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#1 Sunbeam

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Posted 25 July 2020 - 06:29 PM

Hi all, can anyone advise me as to what diff ratio to use. I’m fitting a 998 a plus to a mk1 . I’m going to fit a stage 1 upgrade, hs4 carb , maniflow exhaust and port the valves. I want to keep the 10” wheels and fit 7.5” discs. Any advice appreciated.

 

D45AE931-0966-4C39-8B32-469FF50A9BB9.jpeg

 

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#2 nicklouse

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Posted 25 July 2020 - 06:35 PM

what is in there now?



#3 Sunbeam

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Posted 25 July 2020 - 06:40 PM

850

#4 Moke Spider

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Posted 25 July 2020 - 08:08 PM

I'd suggest a 3.44 or if you don't do much motor way driving, a 3.6.



#5 Cooperman

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Posted 25 July 2020 - 08:29 PM

+1 on the 3.44:1.



#6 Sunbeam

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Posted 26 July 2020 - 08:18 AM

Thanks for the info. Any idea on what speedo drives I would need or where to find out? Thanks again.

#7 nicklouse

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Posted 26 July 2020 - 08:51 AM

Read this http://www.guess-wor...Tech/speedo.htm

Then pit the info into this http://www.guess-wor.../Tech/ratio.htm

And it will tell you what is needed.



#8 Moke Spider

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Posted 26 July 2020 - 09:10 AM

Thanks for the info. Any idea on what speedo drives I would need or where to find out? Thanks again.

 

I think you'd have a 3.7: 1 ratio now, with a 6:17 Speedo Drive.

 

For a move to a 3.44 FD, you'd likely go to a 7:17 Speedo Drive

For a move to a 3.6 FD, you'd likely go to a 7:18 Speedo Drive



#9 unburntfuelinthemorning

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Posted 26 July 2020 - 01:12 PM

For a 998, 3.44:1 is a great all rounder but 3.76:1 is good fun and it'll still do 70mph all day.  Depends on your priorities.



#10 Minigman

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Posted 26 July 2020 - 02:13 PM

3.76 in a 998 is great but will be higher revving and noisier at motorway speeds. If you want something that accelerates well and is fun to drive on the B roads then go with 3.76. If you want something to munch miles at 70mph 3.76 can be wearing so 3.1 maybe better. 3.44 is a good all rounder. All depends what you want from the car.

#11 goudoogje

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Posted 27 July 2020 - 01:49 PM

I think this is very personal, i personally don't like anything above 3.1, because of the noise on the highway.



#12 Minigman

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Posted 27 July 2020 - 06:40 PM

I think this is very personal, i personally don't like anything above 3.1, because of the noise on the highway.


But any ratio higher than 3.1 kills 998 acceleration. Even 3.1 takes the edge off quite a bit. Better with a lower 3.44 or even lower for acceleration but it does depend what the use is.

Edited by Minigman, 27 July 2020 - 06:44 PM.


#13 Cooperman

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Posted 27 July 2020 - 07:26 PM

To put some perspective here, the original 850, the 997 & 998 Coopers all had 3.76:1.

The original 1071 'S' had a 3.76, whilst the 1275 'S' had the 3.44:1. The 'S's had a higher 1st, second & 3rd gear though which needed a fairly low FDR in order to get a really good 0 - 60 time.

It does need to be remembered that we are talking about an over-60 year old basic design here and the Mini is 'retro' driving at its best. Don't be afraid to rev them a bit, it's what they were always intended for. In the '60's we used to cruise our 998 Coopers and 'S's at 80+ mph, which was usually over 5000 rpm. To think, we did this all day long on a journey. That is what classic car driving is about.



#14 Sunbeam

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Posted 28 July 2020 - 06:39 PM

Thanks all, gives me something to think about!




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