Mr Whippy
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| posted on 10/4/08 at 09:58 AM |
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how stong are BEC diffs
Ok rather a vague crappy question I know but how strong are these chain drive diffs used on some of the BEC cars? (no I'm not going BEC I can
assure you) would they for example handle the weight of a saloon car day to day without falling too pieces? Not thinking of masses of power going
through it rather just a high torque most of the time.
Fame is when your old car is plastered all over the internet
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Paul TigerB6
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| posted on 10/4/08 at 10:03 AM |
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We know you really want bits of a BEC in your car but why would you want to put an alternative diff into an everyday saloon car??
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Mr Whippy
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| posted on 10/4/08 at 10:15 AM |
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just pricing stuff out for a project and working out the most suitable parts to use
Fame is when your old car is plastered all over the internet
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Miks15
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| posted on 10/4/08 at 10:18 AM |
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arent some of the chain drive diffs just modified car diffs?
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Paul TigerB6
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| posted on 10/4/08 at 10:20 AM |
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I would think the weakest link will be the chain myself rather than the diff. I guess a double chain might be an option using two sprockets bolted to
the diff / gearbox output???
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Mr Whippy
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| posted on 10/4/08 at 10:37 AM |
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quote:
Originally posted by Miks15
aren’t some of the chain drive diffs just modified car diffs?
They are? I thought the whole casing turned on the BEC diffs so that only leaves the planetary gears that could be used. I need to check that up.
Two chains is a good idea, plus I was thinking of fabricating an enclosure to keep it clean. This is the kind of diff I was thinking of using -
[Edited on 10/4/08 by Mr Whippy]
 
Rescued attachment diff.jpg
Fame is when your old car is plastered all over the internet
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greggers
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| posted on 10/4/08 at 10:46 AM |
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Is this for your electric car idea by any chance?
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smart51
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| posted on 10/4/08 at 10:47 AM |
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The Sylva R1ot uses a fiesta diff, without the casing. The chain wheel bolts to where the crown wheel used to go.
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Mr Whippy
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| posted on 10/4/08 at 11:02 AM |
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quote:
Originally posted by greggers
Is this for your electric car idea by any chance?
Yeah that’s right. I figured that if I did away with the engine, gearbox, exhaust, fuel tank & radiator, most of the weight of the batteries would
be compensated for. Sounds like using a motor through an auto box is a problem due to the need to maintain oil pressure in it even when stationary so
I was just going to make it direct drive though I have a good manual box in reserve and a new manual steering rack. Just rather do away with the 40kg
of the box altogether...
I only ever use the car for short journeys around town – work, shops etc. Mostly sitting in traffic,  so range and top speed are irrelevant, I have
the Volvo for long distance anyway. The cars getting fully done up right now so thought this was the ideal time to convert it. I was going to use
water cooling for the motor to heat the demister.
[Edited on 10/4/08 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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PAUL FISHER
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| posted on 10/4/08 at 11:18 AM |
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The sprint R users the fiesta diff internals
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MikeCapon
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| posted on 10/4/08 at 11:29 AM |
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If you want to uprate a chain drive, use a duplex chain.
I had found you a lovely piccy but for some reason I cant upload it.
Look for "duplex chain" in Google images.
Edit to add image
Image deleted by owner
[Edited on 10/4/08 by MikeCapon]
www.shock-factory.co.uk
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Miks15
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| posted on 10/4/08 at 11:34 AM |
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Mr Whippy
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| posted on 10/4/08 at 11:37 AM |
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certainly looks the way to go  cheers
Fame is when your old car is plastered all over the internet
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trikerneil
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| posted on 10/4/08 at 11:57 AM |
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I know of a Hyabusa Trike (claimed 178hp) with a single chain driven Reliant Robin axle.
It's been on the road for about four years now with no problems, and the owner rides it like he stole it!
I think the crownwheel and pinion are the weakest link in a normal setup.
Neil
ACE Cafe - Just say No.
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russbost
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| posted on 10/4/08 at 01:13 PM |
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All the chain drive diffs apart from really specialist (& expensive) stuff use car diffs. I would agree that if there was a weak point it would be
the chain, but if you can transmit 'Busa power usedas it is in something like Z cars Mini without a problem I really don't think
you're going to have a problem with an electric motor. The biggets loading on a diff is when you rev up (particularly with a big heavy car
flywheel) & dump the clutch - I can't imagine a similar situation with an electric motor.
You will also be saving most of the weight of a big cast casing - the sideplates on chain diffs don't weigh much.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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Mr Whippy
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| posted on 10/4/08 at 01:43 PM |
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Russ,
What did you uses on the Furor? you put quite a bit off power through it with the two engines. Do you have a linky?
Like you say the initial starting torque really isn't going to be very high especially without using a gearbox, I think the motors peak torque
is around 4000rpm but I'm not after a speed machine so don't care about 0-60 times.
[Edited on 10/4/08 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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matt_claydon
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| posted on 10/4/08 at 04:43 PM |
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Peak torque on a motor (unless there's some kind of controller interfering) is at zero rpm.
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jono_misfit
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| posted on 10/4/08 at 07:06 PM |
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My friends most recent hillclimb cars put nearly 400 Bhp and 300nm of torque through a fiesta diff. They havent melted yet, but then again its
probably done less than a hundred miles.
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russbost
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| posted on 12/4/08 at 12:06 PM |
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On the Furore - the existing car that is - it doesn't have a diff, each engine drives each rear wheel separately so power is split between the
2 drives - around 137BHP & 80 or so Nm torque each.
I'm sure you'd have no problem with any normal chain drive bike diff.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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