Anyone using 3.46 Diff behind a ZF trans?

[Jonny Cash]

Im torn on what diff to use- s52/zf. The car will see 50/50 street and track use.
I have seen some videos of this combo on track, and it seemed perfect, but is it un-bearable on the street?

Probably end up with 3.23, but Id like that little extra oomph' out of the corners. Never really driven a swapped e30, so nothing to compare to.

[cormier]

I'm going with 3.46 in my s52/zf I've heard of people going higher as well

I'm not going to be doin more than 120 (km) on the roads so I don't think I'll be annoyed at it topping out

On some of the YouTube videos the ratio is listed, that helped me get a feel for the ratios

That said I may end up 3.23 down the road if i dont like the 3.46

[Jonny Cash]

Wheel and tire size should also be factored in-

As of right now is 225-45-15 for track- 225-45-16 for street. But I may go for 16's for both street an track. Im reading some older threads, and theres alot of good info- but it seems alot of guys run 17's, which would considerably change things.

[FredK]

I drive my car mostly on the street with a ZF/3.46. I've been to the track a few times and I've never felt like the gearing was too high. I run 225/45R15.

The place where I wish I had a lower gear ratio (like a 3.23 or a 3.25) is while autocrossing. I have to shift a lot more than people who run a 3.25 with taller tires (E36).

[M-technik-3]

I have one as well. In the next configuration it will be but that is only because of FI. I'd love a 6th gear but that's not happening.

[MacBudd541]

I am running a zf with 3.46. I have driven it on long trips to the e30 picnic and other bbqs and such. It is not terrible on the freeway. This combo is flawless at the drag strip. I am right at the top of 4th gear at the finish.

I'm running 225/50r15 in the rear.

-Mac

[e30rapidic]

i have a 3.46, bearable on the highway but I'm holding out for a 6 speed. I love it around town though.

I have 205/50/16's

[nando]

I drive my car mostly on the street with a ZF/3.46. I've been to the track a few times and I've never felt like the gearing was too high. I run 225/45R15.

The place where I wish I had a lower gear ratio (like a 3.23 or a 3.25) is while autocrossing. I have to shift a lot more than people who run a 3.25 with taller tires (E36).

bump your redline to 333hp at 8000rpm and you won't have to shift so much?


;)

if you do the math, the ZF/3.46 is similar to a G260 and 4.10.

I want a 3.23, but I'm stuck with the 3.38.

[LJ851]

I am running a zf with 3.46. I have driven it on long trips to the e30 picnic and other bbqs and such. It is not terrible on the freeway. This combo is flawless at the drag strip. I am right at the top of 4th gear at the finish.

I'm running 225/50r15 in the rear.

-Mac

What are your 1/4 mile times?

[nrubenstein]

I've done the 3.46 with a ZF and the G260. A quiet exhaust is key to making it tolerable. You want something along the lines of nando's recipe. I'm currently running two borla proxs mufflers, but I'll be trying a borla turbo xl (they have a 2-1 merge muffler) and a stainless works chambered muffler on the M3. The M3 will be keeping the stock 4.10, so I figure it's worth giving up a couple hp for a pleasant drive. :)

[E30Strube]

How does tire size play into this? When upsizing tire/wheels, you would typically try to keep the same overall diameter, so it shouldn't matter if it is fat tires on 15s or short tires on 17s, right?

I've been debating about which diff to go with for my ZF also and have been leaning towards the 3.46.

[nando]

generally, yes, but it's difficult to find really fat tires that aren't slightly taller. But if your gearing is short anyway, that won't really matter.

[FredK]

bump your redline to 333hp at 8000rpm and you won't have to shift so much?


;)

Haha, having extra revs will definitely help, but I will definitely try a 3.25.

How does tire size play into this? When upsizing tire/wheels, you would typically try to keep the same overall diameter, so it shouldn't matter if it is fat tires on 15s or short tires on 17s, right?

Yep. I think you'll benefit from a 3.46, because most of the sticky 17s are 245/40R17, which is larger in overall diameter when compared to stock.

[Jonny Cash]

I think 3.38 would be the perfect choice for me since our driving roads are straight+boring, and my wheel size.
But Im also thinking in terms of what I can pull from the yard. 3.46's are pretty easy to find from e28's, but not so much automatic m3's.

[MacBudd541]

What are your 1/4 mile times?

13.06@107mph