I just picked up an 03 325i I'm setting up primarily for a short 2nd gear track (OSW skid pad), and the goal is to be able to keep up in tandem with higher hp cars.
I believe this can be achieved with grip and gearing .. Suspension parts are ordered, time for diff/subframe prep.
For reference I drove this track with a 2.93 welded & a 3.91 welded in my last e36. - 2.93 sucked obviously & 3.91 basically sat on limiter in second, but I used to drive on clapped used tires all the time. I imagine a 3.91 with decent grip would make for a fast car.
So my question is, should I fiddling around looking for an x3 or z4 diff? Or is the e46 auto 3.46 enough to party with?
Having trouble finding one local, and the ones I have found are $3-400..
Here's the diff chart from bokchoy -
These cars have pretty narrow final drive ratio options, but from what I've gathered
z4/x3 pumpkins are smaller but will bolt into 323i/325i/328i when you swap output shafts.
- 330's need a driveshaft from one of these models to work.
Model Final Drive Final drive from Automatic Equivalent E46 323i / ci 3.07 3.46 325i / ci 3.15 3.46 328i / ci 2.93 3.46 330i / ci 2.93 3.38 330i 6sp 2.93 3.38 330i zhp 3.07 3.64 323cic 3.46 3.46 325cic 3.46 3.46 330cic 3.07 3.38 330cic 6sp 3.07 3.38 323i touring 3.46 3.46 325i touring 3.46 3.46 325xi /touring 3.23 3.46 330xi 3.07 3.46 330xi 6sp 3.07 3.46 *M3 / conv 3.62 - E85 / E86 Z4 2.5 (E85) 3.46 3.64 Z4 3.0 (E85) 3.07 3.46 Z4 3.0si (E85) 3.23 3.64 *Z4 M3.2 (E85) 3.62 - Z4 3.0si (E86) 3.46 3.64 *Z4 M3.2 (E86) 3.62 - E83 **X3 2.5i 3.91 3.91 **X3 3.0i 3.64 3.64 **X3 3.0si 3.73 4.44
Any input is appreciated. Thanks guys
I have a welded E46 3.46 at the shop I could sell you.
The vert won't be ready by Saturday but I will be at Auburndale this Saturday. I could bring the diff with me if you are going. Sean said he wants $275 for it. I did the welding on it.
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