TheCowboy 4 Report post Posted February 15, 2019 I have a 328ti, have been told its running mostly 318ti rear end, with a 3.29 small case diff. Sounds as if diff is going, and was looking towards options on what to go to, car is planning on being a street legal track car. Also has a vibration under heavy acceleration and damging center bearings, believed all linked so would look at replacing all gear. So what diff/driveshaft etc should I run that would fit my car? Any help greatly appreciated. Cheers Quote Share this post Link to post Share on other sites
BM WORLD 1286 Report post Posted February 15, 2019 14 hours ago, TheCowboy said: I have a 328ti, have been told its running mostly 318ti rear end, with a 3.29 small case diff. Sounds as if diff is going, and was looking towards options on what to go to, car is planning on being a street legal track car. Also has a vibration under heavy acceleration and damging center bearings, believed all linked so would look at replacing all gear. So what diff/driveshaft etc should I run that would fit my car? Any help greatly appreciated. Cheers ok so its a manual ? or auto normal 318ti auto come with a 4.44 small case and 3.45 if its a auto if you want to upgrade to a medium case you need a med diff from a e30 or z3 etc ratios like 3.64 3.73 3.91 or 2.93 etc depends what you are doing with the car , road or track etc , if road car probably want the lower numbers like 2.93 , 3.15 maybe 3.46 but you might have to get a diff made up uses gears from another model and fit into a e30 /z3 med diff case , you will also need e30 325i axles to suit ,some 320i may suit as well check the flange sizes call me if you want any more info Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2136 Report post Posted February 15, 2019 depends what gearbox you are using as to what ratio is good. I have a 3.4 in my E30 which is short for the ZF gearbox but its not a road car. Z3 have the same output input and output flanges as E36 so it all bolts in, wheras E30 you need to change the output shafts. What drive shaft are you using if it is the 328i one then E36 input shaft on diff. E30 one looks similar but different Beware of the Z3 LSDs, they are not viscous type, might be fine for a road car but they are non-rebuildable and cant be tightened up like the E30 ones. My Diff is all Z3 except with an E30 viscous center rebuilt and an extra clutchpack installed. hope this helps 1 Quote Share this post Link to post Share on other sites
TheCowboy 4 Report post Posted February 15, 2019 Yes car is manual using a getrag 220. If I go to a medium case diff do I need to change drive shafts to a different driveshaft? No idea what driveshaft but either way it is out of balance I believe. Car will be driven just for club cruises and then intermarque series and hill climb events locally, so need something to suit that. Quote Share this post Link to post Share on other sites
Olaf 3341 Report post Posted February 15, 2019 Welcome, Sam! We need photos of your "Texas Special!" ? Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2136 Report post Posted February 15, 2019 prehaps i wasnt clear. if you use a Z3 one you will not have to change your drive shaft or half shafts. you should already be using E36 stuff so will just bolt in and good to go. If you fit an E30 diff you need to change the input and output flanges of the diff so it uses E36 parts. by the way. i forgot to mention that you need to given the body a bit of a tweak with a small club hammer on the reinforcement box section that crosses behind the diff to make room for the breather. doesnt have to much, 5mm was all i did on mine Quote Share this post Link to post Share on other sites
FIAT 131R 223 Report post Posted February 15, 2019 Sam i should be able to help with some, if not all of the things you need. Welly based. Might be worth bringing the car over and putting it on axle stands and having a look. 1 Quote Share this post Link to post Share on other sites
TheCowboy 4 Report post Posted February 16, 2019 (edited) Cheers andy, so for track use a e30 one would be best once change the flanges? Cause wanting to go lsd but if not viable wont be able to. And thanks Fiat would be fantastic. Can organise to meet up at some stage soon. Edited February 16, 2019 by TheCowboy Quote Share this post Link to post Share on other sites
TheCowboy 4 Report post Posted February 16, 2019 Here you go Olaf. Changed wheels since last saw you, just waiting for centre caps to arrive 2 Quote Share this post Link to post Share on other sites
HamishE36 9 Report post Posted February 17, 2019 Hi Sam, mine is running an E30 3.64 medium case lsd behind a ZF box. It's a little bit short on the street, but they're good ratios for the track. I'm getting right to the top of 4th on the back straight at Manfeild, which feels pretty quick for a 20yo car with leather seats and air con. Quote Share this post Link to post Share on other sites
Olaf 3341 Report post Posted February 17, 2019 Looking sharp, Sam! Quote Share this post Link to post Share on other sites
