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What Final Drive


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#1 JXC Mini GT

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Posted 06 November 2019 - 06:46 PM

I will be having the engine replaced on my Mini fairly soon with the Minispares 1293 (ENG004) I will having the gearbox/final drive replaced at the same time with the Minispares MSG34 which has the same final drive ratio (3.44:1) as my current gearbox.

 

Grateful for views/experience on whether the 3.44 final drive is the best one to use, the car is not my daily driver and I would like to be able to cruise at 65-70MPH without the engine screaming its nuts off. The wheels are 5J x 12 fitted with 165/70 x 12 tyres.

 

I have had a look on the guessworks website but would welcome recommendations on the best balance.

 

Thanks

 



#2 Moke Spider

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Posted 06 November 2019 - 07:01 PM

Personally, I like the 3.44 as a good all rounder. I find they give long enough legs while still being 'nippy' at slower speeds.

 

I know the 3.1 and 3.2 are popular, but I found these ratios just that bit too tall around town, especially when running anything more than a stock Cam.



#3 alex-95

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Posted 06 November 2019 - 07:29 PM

I've got a 3.2 diff with my 1293 (kent 266 cam, kieth Calver GT head, 1.5 ratio rockers). I can't compare it to a 3.44 but I find the 3.2 a good all round ratio on motorways, towns and twisty roads. (especially as I had a 998 with a 2.9 diff in previously :lol:



#4 Stevie W

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Posted 06 November 2019 - 08:08 PM

I have a 3.1 diff in my Mini.

 

Engine spec is 1293cc with an SW5 cam and a Minispares big valve head, all running on twin 11/4" carbs and a stainless steel RC40 exhaust system. The 3.1 diff seems a good all-rounder with good acceleration in the lower gears and a comfortable (relatively!) 70mph cruising speed.

 

I think it was Mr Cooperman on this forum who said the good old A series will sustain high revs all day long, that's how older cars used to cruise on the Motorway!

 

I think the issue is most of us drive modern quiet cars with very efficient engines and when we get back in our Minis they're so noisy that we think the engine's going to burst at anything over 4000rpm.

 

My daily driver is a 1.6 i-dtec Honda Civic which is whisper-quiet at 70mph due to good soundproofing and a diesel engine that's barely doing 2000rpm at that speed!

 

After that long ramble, my vote would be a 3.1 or 3.2 diff.

 

Cheers, Steve.     



#5 nicklouse

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Posted 06 November 2019 - 08:09 PM

always ran a 3.44 on mine. 286 1380 with a selection of heads and carbs. would use the same today.



#6 Minigman

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Posted 06 November 2019 - 10:30 PM

I run two minis on 3.44. Both 10” wheeled. I wouldn’t go higher ratio than 3.44 with 12” wheels.

#7 Magneto

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Posted 06 November 2019 - 11:00 PM

I agree with those who prefer the lower RPM at cruise - but it depends on how far you're going. Here where I live in the States any trip is probably a good several hours so I found the taller gears are much better. I ran a 2:76 on my previous car and it was no issue running around town, and still had plenty of acceleration/ As it's not a track car it suited the car just fine. That was a 1360cc with a fast road came and little to no headwork - plenty of power to pull those gears running either 10's or 13"s.....I didn't have to downshift or lose speed on hills either - it was turning under 3500 at 75 mph. My current build has a 3:1 and I expect it to be a good compromise.

 

However, if your long drive is an hour or less, the 3:44 is fine and will not hurt the motor.


Edited by Magneto, 06 November 2019 - 11:01 PM.


#8 Cooperman

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Posted 06 November 2019 - 11:13 PM

I have always found the 3.44:1 to be about the best overall compromise.

Remember, these are old cars and the engine can be expected to need to be revved. Just over 4000 rpm at 70 mph is fine. You can't expect a car designed over 60 years ago to cruise like a modern hatchback.



#9 Zami

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Posted 07 November 2019 - 05:07 AM

I did a refresh last winter and installed a minispares 4 synchro, 3.44 rebuild, sw05, lightened flywheel, wedged crank, 1380 running twin 1 1/2s on a big valve longman head. I rebalanced everything including 4 wheel alignment and running sustained speeds of 4/5k is no problem and I have to say is smoother than I remember from the original 30 yr old build. I have put about 2000 miles on the engine this year mostly running 65-75 mph . I have to say and agree that 3.44 are the best all around.

#10 JXC Mini GT

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Posted 07 November 2019 - 06:33 AM

Thanks to all for your expert advice, I will stick with the 3.44 when it gets changed at the end of the month




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