Pete-B Posted May 31, 2011 Share Posted May 31, 2011 I put my name dowm earlier in the year to have the option of having the BMW diff fitted at the special prices if I wanted to. I've got a Sigma 150 Roadsport which I use for road only, I had my present Sierra open diff rebuilt by Phil at Road and Race last year and it's certainly quieter than it was, but as Phil said, " due to the very nature of the car, how they are built and the power to weight ratio it's never going to be silent so it's a case of learning to live with it". So what is the general consensus of the new diff, there must be quite a few people running with them now, are they quiet, are they just as bad, or somewhere in between or should I just stick with the devil I know? Link to comment Share on other sites More sharing options...
Sheds Moderator Posted May 31, 2011 Share Posted May 31, 2011 I've not compared one with the other but if RRT say "this is as good as it gets" then it's likely to be true. A BMW diff is expensive and in what way does its fundamental design differ from the origional? Not at all as far as I know, so I would suggest you will see no difference worth talking about. You have a metal case full of meshing gears, 2 feet from your ear, in a small car with no sound insulation. It's not going to be quiet, ever. Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted May 31, 2011 Share Posted May 31, 2011 Don't waste your money. Stick with the Sierra diff. Link to comment Share on other sites More sharing options...
sevenmad Posted May 31, 2011 Share Posted May 31, 2011 And the BMW diff is much heavier Link to comment Share on other sites More sharing options...
mic Posted May 31, 2011 Share Posted May 31, 2011 The BMW diff is much quieter than a noisy Sierra diff. The plates in the BMW Titan diffs have been found to be noisy.The material is being changed to rectify this. I think the open diff with the carrier is about 5kg heavier than an open sierra diff. Link to comment Share on other sites More sharing options...
2slo Posted May 31, 2011 Share Posted May 31, 2011 If Caterhams were quiet and refined they'd be luxury saloons and we'd all be reading Westfield chat Link to comment Share on other sites More sharing options...
adz Posted May 31, 2011 Share Posted May 31, 2011 BMW diff dry, with titan LSD is 27Kg - weighed mine before I put it in. I've only done a few 'running in' miles but they were on a track with the hood up 'cos of rain and the diff is not noisy, just a bit of clicking when you corner. no obvious drivetrain shunt. I has a sierra (LSD) diff in my roadsport last year and the BMW is quieter, far less whiny. regards Adam Link to comment Share on other sites More sharing options...
Brian W Posted June 13, 2011 Share Posted June 13, 2011 I have bitten the bullet and I am having the Sierra differential in my year old Sigma 125 SV replaced by Caterham with the BMW diff on Wednesday. I will report back on the comparison between the two. Brian Link to comment Share on other sites More sharing options...
Domus Posted June 13, 2011 Share Posted June 13, 2011 Spooky, whilst reading this thread an email from Caterham has arrived informing me that parts are now available, am I fitting myself or opting for factory fit? Decisions decisions Link to comment Share on other sites More sharing options...
DJ. Posted June 13, 2011 Share Posted June 13, 2011 I'll be interested what you think. I was at Caterham last Saturday for the 1000 mile check, and wanted advice on whether to go for the BMW offer. The mechanic said mine wasn't that bad, and some of the BMW ones can be noisy, so it was best to stick with the Ford one in my case. Duncan Link to comment Share on other sites More sharing options...
adz Posted June 14, 2011 Share Posted June 14, 2011 Brian, Ask them to check the location of the oil seals on the diff before they fit it. My BMW diff leaks oil on the RHS. A chap at dartford said that cos they are having to use spacers on the half shafts, sometimes that means the half shaft is too far out to seal properly. The oil seal itself is just a push in job , but there is no flange for it to rest on, so they can be set too far into the diff. Caterham apparantly have made up a gauge to chek the seals are in the right place. Apart from that I like the diff, have now done 100 miles to and from IVA and it realy is quiet. adam Link to comment Share on other sites More sharing options...
Alan Reeves Posted June 14, 2011 Share Posted June 14, 2011 Well compared to the rented 7 that I used last year the BMW diff is a lot quieter. Link to comment Share on other sites More sharing options...
Pete-B Posted June 16, 2011 Author Share Posted June 16, 2011 Any news about this diff yet? Link to comment Share on other sites More sharing options...
diggerman Posted June 16, 2011 Share Posted June 16, 2011 Hi Brian and any others with the new BMW diff. I really really would like to know how they perform. There has been lots of opinion but little direct experience reported and there must be lots of blatchatters out there who really want to know the truth. Please report PeterC Link to comment Share on other sites More sharing options...
Jason Plato Posted June 17, 2011 Share Posted June 17, 2011 a mate is collecting r500 with BMW diff this weekend, having done circa 20k with a k series r500 he will be able to provide feedback Edited by - Dave Jackson on 17 Jun 2011 07:03:07 Link to comment Share on other sites More sharing options...
7 wonders of the world Posted June 17, 2011 Share Posted June 17, 2011 Reading the above it seems the BMW option can be retro fitted into a chassis previously fitted with the Sierra final drive, I'm assuming this uses additional metalwork, any idea of this weight too in order to get an overall idea of the total weight penalty of going German Link to comment Share on other sites More sharing options...
Brian W Posted June 17, 2011 Share Posted June 17, 2011 I Collected my Sigma 125 SV from Caterham Dartford yesterday after having the BMW differential retro fitted and drove the 300 miles back to Newquay, Cornwall. The drive train clonks and shunt have virtually disappeared and it is also quieter in overall operation compared to the Sierra diff. I do not know the weight disadvantage but I did not feel I was driving a significantly heavier vehicle. From my experience so far I would say there are many pros and no noticeable cons. Brian Link to comment Share on other sites More sharing options...
Jason Plato Posted June 17, 2011 Share Posted June 17, 2011 its been reported that the BMW diff as a fitted assembly is 5kg heavier than the Sierra. The BMW diff uses a cradle to align with the mounting points on the chassis. My mate collected his R500 early and reports that the diff is a little clunky when wheeling around the yard by hand but on the road is so much more refined and fells nice and tight with little or no backlash / clunk / low speed general racket . He is going back to caterham, on the first service to have composite plates fitted - Caterham say that this will further refine the diff and its action will be improved further. The R500 also comes with diff struts that go through the floor to mount on the chassis near the harness bolts. all in all he gives it a big so far on the diff front Edited by - Dave J on 17 Jun 2011 08:57:02 Link to comment Share on other sites More sharing options...
elie boone Posted June 17, 2011 Share Posted June 17, 2011 Thats good news, but agianst the filosofy of a 7 Link to comment Share on other sites More sharing options...
2slo Posted June 18, 2011 Share Posted June 18, 2011 Hmm, the above comments don't compare with my experience so far. New R400 collected yesterday, warned by one of the mechanics to expect some diff noise due to carbon plates in the diff. Clonking and banging on any kind of lock and at motorway speed with the half hood on driving home, the diff whine drowned out the engine noise. Shame I don't have a point of reference to compare. The noisiest diff I've heard in any car to date. Edited by - 2slo on 18 Jun 2011 12:03:57 Link to comment Share on other sites More sharing options...
Martin J Posted June 18, 2011 Share Posted June 18, 2011 Sounds like Michael G's experiences, noisy BMW LSD but with sintered metal plates. I thought the carbon plates were meant to sort out the noise? Link to comment Share on other sites More sharing options...
2slo Posted June 18, 2011 Share Posted June 18, 2011 Well if mine is anything to go by, they haven't succeeded. If only this bloody rain would stop I'd go out and put some miles on it to see if it improves. Link to comment Share on other sites More sharing options...
DJ. Posted June 18, 2011 Share Posted June 18, 2011 I'm really sorry to hear that 2slo, it is such a shame when the rest of the car is so good ☹️ I hope it quietens down for you or Caterham get it sorted soon. I've just done 1000 miles with the Ford (type) diff, and have a noticeable whine particularly between 50 and 60 mph. I was thinking of going the BMW route, and took it for the first service. The engineer said the whine was within normal limits. I'm sure they say this to everyone, so I explained I had the option to buy the BMW diff at a special price, what should I do? He said some of the BMW diffs are turning out noisy and I'd be better sticking with mine one as it isn't too bad. Fortunately, I haven't got any backlash problems, so I've decided to stick with the Ford style one for the summer, but have bought an old Sierra secondhand diff to get rebuilt and plan to try fitting it during the winter. Duncan Link to comment Share on other sites More sharing options...
diggerman Posted June 19, 2011 Share Posted June 19, 2011 Thanks for all the interesting comment. My 150sv is booked in to Caterham Midlands on 6th June for a BMW retrofit. Sounds to me like the noisy versions are all LSD. Mine is open and I can not imagine that any diff destined for a BMW will be clunky, whinny or any thing elsey. Therefore my decision is made. (fingers crossed). Will report on result. Peter C Link to comment Share on other sites More sharing options...
DJ. Posted June 19, 2011 Share Posted June 19, 2011 I hope it works out well for you. I know the LSD diffs are stripped and rebuilt for Caterham, so like you say hopefully and open diff should be better. Duncan Link to comment Share on other sites More sharing options...
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