Mini gearboxs
Turbo Mini Forums

Hi guys... quick question what gearboxs are you using under your turbocharged minis?? And what power are you making??

Trying to decide what to do with my gearbox...
Thanks in advance 😀

On my road car, running 10psi and making at a guess 110 it's totally standard. Up to 130 bananas I be happy to keep it standard.

On my race car making over 180 I run the Minispares ST SCCR set. Never stripped a gear, but eaten may baulk rings!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

generally people are mostly running the minispares clubman kit, and putting lots of oompf through it, certainly it will take 200 brake reliable as long as its built right.

as Will i use the ST abbingdon kit, which is pretty much the same but it includes a new 1st gear rather than reusing the std one as per the clubman kit, it might be slightly stronger or the same... i use it because Im ion a remote box so have to.

apart from that theres not really any stronger options, unless you go to a dog kit, bit then your looking at closer ratios so its not as nice on the road.

there is a new minispares helical kit which has wider gears thats meant to be stronger, but TBH whats the bearing side loading going to be...

Thanks for your replys guys... I only have a factory 1275 gearbox I don't have a factory turbo box will this be a problem. Or will mine be ok?? Il have a look at the clubman kit now

The turbo box was just a standard box, nothing special.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

I see ,that I didn't know.... not many turbo here in nz so not much info on turbo engines /boxes unless reading in a magazine..... I'm hoping for around the 120-140hp Mark so maybe itl be ok with a factory box then...just saw that clubman kit that seems ok.. So do you guys use just the standard diffs as Well??

No, an uprated diff with the turbo torque is pretty much essential. The standard diff can give problems in a normally aspirated 1275. The 4 pinion diff a good starting point.

Maybe for a start if I use a standard gearbox with a 4 pin diff?

I've managed to destroy a standard box with mine running perhaps 130bhp. I'm now running SC box with 4 pin diff however using helical drop gears

Edited by Rob Gavin on 20th Jun, 2017.

Just trying to get people's opinions on what to do...

Apart from the internals, if you haven't already (and assuming we're talking rod change boxes), try and source the later DAM5626 casing, not the early DAM2886.

The early ones with a four bolt 3rd motion shaft retainer plate have a habit of cracking around the bearing, so much so that, even for the standard engine, Leyland/Rover thickened the casting over the top of the bearing and deleted one of the bolts (the steel plate still has four holes but the casting only three).

And, as the others say, definitely a cross pin diff.

Otherwise I'm on helical gears but the early "A" sets in both my boxes, they have a shallower helix angle so are theoretically slightly stronger than the A plus ones.

Schrödinger's cat - so which one am I ???

I went with Minispares ST SCCR also and so far I have no issues with it.

If you are in NZ probably not many A+ boxes there, I'm in Australia and building a turbo 1275 but I've got an earlier rod change box, not a+, do people reckon I'll be right with jus a moderate increase in power on the standard pre a+ rod change, but with a cross pin diff? I'm probably thinking 120hp but that's just a guess.