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Lightweight aluminium Drive shafts

Discussion in 'The Lounge' started by mikecoombs, Sep 29, 2018.

  1. mikecoombs

    mikecoombs Active Member

    Has anyone tried to have one made for the P6? I'm looking into it as according to my rough calculations the dynamic weight saving would be around 150 kg as it's a major rotating member. Also looking at the axle shafts.
  2. Willy Eckerslyke

    Willy Eckerslyke Well-Known Member

    Please excuse my hignorance but what does dynamic weight saving mean? I imagine standard driveshafts weigh 5kg or so.
  3. cobraboy

    cobraboy Well-Known Member

    I shed 4kg off the flywheel on the 4.6, that made it nice and snappy. Going ally or carbon fibre on the propshaft will also help but may be eye wateringly expensive.
  4. PeterZRH

    PeterZRH Well-Known Member

    Presumably you mean rotational energy (mrʊ^2) or angular momentum. The dynamic load in a rotating member when correctly balanced is nil.

    I'd ask what you were trying to achieve. You can save 2kg from the system in 1 minute by removing the fixed engine fan, then more as has been said from the flywheel.

    In terms of throttle response, next stage 1 heads and a freer exhaust and improved headers.
    ButterFingers likes this.
  5. ButterFingers

    ButterFingers Active Member

    I have a better soultion, buy a mini Cooper and go for gold!
    PeterZRH likes this.
  6. corazon

    corazon Well-Known Member

    I’ve thought about adapting aluminium shafts from modern mustangs which can be bought used for reasonable money. They’re a decent length to work with if you can find an economical way to change to a Rover flange of course..
    You’ve probably seen the US companies offering custom made aluminium driveshafts to your spec. They're rather pricey :eek:
    Half shafts would be cool!
  7. mikecoombs

    mikecoombs Active Member

    Mustang shafts were where I started. Dana and others make a large range of components in alloy. pricing is around$700USD. I've already got stage 2 heads and cam plus custom straight through 2.5" exhaust and headers. My Rostyles are each 8.5 Kg instead of the factory 20 odd. Alloy axles would lighten both the unsprung weight and reduce Peter's angular momentum. (Thanks peter i was trying to find a single term to describe the effect of reducing the tailshaft/engine speed rotating weight on the overall acceleration of the car in terms of all up vehicle weight. It was early in the morning and I grabbed the first term that came up, knowing someone would sort it out!)
  8. corazon

    corazon Well-Known Member

    I’ve been researching aftermarket limited slip units for my Jag diff and noticed that Quaife do a complete aluminium cast diff for when weight saving gets serious. Not that it’s unsprung in a P6 though
    I’m still interested in getting an ally driveshaft, currently I have a chunky old S type Jag prop which bridges the gap between my ZF and Jag diff nicely, but weighs a tonne.
    Do Dana etc sell the flanges so you can weld your own?
  9. corazon

    corazon Well-Known Member

    Summit Racing has a large selection of aluminium driveshafts. Their own brand are affordable and are allegedly Ford Racing parts rebranded, which themselves are Spicer/Dana I believe..
  10. SydneyRoverP6B

    SydneyRoverP6B Well-Known Member Staff Member

    My biggest concern would be fatigue failure. Steel, which is also an alloy (of iron and carbon) can withstand many more cyclic loads compared to aluminium alloy. Of course, if the latter is significantly large in cross section, then the deflection would represent a noticeably smaller percentage, and its resistance to fatigue failure would be enhanced.

  11. mikecoombs

    mikecoombs Active Member

    they seem to be about 1/4" thick alloy as opposed to about 1/32 for a commercial steel one. Sonnax appear to make all the bits required including the sliding joint. I'll have to go see one in the flesh...
  12. PeterZRH

    PeterZRH Well-Known Member

    Well as steel is three times the density of aluminium, so 8 times as thick would make aluminium heavier.

    Actually you need to know a bit about modes of failure and these differ somewhat for thin wall vessels. For most cast items anyway cracks usually start and the surface which is why simple techniques like shot-peening can improve service life by orders of magnitude.
  13. Demetris

    Demetris Well-Known Member

    Having in mind that there are all sorts of different aluminium alloys with equally different properties, i think that it is not very proficient to discuss about aluminium in general. The aluminium alloy of a Land Rover front wing is very different from the aluminium alloy used in aircraft structural parts.
    corazon likes this.

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