diff ratios

[SAE30]

Anyone have any idea which diff ration came on which BMW? i read something about the e28 533 having a 3.25:1 lsd?

[BadDave]

Some info from the wiki for you fella

E30 LSD Ratios

Below is a list of ratio and cars in which they can be found.

3.15 - M3
3.64 - prefacelft 325i
3.73 - automatic transmission 325i
3.91 - facelift 325i
4.10 - found optionally on UK spec 318i/318iS 2/4dr in Small Case, and on all US M3 models in Medium Case.
4.27 -
4.44 -

Not too sure about which E28's had slippers fitted

HTH

[Scruffymurphy]

Some info from the wiki for you fella

E30 LSD Ratios

Below is a list of ratio and cars in which they can be found.

3.15 - M3
3.64 - prefacelft 325i
3.73 - automatic transmission 325i
3.91 - facelift 325i
4.10 - found optionally on UK spec 318i/318iS 2/4dr in Small Case, and on all US M3 models in Medium Case.
4.27 -
4.44 -

Not too sure about which E28's had slippers fitted

HTH

The E30 ones are in the wiki,

http://www.e30zone.net/e30zonewiki/inde ... ferentials

[UweM3]

borrowed from E30.de

http://wp1016621.wp027.webpack.hosteuro ... f00023.htm

[SAE30]

What about the z3?

[UweM3]

What about the z3?

what about thanks for your help guys so far? Do you intend to go through the whole BMW model range?? Might be of help if you tell what you are trying to achieve. just a thought......

[SAE30]

What about the z3?

what about thanks for your help guys so far? Do you intend to go through the whole BMW model range?? Might be of help if you tell what you are trying to achieve. just a thought......

im so sorry ... should have thanked u guys, my mistake...


im using the m3 zf box with my s50b30 swap, want to build a diff that goes well with the m3 box, looking for different ratios, heard the z3 diff has the same ratio as the m3 and bolts on to e30 without any modifications


Thanks again

[mike_sayer]

For the M3 ZF 'box that we'll eventually be using, we've just got a 3.25 medium-case LSD from an E30 M3 (other option from M3 is 3.15). That should match the 'box ratios quite well according to my gear speed calculator. Z3 diff is 3.15 medium-case like the M3, but has a slightly different diff cover (finned). From what i've heard, you'll need a medium-case diff as the small-case ones can't take the extra torque supplied by an S50...

[UweM3]

For the M3 ZF 'box that we'll eventually be using, we've just got a 3.25 medium-case LSD from an E30 M3 (other option from M3 is 3.15). That should match the 'box ratios quite well according to my gear speed calculator. Z3 diff is 3.15 medium-case like the M3, but has a slightly different diff cover (finned). From what i've heard, you'll need a medium-case diff as the small-case ones can't take the extra torque supplied by an S50...

3.15 M3's are very hard to find, most M3's came with 3.25.
3.45 LSD is also very very hard to find (fitted to 320iS)

[SAE30]

For the M3 ZF 'box that we'll eventually be using, we've just got a 3.25 medium-case LSD from an E30 M3 (other option from M3 is 3.15). That should match the 'box ratios quite well according to my gear speed calculator. Z3 diff is 3.15 medium-case like the M3, but has a slightly different diff cover (finned). From what i've heard, you'll need a medium-case diff as the small-case ones can't take the extra torque supplied by an S50...

3.15 M3's are very hard to find, most M3's came with 3.25.
3.45 LSD is also very very hard to find (fitted to 320iS)

Thanks.....

The biggest problem i have is that we did not get even close to getting the e30 M3 here so a diff from that vehicle is impossible... please help with an alternative or can the crown wheel and pinion be swapped between diffs?

[UweM3]

For the M3 ZF 'box that we'll eventually be using, we've just got a 3.25 medium-case LSD from an E30 M3 (other option from M3 is 3.15). That should match the 'box ratios quite well according to my gear speed calculator. Z3 diff is 3.15 medium-case like the M3, but has a slightly different diff cover (finned). From what i've heard, you'll need a medium-case diff as the small-case ones can't take the extra torque supplied by an S50...

3.15 M3's are very hard to find, most M3's came with 3.25.
3.45 LSD is also very very hard to find (fitted to 320iS)

Thanks.....

The biggest problem i have is that we did not get even close to getting the e30 M3 here so a diff from that vehicle is impossible... please help with an alternative or can the crown wheel and pinion be swapped between diffs?

yes they can. I bought a open 3.73 and used my 3.25 LSD to get a diff build.

[oze30]

I have a 3.45 open possibly for sale. Any good to you?

[SAE30]

3.15 M3's are very hard to find, most M3's came with 3.25.
3.45 LSD is also very very hard to find (fitted to 320iS)

Thanks.....

The biggest problem i have is that we did not get even close to getting the e30 M3 here so a diff from that vehicle is impossible... please help with an alternative or can the crown wheel and pinion be swapped between diffs?

yes they can. I bought a open 3.73 and used my 3.25 LSD to get a diff build.

so what you're saying is that i can take my diff that i have now(3.91LSD) and swop out the crown wheel and pinion and keep the LSD unit? if so then which diff do u suggest i get to build my diff?

Thanks

[SAE30]

I have a 3.45 open possibly for sale. Any good to you?

i would love to take it off your hands but i think the shipping would be way too expensive, im all the way in south africa but thanks anyway

[GeoffBob]

Try BEMOW Spares in Pretoria if you can (012 327 6294). They occasionally get hold of LSD's. An option for you is to swop the contents of an E36 LSD into an E30 diff medium casing. These generally have lower ratios due to the fact that the 5th gear on an E36 manual box had a 1:1 ratio, compared to the typical 0.81:1 of an E30 manual box or 0.73:1 E30 autobox.

Also, what ZF box are you using? Do you know its ratios? If its from the E36M3 where you got your engine (??) then you'd best be careful which E30 diff you fit with it!! Most of the higher ratio E30 diffs will have you redlining in 5th soon after 120km/h due to the above mentioned differences in gearbox ratios.

If you have the ZF box I am thinking of then its a Type C five-speed manual gearbox with ratios:
1st: 4.20:1
2nd: 2.49:1
3rd: 1.66:1
4th: 1.24:1
5th: 1:1

You'll need to find a loooow ratio E30 diff (imported E30M3 or similar) to give you any speed if you plan to use this box with your S50 engine! Fortunately, the E36M3 also had a 25% LSD with ratio 3.15:1 (very low!!). Thus, why not take the LSD off the E36M3 (where you got your S50 engine and ZF box in the first place) and transfer the contents to the casing of a medium E30 diff? That'll do for you just fine

Am I overstating the obvious here or have I missed something in the earlier posts? I probably missed something, duh, again.

I hope this helps.

[UweM3]

Thanks.....

The biggest problem i have is that we did not get even close to getting the e30 M3 here so a diff from that vehicle is impossible... please help with an alternative or can the crown wheel and pinion be swapped between diffs?

yes they can. I bought a open 3.73 and used my 3.25 LSD to get a diff build.

so what you're saying is that i can take my diff that i have now(3.91LSD) and swop out the crown wheel and pinion and keep the LSD unit? if so then which diff do u suggest i get to build my diff?

Thanks

???? that's what I suggested. Use ANY LSD diff you can find and buy crownwheel and pinion you want and get it swapped.

EDIT:
I mean any E30 medium case LSD (I don't know about the others)

[DanThe]

E36 M3 diffs are a large case, the internals are not compatible with the E30 diffs, I would go for an E36 325i diff, medium case and 3.25:1 ratio

[Brianmoooore]

I have a LSD (medium case) fitted to a project E30 that came from a '99 2.8 Z3 (IIRC).
Fitted on with no mods, and has a ratio, (again IIRC) of 3.15.
The diff is a torsen type, rather than the older clutch type.

[SAE30]

Try BEMOW Spares in Pretoria if you can (012 327 6294). They occasionally get hold of LSD's. An option for you is to swop the contents of an E36 LSD into an E30 diff medium casing. These generally have lower ratios due to the fact that the 5th gear on an E36 manual box had a 1:1 ratio, compared to the typical 0.81:1 of an E30 manual box or 0.73:1 E30 autobox.

Also, what ZF box are you using? Do you know its ratios? If its from the E36M3 where you got your engine (??) then you'd best be careful which E30 diff you fit with it!! Most of the higher ratio E30 diffs will have you redlining in 5th soon after 120km/h due to the above mentioned differences in gearbox ratios.

If you have the ZF box I am thinking of then its a Type C five-speed manual gearbox with ratios:
1st: 4.20:1
2nd: 2.49:1
3rd: 1.66:1
4th: 1.24:1
5th: 1:1

You'll need to find a loooow ratio E30 diff (imported E30M3 or similar) to give you any speed if you plan to use this box with your S50 engine! Fortunately, the E36M3 also had a 25% LSD with ratio 3.15:1 (very low!!). Thus, why not take the LSD off the E36M3 (where you got your S50 engine and ZF box in the first place) and transfer the contents to the casing of a medium E30 diff? That'll do for you just fine

Am I overstating the obvious here or have I missed something in the earlier posts? I probably missed something, duh, again.

I hope this helps.

tHANKS, I tried them already, nothing at the moment...im using the e36 m3 box, the car that i got the engine from is no longer ....
i think im gonna do what UweM3 has suggested...

[SAE30]

E36 M3 diffs are a large case, the internals are not compatible with the E30 diffs, I would go for an E36 325i diff, medium case and 3.25:1 ratio

thats the ratio i need to find, its slightly shorter than the m3's 3.15...

Got my box changed yesterday, im now driving the car with the the old diff and m3 gearbox... 3.91:1 , car revs very quickly but too high revving in 5th.... need to do the diff swap asap

[GeoffBob]

Sorry that they didn't have. I know, they are like hens teeth over here. You can also try your local Gearbox and Diff centres, they like to collect them and sell them at huge profit to suckers like you and me.

Keep in mind that the early E36M3's over here were not the same as the Euro and American versions. Our version came out of the Rosslyn plant north of Pretoria and used a combination of imported and local parts. You'll find the larger diff to which DanThe refers on the later imported E36's after 1994. Unfortunately, only 748 of the early examples were produced locally and are hard to find. I think they used the same diff from the E36 325is in Europe and UK. Remember, even though SA may have been the first to put the M30 motor in the E30 body (The 333i), our first M3, of the E36 variety, (given that the LHD E30M3 was never imported) was substantially diluted. You can tell the later RHD import cars straight off since they had the European M-style sports seats inside, ours didn't. I don't know how many of those were imported. I stand corrected (I can only speak for local), but I think the US version was also diluted compared to the Euro version.

I'd be interested to hear what engine you managed to pick up. Does it have individual throttle bodies? If so, its from a Euro car and the diff would have been no good to you.

[SAE30]

Sorry that they didn't have. I know, they are like hens teeth over here. You can also try your local Gearbox and Diff centres, they like to collect them and sell them at huge profit to suckers like you and me.

Keep in mind that the early E36M3's over here were not the same as the Euro and American versions. Our version came out of the Rosslyn plant north of Pretoria and used a combination of imported and local parts. You'll find the larger diff to which DanThe refers on the later imported E36's after 1994. Unfortunately, only 748 of the early examples were produced locally and are hard to find. I think they used the same diff from the E36 325is in Europe and UK. Remember, even though SA may have been the first to put the M30 motor in the E30 body (The 333i), our first M3, of the E36 variety, (given that the LHD E30M3 was never imported) was substantially diluted. You can tell the later RHD import cars straight off since they had the European M-style sports seats inside, ours didn't. I don't know how many of those were imported. I stand corrected (I can only speak for local), but I think the US version was also diluted compared to the Euro version.

I'd be interested to hear what engine you managed to pick up. Does it have individual throttle bodies? If so, its from a Euro car and the diff would have been no good to you.

i have the 4 door m3 motor we have here, 3.2 euro... itb's etc.