Std vs S/C Drops and box (I don't want it too loud!)
Turbo Mini Forums

Hi,
This is probably going to sound stupid, but I don't care
I'm looking to get around 160 curley whirleys out of my turbo engine.
I'm fairly sure the std drop gears will get out of the box at that, (unless you have success at this level?) but do I need S/C gearbox for that?
I'd like to keep it as quiet as possible, so I can hear my tunes!
Cheers,
Gavin :)

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i dont know, but you can pop in lots of sound proofing and a thick carpet

turn the music up louder to hide the Scalextric car noises

Previous Engine: 1040cc Morespeed engine, 1275 turbo head T2 Turbo Mirage Manifolds Megajolt
Previous engine: STD metro turbo, megajolt
Drives: 399bananahp (flywheel) Honda Civic Vtec b18c4 T28 Turbo 1968 Mini

Megajolt maps to download: http://www.jamesfawcett.co.uk/cms/index.ph...&gid=3&Itemid=3

The gearbox itself is not THAT noisy. It's the drops which are a pain. You'll never hear the gearbox over the drops. You might as well go the whole hog.

tunes slow you down, pretty sure you can keep 4th standard so it doesnt whine when cruising just a thought

Yes, I'd agree with Vegard.

The main gearset gets a bath in plenty of oil to quieten it down, its the drops that make the racket, as they only get a splash lube really.

do you run s/c drop gears tom

1293 Turbo mini

The engine in my Mini has s/c drop gears yes. It hasn't been run up the road yet as the car isn't finished. But I have run minis in the past with s/c drops, they are loud. But I personally love the whine.

Edited by Tom Fenton on 28th Feb, 2006.

http://www.rabdunn.co.uk/

i agree with vegard and tom

around that power levell you want, the helical Drops will wrap up!

the helical box is far more stronger than most peeps give it credit for as long as the bearings are replaced. if your on a budget

and SC drops are used.

oh! dont forget the minispares 4 pin diff will you

Hi,
Thanks for the replys so far, keep 'em coming!
I'd like to know if you can keep 4th std, but from what's been said here, it's the drop gears that make all the noise!
So is anyone running helical(std) gears in the main box and what sort of torque will they stand?
Also is one brand of drop gears any quieter than another?
As Tom said the main gears are quieter due to the oil bath, can I spray oil onto the drops to quieten them down? Or am I talking bo****ks?
Cheers,
Gavin :)

Edited by Bat on 28th Feb, 2006.

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benross to what power ?

1293 Turbo mini

turbo dave coverd this issue about a year ago concerning helicals in the box.

i was inclined to agree with him

if the g/box is brought up to full scratch & SC drops are used which is the weak link!

and the diff pinn is changed for 4 pin type

i cant see any problems in pumping at least 160ftIb + in there.

of coarse this is only my oppinion.

Hi,
I've run 100 lbft 1380 on top of a ropey old box I threw together, the drops chatter alot, the input bearing's shot but I've not blown it up. And neither has my brother, he drives it like he stole it!
@ Mini 1071. I dont know if S/C drops are actually any stronger, but because the teeth are straight they're not trying to twist on the shafts, which is what destroys the bearings and then the gears!
Cheers,
Gavin :)

Edited by Bat on 28th Feb, 2006.

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helical V straight cut

helical gears are far stronger, thats fact!

its the twisting motion you referd to
with the turbo torque, which quickley kills them

I lost 3rd gear last year on a helicol box I have around 120bhp the box was ok to look at and the bearings were ok but I dont know how old it was it ripped all the teeth from the gears.
It was probably just because it was old.
Allan

http://www.rabdunn.co.uk/

its the worn bearings which cause the problems allan

Hi,
@ Mini 1071s.... This isn't my field of expertise either, but I think the same applies to the main box as the drops, but in the box the main shaft and layshaft would be trying to push each other apart and each gear trying to twist on its axis, I can see how it could strip all the teeth off once you get a bit of wear in there or dramatically up the load by increasing engine power or a higher FD ratio.
Cheers,
Gavin :)

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The only failures I've ever had on a box are the nose bearing and syncros wearing. Never bust the gears. We ran a helical box for ages with around 120 bananas.

We changed to straight cut gears for the ratios (and boy what a differance), as pointed out for small companies to make these kits helical would be far more expensive.

Again as pointed out the SC box is not much louder than a standard box, but the drops are noisy buggers, especially if you have a 14 thou float on the idler gear!!

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

Hi,
I've got a MPI box in my garage, it's done 26K. Should I pull it all to bits and put in a rebuild kit, or measure the clearances change the diff and drop gears and put it in? Is everyone using the baulk rings in the Minispares rebuild kit or the uprated ones, please?
Cheers,
Gavin :)

Edited by Bat on 1st Mar, 2006.

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i'd definately rebuild it personally, i know quite a few people who's mpi boxes have shat themselves after very few miles. my mates spat the diff after about 26k i think it was...

Don'y just go out and buy new baulk rings. Old ones are very good, but check the cleareance.. I use old ones every time I can. Cones vary greatly in diameter as well.

BIR1 did sport an S/GT box for years and years. Mark could probably tell you what he found. I Changed it for the better ratios of the SC box. The box was rebuilt and put into another car after I removed it...

Edited by Vegard on 1st Mar, 2006.

lol ive seen 2 broken helical box's as of late both of them belonging to my lead footed mate ben, both of which im guessing were down to bearing failure, stripped 4th on one box after a lot of miles grinding away. and the other ive never seen happen before, he managed to shear off the pinnion gear and shaft, was a clean cut too!? what realy makes it astonishing is he managed that with a standard 998 setting off quick from some traffic lights!

i ran just a set of minispares s/c gears for a while and they wern't realy audable over the induction / exhaust noise i was quite disapointed untill i got the s/c drops, gotta love that noise
steve.

doh! why did i start messing with it!

Hi,
Sound like it's a good job I've been stockpiling sound proofing for a while. I'm starting to wonder why I'm going for the turbo now, I was looking to reduce noise by not having a 45 dcoe stuck through the bulkhead, so I'm going to replace it with some screaming drop gears!
Cheers,
Gavin :)

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more fun with a turbo

1293 Turbo mini