New gearbox design
Turbo Mini Forums

How much would you pay for a road going 5-6speed in sump gearbox for the a-series?

I see no reason for a different gearbox, the std one is fine	5 Votes - 0%
i still break metros for engines and will ignor the fact they are rapidly decreasing	0 Votes - 0%
pleanty of spares for the originals and will stick with that	0 Votes - 0%
i want a better gearbox, but even £1000 is too much for it	2 Votes - 0%
i want a better gearbox and will pay upto £1000 for one	5 Votes - 0%
i want a better gearbox and will pay upto £1200 for one	2 Votes - 0%
i want a better gearbox and will pay upto £1400 for one	1 Votes - 0%
i want a better gearbox and will pay upto £1600 for one	2 Votes - 0%
i want a better gearbox and will pay upto £1800 for one	0 Votes - 0%
i want a better gearbox and will pay upto £2000 for one	2 Votes - 0%
i want a better gearbox and will pay upto £2500 for one	0 Votes - 0%
i want a better gearbox and will pay upto £3000 for one	0 Votes - 0%
i want a better gearbox and will pay over £3001 for one	0 Votes - 0%

I've seen the future and tbh its Pie

if you add...

"I'll pay a reasonable and fair price if you can supply an unbreakable 5 speed when fitted to an A-series"

Oh, that can keep a 3.1 diff, and have a decent strong LSD.


Then I'd choose it.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

need to also clarify if we're talking synchro box here - there is already a few 5-speed dog boxes aren't there?

I concurr with Steve's unbreakable comment aswell LOL!

I think the answer to the question is none of the above. Mainly due to the fact there are so many different a-series engines in different states of tune.

You may be better off asking how much would you be willing to pay for a gearbox that can handle x amount of curlys. Therefore people can judge if the expense is worth while or it is well over spec'd for there engine.

I for one would pay good money for a gearbox if I had a 16v a-series turbo, but i wouldnt pay more than £1200 (straight cut x pin diff plus drops) for a 140bhp engine for example. You need to pitch it at a market not just the greatest ever gearbox as everyone will have different requirments.

eg tall first gear for the drag strip but less so for hillclimbing etc

mmmm, I reckon somthing simmilar to swiftunes gearkit would be good where you can change/replace ratios ( multipeice laygear)
but with syncros.

as well as that perhaps something like layshafts that have replacable bearings that go in the gear case (like in the 5 speeders?)

just a couple of ideas...

Multipiece laygear sounds cool...

Mine has the Tran-X kit, and I ended up having to replace the laygear and 2nd gear after stripping some teeth.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Unfortunately I had some problems with this poll, as the above mess clearly shows. Anyway, to elaborate a little further on my current progress plans and suchlike...

About a year back I suddenly became aware, after discussions with several others, that the problems with the a-series are going to come to ahead not with the lack of blocks (now that there is the option of re-lining to std from 73.5mm bore) but with the lack of gearboxes which seem to be dieing a death at a rapid rate with dropped diff pins and stretched/knackered casings. That’s the problem as I see it. We'll not quiet, as there is also the fact that even if you do have a good box it'll drop dead (with synchro, bearing, lay shaft problems) when you put more power through it anyway.

By this point I had already decided, and had made progress, to design and build my own gearbox, but in light of this revelation I pondered upon the possibilities of building 'a few' in the hope of solving a common problem. This is not a profit motivated thing, as I am well aware that there is no (or very little) profit in such a product.

The brief for my own gearbox is to make it a road going box with 5-6 gears, in the same place as the original box, but with a completely different internal design - i.e. properly supported shafts so it could survive with my potential 160bhp 16v motor above it for a reasonable mileage. It would have a more robust synchromesh and helical gears (not that the latter would really make much difference).

Those of you who have built/understand the mini gearbox will realise what this all means and hence my question above. I have prices for having gear sets made up, shafts made up and bearings (as I’m going to build myself one anyway). But the list is hardly everything that’s needed, in fact it’s probably half.

At this point I need some help as I’m not sure what people who are prepared to spend some money on an engine (i.e. people with 3kish engines or more) are prepared to spend on a gearbox. I wouldn’t ever imagine marketing it to people with stg1 1275's budget engines as they'll want the world in a gearbox for less money than a cheap s/c gear set.

Thoughts and comments welcome.

Edited by andeh on 29th Sep, 2006.

I've seen the future and tbh its Pie

Aside from that 1 incident where I broke a tooth ( and of course cracked casings )

The Tran-X kit stood up very very well against my car, I drove it for some 50-60,000 miles when turbocharged, and a lot of them were quite abusive miles. There wasnt a day went by that didnt see me hit WOT several times.
Perhaps lack of traction helped the box though ?

I would hazzard an estimate that I was making around 180bhp or thereabouts, with what felt like quite a bit of torque too. I think I could safely say more torque than a n/a 16v A-series will ever produce.

So if your intention is to build a box that will only handle 160bhp....

Is it really that much better than what is already available ??

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I'm not 100% sure I agree with you on the lack of decent transmission casings compared to blocks - 998's are still providing us with many casings - and even Mpi's - both of which have blocks of little / no use to the majority of us.

Personally - I think the ONLY way to build a pukka synchronised 5/6spd transmission is by not constraining yourself to the current casing. Increasing the centre-distance of the transmission by just 10mm would make a MASSIVE difference to bearings and gear life/strength for example. You can't do that in the current casing however.

Why not go the whole hog and switch it to a driven layshaft transmission whilst you're at it? That way you could do away with the idler gear train replacing it with two larger (correctly designed) helical gears instead?

And then - who the hell wants to shift with a stick anymore? Automated shifting is the way forwards. I'd have thought if you made an electronic sequential fingertip - OR - manual lever'd bang-bang sequential shifter that just connected to the standard transmission input, those would yeild more interest (I've looked into this in the past, but didn't have enouigh experience back then to complete it :( )...

Then again - perhaps what peeps WOULD pay for is a properly engineered 4-spd synchro box - that instead of costing £260 - costs £1000. It would have fine-pitch helical CBN ground teeth; suitable bearings; A complete modern synchro pack - maybe something like a twin/triple cone unit pulled straight from a Corsa transmission for example?

Another option is to use a current (OEM) transmission mainshaft assembly (gearing/synchros/bearings) 'as is' but modify it to fit in a new casing to suit the mini?

Take any relativly modern FWD driven layshaft trans like the F20 for example... Only real problem is the ratio's are probaly too wide for most folks - BUT - that is for future development?




However...
Just consider all the hybrid conversions in our favourite little cars( does ANY other car in the world have this many pukka kits to fit so many different engines from other manufactureres I wonder?)?
Surely the time has come - and gone - for major changes, especially something that would cost more than you could transplant a more powerfull OEM engine/driveline for?

I'm not poo-pooing - and will offer my experience of transmission design if you needed it; I just think that there isn't enough demand to warrant the effort to do something that is actually 'worth' doing (if that makes sense?)

I've seen the future and tbh its Pie

I've seen the future and tbh its Pie

How do the ratio's from the biniS / Diesel / ST170 transmission look? This is a pretty recent and very sweet shifting transmission from getrag - which given their pedigree must be a stong, reliable basis?

I wouldn't be surprised if - as it's six - it uses a central wall - ie not too dissimilar to what you're thinking of... The abundance of S's means that they're pretty cheap aswell I'd have thought...

Sounds like you have a plan. As regards transmission housing; rapid casting technigues of today will be your saviour. Look up the units on www.prometal.com for more info.

Rebuilt....for gearbox related problems, aside from the incident, I dont actually recall replacing any gearbox parts, but it has been a long time since I was driving it. But I think I remember ok.

I broke a Withy 4 pin diff, which wrecked 1st gear and reverse, as well as the casing etc.. It was one of the original 4-pins. I replaced it with a Tran-X 4-pin.

I also broke some teeth off 2nd gear once, as mentioned.

So it was rebuilt on those 2 occasions, and I think perhaps another 3rd time, when I had things apart and discovered the casing cracked.

But the actual gearset itself, proved very reliable.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will