Ryder

Having a senior moment

• May 29, 2010

• #1

OK ignoring the obvious complications

If I were to connect the crankshaft output that would normally house the input shaftof the gearbox - to the rear drive flange....

Would that equal one revolution of the wheels for one revolution of the engine?

It's a strange question, I know... but Kai asked me earlier and I hinestly couldn't tell him the answer... so I figured you lot were the people to ask!

Cheers

Chris

 

Davec

New Member

• May 30, 2010

• #2

No.
The gearing is reduced by the differential.
Normally on a gearbox top gear (or 4th on a 5speed box) is direct, that is 1:1, but of course on a Land Rover you also have to take the gearing of the transfer box into account.

 

Ryder

Having a senior moment

• May 30, 2010

• #3

OK... is there a way to calculate the ratio of propshaft revolutions to wheel rotations, possibly using the gear ratio of the diff?

again just a thought

 

The Mad Hat Man

Well-Known Member

LZIR Despatch Agent

• May 30, 2010

• #4

yes

 

The Mad Hat Man

Well-Known Member

LZIR Despatch Agent

• May 30, 2010

• #5

Ryder said:

OK ignoring the obvious complications

If I were to connect the crankshaft output that would normally house the input shaftof the gearbox - to the rear drive flange....

Would that equal one revolution of the wheels for one revolution of the engine?

It's a strange question, I know... but Kai asked me earlier and I hinestly couldn't tell him the answer... so I figured you lot were the people to ask!

Cheers

Chris

Click to expand...

No
You would be turning the input shaft at a ratio of 1:1, but the output would be at 3.9:1, or whatever the diff ratio was; as the wheels would turn 3.9 times slower (revs) than the injun - ie at 4000 RPM (injun speed) the wheels would rotate at <>1000RPM.

 

Ryder

Having a senior moment

• May 30, 2010

• #6

Thanks MHM... at least I can explain THAT to hiim and he will understand... (me too methinks!)

 

The Mad Hat Man

Well-Known Member

LZIR Despatch Agent

• May 30, 2010

• #7

watch [nomedia="http://www.youtube.com/watch?v=K4JhruinbWc"]YouTube- How Differential Gear works (BEST Tutorial)[/nomedia](from 1 minute 50secs)

A very good description of how a diff works.

 

Ryder

Having a senior moment

• May 31, 2010

• #8

Brilliant Video!

 

jai_landrover

Well-Known Member

• Jun 6, 2010

• #9

Ryder it would be like you are in 4th Gear. In 4h gear you lock the input and output shafts within the gearbox together and its why its the strongest gear and why if anything goes wrong like a lay shaft break you can normally get home in 4th gear.

Aswell as the gearbox you have the transfer box ratios to think about well. On Your V8 your one is as 1:1 as LR ever made so you can discount that. your diff input flange to axle (pinion - crown wheel ratio) is 3.54:1.

Another concern is that you will not have a neutral.

 

jai_landrover

Well-Known Member

• Jun 6, 2010

• #10

I heared Kai wants to make a V8 go cart. Maybe he is better of saving £100 and buying an old honda moped for a bit of fun lots of fun and alot cheaper in the long run. Or mabe weld up a frane and get an old Briggs and stratton lawn mower engine.

 

jai_landrover

Well-Known Member

• Jun 6, 2010

• #11

P.S if Kai was thinking of using Series axle ratios its 4.7:1.

 

jai_landrover

Well-Known Member

• Jun 6, 2010

• #12

I did a chart somwhere with various revs, various gearbox ratios, various transfer box ratios in HR and and diff ratios and indeed tyre size rolling circumferance in each gear. My 90 in 4th gear at 4000 RPM (given it had enough power should be doing 148Mph or somthing silly like that) it hasn't got enough power to pull the ratios hence immenant axle swap. by my calculations by changing the axle ratio from 3.54:1 to 4'7:1 using my tyres I will get the ratios back to between standard gearing with 205's and standard with 235's If its too low I will be fitting a RR V8 transfer box to get it taller which should give me a nice and slow low range.

 

Mr Noisy

Coming in your ears.

• Jun 6, 2010

• #13

If he's making a go cart then it'll be ok without a clutch, just!

however, it's gonna take some sourcing to find a back axle that is light enough and strong enough.

You don't really want a rover back axle to lug around.

Engine at front driver at back would make for some tail out happiness, but a heavy back axle would just be slow.

Other option that could work albeit unreliably is to transverse mount the v8 over the rear wheels, and bolt a sprocket to the crank flange, and use a piece of 30mm steel bar for an axle with another sprocket fitted, then just sling a bike chain round it.

Hey presto, direct drive, and you can alter the gearing with the sprockets.

Would be an interesting drive!

And ffs fit a chain guard

 

Ryder

Having a senior moment

• Jun 7, 2010

• #14

Mr Noisy said:

If he's making a go cart then it'll be ok without a clutch, just!

however, it's gonna take some sourcing to find a back axle that is light enough and strong enough.

You don't really want a rover back axle to lug around.

Engine at front driver at back would make for some tail out happiness, but a heavy back axle would just be slow.

Other option that could work albeit unreliably is to transverse mount the v8 over the rear wheels, and bolt a sprocket to the crank flange, and use a piece of 30mm steel bar for an axle with another sprocket fitted, then just sling a bike chain round it.

Hey presto, direct drive, and you can alter the gearing with the sprockets.

Would be an interesting drive!

And ffs fit a chain guard

Click to expand...

We like this idea!