i currently have a fully rebuilt remote change box and 3.4 diff with comp diff pin.

i was thinking of running a 2.9 FD but keeping it together with close ratios and using a quaife ATB LSD

where do i get the gears from and how much are they?
straight cut or helical?
do i buy them as a set or replace individual gears on my set?

will i need to run an A+ or rod change box?

-thanks

If you mean close ratio gears for racing, not just Cooper S ratios, they are all straight cut these days.
Minispares sells them, so do Minisport UK I think.
You can get em for 3 synchro, 4 synchro remote or rodchange, or A+ boxes.
You will have trouble getting off the line with a 2.9 diff in it.

If you mean Cooper S ratios, you just change the 1st motion shaft and cluster gear in your box.
Karcraft sells them, so do most Mini places. Or bring em in from Mini Spares UK.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

is the 2.9 diff on the cards because you want to drop your revs for cruising?

close ratio gears just lift the ratios for 1st, 2nd & 3rd, and put less of a change in engine speed between them, top gear remains 1:1. So when you go to a 2.9 diff, your 1st gear is already taller, and a CR 1st gear makes it taller again. Higher speed, less kick in the backside

Stock ratios: 3.64, 2.18, 1.42, 1 ; Close ratio: 3.32, 2.09, 1.35, 1.

taken from here: http://www.minimania.com/web/Item/c-ajj ... Detail.cfm

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did I tell you that I won a trophy?

ahh i did not realise c/r gears would make it worse with a 2.9.

what do you think about a 3.2 with c/r gears?

what is your feeling about cooper S ratios vs aftermarket?
i dont think i can handle the noise from straight cut gears but will my helical gears survive my 100+hp at the wheels?

i am also thinking of binning the re-13-T for a sw5, so that might help me get off the line?

i know im asking a lot of questions but thanks for your help

willy's recommendation:

Stick with a 3.44 or 3.2 if you really have to : 1 ratio diff.
Combined with the close-ratio gears (Cooper S or nearest equivalent), you'll not be revving the ring off it on the highway and it'll still give you great pickup from down low... well, I assume. Who knows what the motor is like to drive, irrespective of the gearing ratios.

Yes you will be fine with the "100+" horsepowahhhzzz going through the helical gears. It's torque that shears teeth of gears. And arsebean driving.
I know which one you have a lot of

Put the SW5 in if you want it to behave like a "normal" car, but... where has all the fun gone?!

my suggestion is to give GR a call and explain what you don't like about the RE13, the way you like to drive, and he might have a good suggestion for an alternative...

he and I came to the conclusion that RE13 doesn't suit my driving style... so I've got a different cam now

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did I tell you that I won a trophy?

im gonna fit a megajolt also, this might help get the idle to work.

otherwise the re-13 is fine. and i'd guess it would work a lot better with close ratio gears.

as it is now, my 1st gear is almost useless so i'd love a longer 1st gear.

i'll have to have a chat with my mechanic about what he can do

thanks guys

100Hp -->At The Wheels??? that will pull a 3.2 no problem,,, but a 2.9,,,Mmmm i`d say you`d loose tooo much of that grunt with a 2.9 & it won`t want to rev out well enough in top gear

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Helical gears are stronger than straight cut gears...... the have more surface contact, than straight cut gears..... They do zap a little HP but so does being fat........

There was an Nc Mini running here in SA that ran a coopers S ratio helical gearbox and holds the Nc Mini lap record......... and that time was set six odd years ago..............

Keep the RE13, just learn to drive with it.....

This site has a great little caclulator for playing around with gearsets and diff ratios....

http://www.guess-works.com/Gearbox/Technical/ratio.htm

Will show the effects of speed @ x rpm - but not about how well it will start off the line.

it will - from what I experienced sticking it straight on an NA RE13 it gave it a lot more driveability at low RPM

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did I tell you that I won a trophy?

great this sorts out all the questions i had.

i think i should go with a 2.9 diff but retain my std gears.

this will give almost identical 1st, 2nd and 3rd ratios to a 3.1 with close ratio gears but give a slightly longer top gear.

in 4th:
at 60kph it will be 1950rpm and at 100kph it will be approx 3150rpm

the 3.1 with c/r is 60kph=2000rpm and 100kph=3350rpm

btw i am running 165/70 R10