6-speed Auto And 2.73 Diff

[Turbo6man]

OK, now the figures are officially released and they are if anyone remembers just about what I predicted except the diff ratio has blown out to 2.73:1. I really hoped Ford would go no higher than a 3.08 in order to extract the best performance from the new models but anyhow 2.73 is what we've got so this is how it will stack up for all you guys who are into this sort of thing.

The max speeds @ 5,800 rpm shiftpoints are going to be as follows:-

1st 60km/h

2nd 105km/h

3rd 165km/h

4th 220km/h

5th 290km/h theoretical

6th 365km/h very theoretical

It means the car will still only use three gears for the quarter, unmodified motors of course. This, to me is a great waste of the potential for this box especially in the turbo models. I would be whacking a 3.45 diff in quick smart and I reckon you'd see the quarter times come down nearly a full second. But that's just me!

[Guest xrtwpn]

Maybe with min mods you would see it come down but with big mods you would run out of revs putting a 3:46 diff in the rear id say it would be spot on th way it is with the new ratios to choose from

[TBO240]

so what are the gear ratios and are you shore the diff ratio isnt 3.73

[Turbo6man]

Maybe with min mods you would see it come down but with big mods you would run out of revs putting a 3:46 diff in the rear id say it would be spot on th way it is with the new ratios to choose from

<{POST_SNAPBACK}>

No, you wouldn't be anywhere near running out of revs at all.

A 3.45 diff would see 6th gear moving back to where 5th gear is. And 4th would come back to just a tad above where 3rd is now, which would mean the car would use the first four gears to do the 400m. It would still have a little left in fourth to accommodate those who would put say a Phase I kit into their turbo and be getting a terminal speed up around 105 - 110 mph.

[Turbo6man]

so what are the gear ratios and are you shore the diff ratio isnt 3.73

<{POST_SNAPBACK}>

The gear ratios are exactly as I predicted quite some months ago. No-one had to be a genius to work out that Ford would use the same box that they already have in Jags, Land Rovers and Navigators.

1st 4.17

2nd 2.34

3rd 1.52

4th 1.14

5th 0.87

6th 0.69

The diff is definitely 2.73 NOT 3.73.

[Falchoon]

so what are the gear ratios and are you shore the diff ratio isnt 3.73

<{POST_SNAPBACK}>

http://www.fordxr6turbo.com/forum/index.ph...ndpost&p=283631

[Geeseman]

so what are the gear ratios and are you shore the diff ratio isnt 3.73

The gear ratios are exactly as I predicted quite some months ago. No-one had to be a genius to work out that Ford would use the same box that they already have in Jags, Land Rovers and Navigators.

1st 4.17

2nd 2.34

3rd 1.52

4th 1.14

5th 0.87

6th 0.69

The diff is definitely 2.73 NOT 3.73.

Hi Jeff,

What are the ratios in the mark 1 Xr6T and are there any good online calculators for speed with different diff ratios?

thanks

[Turbo6man]

so what are the gear ratios and are you shore the diff ratio isnt 3.73

<{POST_SNAPBACK}>

The gear ratios are exactly as I predicted quite some months ago. No-one had to be a genius to work out that Ford would use the same box that they already have in Jags, Land Rovers and Navigators.

1st 4.17

2nd 2.34

3rd 1.52

4th 1.14

5th 0.87

6th 0.69

The diff is definitely 2.73 NOT 3.73.

<{POST_SNAPBACK}>

Hi Jeff,

What are the ratios in the mark 1 Xr6T and are there any good online calculators for speed with different diff ratios?

thanks

<{POST_SNAPBACK}>

G'day Steve ... auto or manual?

I know there are some online calculators but I just do my own.

I've posted the formula before but here ya go again ...

km/h per 1000 rpm = 60,000/number of wheel revs per km/gear ratio/diff ratio

For the XR6T with 235/45/17 tyres (or 245/40/18 or 275/40/17 or 285/35/18) you can safely use 505 as the number of wheel revs per km.

So a quick working example to illustrate:-

km/h per 1000 rpm in 2nd gear for an XR6T Mk I manual ...

= 60,000/505/1.95/3.45 ...

= 17.66 ...

So at 5,800 rpm redline max speed in 2nd gear is 17.66x5.8

= 102 km/h

PS The full set of ratios for the T5 manual are 2.95, 1.95, 1.34, 1.00, 0.73 off the top of my head. Autos I think are 2.39, 1.45, 1.00, 0.68

[Geeseman]

Thanks Jeff

Im auto Mk1. Do you happen to know the gear ratios for the transmission?

Also does lowering the gear ratio decrease the torque requirements (make it run through the gears faster)?

thanks again

[Turbo6man]

Thanks Jeff

Im auto Mk1. Do you happen to know the gear ratios for the transmission?

Also does lowering the gear ratio decrease the torque requirements (make it run through the gears faster)?

thanks again

<{POST_SNAPBACK}>

Just edited my post and added the ratios for both transmissions.

Yes.

But remember this ... lowering the gear ratio refers to lowering the speed of the car in that ratio. This is the normal accepted vernacular in the motor industry. It is not what the mathematicians like Lawsy will use. I'm not having a go at Lawsy here but just pointing out that if we were to refer to the true mathematical ratio then it is the opposite of this.

I suppose we should use the term shorten the gears to prevent confusion.

But anyhow, in summary:-

lower gearing means shorter gearing means higher numerical ratio as in:-

3.73 is a lower (speed) gear or shorter than 3.45 and 3.73 is a higher number than 3.45.

Is everyone suitably confused now???