Gear box ratios ?????????
Turbo Mini Forums

Right, Am after buying a dog box for the min, got one located secondhand but want to make sure it will suit my needs.

Got these ratios from the guy just wanderd if anyone can help me by letting me no if its any good ??

Lay gear 16T 22T 24T 26T
Other Shaft 27T 24T 21T 19T (Flywheel end of gear box)


Thanks Rick


Hope its in the right place

Edited by cossierick on 31st Jan, 2008.

what ratios?

Sorry thats the bit i forgot. lol

Edited by turbodave16v on 31st Jan, 2008.

Sorry am not that clever doesnt mean anything to me,

Dave are they any good

thats a really high 1st gear , be a bit of a job in traffic with a 3.2 and higher diff

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Sorry am not that clever doesnt mean anything to me,

Dave are they any good

Prob looking at running a 3.9 with a sailsbury lsd

Rick

They are not normally what one would use for a turbo to be honest; they are pretty close.

In short - the 1st gear ratio is not too far from what second is in a stock helical box... Are you going to be happy always starting your mini in what feels like second gear?

those ratiod are very similar to the set in the Don, using a 3.9 FD,

no probs at all setting off,

Rick , who are you getting it off,
you need to make sure the dog's on the selecter hub are in good nick.

carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

ok, I'll pass the ball over to you.

Take a look at:
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=159190

The first gear ratio (eg 2.54) multiplied by your FD number, will give you your overall start gear ratio.

eg
3.647 x 3.44 = 12.5 is stock metro start ratio.
2.54 x 3.44 = 8.73 is a good 'target' start gear ratio for a stock road mini.
2.54 x 2.95 = 7.79 is why matt woods is always slow off the drag strip start line (LOL - he knows what i mean)

So, a 3.9 x 2.28 = 8,89 is a good start gear ratio for all round road / drag. You don't have many ratio's left above this however... Have a play with the numbers, and decide yourself.

Remember - starting a 600kg stripped out racer on the strip, which will be sat on the trailer on the way home, is a LOT different to a near-standard weight road car which has to negociate hill starts in urban surroundings... It's times like this that you need a start-gear ratio of the higher side of 8...

Edited by turbodave16v on 31st Jan, 2008.

Carl is a guy from mini7 that moving from sevens to migs

Sound like my current box , long ish 1st then others close together,

Cars not realy going to be used on the road and definitly not in traffic. Car is going to be running 10s and 170 bhp ish

Should be ideal for sprints and hillclimbs then ?????????????

Rick

Dave thats brilliant thanks, wot sort of top speed can i be looking at then ? planning on 7k limit.

3rd and fourth seam very close or are they too close
Rick

Edited by cossierick on 31st Jan, 2008.

yep i agree dave , my 2.59 and 3.1 diff=8.03 is a bit higher than id like on hills .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

@ Robert - -that's what i'm also using and it sucks on inclines. Guess we need to join weight watchers.

Edited by turbodave16v on 31st Jan, 2008.

2.14x3.9=8.346, so easir on the car than you boys to get moving,lol

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well i m down to 660kg and on the high st hill in burford , im at 3 psi just pulling away from a parking space up the main street , turns heads a bit !!!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Would it be better to change the fd to a higher one or is the real solution to have the gears further apart ?

Rick

Thanks lads

rick , dont worry too much about the ratios,
but if like most turbo engines its all out of puff at 7k you will barely make 100mph in top with a 3.9 and a 19 1/2" tall tyre , used on a 10" wheel.


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Am sure you carnt get much lower than that fd for a lsd tho can yo carl (or can you machine a std one )

I had a synchro version of the dog box ratios. (Challenge set) and first was waaaaay to high. Brilliant for rolling starts or a silly race engine. It was useless though. See if you can plot the cascade curves for your engine and see where the best places for the gears are. I now have a 2.54 set again, which are probably a bit close for a half decent FD which the engine could pull.

Bugger off, I'm getting there.

Thanks for all the help and advice, its realy given me a lot to thing about (maybe too much )

Il let you no what i decide

Rick

rick, you can get 3.54 , 3.6. 3.7 fd's in lsd pattern

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

and 3.4s

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

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