moktar 7 Report post Posted July 15, 2009 Hey all, After getting sick of my open diff i am looking to upgrade to an LSD but i dont know where to start. Please excuse my noobness on this topic as i know just about nothing when it comes to diff ratios ect... I have talked to a few people and they said to make sure that the diff ratio is not too low. As it would be very uncomfortable with motorway driving. My dad races in the the open series and have a few mates in verious race series. I am planning on using my car for open track days and events but still using as a part time daily As i usally am riding my Motorbike. So can someone fill me in on diff ratios what too look for, Price range and where to find one ... also i have had my eye on this, as i said i know nothing on ratios so wouldnt want to fork out the cash and end up with crap. http://www.trademe.co.nz/Trade-Me-Motors/C...n-230483560.htm Thanks alot, Miles Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 15, 2009 Reason for doing this is i have done a few laps around pukekohe and the drive out of corners is hopeless. Lifts one wheel and she starts spinning. Is more frustrating than anything. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted July 15, 2009 What ratio is in your car now ?? Quote Share this post Link to post Share on other sites
westy 614 Report post Posted July 15, 2009 Factory manual?? Should be a 2.98. Where do your revs sit at 100km/h in 5th? If thats the case a 3.73 is way too short. Quote Share this post Link to post Share on other sites
AzonicNick 0 Report post Posted July 15, 2009 Some early 328i M models came with a factory LSD so might be worth having a look for a ratio similar to that? Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 15, 2009 Factory manual?? Should be a 2.98. Where do your revs sit at 100km/h in 5th? If thats the case a 3.73 is way too short. Yeah factory manual 1995 coupe. Id have to check what rev's it sit at, unsure at the mo ill check at smoko. Unsure of standard ratio either im new to the whole diff game. Westy have you fitted an LSD to your car? Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 15, 2009 Some early 328i M models came with a factory LSD so might be worth having a look for a ratio similar to that? Yeah i have heard this before but am yet to see an example in NZ. Quote Share this post Link to post Share on other sites
westy 614 Report post Posted July 15, 2009 Extremly (sp) rare to get an LSD standard even in overseas markets. I had an E30 centre fitted to the E36 housing as did Glenn but mine was a 3.64 ratio. I found it a lot of fun but its not for everyone. Glenn's really the one to talk to, his is much more suited to the road (3.15?). Standard car should rev approx 2500rpm at 100 km/h. Unfortunatly the only marking on mine was a sticker on top of the housing! 3.07 from a NZ new auto (ZF trans). The E30 LSD unit will fit earlier E36 crown wheels but not the later units. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted July 15, 2009 (edited) Yes I'm running a 3.15 :1 which would be quite suitable gives a calculated speed of 245 kph and I'm around 2,800 rpm in fifth at 100 kph Edited July 16, 2009 by *Glenn* Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 16, 2009 Yes I'm running a 3.15 :1 which would be quite suitable gives a calculated speed of 245 kph and I'm around 2,800 rpm in fitth at 100 kph Sounds like it would be the ticket. Now the big question... Where can i find one? Guess this is gonna be the hard part... Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 16, 2009 Just read it properly. so i would have to find a LSD 3.15:1 E30 diff and the insides should or could be fitted to the inside of my diff? Who can help source or know where this can be done? sorry for the stupid questions. Sadly i know nothing about diffs. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted July 16, 2009 Just read it properly. so i would have to find a LSD 3.15:1 E30 diff and the insides should or could be fitted to the inside of my diff? Who can help source or know where this can be done? sorry for the stupid questions. Sadly i know nothing about diffs. All my bits were out of an E28 if I remember correctly. Dave (silverfox) sold me the LSD and I got the C&P from Brent Quote Share this post Link to post Share on other sites
Silver Fox 43 Report post Posted July 16, 2009 (edited) LSD centre and crown and pinion can be from any of the following AFAIK? E23, E28, E12, E30, E32, E34, so long as they are medium case diffs, with 6 bolts on the side covers. I'm sure Brent could confirm this? I have a 3.25 open med case, $150. Edited July 16, 2009 by Silver Fox Quote Share this post Link to post Share on other sites
BM WORLD 1284 Report post Posted July 16, 2009 All my bits were out of an E28 if I remember correctly. Dave (silverfox) sold me the LSD and I got the C&P from Brent your diff 3.15 gears came from a e34 530i auto v8. they run a medium case with high gearing LSD centre and crown and pinion can be from any of the following AFAIK? E23, E28, E12, E30, E32, E34, so long as they are medium case diffs, with 6 bolts on the side covers. I'm sure Brent could confirm this? I have a 3.25 open med case, $150. i also run a 3.15 ratio in my e36 325i coupe that i converted to manual , i might have a spare 3.15 ratio for e36 soon . also have a 3.64 e36 diff also have 3.25 and 3.46 medium case gears from e28 525i etc use a gearing calculator to work out what you want . http://www.unixnerd.demon.co.uk/revs.html you will have to put your gearbox ratios in to work out the revs etc . or select 4th gear 1:1 in the is page thats the same as 5th gear in your 328i Quote Share this post Link to post Share on other sites
bmpower 3 Report post Posted July 16, 2009 I have a 3.15 diff from an early manual 325i e36 if needed - non lsd. Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 16, 2009 Ok i checked last night and the car sits at 2500rpm at 100kms in 5th. Pretty much looking to get an LSD witch is the same as the factory ratio or a little shorter. Say i was to buy the LSD off trademe could the ratios be changed so they are not so short? Im gonna send him a message and see if he can either build something or change the ratios.. Really i dont want to have to go through the process of finding parts and puting them togther ect ect Just wanna spend the cash and have it sorted as i really have no idea about the techincal side of things regarding diffs. Will be droping into a diff shop this weekend to see what they know and if they can help. Thanks for everyones input. Brent if you come across the parts or know where they are availble it would be much appreicated. Quote Share this post Link to post Share on other sites
BM WORLD 1284 Report post Posted July 16, 2009 Ok i checked last night and the car sits at 2500rpm at 100kms in 5th. Pretty much looking to get an LSD witch is the same as the factory ratio or a little shorter. Say i was to buy the LSD off trademe could the ratios be changed so they are not so short? Im gonna send him a message and see if he can either build something or change the ratios.. Really i dont want to have to go through the process of finding parts and puting them togther ect ect Just wanna spend the cash and have it sorted as i really have no idea about the techincal side of things regarding diffs. Will be droping into a diff shop this weekend to see what they know and if they can help. Thanks for everyones input. Brent if you come across the parts or know where they are availble it would be much appreicated. all you need is a lsd diff in a mediuam case size then choose teh gears you want and get them fitted or if its already have the right ratio in a e36 med diff then just get a lsd pack fitted , a diff specialist will do this for you ,. has cost me a about $200 to get lsd pack swap over and about $300 to get gears swapped around i have have used a diff guy in manukau GT sth rd Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 16, 2009 all you need is a lsd diff in a mediuam case size then choose teh gears you want and get them fitted or if its already have the right ratio in a e36 med diff then just get a lsd pack fitted , a diff specialist will do this for you ,. has cost me a about $200 to get lsd pack swap over and about $300 to get gears swapped around i have have used a diff guy in manukau GT sth rd Perfect thanks alot brent. Will look up the diff guy and see what he can do. Will they have acess to lsd packs? or are they redily avalible anywhere? Quote Share this post Link to post Share on other sites
westy 614 Report post Posted July 16, 2009 Be warned the diff you currently have may not work. They were changed part way through the E36 model, the pinion is smaller and the crown offset is closer to the centre. Dosesn't leave enough room for the LSD pack. You wont know till you open your diff. Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 16, 2009 This is gonna be fun. I may just buy a medium case diff that it will fit into and keep the factory one as spare. Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 19, 2009 Thanks for all your help guys. Have spoken to the guy on trademe and he has got a LSD pack for me to buy. Will hopefully fit into my Diff if not will be looking at buying another suitable med case diff and maybe playing with the gearing... Quote Share this post Link to post Share on other sites
moktar 7 Report post Posted July 29, 2009 Recivied the LSD unit today will be fitting this week. Im crossing my fingers that it fits inside my diff... If not i may look at gettin the 3.25 from you silverfox. Thanks for everyones help on this. lsd.bmp Quote Share this post Link to post Share on other sites
