Performance Chip/Modest Engine Mods for 83' 633 CSI

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jbmike
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Joined: Sun Apr 25, 2021 10:54 pm
Location: New York

Performance Chip/Modest Engine Mods for 83' 633 CSI

Post by jbmike »

I've pretty much finished all suspension and interior work on my '83 US 633 CSI and was wondering if there are any performance chips out there for this beast - I had heard the ECU for that year may not allow this but haven't opened it up to see if the eprom is soldered in or has a socket.

Was also wondering what the more common engine mods, if any, for this motor is. Not looking to turn it into a monster - just any additional power would be nice. Alas it's not an M635....

Any sage advice would be greatly appreciated.

TIA

Mike
marc79euro645
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Re: Performance Chip/Modest Engine Mods for 83' 633 CSI

Post by marc79euro645 »

I'm not sure how much you can mill off the heads, but compression is the biggest bang for the buck. I can tell you playing with the air/fuel won't add any power. If you can advance the ignition timing, that you can feel, but you'll be limited by knock to a few degrees max. Advancing the cam timing can improve bottom end response. You'd need an adjustable cam gear, but again you'll be limited to a few degrees, and if you go too far you can bend valves.I'd do an adjustable cam gear, and max head cut, and hope to add a little more power.
bakemono
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Re: Performance Chip/Modest Engine Mods for 83' 633 CSI

Post by bakemono »

When I got the head resurfaced (shaved .010") and put in a B35 cam, the dyno showed +5 HP and +7 torque. Piston to valve clearance was fairly tight but it has been eight years and I haven't had a problem.
'82 528e - M50B25 + GS6-37BZ
'83 633CSi - Megasquirt and a 3.46LSD
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Rambler1963
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Location: California

Re: Performance Chip/Modest Engine Mods for 83' 633 CSI

Post by Rambler1963 »

Besides doing head work the most you're gonna get for bolt up without going F/I is gonna be a B35 and motronic 1.3 plus performance eprom. The 3.2 is a small valve head and there's not much you can do with it. Also having a manual with lsd diff will help lol.
1989 BMW E34 535i
1996 BMW E38 750il
1983 BMW E24 633csi
1995 BMW E34 525i (gone)
1977 MBZ W123 240D
1951 DeSoto S15 Custom
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Rambler1963
Posts: 13
Joined: Wed Dec 15, 2021 7:52 pm
Location: California

Re: Performance Chip/Modest Engine Mods for 83' 633 CSI

Post by Rambler1963 »

Never-ending, found this on chipping 059/061 dmes. Still later then your 633csi but the closest I could find.

https://www.mye28.com/viewtopic.php?t=156241
1989 BMW E34 535i
1996 BMW E38 750il
1983 BMW E24 633csi
1995 BMW E34 525i (gone)
1977 MBZ W123 240D
1951 DeSoto S15 Custom
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