Improving gearbox for higher power output

D1ET · Post by **D1ET** » Sat Jul 18, 2009 1:22 pm

Having more power is awesome fun but gearboxes are hard to find,
what can i do to fix this problem?

And any chance of fitting an LSD to it as well?

Ryan ET · Post by **Ryan ET** » Sat Jul 18, 2009 3:16 pm

Hey Kenny,

Get someone to build you a box with n13 internals, then you shouldt have too many more problems.

Can you please update your members rides with engine bay and car pics? I am keen to see it!

Kimmo · Post by **Kimmo** » Sat Jul 18, 2009 4:26 pm

The word is there's not much you can do about it except drive more smoothly.

From what I gather the advantage of N13 internals is fairly minimal... probably less wear on em and possibly slightly better metallurgy involved. Those in the know should be able to correct or clarify this...

As for LSD, there's a bit of a hack job possible by shimming the bevel gears in the diff to stiffen it up a bit... I can't remember the name of the mob who do this mod ATM, but someone will be able to name em.

Or you could get really serious and stick in a whole N13 tranny with adapter plate and custom driveshafts... but then you might as well swap the adapter plate for custom engine mounts and chuck in a CA18. And modify the hub carriers to take N13 driveshafts and brakes...

D1ET · Post by **D1ET** » Thu Jul 23, 2009 12:27 am

what about a custom gearbox using existing bell housing?? or even a transfer plate of somekind?

dexi_styles · Post by **dexi_styles** » Thu Jul 23, 2009 7:25 am

D1ET wrote:what about a custom gearbox using existing bell housing?? or even a transfer plate of somekind?

This works well with RWD cars but you have to find one thats not too wide as the CV's have to line up as well as the box not being in the wrong position.. up down, too far forward or whatever.

good luck on your ventures as your prob best of getting a custom bell housing and another box, i dont see how or where you will find a custom box.

Dex

Post by **tassuperkart** » Thu Jul 23, 2009 10:23 am

Adapting another breed of gearbox via an adapter plate is an acceptable but very labour intensive and expensive exercise.

You first have to get the box to adapt to the back of the engine via a metal plate.
Or by cutting off the section of the bellhousing that bolts to the engine and welding that to the new box
You then have to machine a new flywheel to carry the new box's clutch and starter motor unless you can keep enough of the bellhousing section to carry the stock starter!.
Youll need to hope here that the new clutch fits into the N12 bellhousing section you cut off or its back to a sandwich plate.
Next is to cut and shut some driveshafts, adding the N12 outer half to the new box inner half.
Make custom gearbox mounts.
Lastly is to adapt the shifter linkages.

None of this is particularly hard but its labour intensive and so very expensive unless you have a real good machine shop and are very very handy with those machines!

Allow at least 600 for a flywheel alone. I paid 580 for mine and that was at M8's rates. It was over 150 alone just for the billet of steel!
You need a new clutch, driveshafts to cut up and rejoin, a starter motor for the new box and so-on.
Itll cost you at least a grand even if you do it yourself.

Consider that the fastest and most powerful N12 ET's in the country drag race week in and week out on stock gearboxes, rarely giving trouble.

Yet, we have had members here (almost being proud of it) advertising how many gearboxes they have smashed on barely boosted up road cars.
I think these failures are largely due to the dickheads behind the wheel and their abusive driving techniques which would end up breaking a Top Loader rather than how much power they make!
If you try enough you can break anything with little power at all!

I think your best off to have your box rebuilt, paying attention to bearing preloads and so-on and seeing how you go with good clutch and driving technique rather than arse around fitting something else!!

Way it is M8
L8tr
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D1ET · Post by **D1ET** » Sat Jul 25, 2009 4:05 pm

fair enough cheers guys for the help probly going to go with n13 gearset, i think i just want this car for hill climbs for now but have to see how i go.