e30 325i with 3.91 diff
Moderator: martauto
Hi Guys
I have a 3.91 diff in the garage and have been contemplating fitting it this weekend. My car is stock standard and drive about 100km to work and back. Would this diff cause the revs to run ridiculously high while cruising on the highway? Currently at about 120kph in 5th, i'm doing round 3000+/- rpm
I have a 3.91 diff in the garage and have been contemplating fitting it this weekend. My car is stock standard and drive about 100km to work and back. Would this diff cause the revs to run ridiculously high while cruising on the highway? Currently at about 120kph in 5th, i'm doing round 3000+/- rpm

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Ziggy
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They won't be ridiculously high, but they will be higher (assuming you've got a 3.64 at the mo? Can't be bothered to work it out from your figs!). I've got a 3.91 in mine (& they were standard on the facelift 325i sports) & it's fine, but you'll probably notice the extra fuel you'll be using... Can't say I'd really recommend it if you spend a lot of time at high speeds!
E30 in need of wiring loom smoke since April '11...
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cliffybabe
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ive og t a 3:91 dif on my cab and im well pleased with it 

Considering Selling the Cabby, looks like its gonna go
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Ziggy
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So am I!cliffybabe wrote:ive og t a 3:91 dif on my cab and im well pleased with it
But if I had a 60 mile drive to work on the motorway every day, I'd stick a 3.64 back on...
E30 in need of wiring loom smoke since April '11...
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cliffybabe
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thank god mine only a weekend carZiggy wrote:So am I!cliffybabe wrote:ive og t a 3:91 dif on my cab and im well pleased with it
But if I had a 60 mile drive to work on the motorway every day, I'd stick a 3.64 back on...

Considering Selling the Cabby, looks like its gonna go
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spence_star
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whats the difference in ratios with an open diff?
Returned after many years out.
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Ziggy
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Don't understand the question really...spence_star wrote:whats the difference in ratios with an open diff?
E30 in need of wiring loom smoke since April '11...
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spence_star
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ok, because i got an open diff, and all i know is it dont save you if you lose the back end. i am not sure what ratio i am running.
Returned after many years out.
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cliffybabe
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very goodGDBN wrote:Weekend car - which you spend in the boot ...
It keeps tent costs down

Considering Selling the Cabby, looks like its gonna go
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Ziggy
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Ok... well nor will a LSD, but anyway... what's the question?spence_star wrote:ok, because i got an open diff, and all i know is it dont save you if you lose the back end. i am not sure what ratio i am running.
If you want to know what diff you've got, have a look at the tab on it, or at least tell us what car you've got!
E30 in need of wiring loom smoke since April '11...
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Ziggy
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Ah, so there is some point to all the cr@p they fit on Pimp My Ride - you should apply Cliffy!GDBN wrote:You should install a coffee machine in the boot so next time you can have a coffee while waiting for help.
E30 in need of wiring loom smoke since April '11...
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cliffybabe
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Ziggy wrote:Ah, so there is some point to all the cr@p they fit on Pimp My Ride - you should apply Cliffy!GDBN wrote:You should install a coffee machine in the boot so next time you can have a coffee while waiting for help.

Considering Selling the Cabby, looks like its gonna go



