Yes V8's and big 6's shared the same large case diffs.
I like this little gear calculator to figure out speeds and rpms.
3.91 will be too high for the 540i tranny though.
Hi David,
I stand to be corrected here, but I think it is very dependant on the gearbox. The 6 Speed M5's run a 3.23 diff, which makes the first 5 speeds the same gearing as a 5 speed, 3.91 diff M5 (which always feels like it needs another gear on the motorway).
I would imagine a 6 speed 3.91 would scream!!
I've attached a spreadsheet I did to calculate gearing for a project I've got in mind. Hope it makes sense...
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Garry
1985 E24 M635CSi Arctic Blue/Pacific Blue Leather
1995 E34 525iT Oxford Green/Silver Leather
1990 E34 M5 3.6 Sterling Silver/Silver Leather (she broke my heart and then she left me...)
1985 E24 M635CSi Arctic Blue/Pacific Blue Leather
1995 E34 525iT Oxford Green/Silver Leather
1990 E34 M5 3.6 Sterling Silver/Silver Leather (she broke my heart and then she left me...)
I think that wuld be astonishing at the track.....
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'95 3.8 6speed ///M5
You wash your car like it was your firstborn child, you tend to its needs like it was your own body, you rotect it like it's your family, then you drive it like you stole it.
Hi guys , I am reasonably sure that a 3.91 5 speed M5 LSD will fit a 540i , although as I understand it , the 540I came with a 2.93 diff as standard .
What would the effect on driving characteristics of fitting the 3.91 to a 540i be .......does the 540i rev high enough to carry a 3.91 LSD ?
TIA .
D
I believe the 540 rev's to about 5800-6k rpm, so fitting a 3.91 will certainly limit in-gear speeds.
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Mike
91 M5 Alpine White II, Silver Gray 3/90 production
17x8/17x9 M system with PS2, 20mm touring roll bar; Ground Control Coilovers; EAT Chip, CD43; bmw/nardi blackline steering wheel, 3.8 Cam Gears
08 535i / 6 speed
Space Gray; Gray; Sport/Premium/Nav
00 M5 Ti Silver; Imola/black sportiv --Sold
Engine:
Supersprint Headers, Dinan CAI kit and MAFS, Throttle Bodies, Cams, Ported heads, Exhaust, Custom dinan software, Evosport Pullies, Dinan clutch and lightened flywheel; Ignition solutions plasma coils
Suspension:
Dinan Stage 3 with front and rear Strut Tower Braces, Beastpower Sway bar brackets, Dinan Wheels with 275/285 PilotSport, X5 Thrust arm bushings, Stoptech 355mm 4 piston front, 355mm 2 piston rear brake kit, Dinan 3.45 diff
Interior/Misc:
Eurodash, updated steering wheel, Bluetooth retrofit, Sirius Retrofit, hardwired V1, Widescreen Mk4 nav, M audio retrofit, Ice Link, BSW Stage 1 speaker upgrade, bmw towbar
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as stated as long as its a big case diff it should fit AFAIK.
HOWEVER, i researched into it a little bit and with the M60 V8 i think that anything over 3.46 will be too highly geared to be of any use when driving! you'll spend all of your time changing gear...
in the end i opted for a 3.15 LSd diff from an E32 750i - straight swap and the gearing is now set for acceleration more than the std lazy 2.91 diff.
i'm in SE london/kent, so if you're in the area you're more than welcome to come and have a go and see what you think...
its just about right IMO, quick enough to stay with my mates E36 M3 evo (probably dodgy ground on here , but i think it would *just* pip a 3.6 M5 in a drag) while not being TOO high up the gears when on a long run.
now everything is a bit more up the rev range, but its still driveable.
ok, for road use I agree with you guys.... but for the track, that 3,91 would be awesome
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'95 3.8 6speed ///M5
You wash your car like it was your firstborn child, you tend to its needs like it was your own body, you rotect it like it's your family, then you drive it like you stole it.
, but i think it would *just* pip a 3.6 M5 in a drag) while not being TOO high up the gears when on a long run.
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