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Diff-specific bunfight thread


Astro_Al
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Well, I figured I'd extend the Great Engine Bunfight Thread theme to other parts...

While I'm miles from my garage pondering on hybrid axles, what are people's thoughts on centre sections?

I'm looking for some steel that'll hold up to a nice V8 (say 500 bhp & lbft for now), be lockable, and have ratios in the 3.x range.

Recently I've been reading about BMW / Jaguar centre sections, of which I know nothing. Now these won't have lockers of course, but they may have LSDs etc and be worth considering. I was going Ford 9" by default, but before I commit to shipping everything over, what am I missing from this side of the pond?

How about other trucks? - Nissan? Toy?

Industrial / lorry type stuff?

Cars?

Don't worry too muchabout the necessary beef, as they'll be upstream of portal boxes of around 2.0 ratio (so halving the torque at the diff).

Cheers people, post up any ideas. Reckon a beefed up Sals could handle it???

Al.

:)

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Well, I figured I'd extend the Great Engine Bunfight Thread theme to other parts...

While I'm miles from my garage pondering on hybrid axles, what are people's thoughts on centre sections?

I'm looking for some steel that'll hold up to a nice V8 (say 500 bhp & lbft for now), be lockable, and have ratios in the 3.x range.

Recently I've been reading about BMW / Jaguar centre sections, of which I know nothing. Now these won't have lockers of course, but they may have LSDs etc and be worth considering. I was going Ford 9" by default, but before I commit to shipping everything over, what am I missing from this side of the pond?

How about other trucks? - Nissan? Toy?

Industrial / lorry type stuff?

Cars?

Don't worry too muchabout the necessary beef, as they'll be upstream of portal boxes of around 2.0 ratio (so halving the torque at the diff).

Cheers people, post up any ideas. Reckon a beefed up Sals could handle it???

Al.

:)

I've heard BWM X5 is the thing to have for independent vehicles - strong diffs and long wishbones.

Salisbury are nice and strong plus fairly easy to source as are lockers in a variety of spline flavours.

Jag's are D44 based aren't they? If so ARB centres are available for them...

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I've dreamt about hybrid axles :lol: , my choice would be Dana 44 centres on unimog portals, the 44's are substantially lighter than the 60's but ARB make a 35 spline locker for them, excellant choice of ratio's although they don't go as high as the Ford 9", stuffed under the back of diesel Jeep cherokee they are quite available. As the axle tubes are just that, tube, makes it a little easier to cut and shut.

Only question mark is whether they are wide enough to allow for offset diffs, don't know the width of the axles or Mog portal box's.

Anyone care to share how wide the Mog portal box's are? Dan, Lewis?

Andy

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Yes, sure the D44 is a possibility. Personally I'm a bit iffy about its ability to take the heat. I think most would recommend the 60 or the Ford 9 for this.

Yes, its for Mog boxes, of which I have gathered one or two... ;)

There's plenty of room to offset - they're not THAT big!

Cheers, Al.

P.S. Fridge - I can see you're about to post: its not TTPOOAD you know!!!...

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I reckon Bimmas are a good bet, can ask my cousin about them as he spends half his life in the scrapyard hunting for BMW bits to fill his bedroom with :D

If you want to know what lockers/ATB's/LSD's are available then have a read here, some unsightly prices but may give you some different ideas...

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Hmm, I was thinking something a little lighter weight? After all, that's the point of swapping out the centre section. For something that belongs in a Sherman tank? I may as well leave the 406 centre in?!

That's why the Ford 9 was the favourite - nice and light weight (can be had with ali or magnesium housings etc), good and strong, has lockers, good range of ratios, freely available, great support.

Hmmm, maybe I have already found the ideal?

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Going off on a potentially silly tangent - what about Ford Transit etc. diffs (Merc Sprinter would be a good candidate as they're pretty nippy) - lots about, reliable, take some abuse, no idea on weight.

Then again I still stand by BMW, with factory LSD's they've got to be up to some abuse, and do you absolutely have to have lockers if you have LSD & fiddle brakes? It's not like this is ever going to leave the drawing board anyway...

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That's why the Ford 9 was the favourite - nice and light weight (can be had with ali or magnesium housings etc), good and strong, has lockers, good range of ratios, freely available, great support.

Hmmm, maybe I have already found the ideal?

Did you see the thread, on pirate I think, relating to Hybrid axles there was some discussion on the pro's and cons of Ford 9" v Dana 44's.

Other thing I forgot to say about D44's is the 35 spline ARB is only available for 4.10 and up R&P's so you'd have to have a spacer made for higher gears.

Are Ford 9" available this side of the pond or is that immaterial.

If you have a plentiful supply of Mog portal box's I could find a home for a set :D

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Great stuff guys. The BMW suggestion is basically why I started the thread. As you say Fridge - and LSD and fiddles could surely be enough? Ok its not a locker, but as long as some torque is reaching the tyre...?

I love the idea of getting spare third members for less than a tonne. Ford 9s are definitely a ship-across item. Meaning megabucks (cos its not cheap in the first place, for a blingy new third). I was wondering if I couldn't use something more local.

IMHO a Ford 9 is comparable with the D60. A D44 isn't in that league. But... with the torque reduction, things get more hazy...

SOA - I could maybe hook you up with a set of 404s if you are interested? Just the portals for hybrids, or the whole axles?

Al.

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Yes, sure the D44 is a possibility. Personally I'm a bit iffy about its ability to take the heat. I think most would recommend the 60 or the Ford 9 for this.

There's plenty of room to offset - they're not THAT big!

Al, when you say iffy about its ability to take the heat do you mean 'heat' or are we talking about strength?

As I understood it they were pretty strong diffs but let down by the ability to only take 33 spline.

Regarding the width, I meant the axles, cut one end off, was the other side longing enough with the portal box's to make up the offset without having to extend the tube.........if you see what I mean :blink:

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Al,

I don't know what ratio your aryan master race portal boxes are but if they're, say, 2:1 then you're (very approximately) halving the load on the diff & shafts, for a light car (well, lighter than a mog) if you start with a Bimma diff that's good for 200+ hp (the new M3 is 340bhp) and stick a reduction box after it you should be onto a winner.

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Al,

I don't know what ratio your aryan master race portal boxes are but if they're, say, 2:1 then you're (very approximately) halving the load on the diff & shafts, for a light car (well, lighter than a mog) if you start with a Bimma diff that's good for 200+ hp (the new M3 is 340bhp) and stick a reduction box after it you should be onto a winner.

Yes Mr SOA - I can probably sort you out with a set then. I can throw in the axle cases too in case you need the flanges / tubes for you hybrid creation? I was gonna make a wood burning stove out of one, but I guess I can let you have it (or chop the ends off for you and use the centre for my stove for some proper garage bling?).

D44s aren't exactly monsters. With a big V8 you are definitely on dangerous ground. Oh, and yes by heat I meant torque... :rolleyes:

Perhaps that explains my mark in 1st year thermodynamics... :huh::ph34r:

Yes Fridge I'm halving the TORQUE - not the BHP (and not the heat either :blink: ...). But there's a hell of a lot of it to start with. I'm not convinced these Bimmer bits are gonna do the job, especially with respectable tyres... Interested though. Its defo on the right lines.

Al.

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Only question mark is whether they are wide enough to allow for offset diffs, don't know the width of the axles or Mog portal box's.

Anyone care to share how wide the Mog portal box's are? Dan, Lewis?

Andy

Mog (404) axle cases are 44 1/8" wide

Al,

I don't know what ratio your aryan master race portal boxes are but if they're, say, 2:1 then you're (very approximately) halving the load on the diff & shafts.

Sory fridge but it doesn't work like that!

a 2:1 drop gear will only save the shafts and diffs by about 30% .

As for diffs ford 9's are easily available over hear. but the ford 8.8 may prove to be a better solution as it can be had in a lot of ratios and lockers and has been fitted to the back of uk spec ford rangers for a while now.

my prefrence would probably err on the side of d60's as they are about the strongest best catered for axle on the market.

But g wagon axles (or 2 rears) would be my favourate very strong diff locker as standard, and a reasonable choice of ratios as the same R+P was used in the 608 vans

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Dont know the details like others here, but what about Volvo axles( not portals), the sort found in good old 240 and 740, 960's. They are a common swap for hotrodders etc, and have a good reputation for strength.

They have been known to survive in Ford Pop hotrods behind some pretty vicious yank V8's?

Alternative on the ford axle front is to find something here in the uk currently residing under a Lincoln stretch limo, also be cheap, IIRC there is a company up near Hetahrow that breaks american cars.

Save shipping from the states?

What about an Iveco Daily for a donor axle?

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There's a lot of talk about BMW diffs in this thread, but I should point out that they are fitted to independant rear suspension setups, which means they will be very hard to graft into a solid/live axle case.

Regards,

Diff

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Sory fridge but it doesn't work like that!

I did say very approximately - it certainly lowers the load, and if you're starting with something that is designed for 300bhp and 100,000 miles it should be fine. All this super beefy stuff adds weight which adds the requirement for big HP to carry it round, which adds weight...

Since we don't know what the hell Al is going to do with this car it's difficult to speculate about what he might need - if it's going to have a big heavy yank lump and big heavy yank transmission then it'll need to be big and heavy to stay in one piece. If he's going to build something like Rog's rock rod then the story is different and big heavy diffs are just weighing it down.

Anything can be broken, if you try to achieve an unbreakable truck you end up with a tank. Try factoring in a bit of mechanical sympathy and build something smaller, lighter and more nimble.

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Has someone spiked my coffee this morning? It doesn't make sense. 2:1 is 2:1. If you try to balance a 10 lb load attached to one end of graduated lever and you place the fulcrum at the 1 ft mark, you will need to push down at the 2ft, mark

(a ratio of 1:1) with a force of 10lb to acheive a state of balance.Disregarding the weight of the lever material, at the 3ft mark you have a 2:1 mechanical advantage so should only need to push down at this point with a force of 5lb to acheive a state of balance. That is half the force that my hands need to apply=half the stress. A pair of gears are just continuous rotary levers and the same principal applies surely ? Discounting frictional losses,with a 2:1 ratio gearbox you put 5ft lb of torque at 100 rpm in one end and you get 10 ft lb out the other end at 50 rpm. and vice versa? I'm confused.If the 30% number hadn't come from Dan I would be more sure of myself.

Bill.

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