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Transfer Case Ratios


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12 replies to this topic

#1
mi8 turbo

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how would i go about changing the ratio of the transfer cases on the 4bie? i would imagine these have to be 1off items. i read an article on the dongle 309x4 saying that it was almost like driving a fwd car until it rained and i think the ratios were 67%/33%

Edited by mi8 turbo, 28 December 2010 - 07:06 PM.


#2
mi8 turbo

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QUOTE (mi8 turbo @ Dec 28 2010, 08:05 PM) <{POST_SNAPBACK}>
how would i go about changing the ratio of the transfer cases on the 4bie? i would imagine these have to be 1off items. i read an article on the dongle 309x4 saying that it was almost like driving a fwd car until it rained and i think the ratios were 67%/33%


dangle not dongle.typo blink.gif

#3
petert1345402284

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Why would you want or need to? The transfer case is 43 x 13 and the rear final drive is 13 x 43. Thus effectively 1:1. The beauty of the system is that you just change the gearbox ratios, or the final drive ratio, which are before the transfer case. So any changes to either changes the ALL the gearing downstream.

The centre diff splits the torque 53% front 47% rear.

Edited by petert, 29 December 2010 - 04:37 AM.


#4
mi8 turbo

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QUOTE (petert @ Dec 29 2010, 05:35 AM) <{POST_SNAPBACK}>
Why would you want or need to? The transfer case is 43 x 13 and the rear final drive is 13 x 43. Thus effectively 1:1. The beauty of the system is that you just change the gearbox ratios, or the final drive ratio, which are before the transfer case. So any changes to either changes the ALL the gearing downstream.

The centre diff splits the torque 53% front 47% rear.


its just something i wanted to try seeing as though i had a spare setup to see how it ventured, the motive behind my idea was to keep most of the power where most of the weight was.im just flirting with ideas that ive read about.

#5
mi8 turbo

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QUOTE (mi8 turbo @ Dec 29 2010, 12:40 PM) <{POST_SNAPBACK}>
QUOTE (petert @ Dec 29 2010, 05:35 AM) <{POST_SNAPBACK}>
Why would you want or need to? The transfer case is 43 x 13 and the rear final drive is 13 x 43. Thus effectively 1:1. The beauty of the system is that you just change the gearbox ratios, or the final drive ratio, which are before the transfer case. So any changes to either changes the ALL the gearing downstream.

The centre diff splits the torque 53% front 47% rear.


its just something i wanted to try seeing as though i had a spare setup to see how it ventured, the motive behind my idea was to keep most of the power where most of the weight was.im just flirting with ideas that ive read about.


when you say center diff do you mean the one that connects to the gearbox housing and sits on the rear of the engine block?

#6
AlexN

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QUOTE (mi8 turbo @ Dec 29 2010, 11:02 AM) <{POST_SNAPBACK}>
QUOTE (mi8 turbo @ Dec 29 2010, 12:40 PM) <{POST_SNAPBACK}>
QUOTE (petert @ Dec 29 2010, 05:35 AM) <{POST_SNAPBACK}>
Why would you want or need to? The transfer case is 43 x 13 and the rear final drive is 13 x 43. Thus effectively 1:1. The beauty of the system is that you just change the gearbox ratios, or the final drive ratio, which are before the transfer case. So any changes to either changes the ALL the gearing downstream.

The centre diff splits the torque 53% front 47% rear.


its just something i wanted to try seeing as though i had a spare setup to see how it ventured, the motive behind my idea was to keep most of the power where most of the weight was.im just flirting with ideas that ive read about.


when you say center diff do you mean the one that connects to the gearbox housing and sits on the rear of the engine block?

That is the transfer box, it contains the center diff amongst other things, like the front differential and a VCU. As Peter says, the ratios of the torque split (governed by the centre diff) is 53/47, and the step up/down ratios of the transfer box output and the rear diff input are the inverse of each other to ensure the ratio is 1:1. Anything other than 1:1 is bad news, which is why I needed a specific Evo transfer box with the same ratio as the Mi16x4 rear diff, and also why you cannot use a T16 transfer box or rear diff in combination with an Mi16x4 one.

It would be very difficult to change the torque split (and very expensive), unlike an Evo where you just buy a centre diff with the ratio you desire. There are a number of parts you can buy to make the whole drivetrain stronger, most are available from a guy in France at ATD Performance. You could also use a T16 gearbox with the rest of the Mi16x4 drivetrain as they are a lot stronger. The only thing you need is the end plate from a T16 transfer box as the bolt pattern to mate the gearbox to the transfer box is different. I might have both of these items for sale in the very near future.

#7
mi8 turbo

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QUOTE (AlexN @ Dec 29 2010, 02:00 PM) <{POST_SNAPBACK}>
QUOTE (mi8 turbo @ Dec 29 2010, 11:02 AM) <{POST_SNAPBACK}>
QUOTE (mi8 turbo @ Dec 29 2010, 12:40 PM) <{POST_SNAPBACK}>
QUOTE (petert @ Dec 29 2010, 05:35 AM) <{POST_SNAPBACK}>
Why would you want or need to? The transfer case is 43 x 13 and the rear final drive is 13 x 43. Thus effectively 1:1. The beauty of the system is that you just change the gearbox ratios, or the final drive ratio, which are before the transfer case. So any changes to either changes the ALL the gearing downstream.

The centre diff splits the torque 53% front 47% rear.


its just something i wanted to try seeing as though i had a spare setup to see how it ventured, the motive behind my idea was to keep most of the power where most of the weight was.im just flirting with ideas that ive read about.


when you say center diff do you mean the one that connects to the gearbox housing and sits on the rear of the engine block?

That is the transfer box, it contains the center diff amongst other things, like the front differential and a VCU. As Peter says, the ratios of the torque split (governed by the centre diff) is 53/47, and the step up/down ratios of the transfer box output and the rear diff input are the inverse of each other to ensure the ratio is 1:1. Anything other than 1:1 is bad news, which is why I needed a specific Evo transfer box with the same ratio as the Mi16x4 rear diff, and also why you cannot use a T16 transfer box or rear diff in combination with an Mi16x4 one.

It would be very difficult to change the torque split (and very expensive), unlike an Evo where you just buy a centre diff with the ratio you desire. There are a number of parts you can buy to make the whole drivetrain stronger, most are available from a guy in France at ATD Performance. You could also use a T16 gearbox with the rest of the Mi16x4 drivetrain as they are a lot stronger. The only thing you need is the end plate from a T16 transfer box as the bolt pattern to mate the gearbox to the transfer box is different. I might have both of these items for sale in the very near future.


well seeing as you mention it ill be first in line for those items if you dont mind if the price is right and cash is available. has anybody read the article of the 309 mi16x4 dangle. the test driver really praises what they did with changing the touque split to 67/33. would this not be a better setup in having most tourque where the weight is.?????????????????? ive heard the dangle are not a fan of selling their items for other users to do their projects so maybe this is just a dream that will never be. ive seen the upgrades for the transferbox on that site you mention they are damn expensive but also they are just for the t16 setup and would cost even more for mi16x4 setup unless there were others intrested and in this climate im not sure there would be many to jump on the bandwaggon. i have 2 full setups for my mi trasfercases gearboxes driveshafts the only thing i dont have is the rear axle.

#8
imaS

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The original weight distribution is about the same as the torque distribution (53/47).

#9
mi8 turbo

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yes thats all good for the original car but mine is stripped out as much as possible and seeing as though most of the weight is from the middle back the this changes things. yes.? reading the 309 gti (dangel) article tells how the chaging of the split torque leaves the car handling like an fwd car with understeer but added grip is still present from the rear. these arnt the exact words but thats what its trying to say and its either 61/39 or 69/31 forgot which way round.

#10
AlexN

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The parts on ATD performance will fit both T16 and Mi16x4 transfer boxes and also with a T16 geabox the new transfer shafts would also fit, but as you say it is an expensive business, hence why I went Japanese!

I'll send you a PM about the other parts if you are interested.

#11
mi8 turbo

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QUOTE (AlexN @ Dec 30 2010, 06:04 PM) <{POST_SNAPBACK}>
The parts on ATD performance will fit both T16 and Mi16x4 transfer boxes and also with a T16 geabox the new transfer shafts would also fit, but as you say it is an expensive business, hence why I went Japanese!

I'll send you a PM about the other parts if you are interested.


yes im intrested. thanks bud

#12
B1ack_Mi16

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Also just thing what happends to the weight distribution once accelerating hard.

Weight transfer will give more traction to rear wheels and less to front wheels.
So don't really think there is any good reason to change the front/rear split.

#13
mi8 turbo

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QUOTE (B1ack_Mi16 @ Jan 28 2011, 02:32 PM) <{POST_SNAPBACK}>
Also just thing what happends to the weight distribution once accelerating hard.

Weight transfer will give more traction to rear wheels and less to front wheels.
So don't really think there is any good reason to change the front/rear split.


yea ive come to my senses and im leaving it as is not that i have the cash to throw away

Edited by mi8 turbo, 29 January 2011 - 09:24 PM.