BMW wheel bolt pattern

I see a lot of people looking for the BMW bolt pattern. It is as follows:


4 lug -> 4x100mm or 3.937 in. ---> All 4 lug BMW's all years


5 lug -> 5x120mm or 4.724 in. (chevy is very close to this) ---> All 5 lug BMW's all years


A four lug or five lug bolt cirlce is an imaginary circle running through the center of the lug holes. A 4 lug pattern can be measured from center of one lug to the center of the lug diagonally across from it. A 5 lug pattern is much more difficult to measure, due to the fact that the lugs are not equally opposite and would require a bolt pattern gauge.

Offset: The offset is where you run into trouble. The offset of a wheel is as follows: the distance from the mounting surface of the wheel to the true centerline of the rim. A positive offset means the mounting surface of the wheel is positioned in front of the true centerline of the wheel. This will bring the tire in to the fender well more. A negative offset will mean that the mounting surface of the wheel is behind the true centerline of the wheel. This will cause the tire to stick out away from the vehicle..

Most 5 , 6 and 7 series wheels will work on each other.
Early 3 series cars were 4 lug. The 3 series cars that are 5 lug, E36, E46 and E90, have a front wheel drive offset (negative offeset). This pushes the hub portion to the outside edge of the wheel and cause 3 series (5 lug) wheels to not fit on 5, 6 and 7 series cars. The back of the wheel will hit the strut before the hub surface makes contact. The 5, 6 and 7 series wheels will bolt onto a 3 series (5 lug) but tend to stick out and rub on the fenders (posative offset).

Here is a link to a bunch of factory wheels
http://picasaweb.google.com/BavarianAutoRecycling/Wheels#

M52 Dual Mass Flywheel

SO my new year started off with a Bang!! Right when I shifted from 2nd in to 3rd. BANG! We'll find out tonight what it was. I think my dual mass flywheel became 2 single mass pieces. The fly wheel has been shaking and chattering for the last couple weeks and I was hoping to get a lightened single mass replacement. No such luck right now. I'll just have to replace the one that's in there with another M52 oe flywheel. Hopefully it's not the transmission.

Late night update.....Dropped the trans out tonight in the driveway. Found out not only is my dual mass fly wheel bad, the car stopped moving because the center broke out of the pressure plate. Wierd! I haven't seen that before, the welds that hold the splined ring that fits over the input shaft on the trans, all broke. Maybe the vibration from the fly wheel caused it to break apart. I will post a picture of it when I get the pressure plate and fly wheel off tomorow.

All righty then, one week later and the E30 is back on the road. I ended up installing a 2000 528i E39 flywheel and self adjusting clutch. The pedal feel takes a little getting used to. Its's kind of soft. I didn't install the pressure valve on the clutch slave. I may add it later this week if I end up not liking the soft pedal.

It took me so long because of a leaky injector that wouldn't seat properly into the injector rail. I had removed my intake to make it easier to get at the starter and top trans bolts. Plus I needed to fix my pinched heater hose. I broke the bottom of the #5 injector when I popped it out of the intake and the replacement injector o-ring wouldn't seat into the fuel rail properly. What a pain in the ass.

I also have a clicking in my right rear axle shaft, so later on today I will be swapping that out. I guess this engine and injection set up is just a little bit to much for some of these old E30 parts. Luckily I can do most of the work myself.

E30 to E34 suspension

I have been getting a lot of hits to my blog from people searching for ways to upgrade their E30 suspension to E34 suspension. My guess would be to go from 4 lug to 5 lug. I haven't heard anything about doing this, but since I have access to the parts, I thought I would investigate. I went out in the yard and grabbed an E30 rear control arm and an E34 525i rear control arm. Just by laying them side by side I can say that if it is possible to use E34 rear suspension it would require some heavy mods.


For starters the E34 is 2 inches wider that the E30. Also, I don't know if you can see it, the E34 shock mount is on the top of the control arm. The E30 shock mount is on the bottom of the arm.

Finally, E34's use coil over shocks where as E30's use springs separate from the shock, so there is no spring perch on the arm. I suppose you could us a coil over set-up on your E30, but for the sake of argument, the perch is missing from the E34 arm.

As for the front struts, I don't think E34is going to work because of the different control arm set-up.





If any one has any more info on doing an E30/E34 swap, feel free to leave me a comment.

Tach

I changed out my Tach. Since my car is a 1986 325, I have the white backed gauge cluster, with a 5,000 rpm tach. I put in a 1984 318i tach which goes to 7,000 rpm. It still doesn't work, I have tried several wires to get it to work. I've been on R3vlimited. Checked my fuses. Checked wiring diagrams from the ETM. Still no signal. My economy gauge has been intermittently working.

I may try a blue backed 325i cluster this weekend.

I've got my fingers crossed!

**********************************UPDATE**************************************
I got my tach working. I kept my original cluster, and used the 84 318i 7,000 rpm tach. I connected a wire from the C101 plug under the dash to the solid black wire on the X20 plug. It works great! I also got my oil level senor working and my coolant sensor working. Now if I could just get my temp gauge working.

Dinan Chip 413 brain

Today I installed a Dinan Chipped silver 413 brain. After I got the exhaust put in and the O2 sensor connected, the car started to stumble and not idle very well. It probably needed to learn the car, but we had the chipped brain at work, so I used it. Now it runs great.



A comment on the red vs. silver 413 brains - the silver brain is found in all the EWS equipped cars. However, you can get silver 413 from a Non-EWS car if the brain has been replaced by the dealer. New 413 brains have a silver sticker EWS or Non-EWS. Red is the safe bet, but if you know the production date of the car, a pre 1/95 silver brain will work.

You could use a 506 brain from a 95 M3. I read that this is a learning brain. It makes adjustments on air to fuel mixture based on O2 sensor readings, where the 413 can only make small adjustments. I think the 506 only came in the pre 1/95 M3's.




No tach yet. I can't figure out which wire to hook up. I guess I'll hunt it down this weekend. I made a split harness to try and use the 528i dual temp sensor. I made a pigtail for the oil level sensor since I used the E36 injection harness instead of the E34. I got the bracket from the E30 318i to make the injection brain bolt up.

I see quite a few people searching for Dinan chips for other model cars. It is my understanding that any car 1996 and newer cannot be chipped. You will need a programmer to download the info or a lap top. Here in Sacramento, Shatz and Krum is a Dinan Distributor.

New Exhaust

I took the car over to the Exhaust Shop today for a custom exhaust. Drove it yesterday for the first time. What a difference in power!

I had the exhaust guys use a stock muffler assy and put a custom head pipe with a Magna Flow high flow cat. Sounds a little tinny, but not bad.



I had to take the car back to the muffler guys again. I couldn't get the O2 sensor out, with a pipe wrench and a 4 foot cheater bar. And the sensor was hitting the fire wall. The muffler guy cut it out, turned it and installed another O2 sensor for me.

Sunday Night

It's Sunday Night and I'm spent. The motor's in and running, started up today for the first time. It would have started Saturday, but I left the unloader positive cable off the starter. I took it out for a hot lap tonight without the exhaust. Man is it L-O-U-D!!! After work tomorrow I hope to hang the exhaust, bleed the brakes again and bleed the clutch.



I still have a lot to do, but it's driveable.




















Tune in for more as it happens

Brett