Blatman Posted November 6, 2002 Share Posted November 6, 2002 IRS weighs more than a dedion 🤔 Is there any empirical evidence to suggest this 🤔 Otherwise I'd say it's close enough to make bugger all difference, especially considering the amount of identical shared parts, and the fact that the Westfield does without the enormous de dion tube......... . I reckon IRS is lighter.......... The Westfield lightweight body work is fairly light, but I don't know by just how much. Certainly on my cars, the ("standard road") bodywork seems to be the biggest handicap to getting down to seriously light weight Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 6, 2002 Share Posted November 6, 2002 IRS has more bits and pieces than dedion which in turn has more bits and pieces than live axle. Thus live axle is the lightest but has the most unsprung weight, then dd, then IRS. So that suggests the heavyweight bodywork is heavier than my ali skin by the same amount the blade engine, box and reverse box is lighter than my K and 6 speed... HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
Blatman Posted November 6, 2002 Share Posted November 6, 2002 IRS has more bits and pieces than dedion Like what 🤔 Link to comment Share on other sites More sharing options...
Julian Thompson Posted November 6, 2002 Share Posted November 6, 2002 I'd like a carbon prop depending on price..........(!) Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 6, 2002 Share Posted November 6, 2002 I'm sure this has been covered before and *agreed* on.... But here goes... IRS: cage around diff to mount wisbones on 8 links from cage to uprights (2 on each of the 4 wishbones) larger uprights to take the two wisbone mounts and prevent the wheel steering DD: DD tube A frame = 2 links radius arms = 2 links dd ears so its comes down to the dd tube against the cage around the diff that the wishbones mount to.... Still can't remember where/when this was discussed... back on topic - both would be lighter with carbon halfshafts ❗ HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
mr_ed Posted November 6, 2002 Share Posted November 6, 2002 >The biggest obstacle you'll face is the weight of the bodywork unless you already have >Westfields lightweight "race" bodywork........... I have. Pretty much managed to turn it inside out when getting it down from the garage rafters ;) Link to comment Share on other sites More sharing options...
mr_ed Posted November 6, 2002 Share Posted November 6, 2002 >I weighed my car against a megabird a couple of days ago. once fuel was taken into account he >was only 10 kg lighter than my K. both of us are aeroscreened, but he's also missing doors and >boot. Ah, but I believe you have magnesium wheels and ACB10s... he was on minators and 205 A032rs. The K is a light car engine, the blackbird is a heavy bike engine! But, of course, like for like Caters are a bit lighter than Westies (say 20 to 30kgs?) Cheers, Ed Link to comment Share on other sites More sharing options...
Blatman Posted November 6, 2002 Share Posted November 6, 2002 The "cage around the diff" amounts to perhaps 4-5 feet of 16 guage mild steel. Say 2-3 kilos, plus wishbones. The Caterham equivalents are, as you say, the radius arms and A frame, DD tube, ears and radius arms. More metal there than my IRS set up I reckon........ so its comes down to the dd tube against the cage around the diff that the wishbones mount to.... You lose then, to the tune of the weight of 1 DD tube, -2 to 3 kilos............. I guess we'll have to compare proeprly at some point.............my rear end is coming out at some point, so I'll take some weights........ In the meantime, entertain yourself with the Fluke Motorsport weights database........... Link to comment Share on other sites More sharing options...
murph7355 Posted November 6, 2002 Share Posted November 6, 2002 .............my rear end is coming out at some point, so I'll take some weights........ If that's why you're not coming to the meet tonight then I reiterate my comment on that thread but am also quite relieved. 😬 Link to comment Share on other sites More sharing options...
Blatman Posted November 6, 2002 Share Posted November 6, 2002 Arf................ and no, that's not it, you big girl.......... 😳 😬 Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 7, 2002 Share Posted November 7, 2002 actual weighings of the rear ends would be good - we could stop waving our hands about them ❗ The point (was there one ) of what i was saying is that i was surprised that the westie was fundamentally that much heavier. 20-30kg is quite a lot... HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
Marius Posted November 7, 2002 Author Share Posted November 7, 2002 Now stay clear with that Westfiled-****, this is a Caterham & Lotus -Forum so I´m not interested in any Westie & IDS details..... I think the original topic had something to do with a carbon-fibre prop-shaft... Marius Link to comment Share on other sites More sharing options...
Mike Bees Posted November 7, 2002 Share Posted November 7, 2002 ISTR that the 4x4 Espace used a composite propshaft to take the drive to the rear wheels. OTOH maybe I've been on the cheese again. Mike Link to comment Share on other sites More sharing options...
Morls Posted November 11, 2002 Share Posted November 11, 2002 Chris Flavell wrote: "I would have thought that the best solution for a BEC would be to use a flexible disc coupling between the bike gearbox and the reversing unit." Sorry to be so daft, but... what kind of flexible disc coupling? Like a rubber doughnut type? I'm sure when these are used with the bike engines, a centre bush has to be used to stop the doughnut distorting under the lateral force of the prop trying to straighten itself up to line -up with either the output shaft or rev box / centre bearing. Or something different? Ed, Which centre bearing do you use? And who built your prop? Mark ☹️ My Caterham Silver Jubilee No. 7 is for sale ☹️ Link to comment Share on other sites More sharing options...
Morls Posted November 11, 2002 Share Posted November 11, 2002 I must not Double post I must not Double post I must not Double post I must not Double post I must not Double post I must not Double post Edited by - Mark Jackson on 11 Nov 2002 12:41:52 Link to comment Share on other sites More sharing options...
mr_ed Posted November 11, 2002 Share Posted November 11, 2002 Errr, perhaps I shouldn't reply, being as I'm a Westy owner and a certain someone gets a bit upset about that... (!) My propshaft was built by Bailey Morris (who've built about 4 props for me over the years, all very good). It uses the "new style" transit centre bearing. I've got the rubber donut coupling on the engine, and yep it has a sort of spherical bearing in the centre to take the weight of the prop and to stop it flailing if the rubber donut was to fail. Cheers, Ed Link to comment Share on other sites More sharing options...
scooby dooby doo Posted November 11, 2002 Share Posted November 11, 2002 mr_ed - just saw your earlier comment - both of us were on A032Rs. Actually my rears are 7" so my tyres are actually HEAVIER HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
Morls Posted November 11, 2002 Share Posted November 11, 2002 Ed, I'm assuming your prop set-up works well? But IIRC you dont have the bother of a diff that moves up and down, like us low tech ital axle people, so that's one less variable for the bearing / prop. Where did the doughnut, not-a-sprocket and tranny bearing come from? What info did Bailey Morris require? How much did things cost? Is there anything you would do differently if doing it again? Why do I ask so many questions? Should I stop now? Mark ☹️ My Caterham Silver Jubilee No. 7 is for sale ☹️ Link to comment Share on other sites More sharing options...
mr_ed Posted November 11, 2002 Share Posted November 11, 2002 >I'm assuming your prop set-up works well? Very well ta! And cos I've got the cush-drive donut, it means I can use 2inch tube all the way through, and so it is lighter than propshafts which have the Torque Resiliant Tube cushdrive instead (cos this requires 2.5inch tube). >But IIRC you dont have the bother of a diff that moves up and down, like us low tech ital axle >people, so that's one less variable for the bearing / prop. Thats right, I have IRS, but, I know loads of people with live axled locosts/furies with a similar setup. With my prop, I have 2 UJ's, one at the diff, and one immediately behind the centre bearing. So although the front prop is fixed by the cushdrive donut/centre bearing, the rear section is free to bounce up and down! >Where did the doughnut, not-a-sprocket and tranny bearing come from? I bought the doughnut & flange from blackbird motorsport. Its the same as the James Whiting Caterblade one, and I think Allens Performance R&D do them too. This is 165quid + VAT. The centre bearing, I bought it from Bailey Morris. They sent it to me, and I fitted it to the chassis, and made a mockup prop using plastic drain pipes. Take a measurement from the diff flange to the centre bearing centre line, and from the centre bearing centre line to the cushdrive flange. >What info did Bailey Morris require? Then sent the bearing back to Bailey Morris, with the cushdrive flange, and those measurements and they made the prop. It has a slider in the rear section, so doesnt have to be MM perfect. >How much did things cost? Less than 200quid from Bailey Morris, including postage 3 times over for the bearing to-ing and fro-ing. Plus the 165+VAT for the cush-drive. >Is there anything you would do differently if doing it again? Ummm. Nope, not a sausage actually. This is my second bike engined car, and I've sucked wisdom from the friendly chaps at Blackbird Motorsport. >Why do I ask so many questions? >Should I stop now? Can I ask some! Is yours an older Caterham, or have you bought a starter kit? Are you going to get a new CWP for the diff? How've you mounted the engine? Is it high enough that you dont need to dry sump it, and has it forced you to run a bonnet bulge? ...might do a CaterR1 or something someday. Cheers, Ed Mark Link to comment Share on other sites More sharing options...
Morls Posted November 11, 2002 Share Posted November 11, 2002 Ed, Cheers for the info. Mine's an older Live axle car, getting rebuilt with mainly new bits. A starter kit / Caterblade would definately have worked out nearly as cheap, but I like to tinker with things and it keeps me out of the pub (except Fridays and Saturdays of course). I'm fitting a 3.31:1 diff into the ital axle to get a reasonable touring capability and will be running 185/70/13 tyres to help this and the ground clearance. I've made my mounts to get the engine as close to the bonnet as possible, but if I can build a semi-remote air box/filter arrangement another 20mm is possible. Changing the engine position slightly will be staightforward as each strut in the subframe (all individual struts to form pin jointed triangles) is rose jointed and the other end (with polysport bushes) can be shimmed. Currently my ground clearance is the same as my dry sumped x-flow Caterham, but in the lakes yesterday this was barely enough, so I'm thinking of useing the Sturt Taylor billet sump to move the plug and gain a little toughness and clearance. I had originally planned a CateR1, having my R1 (now sold ☹️) parked next to the Caterham made this seem so easy. The meaurements don't add up that well ompared to the blade tho. The R1 is that bit taller. A much better engine in the bike tho... a friend's 919 'blade used to seem positively gutless after my R1. And to end... another question.. preumably you have a conventional UJ at the centre bearing end of the front prop? Mark ☹️ My Caterham Silver Jubilee No. 7 is for sale ☹️ Link to comment Share on other sites More sharing options...
R2D2 Posted November 12, 2002 Share Posted November 12, 2002 Flexible disc couplings don't have rubber donuts in them. They have a pack of steel membranes. The idea is that they take up misalignment but are torsionally stiff. They should not only be lighter than a carden shaft but the weight should be a lot less overhung and give the supporting bearings a much easier time. Link to comment Share on other sites More sharing options...
mr_ed Posted November 12, 2002 Share Posted November 12, 2002 Hi Chris, >Flexible disc couplings What is the range of operating angles though? I think I looked into these and found they would only operate at a very small angle. I also looked at using CV joints, as GKN motorsport advertise ones suitable for propshaft rpms, but when I enquired further found that they can only operate at angles of 0.5degrees. If you're gonna run it more or less straight, the rubber donut cushdrive is very good. Cheers, Ed Link to comment Share on other sites More sharing options...
mr_ed Posted November 12, 2002 Share Posted November 12, 2002 Hi Mark, Your car sounds like it'll be very nice. Aiming for sub 400kgs? This 3.31 diff, is it a easily sourceable crown wheel and pinion? If it is, then that's a smart move, cos I'd imagine the bespoke 3.2 that the Caterblade uses is quite pricey. With a 3.31 diff I dont think you'll really need the 70profile tyres, unless you're doing a lot of touring. I've got a 3.2 diff and 185/50/13s for track use and its nice. Aye, the idea of using the Stuart Taylor sump had crossed my mind with a Caterblade project too. This engine really does not need to be drysumped (on the OEM sump), Caterham only do it for ground/bonnet clearance issues AFAICT, and the Stuart Taylor sump looks to be only about 10-20mm deeper than the dry sump pan. >And to end... another question.. preumably you have a conventional UJ at the centre bearing end >of the front prop? Yep, but this is behind the centre bearing. Starting at the engine, I've got: Cushdrive Joint thing. Prop Centre bearing UJ Prop UJ Diff Cheers, Ed Link to comment Share on other sites More sharing options...
R2D2 Posted November 12, 2002 Share Posted November 12, 2002 Typical disc couplings run up to 0.2degrees misalignment, which should be ok on a dedion or independent rear end but wouldn't work with a live set up. The idea of a centre bearing to shorten the shaft is probably a good idea as it helps the lateral critical speed of the shafting. I am sure you could run one of the GKN Motorsport CVs in this position as 0.5 degree alignment should be fairly easy to acheive with an independent rear axle and it may give a tramsission line. I am not a great fan of rubber donuts in the centre of drivelines. I realise that they help to damp some torsional vibrations from the engine but the also introduce a torsional vibration if they run at an angle. This must cause some heating in the joint and some power loss, at least theoretically. The reason I am not too keen on a carden shaft is that it hangs quite a lot of weight outboard of the gearbox bearing and at relatively high revs that can't be too good for its life. Link to comment Share on other sites More sharing options...
Morls Posted November 12, 2002 Share Posted November 12, 2002 Chris, The problem with a blade engine in a LA Caterham is unfortunatly not just the vertical deflection of the diff, but also the angle of the gearbox's output shaft relative to the car centreline. The cam cover of the engine is almost parrallel to the chassis sides of the engine compartment, so it's angle to the tunnel centreline is in whole numbers of degrees. If the engine were mounted with crank and gear shafts parrallel to the centreline the output shaft would be pointing almost at the driver's left foot (or the front cylinder head touching the NS top chassis rail. I've dug out an industrial drives catalogue which has a fascinating variety of flexible / clutching / ratcheting and simple looking ways of connectiong rotating tubes, but I suppose with this angle and torque I'm going to have to use conventional UJs. *idea*The ratcheting bearings looked ideal for stopping the downshift blow-ups reported on some BECs though. Ed, I'm hoping the car turns out to be a lightweight, to make up for it's driver who definately isn't 😳. The diff was in Redline for under £100 and is being set up at SPC as we speak. I think the ratio may be that from a Triumph Vitesse (although in an independant case in this application), or similar, I'm sure I remember seeing the ratio on an application list on the TSSC site. I don't suppose you have an e-mailable photo of the centre bearing assy do you? I assumed I'd need a UJ eaither side of the centre bearing to half the angle (created by the enforced engine position) on each end of each shaft. If so, I'm on e-morls@mark-n-morls.fsworld.co.uk Cheers Mark Mark ☹️ My Caterham Silver Jubilee No. 7 is for sale ☹️ Link to comment Share on other sites More sharing options...
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