The first exhibit is my saphire blau metallic '82 528e (build date sept. '81), currently with 198K miles (16K on new engine). Modifications include urethane upper control arm bushings, KYB gas shocks with Vogtland springs, Powerflex rear subframe bushings, front euro bumper (see below), and a swap of the entire drivetrain.
The original 3-speed automatic transmission coupled to the torquey eta engine was not a bad combination except for the lack of top end HP. Well, now I have changed it into the car BMW shoulda' woulda' made. It all started in 2006...
The first order of business was converting to a 5-speed manual. For the conversion I took most parts from an '84 325e
The driveshaft came from a manual '88 528e. I got the tranny crossmember and shifter boot new from the dealer (both are cheap items). I used a random spring I found in my toolbox to help the clutch pedal come all the way up. And to hold the rear of the shift console up I bent a piece of sheet metal, drilled a bolt hole, rivetted it up in the tunnel, and fastened it to the console with a rubber donut in between.
I replaced the 2.93:1 open differential with a 3.73:1 limtted-slip from a 325is. The only hang-up was that my old diff had not only the early style centered mount, but the cover was slightly longer on the bottom. Rather than risk oil leaks I bought another ('83-'84 I think) e28 cover to put on the new diff. Later on I changed to a 3.46LSD for lower revs on the highway (and 30mpg!)
So where does the extra power come from? The new engine has a 325i cylinder head, intake manifold, and throttle body (plus associated plumbing). Connecting the ICV (in the old location) involves some hacked hoses and tape :) The engine also has custom ROSS pistons which are the same volcano shape (dish within a dome) as stock 325i pistons but with added compression height (1.5mm IIRC) and 0.5mm overbore. Plus I made two changes to the fuel injection: a 3.0bar pressure regulator and a modified EPROM for my 007 Motronic box
I wrote up a page with some info on the early motronic but I was ultimately unable to figure out how to get past certain limitations
Tests on a chassis dynamometer showed the air/fuel ratio leaning out at full power, and rapid loss of torque after 5K RPM. This setup also had an annoying dead spot at 2K RPM due to lean AFRs. So, after six years with hacked Motronic, I converted to MegaSquirt.
The ECU is a V2.2 PCB running modified MS1Extra high-res firmware. I have modified it for better interpolation between RPM bins in the spark advance table. (More mods in the works!) In order to get it going on my engine I had to add the 60-2 trigger wheel from the 325i, VR sensor, and an intake air temp sensor. I also replaced the single wire o2 sensor with a 4-wire (heated one). Everything else remained the same (although later I replaced the AFM with a straight pipe)
Now there is more power and better efficiency.
here is a pic from when I was first getting it going
and the circuit I used to convert switch positions on the stock TPS to voltage levels for the ADC in the MegaSquirt
This is my "custom" body work which consists of a euro front bumper, the later US front valence, and $5 autozone turn signals. At first I thought it looked a little funny but it has grown on me and now I can barely stand to look at e28s with the stock super bumper.
I made a pair of mounts like this for the bumper (the BMW mounts and associated doodads really add up if you buy new).
My previous 3ers (an e21 and e30) having been killed by rust, I've moved on to this '80 320i.
The floor was rusted due to a leaky windshield seal letting water in. Inside the trunk was a bit rusted also, but the car was otherwise much cleaner underneath than the others. I did a half-assed sort of paint job on it (but at least I removed the trim unlike whoever did the last one).
I swapped in the engine from my e30, a 2025cc M10 with L-jetronic.
AC compressor is gone so the battery was moved across to make room for the AEM cone filter. I welded an extra alternator mounting arm to the side of the car for attaching the AFM. I used the alternator and starter from a 533i. Note the adjustable fuel pressure regulator and the red lever for idle speed control.
I converted the M10 to a distributor-less ignition using the Megajolt Lite Jr. control unit and Ford EDIS ignition module and coil pack. Since I am only using the outer-most row of my crank pulley, I welded a toothed ring from trigger-wheels.com to the inside lip of the second row. The VR sensor mounting bracket was fabricated from scraps and attached to the bracket that holds the PS pump on an e30.
Here is the ignition map I have been using since 2011.
I also replaced the small 45mm throttle body from the 318i setup with a 50mm 325e throttle body. I had to modify some stuff but it wasn`t too complicated. (318i TB on left, 325e on right)
The e21 suspension has been modified with Bilstein sport shocks, stiffer springs (cut springs from other cars, roughly double the stock rates) , urethane rack bushings. Eurometric swaybar/control arm bushings are currently waiting to go in.