hello friends glad i could catch your attention, im looking to increase the compression ratio w/o swapping cylinder heads/ block. I heard that 2002, e12, and e21, could have there compression ratios increased because the diameter of the heads are relevantly suitable for the increase. has anyone tried this? what was the outcome and if it was a good thing to do, how do you go about doing it?
thanks for your time,
happy holidays
dont look at this topic
- JodyStevens
- Posts: 347
- Joined: Wed Sep 12, 2012 9:58 am
- Location: Nova Scotia, Canada
You won't be increasing compression without swapping something out! Pistons/block/head/rods/crank. Something has to decrease cylinder volume to raise the compression. I have no idea what configurations work and what don't, but there's no magical compression knob.
Also funny topic heading haha
Also funny topic heading haha
'78 Euro 528i Rubinrot Metallic. Who else has this color?
- CabbageFumes
- Posts: 337
- Joined: Tue Oct 21, 2014 7:07 pm
- Location: Funkytown
M30 heads are all about the same, with the exception of B35 heads, so swapping a head won't make any difference. To increase compression you need pistons. Sorry, just the way it is.
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
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
- Falkenberg
- Posts: 520
- Joined: Wed Nov 10, 2010 6:46 am
- Location: In Europe, far, far away.
The heads used for cars with the 4a1 carb are different, but I am not sure if the volume is smaller. I my case, I noticed that the shape of the combustion chamber of such a head was mirrored, and the head interfered with my pistons because of that.
You can experiment with pistons though. There are differences there.
You can experiment with pistons though. There are differences there.
1961 Simson AWO sport (Brasoveanca)
1968 BMW 114 2002
1976 BMW E12 528 (Malèna)
1987 Kawasaki GPz900r
1996 Moto Guzzi V75 PA NT
1968 BMW 114 2002
1976 BMW E12 528 (Malèna)
1987 Kawasaki GPz900r
1996 Moto Guzzi V75 PA NT
- Peter Florance
- Site Admin
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There was a thread on E12 group on FaceBook where someone came up with M90 head that had smaller combustion chamber volume.Mike W. wrote:M30 heads are all about the same, with the exception of B35 heads, so swapping a head won't make any difference. To increase compression you need pistons. Sorry, just the way it is.
I'll be damned if I can remember details.
Peter Florance
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
http://www.firstfives.org
mailto:peter@firstfives.org
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
http://www.firstfives.org
mailto:peter@firstfives.org
- Falkenberg
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- Joined: Wed Nov 10, 2010 6:46 am
- Location: In Europe, far, far away.
My head(ache) story is over here:
http://www.firstfives.org/bboard/viewto ... highlight=
I also posted on facebook, here:
http://www.firstfives.org/bboard/viewto ... highlight=
I also posted on facebook, here:
1961 Simson AWO sport (Brasoveanca)
1968 BMW 114 2002
1976 BMW E12 528 (Malèna)
1987 Kawasaki GPz900r
1996 Moto Guzzi V75 PA NT
1968 BMW 114 2002
1976 BMW E12 528 (Malèna)
1987 Kawasaki GPz900r
1996 Moto Guzzi V75 PA NT
increasing compression ratio
Just wondering. Can't a standard head be machined (is that called "shaved") to reduce the final volume and this would increase the compression ratio?
Jan
Jan
"Rusty" ' 80 528i 5 speed manual, 285k miles,
'98 528i Automatic, 120K miles...no name.
'98 528i Automatic, 120K miles...no name.