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2.9 diff or not


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#1 pistin broke

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Posted 10 January 2006 - 08:23 PM

is a 2.9 diff any good i will be using it in a 1330 . I heard i will be good for top end
but slower on take off so i have trying to balance it out by using a lightend flywheel and back plate is there anything else i can do . The car is only for summer use odd nights and weekends :tongue:

#2 Guess-Works.com

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Posted 10 January 2006 - 08:32 PM

To be honest with a 2.9 you'll need as much intertia in the engine as possible, or you'll be flat out at crusing speed...

If you want to enjoy a mini, and are running normally aspirated, go with a 3.44... you'll not regret it..

And 4k @ 70's not that bad

#3 R1minimagic

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Posted 10 January 2006 - 08:44 PM

Its a good diff to go for if you have an engine with plenty of torque. Good for over 90mph in 3rd and at least 120mph in 4th

#4 pistin broke

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Posted 10 January 2006 - 08:59 PM

at the moment its been bored to a 1330 cooper rods and crank 1.5.1 rockers
md 266 cam 45 webers on a straight 6 manifold and a stage 3 head bronze guides
comp valves . them speeds sound good is there any thing i need to get them kind of results

#5 miniboo

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Posted 10 January 2006 - 09:08 PM

A honda engine??

#6 pistin broke

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Posted 10 January 2006 - 09:12 PM

tempting just cost and how to do it

#7 R1minimagic

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Posted 10 January 2006 - 10:00 PM

Nothing special, 100hp should be enough

#8 Guess-Works.com

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Posted 10 January 2006 - 10:35 PM

Its a good diff to go for if you have an engine with plenty of torque. Good for over 90mph in 3rd and at least 120mph in 4th

Yes if you like running @ 6.5K rpm constantly...

but the actual fact is you wont get there...

Example being the late coopers which have a 2.7 diff and they are absolutely hopeless...

2.9's should be reserved for the economy seeker, motorway driver and extreem Force induction motors, which have spades full of low for torque to pull the diff round..

at worst go for a 3.1, which will be 70 @ less than 4k.

But I stand by that the 3.44 is the best diff for a normally aspirated mini, unless it's a massive stroker.

#9 Jackman

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Posted 10 January 2006 - 10:44 PM

My 998 does pretty well on the 2.9 diff, however id does loose 22bhp in the process.

#10 minidaves

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Posted 10 January 2006 - 11:03 PM

i'll kinda disagree to agree, I like the 3.44 diff in a mini i like the 3.2 turbo diff, and like the 2.9 if running 1:1 sc drops and if the engine has a few bhp because it gives nice long overtaking gears. but for the overall i thing a 3.2 is the best comprimise and we are talking a mini here

dave

#11 minimanclive

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Posted 11 January 2006 - 07:43 AM

I put my 1275 engine together with a 2.9 diff, and while it was great on the motorway it was annoying around town. I was forever changing between 3rd and 4th.
That gearbox died and I put a box on with a 3.1 diff. It's so much more fun. much better in town, accelerates quicker. The downside is a few more revs on the motorway, but it overtakes much more easily now.

#12 eddyg

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Posted 11 January 2006 - 08:08 AM

all newer coopers have 2.9 difs don't they? cause i don't mind mine. IT lets u really get going in 1st. Anyways i am not really used to quick cars cause was only drivin a clio before and this seems quick eneough!!!

#13 mighty_mini

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Posted 11 January 2006 - 08:20 AM

Dilly has a 2.9 and i wouldnt change it for the world!

Acceleration in first was a bit poorer than the 3.2 ill agree, but nothing too noticeable.


The thing i find about the 2.9 is its very versatile, especially 3rd as you can either cruise at 30 or rake it at 90+. Like an automatic :tongue:


IIRC the Mini 25 had a 2.9, and that sucked. That was my mates first mini, and we both had 998's at 17. I would rape it bottom end, but that was it. once he had his momentum... vroom!




Dave

#14 eddyg

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Posted 11 January 2006 - 08:24 AM

yea its always nice when most people have to shift out of first you can keep your foot firmly planted!!!

#15 Wiggy

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Posted 11 January 2006 - 01:07 PM

I love the long second on my 2.76, but it is most irritating around town. Feels like I need a '1st and a half' gear. If you know what I mean.




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