2.93, 3.25, or 3.73 for S50

[flyboyx]

I have and it's pointless IMO. The only reason to get a 6 speed IMO is to run fairly short final drive gears, while still cruising at low revs in 6th on the highway. Gas mileage is always cool, but not worth the extra money for the trans IMO. I'd rather run a 3.25/3.46 with a getrag 260 for gas savings.

i agree with e30polak as these are my thoughts as well.


i realize the purpose of this thread is to find the ONE diff that perfectly suits every need for a 24v swapped e30. if you use your car for more than one purpose you really need to have the correct ratio for each use. otherwise you will be compromising on both ends.

as i mentioned above, i use two. one stays in the car(in my case-3.25, soon to be 3.38 ) and one stays under the work bench in the garage(2.93) and is used when i need the car for a driving vacation. i actually made a special cradle that replaces the cup on my floor jack to facilitate the change out. i also made a special wooden storage crate so i don't break those fragile fins on the bottom of the mz3 diff cover. i put red locktite on the bolts every time i remove them. i am to the point now that i can get the car on jackstands, change the diff and get it back on the ground in about 20-25 minutes or so. this is about the same amount of time it takes me to change the oil. lets see...i think there are 21 bolts and 4 nuts on the drive shaft required to do the job.

if you track your car once in a while, keep a 3.73 or a ratio that suits your purpose as the spare. i mean, hell....they are so cheap compared to other types of vehicle. where else can you get a good used lsd differential for 300.00 or less? if you can find one at an lkq, they are likely under 100.00. if that sounds expensive to you, price one for a mustang sometime.

btw....i have never heard of a 3.07 for an e30?

[flyboyx]

I'm using 3.15 with the 5-speed ZF right now but I haven't driven the car much so can't tell if it's too short at the moment.

from what i understand about motor vehicle rules over there is that is very very expensive to license any vehicle over 10 years old? doesn't it cost several times more than the car is worth?

[Gooch]

I am going to be running a ZF and I thought I was going to be using a 3.25 for sure, but this thread seems to be swaying me to a 2.93.

[E30_80Y]

i have Zf with 3.25 and i dont think i like doing the 3400rpm on the highway, i would switch to 2.93 if could.

[kalib0y]

Well I just picked up a 3.25 but I wont put it in yet till after I have run Streets of Willow with a few times with the 2.93 to see if I will still want the 3.25 gearing. The 2.93 is plenty fast and I love daily driving the car with it. As I said before my 80mph is about 3400rpms.

The only reason why I keep thinking of the 3.25 is becuase I knew the S50 was originally paired with a 3.15 so I think I the 3.25 shouldnt be too bad. We will see...

[ck_taft325is]

An S3.25 should be just fine honestly. I love the S3.46 gears but it's not the best for highway cruising. I recently, last night actually, drove 380 miles round trip in the S50 with 3.46 gears and at an average of 80-90mph I got around 25mpg. I can't help but think that the 2.93 would be much better suited for highway driving if that's what you do on a regular basis like myself.

The acceleration was insane though ;)

[Wh33lhop]

I have and it's pointless IMO. The only reason to get a 6 speed IMO is to run fairly short final drive gears, while still cruising at low revs in 6th on the highway. Gas mileage is always cool, but not worth the extra money for the trans IMO. I'd rather run a 3.25/3.46 with a getrag 260 for gas savings.

Honestly I would think that a 6 speed with a 3.73 may actually slow you down with a broad powerband motor like an S52. There is no real reason to be shifting so often and the extra ability to pinpoint the powerband would not be beneficial enough to offset the amount of shifting you would have to do. It would probably be more fun to drive... well until the novelty wore off and you got sick of shifting out of first at 10mph (since it would be useless anyway) and a second gear that only took you to 50, then by the time you're cruising at 80 well, forget about third gear (that's over at about 78mph), if you want to pass anyone you'll have to use forth. From then on the closer 4-5-6 would be fun but you'd still be sitting at 3600rpm at 80 (since the G420's sixth is a .85 as opposed to the .81 fifth of the G260).

Personal preference obviously plays a big role here, but as a DD I would probably leave a 2.93 or a 3.25 even if it were a 6 speed. At least then you'd be running a tamer 3000rpm at 80 which would be a lot more bearable for highway cruising. First and second would not be completely useless either, and third would take you to 95 or so before you shift back into the reasonable 6th.

[e30polak]

Honestly I would think that a 6 speed with a 3.73 may actually slow you down with a broad powerband motor like an S52. There is no real reason to be shifting so often and the extra ability to pinpoint the powerband would not be beneficial enough to offset the amount of shifting you would have to do. It would probably be more fun to drive... well until the novelty wore off and you got sick of shifting out of first at 10mph (since it would be useless anyway) and a second gear that only took you to 50, then by the time you're cruising at 80 well, forget about third gear (that's over at about 78mph), if you want to pass anyone you'll have to use forth. From then on the closer 4-5-6 would be fun but you'd still be sitting at 3600rpm at 80 (since the G420's sixth is a .85 as opposed to the .81 fifth of the G260).

Personal preference obviously plays a big role here, but as a DD I would probably leave a 2.93 or a 3.25 even if it were a 6 speed. At least then you'd be running a tamer 3000rpm at 80 which would be a lot more bearable for highway cruising. First and second would not be completely useless either, and third would take you to 95 or so before you shift back into the reasonable 6th.

I understand your point Nathan, I guess I'm against 6 speeds in general. I will be running a ZF320+3.23 lsd with my s54. No need for a 6th gear, when 1st through 5th are long enough. ;)

[hoveringuy]

G260 and a 3.25 here. I think it's perfect. 3.73 was ridiculous for 1st gear.

Overall, I think the ZF has better ratios for the bigger motors.

[kalib0y]

Got curious and impatient yesterday. Put the 3.25 in and now my 80mph is ~4100rpms. Acceleration is pretty nice. I do like the longer "pull" of the 2.93 in each gear so I will be keeping it for my future mods hehe