1980 Euro 728i

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canada karl
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Joined: Tue Jan 06, 2009 3:50 pm

1980 Euro 728i

Post by canada karl »

Is there any difference between the M30 motor
in this model and the one in a 530i? Do they have the same ECU?
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
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Mike W.
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Location: Sonoma County

Re: 1980 Euro 728i

Post by Mike W. »

A Euro 728 would have a higher compression 2.8 engine, probably 9:1 instead of the 8.3:1 of a US spec 530i. About the same power but a touch less torque. The euro car might have a hotter cam and would have a different curve on the distributor, and of course would not have come with all the smog equipment that was on US cars. Different ECU, but I bet you could interchange them and they'd run just fine. Very similar engines, but not exactly the same.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
tlake
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Joined: Wed Feb 03, 2010 6:33 pm
Location: WA

Re: 1980 Euro 728i

Post by tlake »

Mike W. wrote: Sun Oct 23, 2022 12:41 pm A Euro 728 would have a higher compression 2.8 engine, probably 9:1 instead of the 8.3:1 of a US spec 530i. About the same power but a touch less torque. The euro car might have a hotter cam and would have a different curve on the distributor, and of course would not have come with all the smog equipment that was on US cars. Different ECU, but I bet you could interchange them and they'd run just fine. Very similar engines, but not exactly the same.
For 1980 model year in Europe the e23 7 series went completely fuel injected. in 1977-79 they had the single carb 728 & 730, and the injected 733i (3.2L). For 1980 it was 728i, 732i, 735i & 745i.

Euro 1980 528i/628CSi & 728i all used a 184 hp M302.8 with 9.3:1 comp ratio. The earlier Euro carb engines were 9.0:1. The higher comp ratio, and weight cutting program (thinner glass, hoses, panels etc) was all to boost fuel efficiency in the wake of the 2nd fuel crisis. Tachs even had a green segment, in the lead up to the pending swinging fuel economy meter needle. 8)
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