What difference

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zaust
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Post Tue Feb 07, 2006 1:43 pm

Im currentley running a 63 lsd and it's mullered again, the people that
im getting to rebuild it say they have a 73 ratio slipper with a 60-70% lock done already but dont know the speed affects on the car. so theres my question. i do a lot of motorway driving so i thought the lower the number the longer the gear.???
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DieselMeister
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Post Tue Feb 07, 2006 1:57 pm

That's right.

Small numbers equals "taller" or "longer" gearing (i.e. fewer revs at a given speed).

I would have thought that 3.73 isn't a huge difference from 3.64. It should make your car feel a bit more spritely under acceleration though.

70% locking action under power is quite aggressive and would make power oversteer nice and prevalent :)
zaust
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Post Tue Feb 07, 2006 2:02 pm

when you say not much differece at the moment 3750 rpm= 100 mph
so would i expect to be at 4k @100 or higher ??
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Post Tue Feb 07, 2006 2:12 pm

Got to laugh... I'm doing 95mph @ 2500rpm... winkeye

Okay, so it's an E28 525e, but it's bloody good on fuel! Think it's a 3.1 something... can't remember.
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DieselMeister
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Post Tue Feb 07, 2006 3:40 pm

zaust wrote:when you say not much differece at the moment 3750 rpm= 100 mph
so would i expect to be at 4k @100 or higher ??
Possibly something similar. I don't know the exact gearing of the car per 1000rpm but you should be able to do a percentage increase (looks like a 2-2.5% difference in the gearing itself).

by way of comparison, I believe an E30 M3 diff is 3.25 (as are some E28 diffs I think).
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Post Tue Feb 07, 2006 3:44 pm

zaust wrote:when you say not much differece at the moment 3750 rpm= 100 mph
so would i expect to be at 4k @100 or higher ??
Mines about 4.5k at 100mph, in third, only joking. No idea what the ratio is. Makes cruising at 90mph very pricey. :(
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Post Tue Feb 07, 2006 3:45 pm

if you wanna get it exact, plug the details into this...

http://www.unixnerd.demon.co.uk/revs.html

you'll need your gearbox ratios and tyre sizes

to be honest 3.64->3.73 is not much of change at all. infact it may be difficult to detect any REAL change in acceleration :D
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