42 replies to this topic

[claysummers]

Pretty sure the diffs in Commodores from VL on are a BW78.
Same diff as Ford, Nissan and many others.
They are supposedly rated at 500hp.
As strong as the original "big" salisbury fitted to 308 V8 Holdens?

Lots have used them for getting some serious horsepower to the ground.
Lots of ratios and heavy duty bits available too.

Cheers

Rob

BW supposed to be a lot stronger than Salisbury I think. Also pretty cheap. VL not that plentiful but probably don't need to be shortened.

early Holden nut

[gtrboyy]

Quite like b/w diffs & most of my cars had them as conversions for years...but these days crap parts availability & crazy pricing make them less attractive compared to an all new & stronger 9' diff.

 

Don't just buy cheapest thing you can find that may fit.

Edited by gtrboyy, 04 October 2021 - 12:54 PM.

[Rockoz]

A 9 inch robs a lot of horsepower due to the weight of the components in it compared to a BW78

If you are looking at over 500hp, then the 9 inch is a no brainer.

The BW78 has been used in lots of modern cars.

And cars with significant power. Quite successfully.

 

Given the shipping problems with Kung Flu, parts for most things are being delayed.

And, those that are doing the conversion work will also likely be flat out.

Again because of Kung Flu.

Lots of people are finding extra time to work on their projects.

 

I needed a bellhousing to fit an LS1 into my Toyota Dyna Tilt Tray.

From the time I first contacted Dellows, it more than 6 months until I got my order filled.

Talking to Jeff, he had more than 4 months of work waiting to be done.

He ended up not taking any more orders for a while, so he could catch up a bit.

He said he hadnt been that busy at any time that he could remember.

 

Good luck with the project.

But be prepared for unusually long waiting times for a lot of parts due to supply chain problems.

 

Cheers

 

Rob

[Ice]

Again I would advise that you talk to some diff conversion places before you spend any money, you might be wasting your money buying something they can't (or won't) use?

Prob the best advice yet Andrew and no silly shit aye  

[dattoman]

BW75 in Pintara (25 spline axles) Skyline (28 spline axles) and Commodore

BW78 is very rare in Commodore

BW78 is Falcon

[UCSLE]

skyline diffs are almost 40 years old and commodore stuff is getting old too , your almost guaranteed it has been thrashed the crap out of 

 

get a 9 inch with all new components and be done with it

Edited by UCSLE, 05 October 2021 - 12:23 AM.

[Heath]

Maybe pre 68. All the Crowns I've had had the F series. They use them for AE86 drift cars so just a bit stronger than a banjo.

Well keep in mind that you can buy a Crown (example an MS4x) of the same year as a CKD/PKD base model or a fully-imported 'Crown Deluxe'.

The year of manufacture is not the only determinant. Anything they made in Australia was full of local content like Banjo diffs obviously, at least for certain periods.
If you only owned Japanese Crowns you'd never have heard of a Banjo diff, and if you only owned R31 Skylines built in Japan you wouldn't know what the hell a Borg Warner diff is.

[RIM-010]

That $1600 9" is about $3k away from fitting your car, and you'll still have drum brakes and an open centre.

Go a BW78 out of an EF/EL Falcon.

[Zook]

If you don't want gears lower than 3.5 the toyota G142 might be worth a look. Leaf spring Hiluxes are 1400mm track, heaps of different ratios, lockers and disc brake conversions available and good reputation for strength.

This is the best, least silly, advice I've seen here. Lots of big HP rotors run Hilux diffs. And 9"s.

[claysummers]

As long as you don’t want a tall ratio


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[rodomo]

 big HP rotors 

[Zook]

For reals.

[S pack]

For reals.

Wankel.
 

[Zook]

Wankel.
 

S pack

[Ice]

Wankel.
 

Thats not very nice 

[LJ RB30]

I've had a BW75 in the Torana all along.

 

I've twisted 2 diff tubes & multiple slip yokes & axles etc.

 

The twisted diff tubes i put down to using standard Holden diff mounts welded onto the diff & collapsing with the grunt.

 

I now only use McDonald Bros racing mounts.

 

403rwhp 500 flywheel ft/lb torque & manual box.  403HP.jpg   222.06K   4 downloads

 

Now has 31 spline billet axles, fully welded tubes & mini spool (as i got sick of destroying LSD's but car is not road going now) would probably do a truetrac if was on road.  

 

It does not get driven politely as mostly drags with a bit of circuit but the BW75 is tuff.

 

My mate has a 360 Charger with vortec belt driven hairdryer that runs high 10's & still has the BW in it with a truetrac.

 

My vote is BW 

 

 

[rexy]

Counterpoint.

 

After getting sick of destroying banjo axles and centres in my old 4 door LX I fitted a nine inch with 3.5 LSD, genuine ford gears and billet axles built by the crazy guy at RUCPOL.

 

I gave that a flogging behind a 383 holden/ R154 manual combo on drag radials for 80,000 kilometres without it missing a beat.

Even got my money back on it when I parted the car out.

 

Whichever option you chose I encourage you to spend enough money to do it right the first time. Cheap shortcuts are soon regretted when you are paying for yet another tow home and more bits to fix it.