View Full Version : Changing diff ratio bf ute
Drift_R32
01-07-2012, 04:47 PM
Just after some advice..
I have an 06 bf xr6t ute
Currently it has the zf 6speed auto
So I'm guessing the diff gears are the 2.73s
Now the question I'm after is, is it worth upgrading the ratio to atleast 3.7s
Ive heard that the manuals come out with 3.7a from factory so is it just as simple as sourcing a manual diff?
And also been told you have to change something computer wise because of the speed sensor on the box not liking the ratio to be changed?
And finally has anyone done it and is it worth it?
Thanks all for your help
ovaxitd
01-07-2012, 05:33 PM
looking around the fraud forums it doesnt look like a major thing that many people do, i recon daisy would be the one to have a chat to about it, these zfs practically have no first gear as it is so going higher wouldnt really be any point.. but have been wrong b4..
Drift_R32
01-07-2012, 06:03 PM
Yeh you are right 1st is pointless
But I'm pretty sure mine stays in 2nd alot when I come to a stop
Because once I take off it's sometimes abit doughy unless I stop it.
And off boost it's pretty doughy alot of the time.
Would be nice to be abit nicer to drive around off boost
Steppo_GT
01-07-2012, 07:26 PM
Manuals are 3.45. Having a 3.45 in a 6sp auto would be almost the same as 4.11's
Im pretty sure Manual fg's came with 3.7's
XF Falcon
01-07-2012, 07:31 PM
The 6 speed will take off in 2nd gear unless you put the accelerator down far enough to reach the detent (you will feel a little switch click when you put the pedal down fully - try it with the car turned off next time)
Drift_R32
01-07-2012, 07:42 PM
Manuals are 3.45. Having a 3.45 in a 6sp auto would be almost the same as 4.11's
Im pretty sure Manual fg's came with 3.7's
Ah ok..that sounds about right
Oh well lol 3.45s here I come
Should drive well with the 6 speed auto.
Drift_R32
01-07-2012, 07:43 PM
The 6 speed will take off in 2nd gear unless you put the accelerator down far enough to reach the detent (you will feel a little switch click when you put the pedal down fully - try it with the car turned off next time)
Ah really? Wasn't aware of that.. But had a feeling it did.
Will have a go and see what u mean.
KAL SPL
01-07-2012, 08:29 PM
Mate changed diff gears in 5 speed manual xr8 ute and now cruise won't work in 5th fwiw.
Drift_R32
01-07-2012, 08:41 PM
Mate changed diff gears in 5 speed manual xr8 ute and now cruise won't work in 5th fwiw.
Strange.. Probably a ford thing lol
Turbo2.6L
02-07-2012, 09:06 AM
Manual BA MkI's came out with 3.45:1 gears
Manual BA MkII's came out with 3.73:1 gears
Manual BF MkI's came out with 3.73:1 gears
Manual BF MkII's came out with 3.73:1 gears
Manual FG MkI's came out with 3.73:1 gears
Manual FG MkII's came out with 3.73:1 gears
Daisy changed his 2.73:1 gears (zf) to 3.45:1, but he had a GTX42 turbo hanging of the side of the engine. Diff swap is pointless in a stock turboed car & the $1500 (cheap way) or $3k with TruTrac centre (proper way) can be better spent elsewhere, as in a decent brake upgrade or retune with decent non-drilled factory injectors.
Drift_R32
03-07-2012, 09:36 AM
Why's it pointless?
Car is pretty quick has gone 11.9
I can do it cheaper then 1500 so that's why I'm thinking it's prob not a bad upgrade.
i think it would be well worth it. 3.45's in daisy were great.
if you set off fast in first, you have to grab second pretty early not to bash limiter in first. no issue just something to get used to.
you need to be change the selected diff ratio in the tune for cruise to work properly.
Drift_R32
03-07-2012, 08:48 PM
Yeh I think I'm gonna do it..
Already have someone who's gonna change the ratio for me :-)
i think it would be well worth it. 3.45's in daisy were great.
if you set off fast in first, you have to grab second pretty early not to bash limiter in first. no issue just something to get used to.
you need to be change the selected diff ratio in the tune for cruise to work properly.
Turbo2.6L
04-07-2012, 08:39 AM
Why's it pointless?
Car is pretty quick has gone 11.9
I can do it cheaper then 1500 so that's why I'm thinking it's prob not a bad upgrade.
Because a zf car can sixty foot in the 1.6's with no converter & no zf tune, on drag radials with lowered suspension. Now that the zf tuning capability is available & converters are also available, diff gear swaps are pointless unless you want to increase fuel consumption.
When did this ute run 11.9 that you know of? I know when it did it one time, but could never back it up... Keen to know if you or the owner before you managed to get it back in the 11's.
Ran 4 11.9's.
Never ran faster then it first 11.9 pass, mainly cos i think drag racing blows and never took it back when it made it's most power.
Turbo2.6L
04-07-2012, 08:51 AM
In one night is what i meant
As it is, cars got a 6 speed box, yet you can hit speed cut in 4th. Diff is miles over geared. Shorter diff gears gives better acceleration, more usable torque curve, no difference in fuel consumption. fuel consumption in turbos is effected by load, not revs. diff gears reduce load, might actually help fuel consumption.
Sure first is a little short, but most time the car sets of in 2nd anyway.
Daisy
04-07-2012, 09:13 AM
^this.
given i had a big snail, but i`d change the gears if i had another car with the stock turbo.
also, fuck changing the converter. not many people have done it so i sure as fuck wouldnt go pioneering for other pingpingpingpings.
tune the box, maybe, but that would require buying a flash 3 box.
do the gears if you can do it on the cheap. i`d also recommend a true track whilst your at it. will paint lines like a boss.
Drift_R32
06-07-2012, 05:47 AM
As it is, cars got a 6 speed box, yet you can hit speed cut in 4th. Diff is miles over geared. Shorter diff gears gives better acceleration, more usable torque curve, no difference in fuel consumption. fuel consumption in turbos is effected by load, not revs. diff gears reduce load, might actually help fuel consumption.
Sure first is a little short, but most time the car sets of in 2nd anyway.
Yeh im not doing it for drag purposes, it's mainly for just putting around the city
They just seem to be abit doughy for my liking when cruising around
If I source the gears I can get them installed cheap, and already set up someone to change ratios in the tune
So to me it's not a bad deal I think
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