17 replies to this topic

[pistin broke]

whats the differance between a close ratio and a normal one.
are they better and why.cheers

[Jackman]

Similar line, can a close ratio be used on a road car or will it be hard to drive?

[Jammy]

As I understand it a close ratio gearbox is one where the gears are 'closer' together. What I mean by that is where a standard gear will hit a speed at a certain rpm, if the ratios are closer together then it won't take as long to reach the same speed. I think close ratio gearboxs improve acceleration. I think Guessworks will be able to provide a better explanation.

[Guess-Works.com]

As Jammy says, and the clues in the name... the gear ratios are close® together...

The idea of the close ratio setup is that there is less of a engine speed change between gears going either up or down.. therefore, in theory, enabling the driver to keep the engine speed in the power.

I had started to write an explanation of close ratios, but it was getting complicated, but surfice to say... as 4th is set at 1:1 ratio in all mini gearboxes therefore to bring the ratios closer together 1st has to move nearer to 4th in terms of ratio, in a MK3 cooper or 1275GT CR gearbox the change is small, but in a clubman SCCR gearset its fairly large, I hope the picture below will show this...
This shows the RPM vs Speed of the three gearsets std, GT and SCCR and the RPM drop when changing gear @ 7000 rpm, notice they all converge in 4th or the final direct drive 1:1 ratio.

[Jammy]

So Set 1 is normal gears, set 2 is Mk 3 or 1275GT, and set 3 is clubman SCCR?!

[Jackman]

How Reliable are SCCR gearboxes, do they last longer than standard boxes or for not as long. Although dont think there is much point on a 998 with a stage 1. Apart from the noise.

[Jammy]

If your really interested in minimising power loss through the drivetrain then get SC drops and/or gears. The close ratio part is just down to preference/use. They are no more reliable/unreliable than normal gears.

[mattvallins]

There is less sideways load on a tooth in a straight-cut gearbox, so it is able to withstand more power and more impact (generally). They should last longer than a standard tooth if you are putting silly power through it. It also gives a better efficiency. However, its not likely that any gains would be noticable on a 998 unless its been REALLY tuned would think. The only difference would be the whole gearbox sounds like the reverse gear (which is straight-cut as standard). The noise must get annoying after a hundred miles........
Correct me if I'm wrong anyone with more knowledge than me in this? Thanks :tongue:

[Jammy]

It depends, some people (like me) love the sound of straight cut gears/drops. Although my car is just generally loud, but I can stand it on long journeys.

[Purple Tom]

sccr gearboxes sound awesome. I've done 450miles in my Clubby now with one, and the noise is LOUD! I think having no soundproofing and solid mounted everything doesn't help though.

Earplugs bring the noise down to less than a standard Mini, its just all you can hear then are your own thoughts, but there's nothing to distract you from the road, which is nice.

I'm hoping to get some film of the inside of my car soon, which might give you an idea.

[Jackman]

How loud is the SCCR gearbox?? If i get the gearbox now it will save me £250.

[Purple Tom]

I don't think the 'box itself is as loud as the drop gears - but it will be noisy. See if you can download a vid of a race Mini, that will give you an idea.

[Jackman]

I heard some at drag wars from the outside, as mine is a daily drive i dont want it to be too loud, i love the sound of first and reverse though.

[pistin broke]

:cheese: cheers every one for the help i understand a bit more now
thanks to you guys and the forum. keep it up CHEERS.

[Turbo Nick]

I've got a clubman gearset on my car and find it really useful on the roads, i reckon i'd find it weird driving a normal mini again now. I can actually use 1st gear now and dont have to change halfway out of a junction...lol

If you're after a crude idea of how a full SCCR box and s/c drops sounds with no soundproofing just download this vid (1.5mb ish) my mate took it on his phone sat in the co-pilot seat of my car. it starts off in first gear for quite a while, then you can kinda tell when the turbo kicks in
http://www.bud666.pw.../video-0002.wmv