Xf diff strength.

[BTS666 15]

What kind of hp do these different generally hold before they grenade?

 

Is it worth rebuilding the factory diff with the gearing I am after, or should I just bite the bullet and source an eb v8 diff? The diff will probably be getting narrowed, as I am planning on running mini tubs.

 

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[deankxf 20,292]

4 minutes ago, BTS666 said:

 

What kind of hp do these different generally hold before they grenade?

 

Is it worth rebuilding the factory diff with the gearing I am after, or should I just bite the bullet and source an eb v8 diff? The diff will probably be getting narrowed, as I am planning on running mini tubs.

 

the EB diff is much stronger,  

XF diff is 25 spline 2 pin center

EB diff 28 spline 4 pin center. 

 

if you stick a mild 351 in front of a NON LSD XF diff, it will break especially if you are spinning one wheel *(heats up the spider gear pins) 

if you have an LSD one they are better, i've had no issue with LSDs on 140rwkw ish power/torque (1UZ lexus or mild 351 both manuals) 

 

the reason I stuck with the XF LSD with the 1UZ is due to the engineer wanting Vented discs on rear retained (EB ones are solid) otherwise i'd have stuck the EB diff in. you can get 28spline in the XF style diff, the XE 351s had it and LTD with 351 etc. but they'd be barely possible to identify if you could even find one. 

[BTS666 15]

 
the EB diff is much stronger,  
XF diff is 25 spline 2 pin center
EB diff 28 spline 4 pin center. 
 
if you stick a mild 351 in front of a NON LSD XF diff, it will break especially if you are spinning one wheel *(heats up the spider gear pins) 
if you have an LSD one they are better, i've had no issue with LSDs on 140rwkw ish power/torque (1UZ lexus or mild 351 both manuals) 
 
the reason I stuck with the XF LSD with the 1UZ is due to the engineer wanting Vented discs on rear retained (EB ones are solid) otherwise i'd have stuck the EB diff in. you can get 28spline in the XF style diff, the XE 351s had it and LTD with 351 etc. but they'd be barely possible to identify if you could even find one. 

Ok cool. It will have a barra in front of it, with cams and an auto with a stallie.

Then turboed. Maybe turboed straight away if I can find a decent turbo conversion straight away for the coins I have.

So if I rebuild the original diff, I will try source 28 spline internal and axles?

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[deankxf 20,292]

1 hour ago, BTS666 said:

So if I rebuild the original diff, I will try source 28 spline internal and axles?

there's possibly threads By @gerg regarding fitting 28 spline stuff to the 25 spline axles, but generally you'd just fit an EB ED EF EL diff (EF EL had the hand brake inside the disc but very much the same diff, probably more differences) 
the EB diff has a wider bush for the lower trailing arm, fit that (better) on one end of your XF trailing arms or if you get the EB ones, fit an XF one at the front and it will bolt in.
some of the later diffs have adjustable pinion angle (2 sets of top trailing arm mounts, assume for lowered XR6  possible EB GT etc) i've had one and it was from a basic falcon but it wasn't in another so there's no definite finding source. 

[gerg 10,871]

Hey Deano i've done stuff like that years ago, can't remember where it is.

Generally, keeping to the same series of diff (ie 75 or 78) will ensure carriers and gears will interchange. For the shorter ratios, ie 2.92 and upwards, the housing will need to be 78 series.

My 302 is still running a 2-pin, 25 spline and 3.08 gears from a commo. It's holding up ok but has seen better days. The axles are twisting a bit and the spider gears are getting noisy around corners. Housing was from an XG with solid rear rotors. My car is a wagon so ute stuff is what you use in the rear end (same floorpan).

I have a 28 spline centre and axles to throw in it (using the 3.08 gears), when time permits.

So to answer your question, yes you will need to upgrade to 28 spline internals and axles. A 25 spline limo will not live a happy and prosperous life behind anything more than a stock 6.

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[BTS666 15]

Got a couple of supposedly decent diff builders in Rockhampton who do alot with the speedway cars, so hopefully one of the older guys will be able to help me.

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[BTS666 15]

Talked to the diff guys, and they said just go a 78 series diff. Heaps cheaper in the long run.

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[deankxf 20,292]

2 hours ago, BTS666 said:

Talked to the diff guys, and they said just go a 78 series diff. Heaps cheaper in the long run.

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much easier also if you do make it go bang or just want to swap ratios by way of slapping in a whole diff.  (common ratios EB to EL had are 3.08, 3.23 /3.27 and 3.45 for the XR6) 

[BTS666 15]

I assume a 3.46 or 3.27 will be best for a 6spd auto.

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[Mr Polson 10,214]

I assume a 3.46 or 3.27 will be best for a 6spd auto.

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Depends what you mean by "best".

Late model Falcons with the ZF6 had 2.72 diff ratio, unless it was a XR6/XR8 etc.

Tyre size will also contribute - my LandCruiser with the Barra and ZF6 has 4.11 diffs, but that combined with the 33" tyres means it sits at 2k rpm at 100km/h.

[BTS666 15]

I mean best, by using ???/60/15s on the rear. I would like reasonable launch speed and a reasonable 100kmh highway rpm. 

 

May take a bit of mucking about. 

 

Anyone used the Ford explorer 8.8 different?

[gerg 10,871]

The 8.8, from what I understand, is a stout bit of gear, more than able to handle decent V8 torque and hard launches. The downside is that parts would be much harder to source here in Oz because of their limited use.

My opinion: I think a properly built 4-pinion, 28 spline BW 78 diff would have ample capacity to handle what you're planning to build. Going over to a completely different axle and brake setup is just creating more headaches for compatibility and engineering/roadworthiness.

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[BTS666 15]

The 8.8, from what I understand, is a stout bit of gear, more than able to handle decent V8 torque and hard launches. The downside is that parts would be much harder to source here in Oz because of their limited use.

My opinion: I think a properly built 4-pinion, 28 spline BW 78 diff would have ample capacity to handle what you're planning to build. Going over to a completely different axle and brake setup is just creating more headaches for compatibility and engineering/roadworthiness.

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Yeah. Don't see them at the wreckers much anymore. I do recall a Volvo, called the lolvo, using the 8.8 behind a turbo ls motor. It broke other stuff but not the diff.

Will just stick with what's cheaper and easiest.

Was just curious and seeking info. Thanks mate.

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[Thom 6,651]

All e series from ea series 2 have 28 spline 4 pinion btr diffs, the diffs are pretty easy to fit to xe/xf if you do some mixing and matching of e and x series diff bushes, alternatively Nathan's precision machining in Ballarat makes up bushes for the swap, he's a member from this forum (don't think he's active on here any more but his business cand be found on Facebook) and has an xf with a turbo sohc 4.0 that runs 9's using an e series diff, he's successfully done a few drag and drives with the car so he'd be the person to talk to

[BTS666 15]

All e series from ea series 2 have 28 spline 4 pinion btr diffs, the diffs are pretty easy to fit to xe/xf if you do some mixing and matching of e and x series diff bushes, alternatively Nathan's precision machining in Ballarat makes up bushes for the swap, he's a member from this forum (don't think he's active on here any more but his business cand be found on Facebook) and has an xf with a turbo sohc 4.0 that runs 9's using an e series diff, he's successfully done a few drag and drives with the car so he'd be the person to talk to

Cool. Thanks mate.

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