8 replies to this topic

[Nu2mini]

Just refreshing my memory of Mr Calvers old technical articles 

 

 

Injection Tuning

http://www.calverst....tion tuning.htm

 

 

 

in which he says

 

Aside from what’s been mentioned above, the single biggest improvement in the performance stakes you can make to your injected Mini is to haul the engine/gearbox out and stick a 3.44 final drive in it to replace the ‘brick wall’ effect 2.7 standard one. You really won’t believe the difference!!

 

Now I thought the standard ratio was 3.44 so has he got these two transposed and is he recommending swaping the 3.44 out for the 2.7.

 

It certainly looks interesting from a cruising perspective

 

 

 

[Fast Ivan]

standard ratio for the MPI is, as Keith has said, 2.7

[Nu2mini]

That's interesting.

 

Was the SPI also the same ratio

 

I must be reading Guessworks gearbox calculator wrong

 

http://www.guess-wor.../Tech/ratio.htm

 

He quotes 3.4 final drive as 'Most mini's and post 84 metros'

[Swift_General]

3.44 was the final drive for most post 84 minis - the MPIs only making up a small proportion of such cars. I think the SPI was 3.21:1.

[Mrpeanut]

3.44 was the final drive for most post 84 minis - the MPIs only making up a small proportion of such cars. I think the SPI was 3.21:1.

The spi cooper was 3.2 and the non cooper spi 3.1 I believe.

[Spider]

I know many guys like the taller (3.1 to 2.7) FD ratios but I have to say, while I have tried a 3.2 and a 3.1 I don't like them one bit, especially for around town. I couldn't imagine what a 2.7 would be like.

 

The car just looses it's responsiveness and 'nip-iness', especially if running a Cam, where you need to get the revs up.

 

Personally, in a 1275 engined Mini, I find the 3.44 the best all rounder, I'm quite happy with that to do me around town and for motorway speeds. If it's mostly for around town, then a 3.6.

Edited by Moke Spider, 25 June 2015 - 08:29 PM.

[Cooperman]

The old A-series engine needs to rev. It is not a modern engine and lower gearing is needed to extract decent acceleration. As 'Moke...' says, the 3.44 is super for general driving, giving around 16.5 mph/1000 rpm in top. Remember, 3.44:1 was the ratio of the original and superb Cooper 'S' 1275, whilst the 998 Cooper had a 3.76:1 as did the 850, 1071  & 970 'S' and Mk.2 998.

[Nu2mini]

Thanks all,

 

I'm sure it's currently standard, so I'll add it to my things to consider the next time I haul the lump out

Edited by Nu2mini, 26 June 2015 - 08:26 AM.

[Mini Manannán]

My car was getting on my nerves revving its proverbials off all the time (hadn't had the engine apart to find what the FD was) got it apart and it was all explained in the tooth count - 3.9:1  A 3.44 will be going in it this week.