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1. NOT KC As far as I know the bearings on a diff have to be set pretty carefully for lash Set the lash too high and you get noise and higher impact forces on the gears Set the lash too low and the heat expansion makes for interference and wear of the gears Various shims are involved when setting the lash Brett Anderson once mailed me a procedure on rebuilding a diff I read the some 30 point procedure file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 22 Choosing a Pertormance Ditterential E28 9 10 08 and decided it was not worth it for now Perhaps when I have spare transport I will do this out of interest Mr Jack Money has rebuilt a Mustang diff at work and I d probably enlist his help Neil Hitze has witnessed a diff rebuild done by a mechanic friend and suggested getting it done professionally gt From what I can tell it is a tedious task but with some mechanical common sense and lots of patience and a spare car one can pull this off Not at all in the same category as doing the seals though Those are easy Neil Deshpande 1988 325 iS 1989 325 iC KKK I believe that the bearings are DIY replaceable If anyone knows any differently let them speak now or forever hold their peace I m just doing the seals amp mounting bushing on the diff going into my car I m still waiting for the rubber to show up though Date Sun 2 Apr 2000 From Brett Anderson lt brett koalamoto2. Subject Re uuc 3 23 1 vs 3 4 diff for 328i 96 The rpm is proportional to the gear ratio 3 23 2 9 1 11 Your new rpm will be 11 higher With the 3 41 the new rpm will be 18 higher That is about the same as driving around in 4th gear Just do that its way cheaper If you can spin the rear tires in first gear with the setup you have a lower axle gear will not improve the 0 60 time Gary Derian lt gderian oh verio com gt file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 5 Choosing a Pertormance Ditterential E28 9 10 08 Date Sun 28 May 2000 From Richard Nott lt gis s054 aone net au gt Subject Determining the RPM s with a new Diff Ratio Maths To determine the difference in RPMs when changing your diff ratio I ve included a demonstration of the equation you need to use RPM Diff Ratio x Transmission ratio x 336 x MPH Tire Diameter in inches Eg RPM 3 46 X 0 73 x 336 x 87 24 3000 3 46 X 0 73 x 336 x 87 24 3076rpm 2500 3 46 Xx 0 73 x 336 x 74 5 24 2634 rpm 120kph 2637 3 64 Xx 0 73 x 336 x 74 5 24 2771 rpm 120kph Real Road Speeds corrected for speedometer inaccuracy 3 46 1 Diff 2500 3 46 x 0 73 x 336 x 68 35 23 875 2430 rpm 120 kph 68mph 3 64 1 Diff 2626 3 64 x 0 73 x 336 x 68 35 23 875 2556 rpm 120 kph 68mph You will notice that both this formula and the one from Gary above will both give the same results
3. you go 3 64 3 73 3 91 the worse this compromise becomes What Works Best In Your E28 General consensus suggests the best final drive ratio for a manual E28 535i 528i is 3 64 Many argue that the 3 73 will provide the best Bang for the Buck because of the slightly higher acceleration if your going to generate extra cabin noise you may as well select the ratio that gives the best acceleration However going higher to a 3 73 means Ist and 2nd become too low and this can actually harm your acceleration from the lights and make driving around town a real pain The benefit though is on the track where the car will have noticably better pulling power through 3rd and 4th gears Using a higher ratio means your engine is working harder all the time and generating a lot more cabin noise If you want your car to be more suited to highways than the track the 3 46 is the best choice because it will minimise noise and you really don t gain that much pulling power going to the 3 64 Of note BMP recommends the 3 64 as the best performance ratio for this model If you own an automatic 535i 528i or 735i however the best performance ratio is the 3 73 This is because the automatic gearbox is taller geared and therefore acceleration through Ist and 2nd is still good The penalty here is that revs will increase by 500rpm and your car will always be noisier inside the cabin Personally I chose the 3 64 for my 5351 automatic because I wanted to keep th
4. Gary s method is the quickest Eg 3 64 3 46 1 05 or 5 higher Therefore 2500rpm x 1 05 2630 rpm almost equal to 2637 above Cheers Richard E28 E23 E24 General Information Date Fri 26 Feb 1999 From Jason Lile lt jason zionsvilleautosport com gt Subject Re lt E24 M6 gt LS Diff was Re lt E 30 gt lt 86 325 ESI gt Diff James Moran wrote gt gt Jason and others gt gt Any leads on where I can find a limited slip diff with a ratio higher than gt 4 10 E30 M3 I m contemplating a swap and am wondering what options are gt out there I thought I saw a model that had a 4 45 maybe an A T 318ti gt gt Jim Moran gt 88 M6 Hi Jim file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 6 Choosing a Pertormance Ditterential E28 9 10 08 I ll assume your wanting this for the M6 In that case you only have one option There are only three cars in the US that come with shorter gears than 4 10 and none of those diffs will actually bolt into your M6 The E30 318ic cars came with 4 27 gears and the 318ti and 3181 AT cars E36 both came with 4 45 gear ratios However these are small case differentials and they will not bolt into your car The ring and pinion set is also smaller and will not transfer to your diff case That leaves the late model E34 5351 AT cars The later years like 91 or 92 and later came with a 4 27 in a larger case diff that w
5. and had 236k miles The newer one has 177k miles and appear to be quiet The 10 difference in gearing feels seat of the pants faster but not to bad with rpms or noise I am happy with the swap and found it was pretty easy just about 2 50 hours for the R amp R Date Fri 8 Oct 1999 From bricks dreamscape com Subject Re uuc re E24 Gear Ratio Options Hey group A discussion on 6er gear ratios has been recently going on in the 6er group Here is a copy of the info I m not the author and I m not sure he s on this list Hope it is helpful to all BR 85 635csiA Syracuse NY My info source tells me that the standard non M diff cases are as are the ring and pinion and diff body of course interchangeable with all of the E23 E24 E28 E30 and I think E36 s The covers and stub axles are different for some of the cars E30 E36 but E24 covers and stubs same as E23 E28 are swappable directly on to a donor diff case from any of the above So you can do 3 07 3 XX 3 YY 3 73 3 91 4 10 LSD or non LSD and so on any ratio that you can get you hands on As you may remember I did this exact thing by taking a 4 10 LSD off of an E30 M3 and swapping a cover and stubs from an E23 to make my super low diff that s currently on my M635 Ahh the options I posted the story back a few months ago but here goes I located a 4 10 LSD off an E30 M3 from a Roundel advertiser After ordering the diff I purchased refurbished E
6. of them will fit the E30 with a rear cover change and a swap of the stub axles I happen to know where one is if you re interested Date Sun 7 Feb 1999 From BMWROSS aol com Subject Re lt E 30 gt Diff swap gt Date Sun 07 Feb 1999 gt From Pat Donahue lt pdonahue erols com gt gt Subject Re lt E 30 gt Diff swap gt gt Keith asks gt gt gt gt Hiall gt gt I may have located a 4 10 limited slip to suit my needs It s out of an E 30 gt gt M3 Will it swap directly into my 84 3181 gt gt You must be raving mad Actually the E30 325 and M3 share the same axles gt but the 318 axles are smaller I _don t_ know for sure if the axle flange on gt the sides of the diff is smaller I do know you can t just swap in the parts gt outside of the diff The flanges on an e30 323i are definitely smaller than a 325i ask me how I know anyone want to buy a used 3251 3 25 open diff I read in European Car that the 318i uses the smaller diff I heard you can swap the shafts just by prying them out but when I tried this the replacements from the 323i didn t mate properly with the 325i housing Ross Walsmith 83 3231 2 7 84 528e Date Sun 7 Feb 1999 From VeeDubJeff aol com Subject Re bmwuucdigest V1 62 I don t think they will swap directly If I remember right E30 differentials will swap right in all 6 cylinders and all 4 cylinders with exception of the M3 that uses 6 cyl pa
7. 0 to me says that it will make gt gt the car accelerate much faster I have a 4 10 diff in my E30 325i instead of the stock 3 73 and it is definitely the best bang for the buck modification wise that I have done better than the conforti chip better than the K amp N cone filter better than the lowering springs I just drove a similar aged 325is back to back with my car and mine definitely felt peppier squirted away with more torque yes mpg is down a couple yes rpm cruising are up 500 but it is certainly not annoying or intrusive as far as better gearing for me I find the gearing better no need to downshift to get the oooomph ie cruising at 90mph in 5th is 4000rpm which is right on the power band want to pass push the go pedal and you are gone Note 60mph in 5th 2700rpm Ed cruising at 60mph in 4th back roads spirited driving same thing chris pawlowicz 89 325i 74 2002 Date Sun 07 Feb 1999 file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 18 Choosing a Pertormance Ditterential E28 9 10 08 From Pat Donahue lt pdonahue erols com gt Subject Re lt E 30 gt Diff swap Keith asks gt gt Hi all gt I may have located a 4 10 limited slip to suit my needs It s out of an E 30 gt M3 Will it swap directly into my 84 318i You must be raving mad Actually the E30 325 and M3 share the same axles but the 318 axles are smaller I _don t
8. 2001 From Neil Deshpande lt neildeshpande yahoo com gt Subject uuc Upgraded diff bushings Joel I asked the precise question a few months ago The M Coupe bushing fits Price is a few cents different at The BMW Store Cincinnati OH Check http yp yahoo com for their number Check http www e30m3performance com for details on the bushing Neil Deshpande http www neilwerke com KKK Joel Gallun lt joel tux org gt I ve got a 4 10 LSD sitting in the back of my truck just waiting to go in my E30 track car Before I put it in I was thinking that it might be nice to upgrade the bushing Does anyone know of a source for an upgraded bushing I checked Turner and Bimm file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 25
9. 23 E24 stub axles and a refurbed cover I also rounded up some new waver washers and a few correct file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 9 Choosing a Pertormance Ditterential E28 9 10 08 length bolts for the cover attachment check your fiche or CD the E30 cover has a couple long ones the E23 E24 bolts are all the same length Lastly I got some replacement lock nuts for the drive shaft attachment Next I jacked the car up as high as you can get you ll need all the leverage you can get on some of those diff to subframe bolts Follow the diff removal steps per the service manual making sure to support the lump with an extended jack to keep from squishing your skull as you remove that last bolt The removal involved all of 5 bolts 4 diff to subframe one cover to diff mount and 4 nuts diff to drive shaft Of course you ll also have to unbolt the half shafts too 8 hex head bolts per side The whole thing lowers nicely after that In my case I actually cleaned up and sold my M sized read large 3 73 diff as the cover and stub shaft splines are larger on the M diffs not retrofittable to the E30 diff So after waiting a week or so I got the donor diff took the cover off popped the stubs out they re just held in with spring loaded circlips cleaned it up a bit and replaced the cover and stubs with the E23 E24 bits I got from Jim Now would be the time to check the st
10. Choosing a Pertormance Ditterential E28 9 10 08 Performance Differentials Contained in this document Choosing a Performance Differential Doing the Maths What works best in your E28 Real World Examples E28 E23 E28 Final Drive Ratios E28 E23 E24 General Information E36 Final Drive Ratios E36 General Information E30 General Information Rebuilding Tips What Does a Limited Slip Differential Do Differential Bushing Upgrade See also Differential Oil Recommendations Final Drive Ratio Calculation Driveline Shudder Choosing a Performance Differential Date Sun 24 Jan 1999 Update 11 Jan 2001 From Richard Nott lt Richard Nott dpws nsw gov au gt Subject E28 Diff Swap Options for 5351 5331 5281 There are two reasons most people change their differential ratio Either the original gearing is too tall or they are sports oriented drivers wanting a lot more power in 3rd and 4th gear The people who benefit most from a ratio change are those whose car is too heavy for the engine such as the E36 320 325 or the E28 528 Your Gearings Too Tall Originally the 528i 535i amp 735i were sold with a 3 25 1 diff ratio Whenever you approached a small incline with a headwind the cars were too heavy to maintain the speed and it was necessary to change down a gear In some markets BMW later changed the ratio to 3 46 1 to overcome the problem They didn t go to the 3 64 because this would have hurt fuel economy and made t
11. _ know for sure if the axle flange on the sides of the diff is smaller I do know you can t just swap in the parts outside of the diff Pat Donahue CCA 125031 Vienna VA 91 M5 4GTFUL lt For sale http www bubbaclub com pat mS5sale html 88 325is destined for ITS lt cause of this one Date Mon 8 May 2000 From Henry Caldwell lt ohenric mindspring com gt Subject uuc RCM Driving School K C I m curious about the diff comment What was the original diff ratio and which one did you install My experience with diff upgrade was quite an improvement in acceleration in all gears Henry 92 325i with 3 46 diff gt Also the E36 steering rack made a big difference less sawing at the gt wheel It was interesting because the rack and the diff don t make a gt huge difference on the street but boy do they on the track Date Tue 9 May 2000 From K C Boyce lt k_boyce yahoo com gt Subject uuc Diff ratio was RMC driver s school Henry asks about my diff ratio My car came stock with a 2 79 open diff Geoff Patterson and I changed it out for a 3 25 limited slip diff from an E28 533i Acceleration is noticably quicker as is the fact that the wheels are file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 19 Choosing a Pertormance Ditterential E28 9 10 08 mechanically connected now KC Boyce 85 325e E30 Eta Page http rikki coloradocollege edu k_boyce Dat
12. aine Desktop Choosing 20a 20Performance 20Differential 20 20E 4 Choosing a Pertormance Ditterential E28 9 10 08 Final Drive Ratios BMW occasionally change these to suit the individual market There are lots of other ratios fitted In E23 E24 E28 E30 E36 the Crown Wheel and Pinion that determine the Final Drive Ratio are interchangeable even though the housings are different and not interchangeable eg E28 E30 E36 Hints Tips amp Tricks 1 The ratio is always stamped on a metal tag and can be found on the back plate of the diff joined by a bolt to the housing Don t trust this though it could be swapped 2 An S stamp at the beginning of the number indicates that the Diff is limited slip eg S 4 10 indicated Limited Slip with 4 10 1 Final Drive Ratio These are also marked with a large white S spray painted onto the diff housing 3 The E28 520i diffs have different half shaft output flanges compared to the E28 5281 but these can be simply prised out from the side and swapped for the original 4 Someone suggested that E30 differentials were interchangeable with E28 s by swapping the rear plate with the original I can t verify this It may be possible as long as you know the trick of prising out the wheel flanges to the half shafts to swap with your originals Good Luck Richard Doing the Maths See also Final Drive Ratio Calculation Date Sat 29 Apr 2000 From Gary Derian lt gderian oh verio com gt
13. auto and lightweight comes stock with 3 23 ratio I upgraded my stock 3 15 diff to a 3 46 with 50 limited slip This provides a significant increase in acceleration in all gears The rpm s increase is about 400 more at any given speed I had mine rebuilt at Kormans for 1 500 00 and 220 00 more for the increase limited slip from 25 to 50 I ve seen BMP advertise rebuilts starting at 1550 00 and Turner at about 1600 00 I did not think the car could accelerate any faster after the diff upgrade until added an aluminum lightweight flywheel last week Now I m getting paranoid because there must be a law against having so much fun driving officer I have tried to slow down but these damn mods just make the car take off like crazy honest Henry 92 325i sharked 3 46 diff lightweight flywheel ram air and borla Date Sat 29 Apr 2000 From Henry Caldwell lt ohenric mindspring com gt Subject uuc 3 23 vs 3 41 Differential in a 328 J G Going from a 3 15 to a 3 46 in my 92 325i 5sp resulted in 450 rpm s difference No drivability change whatsoever Big difference in acceleration I would suspect the 3 23 would be a better choice as a daily driver You might contact Kormans at their website for more info at www kormansfastbmw com Henry gt Does anyone posess a set of charts which show the increase in rpm gt when either a 3 23 differential or a 3 41 replaces a 2 9 stock in the gt 3281 96 5 speed file Users rodpai
14. e Mon 13 Nov 2000 From VanAusdal Thi lt thiv crystal cirrus com gt Subject RE uuc RE 325 mods gt thanks so it s obvious you can t just upgrade to an i head gt I presently cruise at 2 000rpm 60 mph I ll double check on gt the way home gt What can I expect with a 3 25 or a 3 73 The 2 91 gear changing to 3 25 means 2000 rpm gt gt 2234 rpm The 2 91 gt gt 3 73 means 2000 rpm gt gt 2564 rpm I personally drove an E21 3231 with a 3 90 motor and eta longblock In spite of using the stock K Jet I got 24 28 mpg And man that thing was at least even with my dad s 87 325is gt What is HP and torque for an 1 motor gt What is HP and torque from an M50 I have heard about Snip gt Thanks gt Ist The M20 3251 SOHC motor is 164 bhp 170 lb ft But the eta motor has just as much torque across a low and broad RPM band The i motor has to spin up The M50 3251 DOHC is er 189 bhp Thi Date Fri 26 Feb 1999 From Jason Lile lt jason zionsvilleautosport com gt BRI29ATL aol com wrote gt Digesters gt gt I am wanting to upgrade my rear end again What Bmw had a 3 45 LSD Diff that gt will mate up to the E 30 file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 20 Choosing a Pertormance Ditterential E28 9 10 08 The E23 735 AT cars came with 3 46 ratio diffs You can also find them in some 88 528e cars and some of the 635csi cars Any
15. e Tan lt jtan71 yahoo com gt Subject limited slip differentials Man This guy needs a lot of help Anyone nobody ok then I ll give it a shot James A limited slip differential LSD will not add any power to your car It will however make better use of the power you already have When cornering a car with an open differencial non LSD the inside wheel will get too much power and it will smoke your tire thus wasting your power With a LSD the power will be transfered to the outside wheel where it can make better use of it and help you power you out off the corner faster The only way a LSD will add more power to you car is if the differential is numerical higher where you would get better off line accleration in exchange for a nosier ride at highway speed If you are looking to add some real HP you will need to do some engine work or forced induction Joe T Note Many road accidents have occurred to non LSD equipped cars when driven quickly around corners because the inside wheel lifts all power is transferred to the spinning wheel which upsets the cars balance loosing rear traction and causing the car to spin If you don t catch it it could spin off the road and cause a serious accident Limited Slips help reduce this possibility Ed file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 24 Choosing a Pertormance Ditterential E28 9 10 08 Differential Bushing Upgrade Date Wed 7 Mar
16. e noise down Revs increased by only 300rpm If I wanted maximum performance I would have chosen the 3 73 but I have a later 155kW engine with Schrick cam so I thought I d have all the performance I d need without it Apart from performance the other considerations when choosing the best differential ratio are engine noise additional frequency of gearchanges esp in lower gears and your cruising speed Do you want your car to be quiet do you want more power in 3rd 4th and 5th do you want Ist and 2nd gears to be too low The additional performance isn t free It comes at a cost Consider the power of your engine higher power means you don t need as big a change What will your RPM s be with this new ratio What ratio will you be most happy with over the long term This is the hard part It costs quite a bit to change your diff ratio so be warned if you select a ratio that s either too tall ow number eg 3 23 or too short high number eg 3 91 you ll end up with a costly mistake that s actually worse than your existing setup Begin by deciding whether you want to build the car for driving around town or long highway trips My final tip is too look at what BMW chose for your model They spent a lot of time and money deciding which ratio would be the best compromise for both city AND country driving Deviate too far from this and you will impair one or the other Sometimes even BMW gets it wrong and will alter the ratio at a later t
17. ent 3 46 1 Differential w Alpina cover LTW Oil Pan Porsche Big Brakes in the box Roll cage on the way Lost my mind already Date Mon 28 Aug 2000 From Dave Meyer lt dbyker ix netcom com gt Subject uuc lt E36 gt 99 328is Mods amp Results Long file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 13 Choosing a Pertormance Ditterential E28 9 10 08 Greetings fellow listers I ve gotten a lot of good information from this list in the past and want to give back in a very small way if I can I purchased a new 99 E36 328is Sport 5 Speed in April 99 and have made a number of modifications based primarily on recommendations from fellow listers here Snip Snip Performance Straight line acceleration Snip E36 M3 3 23 Limited Slip Differential This is not a no brainer upgrade It has trade offs besides initial cost On the plus side it does improve acceleration noticably over my stock 2 93 open diff though not quite as much as I had hoped It also adds limited slip to the car which should improve both dry and wet weather handling On the minus side it increases revs and so engine noise at cruising speed requires more shifting and necessitates fourth gear instead of third around town to keep the revs and engine noise down Where I used to cruise at 80mph in 5th gear at 3 100rpm I now do it at 3 500rpm which significantly increases engine noise If u
18. ferential 20 20E 9 10 08 15 Choosing a Pertormance Ditterential E28 9 10 08 gt to put in a 3 46 but if I ve got some sort of rare factory setup I may want gt to leave it alone The car also came with LTW wheels gt gt Frank Nelson gt 95 M Frank See below for my reply from a long term supplier on different ratios as to what was and is available originally RA Bob G From Armand VAC Motorsports Subject E36 E46 Differential Ratios Bob there is no direct factory bolt on in that ratio 3 46 LSD for E36 Stock options were only 3 15 3 23 3 38 amp 3 91 We may have some of those ratios in used items We can custom build LSD ones in 3 46 3 64 amp 3 73 usually for about 1 200 Date Fri 23 Jun 2000 From Rob Hatrak lt Hatrak ix netcom com gt Subject uuc 95 M3 gets a 3 38 rear end A few weeks ago I asked the group for opinions about upgrading the rear end in my 95 M3 to a 3 38 I got a bunch of great emails and help from many people I would like to throw a special Thank You out to Bob Tunnel Skip Bogard Sean Hester Ben Liaw and Mike Mount Thank you gentlemen for helping me make this decision I truly appreciate it For those that are curious I am very pleased with the results The car really pulls a good bit harder Some people warned me that I would be shifting a lot more with the new gears but I have found the reverse to be true Previously I would need to downshift i
19. he car a lot noisier The later E34 535 was heavier than the older E28 so BMW was forced to select the 3 64 ratio for the manual and 3 91 for the automatic while using the same ratios in the gearbox as the older E28 Some E28 528i owners changed the diff to a 3 46 and removed the air pulse tubes from the exhaust manifold This transformed the car It no longer ran out of puff in 5th and became a strong motor with plenty of power in all gears On the US M5 the factory selected a 3 91 to achieve similar performance to the higher power and lighter European M5 with 3 73 diff ratio The M5 used lower gearing because they were made for Sports Oriented Drivers Sports Oriented Driver People who want more power for sports driving and like to listen to the engine don t mind the extra noise By going from 3 45 to a lower 3 64 1 ratio you benefit most in 3rd 4th and 5th Gears by the engine accelerating more strongly The disadvantage is that 1st and 2nd Gears are much lower and are no longer matched to the engines power For example you ll feel that if 2nd was a fraction lower you wouldn t need Ist at all meaning that on an everyday basis you have to change from Ist to 2nd before attaining any real speed and wasting time This is the compromise you make when file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 1 Choosing a Pertormance Ditterential E28 9 10 08 selecting a lower ratio and the lower numerically higher
20. ime but this will usually be no more than one step in either direction Because this is so important it is my final tip for you When you change ratios only go up by one or two steps Be very careful when you go further than this I can almost guarantee you any more than two steps and you won t be happy with the result Real World Examples E28 E23 file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 2 Choosing a Pertormance Ditterential E28 9 10 08 Leaded 1986 E23 7351 Automatic with 10 1 compression ported head free flow exhaust and the 3 73 final drive delivering 150kW 201HP to the rear wheels This is an impressive car with the heavy 7 easily able to spin the wheels when pushed Surprisingly the 3 73 does not feel too low geared in the Seven with the sports auto I was surprised as the 3 91 in a manual 5 Series with 5 speed overdrive was too low and unpleasant to drive in lower gears This emphasises just how different the gearing is for Automatics compared to Manuals and shows that what works for one will not for the other The Dyno Shop that tested the car said they d never had a six cylinder put that much power to the rear wheels impressive Of interest to Automatic drivers will be BMW s decision to use the same gearbox ratios for I II If amp IV in all their Automatics E28 5351 E23 735i E34 535i Surprisingly Porsche also uses the same gear ratios in their Tiptronic S 911 wi
21. ltimate acceleration is your objective this is one way to achieve it OTOH it has changed the character of my car so much from a nice sporty daily driver to a more narrow focused sports car that I am actually considering going back to stock on this one mod although I am getting used to the additional revs and noise Your call About 800 1 100 Snip Note To see this article in full click here Ed Dave Meyer 99 328is Lorton VA Date Thu 17 Aug 2000 From abigG webtv net gggg gegg Subject Re uuc lt E36 gt What are the different diff ratios Sir Rob Having just put a 3 23 in my 96 328ic I can at least tell you stock with five speed was 2 91 I can only say that this increase is quite enough for me and when I asked on this site most but not all respondents said about the 3 46 that its cheaper and the same to just leave your car in fourth gear You might try the M3 automatic which I believe is 3 39 but I really wouldn t want anymore highway noise than file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 14 Choosing a Performance Ditterential E28 my mod ratio has added Good luck JG Date Thu 17 Aug 2000 From TeamZ3 aol com Subject uuc Re E36 diff ratios I believe the auto E36 M3 s have the most favorable diff gear ratios 3 23 for 95 auto model same for 96 manuals and 3 31 for 96 auto M3 models Best bet is to go down to the dealer and peruse
22. ne Desktop Choosing 20a 20Performance 20Differential 20 20E 12 Choosing a Pertormance Ditterential E28 9 10 08 Date Fri 19 Feb 1999 From Holeman David lt david holeman viaticus com gt Subject Diff upgrade response John I have a stock 1994 325i with a 3 23 1 differential I am looking for more off the line performance without the cost of a supercharger Have any of you upgraded to a higher ratio Im not looking to get to radical Maybe 3 73 1 at the most What kind of cost am I looking at Thanks John I upgraded to a 3 46 1 50 limited slip from a 3 15 1 and this had a significant impact on my acceleration This does come at a cost of high end speed You can count on a cost of about 500 rpm per gear In other words when I was comfortable in 2nd I am now in 3rd This is an awesome upgrade given my original low ratio You are already at a decent ratio for your car You have to accept that your car will be more of what is known as a buzz bomb Quick on the start but short on the top speed The cost for an M3 is anywhere from 1500 1700 depending on the condition and level to which it was rebuilt This does not include cost of labor Hope this helps David Holeman Wwww mpower com E36 M3 1995 Alpine White JimC Euro HFM and Dinan cool air intake with K amp N cone Bilstein sport shocks and springs Motorsport strut bar X Brace Euro floating rotors Stillen DOT stainless steel brake lines BL SS B
23. nto 4th on the freeway or 3rd on the street to make a pass but now it seems like the car has great power in every gear The car will still hit 60 in second gear with my slightly taller than stock 245 40 tires and the loss of 350 RPM at redline is soon forgotten I am not sure if it would be worth spending money on this upgrade if you are going from a 3 23 to the 3 38 but from my original 3 15 this is a very worthwhile upgrade I highly recommend it for the 95 M3 crowd Thanks again to those people listed above Rob file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 16 Choosing a Pertormance Ditterential E28 9 10 08 Sin City Chapter Date Fri 23 Jun 2000 From ra rabmw lt rabmw hotmail com gt Subject Re uuc 95 M3 gets a 3 38 rear end Rob Thanks for the report The cars running 3 23 s can get the same results using a 3 46 diff That s not a stock ratio but can be easily made up for a reasonable price in open and LSD by VAC Motorsports and others o o RA Bob G O0 00 00 E30 General Information Date Mon 15 May 2000 From K C Boyce lt k_boyce yahoo com gt Subject uuc lt E30 gt diff Manuel My experience is with the 6 cylinder diffs which differ slightly in the way they mount from the 4 cylinder diffs So this advice may or may not be applicable though I suspect the gist is similar However the procedure is fairly simple You don
24. ould fit into yours You d have to pick one of these up used and swap the gears into your case or another that fits into your M6 because the E34 differential case will not fit the E24 BMW no longer sells ring and pinion sets so your only option is used I ve heard you can buy some 4 45 sets directly from the Motorsport division but I m sure they ain t cheap Good luck Jason Lile Administrator Parts Manager BMW Parts Digest Zionsville Autosport ICQ 31376168 http www zionsvilleautosport com Date Thu 1 Apr 1999 From ABARTH037 aol com Subject Some Differential opinons lt ALL gt Manual I recently put a 3 73 in my 535i stock is a 3 25 this yeilds a 15 difference in Ratio I drove the car for about 2 weeks then I reinstalled the 3 25 The car seemed no faster to me and having to yank 3rd at 45 mph Note I can confirm this I installed a 3 64 in a 4 speed auto 535 and this made no difference to acceleration or power on hills It simply raised revs by 300rpm However I d recommend a 3 46 ratio for a 5sp Manual so the engine s transmitting a bit more power to the road The main benefit is on long hills in top gear meaning that way you won t have to change gears as much on long trips Going any higher than that seems to be too low for 1st amp 2nd However BMW fitted a 3 64 to the E34 5351 Ed sucks I honestly believe that BMW the best engineered cars in the world did their homework to assure the best ratio to use ho
25. r diff size So BMW has a family of diffs Baby Bear E21 E30 E36 4 cyl Mama Bear E23 E24 E28 E30M3 E36 6 cyl Papa Bear M Cars 8cyl and 12cyl E36 Final Drive Ratios Date Wed 27 Jan 1999 From ohenri bellsouth net Subject E36 Differentials Model E36 Stock Gear Ratio Recommended Ratio 318iS Ti Manual Transmission 3 45 3 90 318iS Ti Automatic Trans 4 44 4 75 325 Manual Transmission 3 15 3 46 328 Manual Transmission 2 93 3 46 325 328 Automatic Transmission 3 91 4 27 M3 3 0 3 15 3 46 M3 3 2 Auto and Lightweight 3 23 3 46 The above information comes from Kormans website catalogue I am not associated with Kormans in anyway Henry 92 325i sharked 3 46 diff wow E36 General Information Date Fri 19 Feb 1999 From ohenri bellsouth net file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 11 Choosing a Pertormance Ditterential E28 9 10 08 Subject Differential Upgrade Date Fri 19 Feb 1999 From Skoobahead aol com Subject E36 Differential upgrade I have a stock 1994 3251 with a 3 23 1 differential I am looking for more off the line performance without the cost of a supercharger Have any of you upgraded to a higher ratio Im not looking to get to radical Maybe 3 73 1 at the most What kind of cost am I looking at Thanks John John I believe the stock diff in the E36 325i is 3 15 with manual transmission and 3 91 with auto transmission The M3 3 2
26. rsepower and torque Another note the car went from 2000 rpms 50 MPH in Sth to 2500 rpms It sounded like the thing was ready to explode Do want you want with ratios I am just stating my point of view and experience with the whole diff swap thing Now I guess all you other 535 owners will be hounding me for the 3 73 right Well sorry I traded it back to the place where I got it Nathan 85 535i file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 7 Choosing a Pertormance Ditterential E28 9 10 08 The Matrix ROCKS Go see it It could be happening right now Date Wed 08 Nov 2000 From TR lt tomrobsn gis net gt Subject uuc 5351 is Diff Don t feel short changed if you have an E28 5351 or is with an open diff or Isd Put in an E30 3 73 Isd and have Fun Not much money used for a lot more bang TomR Date Mon 07 Feb 2000 From Carol amp Steve Willoughby lt willoug4 gte net gt Subject uuc 3 Chip Comparison 528e After a few upgrades to my 87 528e rebuilt head i cam springs 3 25 LSD larger throttle body from 88 325i I replace the stock chip with Dinan s latest No dyno figures etc but there seemed to be an increase in upper rpm performance No noticeable change until around 3k and then the power increase is apparent After a few months I replaced the stock chip for comparison and there wasn t a lot of difference Either stock or Dinan I attributed the bet
27. rsport com gt Subject uuc Re E30 diff install BA gt From K C Boyce lt k_boyce yahoo com gt gt Subject uuc E30 diff install gt gt Raymond asks about the seals amp output bearings on a 5 series diff going gt into an E30 Eta gt input shaft seal remove big tight nut on input shaft remove flange gt with a puller then replace the seal One HUGE caveat here Mark both the nut and the pinion before removing the nut DO NOT tighten the nut more than 1 or 2 degees past the original position use Loctite to make sure it stays there Tighten it further and you ll chew up your pinion bearing in an instant gt I believe that the bearings are DIY replaceable If anyone knows any gt differently let them speak now or forever hold their peace Absolutely not The side bearings are not entirely difficult to change but will require setting of back lash afterwards file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 23 Choosing a Pertormance Ditterential E28 9 10 08 Pinion bearings require a number of special tools and I d also suggest some experience Incorrect setting of the pinion can and will result in bearing and or gear wear Trust me I blew up my first one or two in my own cars of course Brett Anderson www koalamotorsport com Home of the E30 M3 CD ROM repair manual What Does a Limited Slip Differential Do Date Thu 18 May 2000 From Jo
28. rts down there Somebody please correct me if I m wrong because there is a GOOD chance I m wrong A nice guy with a E30 set up a E30 page he also has a copy of European file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 21 Choosing a Pertormance Ditterential E28 9 10 08 Car s tech review on E30 diff swaps go read it trust me it will give you all the info you need Here is the URL http rikki cc colorado edu k_boyce Good luck and let me know on how the job comes out if you do it Jeff Patch 86 Alpine White 325es K amp N 17 Giovanna Dunlop lt lt Hi all gt I may have located a 4 10 limited slip to suit my needs It s out of an E 30 gt M3 Will it swap directly into my 84 318i gt gt Date Fri 30 Jun 2000 From ra rabmw lt rabmw hotmail com gt Subject Re uuc Diff ratios for E30 3 2 Dwight is right about the 2 93 but if you want a bit more I would suggest you go no farther than the 3 25LSD you will find out of 5 speed E28 535i s it should give you more than enough extra and not shorten things too much The nice part is that I ve advised a few digesters recently to remove their E28 3 25 s in favor of E30 3 73 s and you can probably pick up a 3 25LSD very reasonably o o RA Bob G O0 00 00 Rebuilding Tips Date Sun 02 Apr 2000 From Neil Deshpande lt Ndeshp Roushind com gt Subject uuc lt E30 gt Diff Bearing DIY
29. t and cam was unable to accelerate up hills in top gear Therefore I chose the 3 64 knowing there is a noise penalty I d rather have the engine quiet to enjoy a good sound system This resulted in a very slight improvement up hills but no difference in 0 100km h times At this time I still haven t had a custom chip made for the engine conversion and the standard Motronic program is not able to benefit from the higher compression engine So time will tell how big a difference this makes and whether I can go back to the 3 46 Companies such as Alpina or Hartge in Germany fit even taller diff ratios than the 3 25 because their engines are more powerful and they are doing higher speeds so can sit in the peak torque band at around 3500 RPM s doing 160 200 km h file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 3 Choosing a Pertormance Ditterential E28 9 10 08 At 160 km h they d be a beautifully quiet car What are your Options According to BMW the following final drive ratios were fitted to the E28 There is a large range to choose from Ratio s available include Final Drive Ratios E28 Rear Axle Ratio 4 10 3 91 293 3 07 2 93 3 64 3 46 323 3 07 323 3 15 gt a U Copyright 1999 Richard Nott Gear Ratios E28 525 528 535 Gear 5SpOD Auto 3 83 2 48 220 1 48 1 40 1 00 1 00 0 73 0 81 3 46 2 09 Copyright 1999 Richard Nott file Users rodp
30. t need a lift though it does help a lot not to spend lots of time on your back getting road grime all over yourself You ll need to disconnect the half shafts 6 bolts ea and the driveshaft 4 nuts The driveshaft is easy For the half shafts just set the parking brake and rotate the wheels when you need to get at the last two bolts Then disconnect the four axle carrier bolts and the rear mounting bolt s The diff should drop right out assuming you disconnected the speedo sensor The toughest part of the swap was to get the four bolts on the axle carrier undone Penetrating oil large prying and hitting tools and a liberal dose of cursing should do the trick for you Really it s not that bad Be sure to support the diff before undoing all the bolts as you don t file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 17 Choosing a Pertormance Ditterential E28 9 10 08 want that thing crashing down on you all 80 lbs worth Installation is the reverse of removal KC Boyce 85 325e E30 Eta Page http rikki coloradocollege edu k_boyce Date Wed 29 Dec 1999 From Ian Reid lt ian gmail nccinc org gt Subject Jim C VS Dinan Chip and research ever done to see whos best Snip gt gt I was wondering what types of changes would take place if I switched out gt gt my LS diff that is probably a 3 46 to a 4 10 gt gt gt gt The guy that is trying to sell the 4 1
31. ter performance to the other upgrades Until I went to the Conforti chip that is This chip unlocks this motor and the power comes on smoothly all the way to the limiter 5300 rpm Torque is great at lower rpm and gas mileage is fine at 22 25 in town Better than 30 on the road and the car will run all day at 75 80mph while turning around 3k rpm even in the mountains of western Washington So if you want some great bang for and I mean cheap get a Conforti chip and 3 25 LSD I experimented with a 3 46 LSD and it made the motor too busy at most speeds Went back to the 3 25 If you re inclined an i cam makes a huge difference over stock and they are cheap too Don t do this one until you re ready to pull the head for some other reason i e leaking gasket etc If you have an eta motor built prior to 88 don t bother with a larger throttle body You won t get much if any improvement using this on a stock head valve configuration BUT if you want to buy a T B I ll sell mine for 100 and throw in the intake bellows Date Sat 19 Feb 2000 From shilohz jps net Subject uuc lt e28 gt swapped final drive I swapped out the old 2 93 final drive in the 86 528e and put in a 3 25 file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 8 Choosing a Pertormance Ditterential E28 9 10 08 final drive from a 533i I had to swap the cover as they were different The old final drive whined a bit
32. th 3 64 Final Drive Ratio the E34 Auto uses a 3 91 The Tiptronic S accelerates 0 100km h in 6 4 seconds with 210kW 6100rpm 3 6 liters 340Nm 5250rpm 11 3 1 Compression 1425kg The BMW E34 535 accelerates 0 100km h in 9 5 seconds with 155kW 5700rpm 3 4 liters 305Nm 4000rpm 9 0 1 Compression 1540kg Earlier I wrote about my 1983 E28 5281 5 speed with 3 25 diff ratio This gearing was too tall and the engine could not maintain speed up slight inclines at 100 km h 60mph unless the pollution equipment was removed Later BMW changed to a 3 46 ratio after realising 3 25 was too tall for Australian Conditions 110 Km h max 3 46 seemed an ideal compromise for low noise good fuel economy and good power for general highway driving I wanted the car to accelerate up hills in 5th gear so I decided to change the crown wheel and pinion diff ratio to 3 91 Unfortunately this was not a good choice and actually slowed the car down because reaching 80 km h required 3 gearchanges instead of 2 Not good for city driving On the highway it was also bad because of the extra noise generated by the engine revving hard It was simply too low geared If I did this exercise again I would choose the 3 64 as the best compromise good power up hills in 5th and not too low in Ist and 2nd driving around town For my larger 535i auto I was hoping to keep the 3 46 final drive ratio But the 3 5L E32 155kW engine even with a free flow exhaus
33. the parts CD for the various models Sipe Date Wed 29 Mar 2000 From Daniels Jason S lt JDANIELS amfam com gt Subject Re uuc 328ic M3 John Chips work try a conforti chip I you want that shove in the back you picked the wrong car Only forced induction will really help there And final drives are fine if you have a track car Trust me you don t want to do that because the 600 900 gain in RPM s at highway speed may not seem like a lot but after an hours it is Your gas milage will also go down and you will be right in that 5000 plus thing you don t want a lot faster Besides Itd slip diffs are expensive jason daniels Date Wed 31 May 2000 From ra rabmw lt rabmw hotmail com gt Subject Re lt E36 gt lt M3 gt Differential Ratios gt From Franklin W Nelson lt fnelson earthlink net gt gt Subject lt E36 gt lt M3 gt Differential Ratios gt Date Wed 31 May 2000 gt gt I have a late production 8 95 95 M3 According to Korman s website I m gt supposed to have a 3 15 Isd However when I do the calculations using the gt formula also provided by Korman it keeps coming up 3 23 I thought only gt auto trans cars mine s a manual and LTW s came with 3 23 s in 95 Can gt anyone explain this Is there any way other than driving the car and doing gt the calculations to verify what ratio I have in my car I was getting ready file Users rodpaine Desktop Choosing 20a 20Performance 20Dif
34. ub seals for wear too I used silicone gasket during the reassembly as my paper gasket always tended to seep fluid I torqued the bolts to the correct specs in the correct order filled it with redline hypoid much easier before assembly and slapped the doner diff back up on the car assembly is the reverse of dissassembly All in all a pretty straight forward but muscle intensive job it probably took me 8 hours total a couple of weekends part time Better than paying the service dudes 200 plus though Make sure you use your jack to support the old diff and to help line up the new one these suckers are heavy other than that enjoy I have a feeling that E30 4 10 s might get as scarce as the Motorsport gearsets are if everyone follows my lead but hey the whole thing cost me 450 for the diff and 130 for the covers stubs and hardware a lot less than the 1500 plus the Korman s or MM guys of the world are charging for the Motorsport gearsets not to mention what they would charge for the retrofit and the rebuild they would want to do while the thing was apart file Users rodpaine Desktop Choosing 20a 20Performance 20Differential 20 20E 10 Choosing a Pertormance Ditterential E28 9 10 08 Hey everyone likes cheap torque One thing that I failed to mention was the the compatibility of the different platform differentials E23 E24 E28 E30 are only for 6 cylinder motors The E30 4cylinders except the M3 use a yet smalle
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