dcmackintosh

The torsional spring constant formula is given under A.4 here.  Whether or not you have reason to calculate it, it may be of interest to note that the stiffness is directly proportional to the inverse of the length of the bar or tube, and proportional to the 4th power of the diameter.  For example, going from a 1.0" to a 1.25" bar increases the stiffness by a factor of almost 2.5.  The effective linear spring rate applied by the end link is also directly proportional to the length of the lever arm, of course.  The shear modulus for carbon steel is 11.2 x 10^6 psi. 

Sum'buddy been reading the stock- car parts catalogs.

Nah, I'm just an ME.  Basic concepts.

I expect those bars have very close to the same stiffness as a 1-piece bar of the same size tube or rod and geometry.  Even with a 1-piece bar, torsion of the center section has a much softer spring rate than bending of the arms (I admit that I haven't calculated it).  Possible adjustments would be changing the length of the arms or the diameter, wall thickness, or length of the transverse torsion spring.

The light weight is what makes an '02 so great to drive, but power rear vent windows would be cool, since those are the ones that aren't really easy to actuate while driving.  My 2004 Toyota Sienna van has them, but they regressed to manual levers in the new ones.

Nice looking '02 and early 911s!  I've always loved the Gulf colors, I'm tempted to add the blue to my (not originally) Inka '02.

I decided to run with the 14's today, for a change.

I can't explain why I think these steelies so good, but I do.  I'd love a set in 15x6.

The RE-11s look great, but I've got a 100-mile round trip commute and I think I'd burn them up too quickly.  I need to get my car set up to stop wrecking fronts like it does now.

I did find another option, Discount Tire has the Kumho Ecsta ASTs for only $60.  They have a 400 treadwear rating and I've been pretty happy with them on my '94 Miata (in 205 width on 15x7s).  Not real sticky, but predictable and they take some abuse.   I imagine the s.Drives would be somewhere between those two. 

I did find recommendations for s.Drives, but I figure there are always new models and better deals.  

What do you like for 195/50-15 tires right now?  S.drive and g-Force are the same price at Tire Rack, although the g-Force is out of stock in that size.  Others in that category I should consider?  I'm looking for good DD canyon road performance, possible HDPE days, reasonable $/mile.

How rough are your roads?  I've got Sports with H&R springs and it's pretty bad on rough roads, but fine on smoother ones.  I haven't tried HDs, but it seems to me that even the Sports are a little light on rebound (but very firm on compression).  The car doesn't feel as buttoned down near the limit in lumpy corners as I'd like.  I plan to go to a f/r GC setup on shortened front struts, but I need to decide what dampers to use.

This.  For the Kamei spoiler (which is the one you're looking for Kris), seek out Pierre here on the forums.

Here's the Kamei style, it looks good.

http://home.roadrunner.com/~pchamaa/kamei_repro_spoiler.htm

I have an IE one that's never been mounted or painted that came with my car, which I should sell.   I think I'd prefer to do some kind of duck-bill spoiler, if anything.

http://www.iemotorsport.com/bmw/2002-body-chassis/02airdam.html

I'd have to tape together a box of some kind to ship it.  If anyone in the Portland area is interested in it, that would be easier.

Let us know if you find a kit, I don't know of one that's available now and I don't have any kind of shop set up right now.

Mulholland does not like blue 2002's.

 

Do I want to know what the rider was doing with the shovel at 0:35?

You'd think with all the people hanging around that at least a few would help the car roll back over a bit more gently.

That was painful to watch.  I imagine the tow truck driver would have told everyone to stay clear, and wouldn't care about any additional damage except to his equipment.

I hope you do make it to PIR, I'd love to see it there and get some photos.

What do you like for a 20-pin plug code reader?  We can't do the "stomp test" to read the codes like the e30 guys.  I'm looking for a used Peake Research R5/fcx or other inexpensive unit.

I'm in the market, but neither the included display or the accessory analog gage seem to have a rich/lean indicator that changes color, which I think would be helpful when evaluating your tune on the road.  I'm considering the Miller WAR chip for my M20, and it would be even nicer to have auto-tuning or datalogging, but I'm not quite ready to go to a standalone ECU.  Anything thoughts from those who have used one?

More than likely its not wired right from the back of the alternator had that problem one of the wires has to be connected cluster or it will not excite the internal voltage regulator until its reeved up

I believe you're right.  I found a detailed explanation of the problem from a Porsche 928 forum.  I'll have to poke around and see if it was never wired up correctly.  Fortunately, once I understood the behavior it's not a big problem.  I just let it warm up for a few blocks, then let it rev until the charging light goes out (3,800 rpm this morning) and the voltmeter jumps.  The headlights also get a lot brighter between 11 and 13.5 Volts.

#3, find your ETM. for your year of donor E30. 

 

http://www.wedophones.com/BMWManualsLead.htm

Wow, that's extremely helpful.  I don't know if I've ever had a car where that sort of information was easily available.  Every connector in the car and it's location.  I've bought a completed conversion and was dreading having to reverse-engineer it for any troubleshooting, but this should really help.  I've put over 1k miles on it in the past few weeks and haven't had any issues related to the conversion, except that the CSB outer ring seems to be cracked.

One thing that did bother me initially is that the car has a real volmeter and a red "not charging" light in the dash and when cold, the battery will drain (at around 11V) for sometimes several minutes before it jumps to 13.5V.  I thought the alternator or regulator was bad so I installed a new rebuilt one and got exactly the same behavior.  I've since figured out that it will start charging when the rpm first hits about 3,800, but once it kicks in it will charge at idle.  With a warm restart it seems to kick in at around 3,000 rpm.  I have a new Optima AGM battery in the trunk.  Can anyone confirm if this is normal charging behavior for the M20?

A spring is designed to compress a certain length for a certain load, cutting them won't change how much it compress when loaded, but your car will be lower.

Not exactly true.  Cutting a spring does increase its rate.  A coil spring works by torsion of the wire, so shorter wire length (or fewer coils) equals a stiffer spring.  A progressive spring increases its rate by having coils meet as it compresses, reducing the number of active coils.  The coils that meet become a spacer.

On the other hand, if you have a progressive spring and remove a coil that is already bound when the car is at rest, you would lower the ride height without otherwise changing the spring.  That may be possible with H&Rs, you'd have to look under the car.  I'd say that you're better off removing some length from the free coil end so that you do increase the rate.

Without a GPS you can always measure your actual speed the old-fashioned way, by timing yourself between mile markers.  Divide 3,600 by the time in seconds to get your average speed over the mile.

Very cool!  What's the story with the Calder-esque car with the lumpy hood?

I used a place called National Auto Shippers from FL to OR for my eBay 02 a few weeks ago.  They were one of the cheapest quotes.  They picked up the car three or four days later than they had said when I gave them a deposit, with very little notice to the seller.  I called while it was en route and could never get them to tell me where it was or when it would be delivered, other than "7-10 days from pickup."  Basically no customer service after the sale.  I did get a call after 6 days that it was 90 minutes away, so it's a good thing I was available.  One of the front tow hooks was torn off, which I didn't notice until later.  They had marked on the original inspection sheet something like "car picked up in rain so could not be inspected" which might have made it difficult if I had found any damage.  There was one very small ding in the roof which I also didn't notice until later, but I didn't try to pursue it.  It wasn't a great experience, but I'm happy with the car and it certainly could have gone worse.

A couple shots I took a few months ago on top of Donner Summit here in Truckee. Landed me on petrolicious.com so I'm pretty happy about that! Let me know what you guys think, I need as many photog tips as I can get.

Here are couple of photo tips.  The shots (especially the first and third) are underexposed, which is common when shooting things like a white car and snow.  The camera adjusts the exposure to an average luminance value equivalent to 12 or 18% gray, depending on who you believe.  You ideally want to adjust your exposure compensation (try +1 stop for a bright scene) before you take the shot, or correct it in post-processing afterwards.  I like the composition of the second one, although once you brighten it the sky is going to be blown out (white).  You took these on a bright sunny day, which is challenging.  Make sure to position the car so the visible surfaces aren't all in shadow.  Nice looking car!