Area Representative Nick Bassett Posted September 20, 2016 Area Representative Share Posted September 20, 2016 Hi there,Bit of advice needed - might have the opportunity to purchase a Sierra 7.5" LSD - 3.62 ratio... questions are:1. Would it fit a 94 K series?2. Would that ratio work with a standard 5 speed box?3. Is it a worthwhile upgrade for a c. 150bhp road-going Caterham?Anything else I should be thinking of?ThanksNick Link to comment Share on other sites More sharing options...
garybee Posted September 20, 2016 Share Posted September 20, 2016 Hi, straight to the point...1. No (7.5" is from a Granada, looks similar though. Also, Ford LSDs have bolt on CV joints (lobro) which can be converted but the parts to do so are only found behind rocking horses).2. It would give you a massively long (in Caterham terms) 5th (if it fitted).3. Debateable. I won't bother offering an opinion as the next post will be telling me that I'm wrong / an idiot / of questionable descent etc.Other things you should be thinking of:-a) Converting current (7") diff'.b) Buying 2nd diff to convert (probably 3.92:1 ratio).c) Why is orange jam called Marmalade?d) Reading up on differences between limited slip and torque biasing diff's and how to identify them.e) Couldn't think of anything else diff' related...sorry.Hope this helpsGary B Edit: before the pedants start - yes I know that you can get a 7.5" Sierra diff (South African XR4) and yes I know that I've included an apostrophe in diff's (this is because I've shortened differentials, not pluralised diff) etc. etc. Link to comment Share on other sites More sharing options...
Mark Durrant Posted September 20, 2016 Share Posted September 20, 2016 NickWhat make of LSD is fitted as this will dictate if it is suitable, as the pre-load and ramp angles are important.The answer to your questions are as follows:1. The Sierra diff is 7" not 7.52. The standard ratio for a 5 speed is 3.9 so by using a 3.6 the acceleration will not be as good however, the top speed and speed in each gear will increase. Personally I would not use a 3.6 diff/5 speed with just 140bhp. It is possible for your 3.9 crown wheel and pinion to be fitted to the diff with the LSD so you retain the existing ratio.3. An LSD is a good upgrade as it stops the unloaded wheel spinning up when exiting a corner. However, depending on the type of LSD it will increase noise.Hope that helps Link to comment Share on other sites More sharing options...
Area Representative Nick Bassett Posted September 20, 2016 Author Area Representative Share Posted September 20, 2016 Thanks all - very prompt & tells me everything I need to know!Gary B - cannot answer your marmalade question I'm afraid, but have you ever wondered why cricketers wear long trousers in the summer, yet footballer wear shorts in the winter?!! CheersNick Link to comment Share on other sites More sharing options...
garybee Posted September 20, 2016 Share Posted September 20, 2016 Nick,Like it! May have to get back to you on that one. Link to comment Share on other sites More sharing options...
SM25T Posted September 20, 2016 Share Posted September 20, 2016 ...... or why Kamikaze pilots wore crash helmets ? Link to comment Share on other sites More sharing options...
JonL Posted September 20, 2016 Share Posted September 20, 2016 or why shops that are open 24 hours a day have locks on the doors Link to comment Share on other sites More sharing options...
Tony Whitley Posted September 20, 2016 Share Posted September 20, 2016 To get back to the warning that I received. You may take it with however many grains of salt that you wish. That the brown acid that is circulating around us isn't too good. It is suggested that you stay away from that. Of course it's your own trip. So be my guest, but please be advised that there is a warning on that one, OK? Link to comment Share on other sites More sharing options...
Superwhite R283 Posted September 20, 2016 Share Posted September 20, 2016 Hi Nick, I might have a standard 7 inch 3.92 diff from a sierra for sale if you're after one. Link to comment Share on other sites More sharing options...
ChrisC Posted September 20, 2016 Share Posted September 20, 2016 Caterham have a Titan on ebay. http://www.ebay.co.uk/itm/CATERHAM-WESTFIELD-LOCOST-ETC-3-92-LSD-TITAN-LSD-/262625116949?hash=item3d25ad4315:g:UUQAAOSwmfhX2Rc0 Link to comment Share on other sites More sharing options...
Area Representative Nick Bassett Posted September 20, 2016 Author Area Representative Share Posted September 20, 2016 Thanks Chris - I think this could go for a lot of money!Superwhite - thanks for the offer, but will pass. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted September 20, 2016 Share Posted September 20, 2016 Nick,Worth spending a few minutes.................. well an hour on the phone with Steve @ SP components.He has his own LSD which blows the rest out of the water, and he can build a pukka Sierra final drive thats silent too. Link to comment Share on other sites More sharing options...
Ian Mackenzie Posted September 26, 2016 Share Posted September 26, 2016 And the eBay LSD sold for.....£1,112.00.... Link to comment Share on other sites More sharing options...
Alan Archer Posted September 26, 2016 Share Posted September 26, 2016 It sure did, very strong money in my view. Link to comment Share on other sites More sharing options...
Area Representative Nick Bassett Posted September 26, 2016 Author Area Representative Share Posted September 26, 2016 £1,112.00... ouch! Link to comment Share on other sites More sharing options...
7 wonders of the world Posted September 26, 2016 Share Posted September 26, 2016 and its a Titan ! Link to comment Share on other sites More sharing options...
LesG Posted September 26, 2016 Share Posted September 26, 2016 To the OP;if your car has the early, Sierra-derived driveshafts (the cv joints will have a cylindrical shape, not the 'pinched', tri-pedal design), then it is a very easy swap to a 7 inch Sierra viscous LSD, but I would advise you swap your 3.92 crownwheel and pinion over from your standard, open diff Link to comment Share on other sites More sharing options...
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