2.93, 3.25, or 3.73 for S50

[kalib0y]

I DD this car and track it on the weekends. I currently have a 2.93 and it feels pretty good but want an optimal ratio. What diff ratio do you guys prefer?

[JGood]

That would depend on your transmission.

Even knowing that, your idea of "optimal" may not be the same as everyone elses. There are some gear ratio calculators online that can help you. You're the one who knows what kind of speeds you'll be hitting on the tracks you go to. Road racing and DD don't fit in the same sentence, so I'll assume you mean HPDE's, in which case you need to decide just how much you're willing to sacrifice in highway RPM's to gain a little acceleration in a non-competition environment.

[Eric]

3.46 and 3.64 are good ratios for the ZF 5 speed that the E36 comes with. I have a euro S50B30 the trans that came stock with the that motor and a 3.73LSD in mine, and while I can hit 120+mph easy in 4th, the car is screaming at 80mph in 5th.

1st gear is worthless, and even 2nd is really short. The only time ive had it on track, on the Nurburgring GP circuit, I was using 3,4,5-5,4,3 all the time... never went into 2nd.

If I had unlimited gear choices, I'd toy around with both the 3.46 and 3.64 and see which I like better.

[kalib0y]

What are your thoughts on the 3.25? Still too tall?

[bmw2002tiiagave]

I have 4.10 that came with my car. I have yet to determine how bad its gonna be on the highway lol.

[Wh33lhop]

What are your thoughts on the 3.25? Still too tall?

3.25 is as high as I would want to go if I did much highway driving, unless you like buzzing along at 4200rpm at 80mph (which is the next step up, the 3.46).

Personally if I did an S5x swap I'd want to stick with a 2.93 for highway duty. And even then, 3400rpm at 80 is still pretty lofty for a torquey motor--I'd be looking into 6 speeds.

[10Toes]

I have a ZF320 with a 3.25 and I'm going to switch to a 2.93. It gets old driving on the freeway at 3500 rpm's.

[monkeytaco]

My m52b28 is mated to a zf320 and 2.93, and i've just driven it from here to the exhaust shop and up and down the street a couple times and it feels pretty perfect. I'm also primarily daily driving this car so that might make a difference...

[rpob5t]

I've got a 3.25/ZF 5spd combo in my car; for track use and an aprox 23" tall tire (225/45/15) the gearing feels pretty good, but as others said it can be a bit buzzy on the highway (its still way better than the 4.10 G260 combo I was running with the M20). A good run into T1 and up the esses at the glen I'm close to 6500 RPM in 5th (with a miss over 6k due to a weak coil) and I'm running an OD1 M52 with S52 cams so I'd imagine that extra torque of the 3.2 would be even better. I can't imagine wanting much more gear unless I went with a 5 lug and the associated generally taller tires...

[surebimmer]

Stock E36 5 speeds had a final drive of 3.23. Just food for thought. I would like a 3.46 but don't mind a higher RPM on the freeway.

[flyboyx]

i tend to agree with the first post in that it really depends on whether you are using the zf320 or getrag 260. for both transmissions, first gear is a waste of time if you run 3.73 or lower. i am pretty sure my needs are different than yours since i own a cabrio and have no intentions of using it on the track. however, i am running a g260 and i have 2.93, 3.23, (and a 3.38 ring and pinion that i need to install in a carrier). when i go on long road trips with the car, i generally swap in the 2.93. otherwise, i like the 3.23 for general daily use. my plan is to get the 3.38 swaped into a carrier and use that ratio as the daily and the 2.93 for trips. i am rolling on 17" alpinas that have a tire diameter of 24"

[ck_taft325is]

I have an S3.46 gearing on a ZF320 right now and honestly, for DD duties I'll be putting in an S2.93 so I'm not at nearly 5,000 rpm cruising at 70-80mph on the freeway.

That said, the S3.46 is a fucking amazing gear ratio for an S50. No joke, I have so much fucking fun busting around my podunk area. Insanely quick with the S50 pushing it and I can literally break loose 1-2-3-4 stepping on it.

[e30polak]

I have an S3.46 gearing on a ZF320 right now and honestly, for DD duties I'll be putting in an S2.93 so I'm not at nearly 5,000 rpm cruising at 70-80mph on the freeway.

That said, the S3.46 is a fucking amazing gear ratio for an S50. No joke, I have so much fucking fun busting around my podunk area. Insanely quick with the S50 pushing it and I can literally break loose 1-2-3-4 stepping on it.

This.

With my s52+ZF, first I had a 3.25 which was great. Then I wanted to shorten 3rd and 4th up, so I got the 3.46. For canyons and street driving, it made the car noticeably torquier. However, for high way driving, even with my 235/40/17s all around, I'd cruise 80 around 4200.

A week before selling my car I put a 2.93 in because the 3.46 was too rare to give up. I wish I would've run this the whole time. It really is the perfect gearing IMO with the ZF and an s50/2. You can hit 64-65 in 2nd, over 100 in 3rd, and cruise 80 at around 2700! The longer gears give you more time in powerband, making you faster overall.

When Jasper (jahnaboi) and I raced, I could only beat him from a launch. We had almost identical set-ups except he had a 2.93 and I had a 3.46. From 2nd it was about even, then 3rd, and 4th I got pulled on steadily because of all the shifting.

2.93 = better gas mileage, and more usable power.

[e30polak]

sorry duplicate

[kalib0y]

Thanks for the very good info guys. With the 2.93 it pulls very hard and at 80mph i am at about 3400rpm and I really love the torque and use of the gearing. I may just go with a lighter flywheel to make it feel peppier and rev happier