Straight Cut Drops
Turbo Mini Forums

Hi! i am debating on wether to get myself some straight cut drop gears for my supercharger build, at what point do you know when you need straight cut gears? as i have no idea of what my power output is going to be but i have heard that anything over 100bhp and straight cut drop gear will be needed.

would i need them for my spec? and also can anyone suggest a decent supplier of straight cut drop gears?

1293 A+
21253 pistons
centre main strap
12g940 33/29mm 28cc chambers standard ports doule valve springs
8:5.1 CR
BP7ES plugs
SW5-07 cam
alloy vernier duplex timing gear
Balenced internals
lightened flywheel [cast]
hif44
M45 Eaton supercharger, home made manifolds - suckthough set-up
k&n cone filter
maniflow stage 2 manifold
maniflow centre exit exhaust system
65DM4 dizzy - standard curve, going to go megajolt at a later date
GT ratio box
3.1 Fd
x-pin diff

Cheers!

Have a search for Robert's thread on these. He is running hellical drops at over 200BHP with no problems.

It has been debated about the need for straight drops....I have them and found my weak point to be the laygear. I would suggest straight gears in the trans and helical drops so that you don't go half deaf like I am now...

This was on my N/A 1380 setup....

Eric
my pics.... http://www.fototime.com/inv/7AAF37CF3EFA956

Could the failure have been caused by the hardening on your laygear breaking down Eric?

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

I had the surface hardening go i a gear box, all it did was wear out in the blink of an eye that is a tooth letting go and taking all his neighbours for the ride

Own the day

The spots of rust make me suspect that this is the case on this gearset.

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

the box i have is a minispares A+ GT ratiobox - semi close ratio but not straight cut! but it has been fully rebuilt so it should last a fair while, i may just stick with my helical drops with the scope to upgrade in the future if needs be, do that sound like a good idea?

Should be OK as long as everything is well put together and to close tolerances.

We are putting 150 bananas through a 20 year old used helical box on our van and to date it's coped. Sod's law it will blow up on me tonight...

Not sure...was a rebuilt box from a reputable shop in the U.S. with unknown history to me before I got it. I've got the clubman straight cuts now....:) One thing is for sure, I always put 100% of the 1380 cc's into full use, so some sort of failure was not really a suprise....

Eric
my pics.... http://www.fototime.com/inv/7AAF37CF3EFA956

If your going on the track may be. Mines about 130bhp took them off mine as the noise after 50mph on the motorway was to much. I would get to shows and my ears were ringing for the rest of the day. I had drop gears and box I now run jk 5 speed box 10 times better.

Craig

my mini van http://www.turbominis.co.uk/forums/index.php?p=vt&tid=448248

that is wear 90% of failure will occure on the input gear of the layshaft, normally fails when blasting of the line or lights a torquey engine can soon strip these if you aint carefull on the pull away

always looking for them bigger bunches of bannanas

Yeah....in the pic above of my trans, this was on a 2nd to 3rd shift about 2 seconds after letting the clutch out on full bore at about 4.5k rpm's. Another thing that may have added to the failure is that it is in an ADO16....a bit heavier than a mini with the same drive line.

Eric
my pics.... http://www.fototime.com/inv/7AAF37CF3EFA956