E28 528i LE-Jetronic

ed323i
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E28 528i LE-Jetronic

Postby ed323i » Sat Oct 16, 2010 3:30 pm

BMW E28 528i 1982 (Euro / German car) - M30B28 engine with CR=9.3, stock internals, free-flow exhaust manifold, M50B25 injectors @3bar, M30B35 VR-sensor and toothed wheel (front) from E34 535i (both bolt right on), Opel/Vauxhall V6 Bosch DIS-coil (bolted to firewall), no idle valve, M50 TPS sensor (made an adapter bracket), TechEdge Wideband 2J1, air flow meter is replaced by a 70mm diameter PVC pipe. The distributor, stock coil and electronics have been removed. I have reused the stock wiring (injectors, coolant sensor, ground) and added wires for TPS, ignition, VR and wideband.
Firmware: MS2Extra 3.0.3u

It runs great and really likes to rev a lot better. Midrange torque is much better also.
It does 0 to 100 km/h (62.1 mph) in 7.1 to 7.5 seconds. 0 to 60 MPH possible in less than 7.0s.
Stock 100 km/h time should be 8.4 seconds, but I haven't timed the car before I installed the MS2.

Here is one run, taken from MegaLogViewer (3.25 differential, 5sp Getrag transm. I:3.83 II:2.2 III:1.4 IV:1.0 V:0.81):
clutch drop 0s (1266,131s, 2500rpm)
6240 @1 3.18s (60 km/h)
3686 @2 4.02s (61 km/h)
5822 @2 7.0s (60 MPH = 96.5 km/h)
6034 @2 7.34s (100,3 km/h)
6399 @2 8.09s (106,3 km/h)

I'm still fine-tuning the ignition.. Fuel economy should still improve a bit. Last time it was 9 kilometers out of each liter of gasoline (21.5 US MPG). With a nice right foot I think 10 kilometers per liter (10 liters per 100 km, 24 US MPG) should be possible. On long highway stretches 27 MPG I guess.
The M50B25 injectors at 3 bar are not up to the job as I run into 96% duty cycle at high RPMs. So I should up the pressure to 3.5 bar. Luckily Porsche 944S2 has a 3.5 bar FPR that fits a Motronic fuel rail.

Overall: A great improvement in power! For a really nice idle it still needs the idle valve (now it's a bit too low cold and a bit too high warm). Economy has improved slightly I guess, but not as much as I had hoped.
I still have a minor problem with the wideband as it jumps to 18.9 when the AFR's drop below 14 for a while. After a short overrun fuel cut the wideband will recover. Not sure why this happens. The spark plugs look clean. Ignition seems okay; capable of sparks over an inch long.

Downloads:
MSQ File
MSL Log file (including 0-100 run above) and MSQ File in zip file
1982 BMW 528i MS2Extra 3.0.3u - MSQ file

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