgrades for E34 525 the idea is indeed to move bias to the front. another aproach would be bigger calipers on the front, complemented by much bigger calipers on the rear. current brake bias is around 70% front. I'm looking for more along the lines of 65% to 63% front. I'm not looking to move the brakes ALL to the rear, but currently the rear brakes don't do much of anything ... especially when braking hard. - -Michael McCoy - ----- Original Message ----- From: "marco" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, June 19, 2003 1:15 AM Subject: Re: [uuc] Brake upgrades for E34 525 > Michael, > > Do I understand what you're saying correctly? Do you want to put > smaller calipers in the front to move brake bias to the rear? > > I also think that if you really want to as you write > > " I'm really looking for a system that is truly balanced. as in the > limit of adhesion in braking is attained at all 4 wheels at the same time." > > I hope you're not forgetting that weight transfers forward as you jump > on the binders, so by making your bias move more to the rear without > addressing forward weight transfer you're going to lock the rears up > sooner and make the car pretty loopy. Or are you also putting some > really fast computer controlled bias valve that compensates for the > weight transfer. > > I'm obviously a bit puzzled as to what you're trying to do. > > BTW you can buy a cockpit adjustable brake bias valve that allows you to > play with bias to your hearts content. Just don't test it on the highway. > > Marco > > Michael McCoy wrote: > > ----- Original Message ----- > > From: "Rob Levinson * UUC Motorwerks" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Wednesday, June 18, 2003 7:26 PM > > Subject: Re: [uuc] Brake upgrades for E34 525 > > > > > > > >>The E23 calipers are not compatible with the E34. > >> > > > > > > hmm. now you tell me. :oP > > they have the same pistons as the M5/M6 so I was hoping that maybe they were > > just a cheaper version made by ATE. > > they are quite small. so that would definately have served my purpose in > > moving lots of the brake bias to the rear. > > oh well. they are on their way... less than $16 including shipping. maybe > > I'll find a place for them to sit and look pretty. > > > > > >>As posted previously, almost your entire menu of BMW factory-sourced > > > > options > > > >>is found right here: > >> > >>http://www.bmwe34.net/e34main/upgrade/brakes.htm > >> > >>(There's a rare E32 tiny 4-piston setup I left out of the list). > >> > >>How crazy do you want to go with the brakes? In about a week or two, UUC > >>will have the 355mm 4-piston front and 328mm 4-piston rear available for > > > > the > > > >>E34. They fit under 17" wheels and will be very reasonably priced for > > > > this > > > >>level of braking capability. > >> > > > > > > you done the math yet on brake balance/bias/dynamics yet? and if so, you > > care to share those numbers? > > > > I'm really looking for a system that is truly balanced. as in the limit of > > adhesion in braking is attained at all 4 wheels at the same time. also, for > > a balanced braking system, the thermal load at all 4 corners would be > > similar. as in the % utilization of the heat sink capacity is equal front to > > rear, so all the brakes would overheat at the same time. so not cooking the > > fronts and the rears only warm to hot (which is what the car does now). > > > > also, why such big rotors in the front? seems a bit excessive. 330mm was > > more than enough for most LMP cars (granted they are only 1500lbs, but they > > do more repetetive stopping from higher speeds than a 5 will ever see.) > > > > > >>Big brakes are not an option on the E34 - they are a _requirement_. I've > >>had 5-series for quite a few years now, and have experienced virtually > > > > every > > > >>setup listed on the BMWE34.net website. Frankly, all of the factory parts > >>(even the Nurburgring calipers) are insufficient, especially if you're > >>building a big-power car. > >> > > > > > > i don't know if bigger is always better. granted the E34 needs better > > brakes, but I think sizing the calipers to match the balance and maximum > > grip of the car is best. and then size the rotor to accomodate the heat > > characteristics of the system. > > > > i've been trying to work the math backwards, but keep finding things wrong > > with my approach. I want the math to be perfect before I figure out what > > calipers/rotors match the needs. the trial and error methodology would be an > > expensive way to approach this problem. > > > > -Michael McCoy > > > > > > > > > >>- Rob > >> > >> > >>----- Original Message ----- > >>From: "Michael McCoy" <[EMAIL PROTECTED]> > >>Subject: Re: [uuc] Brake upgrades for E34 525 > >> > >> > >> > >>>ok, so those are the fronts. what about the rears? > >>> > >>>I'm trying to get rid of the excessive front bias. (getting rid of heat > >>>faster too would also be a plus.) > >>> > >>>what can people tell me about the E23 7 series front brakes? they look > >> > > to > > > >>be > >> > >>>very similar to the front brakes on the M5/M6 of the early 80's. they > >> > > use > > > >>>the same rebuilt kit... but don't have the same caliper PN and such. > >>>any info on rotor size and the likes? > >>> > >>>thanks > >>> > >>>-Michael McCoy > >> > > > > > > > ------------------------------ End of [uucdigest] V3 #6484 *************************** | | 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 |__________________________________________________________
