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#1. Re: [E36M3] Bumpstops are not springs! (long) - from John Van Houten
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Date: Wed, 11 Sep 2002 11:24:44 -0500 From: "John Van Houten" <jvh_lists@ix.netcom.com> Subject: Re: [E36M3] Bumpstops are not springs! (long) Oh boy, where to start. > I'm going to get on my soap box. No offense John. None taken, but I disagree. First, the facts. Suspension went from 62K miles on: Stock springs Stock shocks Original rear trailing arm and front control arm bushings Full length stock bumpstops Swapped strut hats To corner entry/mid-corner oversteer with: Eibach Pro-Kit Springs Koni SA shocks New RTA and FCA bushings 20mm cut from front and rear bumpstops. Swapped strut hats X-brace Behavoir went from a "normal"/neutral handling M3, but with tired shocks (little bit bouncy, poor compression response) to one with a lot of rear body roll and a lot oversteer. In tight, fast turns, like a 90 deg turn in a auto-x, the clunk would happen. > I don't know where in the world this idea that bumpstops are "part of the > springs, designed to increase the spring rate, tune the springs, etc ...." > crap came from or started. I've seen many many guys claim this on our list. Well, on my car it all started with some engineers in Bavaria, and if you include other auto manufacturers, the rest of the world. The bumpstops are largely used today to create a progressive effective spring rate at the extremes of shock travel, as well as protect the shock. By using a bumpstop in this way, the suspension can be "soft" and compliant in normal travel on bumpy roads, etc, but can provide a dramatic increase in spring rate in high load situations to improve cornering. > Let's think about it logically and from an engineering point of view. You > have to support the weight of your car somehow. That's the function of > springs. They are fairly important. Take the spring out or if the spring > breaks, the car isn't drivable. Agreed? yup. > Then there is this claim that BMW uses foam rubber bumpstops for springs in > the M3. Foam rubber, that's the same stuff used in Nerf footballs, right? I think you are misguided into thinking that foam rubber in the bumpstops is the same as a nerf football. A considerable amount of engineering went into the design of the material and the shape of the bumpstop. > Let's look at the serviceability requirements of car springs. First is > longevity. Your car could last 20+ years. Then you have rain, heat, > dryness, temperature. Not to mention the constant motion that springs > endure. > You really want a wet soggy Nerf football to support you M3 at 1g cornering > loads? How long do bumpstops last? How long do trailing arm and control arms bushings last? They certainly are critical to the suspension in your car, but aren't made of steel and do wear out. However, these components, along with springs, are in constant use when driving your car, your bumpstops are not and see a much lower number of cycles. > Now let's look at what bumpstops really do. If your car is often bouncing > off the bumpstops or riding on the bumpstops, then there is a simple reason > why: But that is not the case, I was not constantly riding on the bumpstops. With my shortened bumpstops, I was not getting the increase in spring rate that I should have under high cornering loads. Under normal "street" driving, the suspension felt great. > 1. Your car is overloaded and you need stiffer *steel* springs to support the > load. Not the case. I increased the spring rate with the new setup from 105 to 148 lb/in front and 335 to 428 lb/in rear. This issue was not present with my softer stock springs. If I went to much stiffer linear springs like on my track/race-car-in-eternal-progress, bumpstops would be less involved. This is our daily driver and occasional track car, so 1200 lb/in springs are not an option. > 2. Your *steel* springs are too short. You need longer springs. Possible but not likely. Static ride height was only reduced by ~.75" in the rear. The Eibach Pro-Kit spring is not uncommon and we probably would have heard of these problems elsewhere. > 3. This would be very very unlikely but it is possible your *steel* springs > have fatigue. It is unlikely because it would take a million miles of > driving to fatigue the steel. Fix would be new *steel* springs. Very unlikely b/c the springs were new installed in the car. It is possible to get a defective spring, but I don't think this is the case here. Bottom line, I installed new bumpstops, street comfort is the same, rear body roll was greatly reduced and the massive oversteer issue was abaited. As Gary says, correlation does not imply causality, but in this situation, you could make a pretty strong case. The lesson here is, the bumpstops _do_ play a roll in the handling of the M3 and you should not trim them unless you know what you are doing. John
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#2. Re: [E36M3] Cross drilled rotors? - from James Clay
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Date: Wed, 11 Sep 2002 12:32:08 -0400 From: "James Clay" <james@bimmerworld.com> Subject: Re: [E36M3] Cross drilled rotors? We sell them but we tell everyone that buys them that they look good but are not functionally better. On the track, they have a tendency to crack from hole to hole, greatly decreasing rotor life. There is no performance advantage to them either if you are using a good pad. OEM or floating rotors are the way to go for track stuff, both are equal in most ways, floating are more expensive but will lengthen hub life. James ------------------------------------------------------------------ James Clay http://www.bimmerworld.com Engineered BMW Performance World Challenge / SCCA / BMWCCA Racecar Rental Genuine and OEM BMW Parts (540) 639-9648 ------------------------------------------------------------------ Please inquire about our new line of performance street, track, and full race clutch/flywheel systems.
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#3. Re: Negatives to E30M3 Control Arms? [Long] - from Bob Stommel
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Date: Wed, 11 Sep 2002 12:06:02 -0500 From: Bob Stommel <rstommel@iquest.net> Subject: Re: Negatives to E30M3 Control Arms? [Long] Neil Maller did a good job describing the problem with control arms, but the reason for the Club Racing tech bulletin on the E30 M3 control arms is because the OEM steel control arms for the E30 M3 are actually weaker than the aluminum ones. On the E30 M3, the steel rod on the inner ball joint fails more easily on the steel control arms. The aluminum control arms have ball joints made of higher strength steel. Here are the values from an analysis done in 1997: Steel arm ball joint : 4100 series steel, 19 HRC Alum. arm ball joint : 4100 series steel, 26 HRC HRC is the Rockwell Hardness measurement and equates to tensile strength of the metal. This steel with 19 HRC probably has a tensile strength of around 95,000 psi, while the steel with 26 HRC could have a tensile strength of 136,000 psi. Historically (and probably because of these differences in strength), the E30 M3 racers have seen fewer ball joint failures on the aluminum control arms than on the steel ones. Unfortunately, the ball joints on the E30 M3 control arms are not replaceable. You have to replace the entire control arm. It is also very difficult to see any fatigue cracking of the ball joints when the control arm is on the car. Hence the Club Racing tech bulletin. Sorry, but I don't have any strength data on the E36 M3 or E46 M3 control arms. HTH, Bob Stommel
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#4. cam replacement - from Jay Johnson
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Date: Wed, 11 Sep 2002 10:12:13 -0800 From: Jay Johnson <jay@pactitle.com> Subject: cam replacement Has any of you with or with out high mileage (I have 150,000 miles on a 95M3) needed to replace your cam due to excessive lifter noise. I've had the engine flushed and tried every weight of Mobile 1 oil and still have what now has become a persistent lifter tick. If I pull off the valve cover to check the wear will I be able to see if the cam lob has been worn. Are there any other reasons why the lifters would be so noisy? ( I put at least 8 quarts of oil in) thanks for any insight Jay 95M3 sharked/intaked
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#5. Re: [uuc] E36M3 Service II / what to do? parts? - from matthew c. mead
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Date: Wed, 11 Sep 2002 14:24:55 -0400 From: "matthew c. mead" <mmead-bmw@goof.com> Subject: Re: [uuc] E36M3 Service II / what to do? parts? On Wed, Sep 11, 2002 at 07:21:07PM +0200, Ulf Bertilsson wrote: > > I noticed from 94 to 95 the interval on O2 > > sensors jumped from 50k to 100k. Should I replace them at 52k? > Your supposed to be able to clean it. > But if your milage is fine, I guess it's no rational reason to mess with > it. Right... I get 23 around town and 28 on the highway. > > www.performancemotorcars.com also lists a Mahle fuel filter for > > the M3. Is this a decent filter? > Fuel filter can be somewhat disturbing and hard to swap IMO :D > Guess you have jacks and all that tho. Yep. I'm not sure if the whole car will go up or just the front. It's supposed to be under the driver's seat on the bottom of the car. Of course it's disturbing to change because fuel leaks out. I need to buy a couple pairs of vise grips and use some cut up rubber hose for fuel line clamps to prevent leaks while I change it. -matt -- matthew c. mead 97 Dakar M3/4 - sharked, xbraced 97 White GS-R/4 - stock (wife's) 92 Black Miata - dropped, dampened, headed towards SM http://www.goof.com/~mmead/
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#6. Re: Negatives to E30M3 Control Arms? [Long] - from twisty M3
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Date: Wed, 11 Sep 2002 11:34:26 -0700 From: "twisty M3" <twistym3@hotmail.com> Subject: Re: Negatives to E30M3 Control Arms? [Long] >From: Neil Maller <neil.maller@gte.net> > >First, I opine there's no way that for equal geometry you can tell the >difference in driving between steel and aluminum control arms. > Darn! ;) I guess this means it's one of three things that cause me to feel a difference then. It could be the new factory bearing hats where I used to have monoball camber plates (though I didn't notice a difference when swapping in the other direction), my messy alignment (which will be fixed this afternoon) or it could just all be in my mind. ;) > >Second, and more important than my opinion, here's what BMW CCA Club Racing >says about E30 aluminum control arms: > >(snippity, snippity, snip) >3. Replace all aluminum control arms after 2 seasons > Oy! I guess I'll just have to keep a close eye on them during future tech inspections, and be sure to change them (possible back to stock E36 M3 arms) after 2 seasons. Of course, our SoCal track season is year round, so I'll just call it 2 years or less. ;) >You do the math...is the slightly > > reduced weight of the aluminum arm worth it? > This is why it would've been nice if I had a chance to research this before it was done. I'll keep a close eye on them, and try to keep believing that I can feel a difference. ;) Jonathan L. _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com
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#7. Re: [E36M3] RE: USAA Insurance - from Jim Bassett
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Date: Wed, 11 Sep 2002 11:37:42 -0700 From: Jim Bassett <jimbassett@attbi.com> Subject: Re: [E36M3] RE: USAA Insurance At 05:13 AM 9/11/02, matthew c. mead wrote: >I don't either. If it's covered, you should claim it. I guess >my big point is that from my experience, there is often some >component to a driver's school that is racing. Yes, you wait for >a point, but what driver's school doesn't drill you to be >observant and poitn faster drivers? How many tales do we hear >about red misting at track schools? If that's the case, you're >not covered in a situation where your carrier excludes competitive >or racing events. Many people make the claim anyway. But here's the flaw in your logic. The *event* was NOT a racing or competitive event. What you describe is one (or more) individuals who's performance/attitude/actions are NOT in accordance with the event guidelines. One person with "red mist" or a couple of people playing cat-n-mouse (i.e. "competing") does not turn the entire event into a competitive or racing event. The actions of a few individuals does not change the nature of the event, as outlined by the organizers & event naterials. My 2 cents, Jim Bassett - never needed coverage at a drivers school/HPDE, but has had several friends who have, and defends their right to do so.
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#8. Re: [E36M3] E36M3 Service II / what to do? parts? - from Jim Bassett
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Date: Wed, 11 Sep 2002 11:47:12 -0700 From: Jim Bassett <jimbassett@attbi.com> Subject: Re: [E36M3] E36M3 Service II / what to do? parts? At 05:53 PM 9/10/02, matthew c. mead wrote: >Looking through the list of items in my Bentley manual, it >looks like I should replace the fuel filter and the spark plugs >as well as check out the power steering fluid situation. Can you >think of anything else I should check that isn't on the list in >the Bentley manual? Check the water level in your battery. >I noticed from 94 to 95 the interval on O2 >sensors jumped from 50k to 100k. Should I replace them at 52k? I wouldn't unless you have a Check Engine light indicating they're bad. >www.performancemotorcars.com (through eAuto) lists Bosch FGR 8 >KQC spark plugs at $5.29 each. Are these the ones to get? For a 3.2L M3? Yes. > At >52K on the clock, should I bother with wires? There are no "wires" - each spark plug has it's own coil. No need to replace them unless they are cracked or otherwise not in good condition. And I'm not sure, but the coils may need to replaced as a set of 6. $$$$ >www.performancemotorcars.com also lists a Mahle fuel filter for >the M3. Is this a decent filter? That would be a stock-brand filter. Jim Bassett
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#9. New Brake Fluid - from Wayne Miller
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Date: Wed, 11 Sep 2002 14:01:32 -0500 From: "Wayne Miller" <m3@waynemiller.com> Subject: New Brake Fluid Has anyone heard of or tried this Project Mu brake fluid: http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=1002 It has the highest dry and wet boiling points out there and is only a little bit expensive: 335C/635F dry, 221C/429F wet, $25/liter. -Wayne P.S. I have ordered parts from Dali Racing before because they are a well known NSX vendor and they usually do have good products.
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#10. Re: [E36M3] New Brake Fluid - from melsilva@mindspring.com
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Date: Wed, 11 Sep 2002 15:17:46 -0400 From: <melsilva@mindspring.com> Subject: Re: [E36M3] New Brake Fluid I have been a(n ab)user of Motul 600 for years and this looks like the only product I have seen with similar specs that doesn't cost $100/liter. The other advantage it has over Motul is the metal can. Motul uses a plastic that they claim is impermiable to water, but I don't know if it really works. Good find Wayne, it's always nice to have options. Mel On Wed, 11 Sep 2002 14:03:11 -0500 Wayne Miller <m3@waynemiller.com> wrote: Date: Wed, 11 Sep 2002 14:01:32 -0500 From: "Wayne Miller" <m3@waynemiller.com> Subject: New Brake Fluid Has anyone heard of or tried this Project Mu brake fluid: http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=1002 It has the highest dry and wet boiling points out there and is only a little bit expensive: 335C/635F dry, 221C/429F wet, $25/liter. -Wayne P.S. I have ordered parts from Dali Racing before because they are a well known NSX vendor and they usually do have good products. ************************************************************* List Commands UNSUBSCRIBE - (in subject line) unsubscribes you from the mailing list. DIR - sends a listing of files available in the list's GET directory. GET filename1.ext,filename2.ext - sends the requested file(s). To issue a command/request to the server: Send a message with the command you wish executed as the subject of the message to the email address e36m3@bmw-m.net. *************************************************************