confused!!
Turbo Mini Forums

hello ivegot my engine nearly sorted out and now im starting on my geabox i realy dont no wat to do .hopefully my engine will be biteing the ass of 150bhp id like a gearbox that would withstand this power any advice would be appreciated..thanks

Edited by sausage-man on 29th Jun, 2010.

the gearbox is not the weak link its the drop gears so to speak............ well here goes .........................

if you are sticking with a standard helical gearbox thats fine, but you need to run straight cut drops then it will survive but the ratios are a little short

the second option is change the the ratios in the box for a minspares clubman set and get the ratios of nearly turbo metro challenge set, and then you can use the helical drop gears which would be more quieter than SC drops,

in both instances you need to use a minispares X pin diff outhewise power outputs approacing 130 bhp and over will shred the standard item

or you could use SC drops and the clubman set ............

the choice is yours ?
what ever work you do please renew all with new bearings if you want i can provide this service for you please PM me................... oh! and dont forget to fit a centrall oil pick up pipe in there, a must for the spirited driver

How do the helical drop gears survive with straight cut gear set if they dont with a helical gear set? what has changed?

Im confused

Other than me has anyone broke a helical drop?

anton has in a nat asp 1293.

Edited by Nick on 29th Jun, 2010.

pushing 150? i would be tempted to use straight cut drops, box, and at least a 4pin diff all from minispares

braking the box could lose you the whole engine

Edited by Brett on 29th Jun, 2010.

Yes i moved to the darkside

Instagram @jdm_brett

Edited by Sprocket on 29th Jun, 2010.

I was discussing this only the other night. Broken drops used to be a common problem in the past, even on low powered engines (50 to 60bhp).

But in all cases, every failed drop I have seen was on an A series with the smaller bearings. The later A+ larger bearing idler is a lot more resillient, as Robert has shown.

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

sprocket, by desighn the helical drops are stronger ......but its the twisting motion which starts from the primary through the idler to the first motion shaft and then on to the worn out bearing in the first motion shaft

which inturn places massive load on third gear and strips the third gear and the third gear head set,

because we ave a SC headset and third gear, the gears are unafected as theres plenty of room for them to move especially .....the new bearing helps !

i think robert on here has run for a few years 197 bhp and shed loads of torque with out any problems

hope this helps, we can now have a quite motor and the right gear ratios spending your money in just the right area

As nick said i mullered a set of helicals with abouth 70-80lb/f they were of the a+ variety.

Isnt roberts seperatly oil fed?

Out of interest, if helical drops fail, where do they fail ???

Is it the teeth shearing off, or a failure of the shaft/bearing/thrust washers (especially as the pre-A plus is a smaller shaft).

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

In my experience it's the idler bearings that fail leading to total failure

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

Yup thats what happened with mine.

I also belive the life of them could be down to the drivers style of driving... i.e. no mechanical sympathy.

Thanks both, I was hoping that would be the answer. (I've never seen a failed one yet....)

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

If something is worth doing, it's worth doing half of.

That was why I said it.

If something is worth doing, it's worth doing half of.