3.0i gearing

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Flight
Joined: Mon 16 Sep, 2013 21:43
Posts: 87

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3.0i gearing

Post by Flight » Thu 05 Jul, 2018 15:25

I like my 3.0i immensely. I find it difficult to fault, it drives fine, handles well, it is quiet, smooth, slick gearbox, and is comfortable. All in all a very nice car. However my one gripe is that it should have had an overdrive to make long distance cruising more enjoyable. Just my thoughts. Could all who disagree form an orderly queue.
Cheers
Flight

Mike Fishwick
Joined: Fri 19 Jun, 2009 11:27
Posts: 2009

  Z3 roadster 2.8
Location: Daglan, France

Re: 3.0i gearing

Post by Mike Fishwick » Fri 06 Jul, 2018 08:31

A friend fitted a six-speed gearbox from a 3 litre Z4, which gives about a 10% higher top gear. He is very pleased with it, and found that the only thing which needed modification was the front section of the prop shaft, which had to be shortened by 40 mm, a job which most prop shaft specialists can handle easily. It did not even need to be rebalanced. An effective and cost-effective modification.
A Z3 is not just for Christmas - it's for life!

Flight
Joined: Mon 16 Sep, 2013 21:43
Posts: 87

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Re: 3.0i gearing

Post by Flight » Fri 06 Jul, 2018 13:56

Thanks for that Mike, I will look into it.
Cheers
Flight

Howard Adams
Joined: Mon 10 Oct, 2016 16:39
Posts: 52

  Z3 roadster 3.0i

Re: 3.0i gearing

Post by Howard Adams » Sat 14 Jul, 2018 21:23

I completely agree, as the 3.0 has so much torque and I’m always wanting to change up.. That’s exactly why they fit a 6 speed to the Z4.
H

Flight
Joined: Mon 16 Sep, 2013 21:43
Posts: 87

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Re: 3.0i gearing

Post by Flight » Sat 14 Jul, 2018 23:20

Hunting around for a good six speed box, Can anyone tell me if it is the same make and layout as the Z3 box. That is having the shift pins on the top. I fitted the modified pins and Teflon bushes to my box, and the change is just about perfect, so I wondered if the six speed box might require a pin change.
Thanks
Flight

4wheels
Joined: Sat 24 Sep, 2016 20:42
Posts: 80

  Z3 roadster 3.0i

Re: 3.0i gearing

Post by 4wheels » Sun 29 Jul, 2018 21:24

hate to dissagree, but i do lol.
its only doing 3000rpm ish? at 70ish mph isnt it?
so its just responsive at speed... which is nice :)

apart from that your right.. its nearly perfect!

malcolm manser
Joined: Mon 06 Sep, 2010 10:23
Posts: 30

  Z3 roadster 2.8
Location: presteigne

Re: 3.0i gearing

Post by malcolm manser » Tue 18 Sep, 2018 17:22

Would make a further point. The tiptronic automatic gearbox fitted to the 2.2 and 3.0 models from late 2000 gives you a much higher 5th gear . I am doing just over 2000 revs at 70 mph. Everyone says avoid the auto, but this was my main reason for changing from a manual 2.8, which was revving like an MX5 at motorway speeds.!

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6414

  Z3 roadster 3.0i
Location: Johannesburg

Re: 3.0i gearing

Post by Southernboy » Thu 20 Sep, 2018 13:10

You could look at the diff ratio. Fitting a longer ratio diff will work through all the gears. I particularly dislike 1st gear being too short - it's more like a truck than a car and with the fan roaring it sounds like one too...
I have fitted a 2.74 : 1 diff which allows 1st gear speed to go up to just under 75kph before 2nd is required - I have managed 80kph but that also requires the redline revs.
5th is hugely more comfortable and although the rpm is down only by 250'ish rpm, that seems to still allow sufficient power for acceleration in 5th.
Basically the diff ratio means that for every "x" times the engine turns the wheels turn once. So a 4.2 : 1 diff would mean 4.2 revolutions of the engine for 1 revolution of the wheels.
That would give you great acceleration, but very short shifts required between gears. If you look into the diff thing, you will find many of the BMW automatics are fitted with 4.2 ratio diffs. They have radically different gearbox ratios too which compensate in the 1st / 2nd / 3rd gears.
So, I think standard diff ratio on the Z3 manual boxes is 3.14 :1 which means your engine needs to turn 3.14 times to get 1 revolution on the back wheels.
Finally, you can also fit cruise control to the car.. Makes driving long trips a breeze..
"Normal is overrated"
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4wheels
Joined: Sat 24 Sep, 2016 20:42
Posts: 80

  Z3 roadster 3.0i

Re: 3.0i gearing

Post by 4wheels » Sat 22 Sep, 2018 23:38

means the gearbox output flange turns 3.14 revs for each wheel rev.
not engine.
4th gear is usually 1:1 and then geared down a further 3.14 at the wheels.
but the right idea :)

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6414

  Z3 roadster 3.0i
Location: Johannesburg

Re: 3.0i gearing

Post by Southernboy » Sun 23 Sep, 2018 07:23

:oops: ......... YES..
"Normal is overrated"
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