View Full Version : 4:10 Differential Questions
325i Fury
02-11-2009, 03:21 PM
Today I found a guy who has a 1993 325i convertable for parts... So I decide to call him and ask him about the interior and how much he would charge for a water valve my car needs, turns out there is a 4:10 LSD differential in the car. I asked what it was from and he said he did not know because he bought it just for parts. He stripped the parts off he needed and was parting the rest out. I would like to know if there is a way of finding out if it really is what he says it is by using the numbers on the differential or a part number maybe? He is selling it for $250 and the car had 80k on the odometer... what should I do? I want a lsd differential and 250 looks cheap but i wanna make sure everything checks out ok. :dunno:
4.10 on the highway will be a blast when your rev limited is bouncing at 80mph.
motorwerks
02-11-2009, 05:14 PM
I don't know any way to cross reference diffs. Are you sure you want a 4.10 though. It'll be fun, but it's going to make your car a gas guzzler.
HyphE36
02-11-2009, 05:15 PM
well if 4.10 is bad then what is the optimum differential for a 325is... say for very "spirited" driving on a daily basis :)
motorwerks
02-11-2009, 05:39 PM
3.23, 3.38, or even a 3.91, but a 3.91 is only a little better than the 4.10.
3.15 is 95 m3 and 3.23 is what 96+ m3's got, I personally think bmw got it right with the rear end ratio. Its not like that 190hp car is going to become a rocket launcher with a new rear end ratio.
Ryan M
02-11-2009, 07:14 PM
You will have no first gear with a 4:10. And you'll be shifting so much, your car might actually be slower. But it will pull harder if that's what you're after.
I don't know any way to cross reference diffs. Are you sure you want a 4.10 though. It'll be fun, but it's going to make your car a gas guzzler.
www.diffsonline.com/techinfo/GearingCalculator.xls
http://www.diffsonline.com/techinfo/index.shtml
A 4.10 would be an absolutely stupid idea. I wouldn't even put one in the race car. Another racer friend had one in his car with a euro 6MT and it wasn't enough for the car.
Don't do it.
well if 4.10 is bad then what is the optimum differential for a 325is... say for very "spirited" driving on a daily basis :)
3.46, or 3.64 if you never drive faster than 65 on the freeway.
Nline6
02-11-2009, 07:50 PM
How do you know what diff. is on your car?
Ryan M
02-11-2009, 07:52 PM
How do you know what diff. is on your car?
There should be a label stating the ratio. It may be covered in grease, but it should be there.
motorwerks
02-11-2009, 07:54 PM
How do you know what diff. is on your car?
If it's stock...
auto 325 has a 3.91.
manual 325 has a 3.15
323 & 328 auto have a 3.91
323 & 328 manual have a 2.93
'95 m3 manual has a 3.15
'95 m3 lightweight has a 3.23
'95 m3 auto has a 3.23
96-99 m3 manual has a 3.23
96-98 m3 auto has a 3.38
Nline6
02-11-2009, 08:05 PM
ok I have a 3.15 then, what does that mean? how do I know if I have LSD? I heard that if you have the winter package you have LSD, is this true?
Ryan M
02-11-2009, 08:08 PM
ok I have a 3.15 then, what does that mean? how do I know if I have LSD? I heard that if you have the winter package you have LSD, is this true?
No bimmer came stock with an LSD unless it's an ///M.
Nline6
02-11-2009, 08:17 PM
oh. ok didnt know that. What does the 3.15 mean? longer gears?
Ryan M
02-11-2009, 08:19 PM
oh. ok didnt know that. What does the 3.15 mean? longer gears?
The number is the amount of times the driveshaft must turn to turn the wheels once. So if you have a 3:15, the differential's input shaft must turn 3.15 times to turn the output shafts once.
Nline6
02-11-2009, 09:10 PM
oh ok, thanks for explaining that
Ryan M
02-11-2009, 09:13 PM
You got it.
the_brouhaha
02-11-2009, 11:18 PM
The guy who I bought my car from said he changed it to 3.23, but I didn't see any records about it. I'm gonna go look at it tomorrow.
Thanks ryan for the info!
E36 Phantom
02-12-2009, 12:56 AM
No bimmer came stock with an LSD unless it's an ///M.
I don't believe that's correct, I've read that winter packages early in the E36 lineup did include an LSD. Could be wrong, but I've heard it several times.
Also, I believe if it has an "S" stamped in it it's an LSD.
I don't believe that's correct, I've read that winter packages early in the E36 lineup did include an LSD. Could be wrong, but I've heard it several times.
Also, I believe if it has an "S" stamped in it it's an LSD.
That is correct. I don't know about the "S" stamp, though.
E36 Phantom
02-12-2009, 05:08 AM
That is correct. I don't know about the "S" stamp, though.
Did some more reading. The S is also correct - If it's an LSD, there's an S immediately proceeding the ratio on the metal tag on the diff. There should also be an ink stamped S on the diff.
Did some more reading. The S is also correct - If it's an LSD, there's an S immediately proceeding the ratio on the metal tag on the diff. There should also be an ink stamped S on the diff.
What the hell are you doing up so early?
E36 Phantom
02-12-2009, 06:15 AM
What the hell are you doing up so early?
You mean late. ;)
Working on a paper - and getting my schedule back on track so I can actually get up on time for my flight soon.
motorwerks
02-12-2009, 06:29 AM
I don't believe that's correct, I've read that winter packages early in the E36 lineup did include an LSD. Could be wrong, but I've heard it several times.
Also, I believe if it has an "S" stamped in it it's an LSD.
This is correct:thumbup: This does not apply to 328's though. There were a couple that made it into the US in '96, but it's nearly always safe to say that 328's don't have an LSD.
BeRzErKaS
02-12-2009, 07:22 AM
Today I found a guy who has a 1993 325i convertable for parts... So I decide to call him and ask him about the interior and how much he would charge for a water valve my car needs, turns out there is a 4:10 LSD differential in the car. I asked what it was from and he said he did not know because he bought it just for parts. He stripped the parts off he needed and was parting the rest out. I would like to know if there is a way of finding out if it really is what he says it is by using the numbers on the differential or a part number maybe? He is selling it for $250 and the car had 80k on the odometer... what should I do? I want a lsd differential and 250 looks cheap but i wanna make sure everything checks out ok. :dunno:
So...is your car automatic or manual??
325i Fury
02-12-2009, 07:33 AM
Alright so you guys are saying not to do it.. I did think that a 4:10 might be a little much. I was wrong about the year the car is actually a 92 325i convertable, would the auto tranny match up to my 95? My tranny is going to hell and I'm going to need another soon I asked him how much for the whole drivetrain (everything) and he said for $450 I can have the whole drivetrain plus whatever else I want in the car and it has a tan interior just like mine :thumbup: I think I'm going to do it just because I can take whatever I need off of it.. Only thing is I need to know if it will fit.. I have heard that earlier years of e36 dont match up after 94 or something but don't know where I got that from. The guy can send me the number on the tranny if needed.. but its the stock tranny on a 1992 325i auto I gotta drive 2 and a half hours to go look at the car and don't wanna come back disappointed. How am I going to figure this out? when I get it I will bring it to the independent BMW mechanic in my town and get it put in by him.. Just need help figuring out if it will fit.
My car is auto.
BeRzErKaS
02-12-2009, 08:03 AM
Alright so you guys are saying not to do it.. I did think that a 4:10 might be a little much. I was wrong about the year the car is actually a 92 325i convertable, would the auto tranny match up to my 95? My tranny is going to hell and I'm going to need another soon I asked him how much for the whole drivetrain (everything) and he said for $450 I can have the whole drivetrain plus whatever else I want in the car and it has a tan interior just like mine :thumbup: I think I'm going to do it just because I can take whatever I need off of it.. Only thing is I need to know if it will fit.. I have heard that earlier years of e36 dont match up after 94 or something but don't know where I got that from. The guy can send me the number on the tranny if needed.. but its the stock tranny on a 1992 325i auto I gotta drive 2 and a half hours to go look at the car and don't wanna come back disappointed. How am I going to figure this out? when I get it I will bring it to the independent BMW mechanic in my town and get it put in by him.. Just need help figuring out if it will fit.
My car is auto.
Everyone was assuming your car was manual.
A 4.10 in a 5sp manual would be a bit much. A 4.10 in an automatic, however, would provide a nice upgrade. Your current ratio should be a 3.91 so you will only be looking at like a 5% bump in RPM's at cruising speed with the 4.10. That's nothing really...actually hardly worth it, IMO. But you are getting a good price plus LSD so I say go for it.
Some people with automatics will even go for a 4.27 which gives a roughly 10% bump in RPMs but offers a much more noticeable increase in acceleration.
The drive train from the '92 should bolt up to your '95 without a problem.
325i Fury
02-12-2009, 08:20 AM
Everyone was assuming your car was manual.
A 4.10 in a 5sp manual would be a bit much. A 4.10 in an automatic, however, would provide a nice upgrade. Your current ratio should be a 3.91 so you will only be looking at like a 5% bump in RPM's at cruising speed with the 4.10. That's nothing really...actually hardly worth it, IMO. But you are getting a good price plus LSD so I say go for it.
Some people with automatics will even go for a 4.27 which gives a roughly 10% bump in RPMs but offers a much more noticeable increase in acceleration.
The drive train from the '92 should bolt up to your '95 without a problem.
Just what I was looking for, Do you think that if I'm getting the whole drivetrain it would be hard to do this myself or do you recomend the mechanic to do it? I know i said i was going to bring it in but if it's not too hard I don't wanna spend the cash. Usually I don't bring it in but for this I'm a little unsure I know it will get done at the shop but if I did it it seems like it would just bolt up and all the electrical stuff would be plug and play. I have a torque wrench, jack stands, jack, and other basic tools.. how long it takes is not really an issue as I have another 5 cars I can drive if this one needs to be fixed.
BeRzErKaS
02-12-2009, 08:34 AM
Just what I was looking for, Do you think that if I'm getting the whole drivetrain it would be hard to do this myself or do you recomend the mechanic to do it? I know i said i was going to bring it in but if it's not too hard I don't wanna spend the cash. Usually I don't bring it in but for this I'm a little unsure I know it will get done at the shop but if I did it it seems like it would just bolt up and all the electrical stuff would be plug and play. I have a torque wrench, jack stands, jack, and other basic tools.. how long it takes is not really an issue as I have another 5 cars I can drive if this one needs to be fixed.
It can be done.
I did my auto-manual conversion myself in about 5 days with handtools and jackstands. It would help to have a buddy around because the tranny and diff are HEAVY and really awkward to work with under the car. Having a lift and some airtools would make things way easier.
No special tools are needed. You will probably need to pick up some extra ratchet extensions though. You will need about 3ft worth to get to the torx bolts that secure the top of the bell housing to the motor.
325i Fury
02-12-2009, 08:45 AM
It can be done.
I did my auto-manual conversion myself in about 5 days with handtools and jackstands. It would help to have a buddy around because the tranny and diff are HEAVY and really awkward to work with under the car. Having a lift and some airtools would make things way easier.
No special tools are needed. You will probably need to pick up some extra ratchet extensions though. You will need about 3ft worth to get to the torx bolts that secure the top of the bell housing to the motor.
Sounds good anything I should replace while I'm doing all of this? I will be swapping the drivetrain and I just ordered a valve cover gasket and new intake manifold gaskets and swapping out my water valve. I can swap out whatever parts I want out of the parts car. I will probably be getting an extra MAF and putting new vacuum lines on while the intake manifold is off. Any other suggestions? want my car to run good for a while after I get done with all this.
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