325ix diff swap???

[E30rider]

Doing a swap on my Bmw e30 325ix. I have everything but the diffs. Does anyone know if I can use the automatic ones (4.10 ratio) with manual trans, I think the manual ones for 325ix are (3.91). I keep hearing different things from different people. Let me know please :) much appreciated

[stonea]

You'll be fine using the 4.10 diffs. I've always wondered how big of a difference there was when driving a 5 speed car with a 3.91 ratio vs a 4.10.

[E30rider]

You'll be fine using the 4.10 diffs. I've always wondered how big of a difference there was when driving a 5 speed car with a 3.91 ratio vs a 4.10.

Thanks! Have you driven it with the automatic diff before ?

[stonea]

Nah, my car is an 88' so it came factory with a 5 speed and the 3.91 diffs. I know Mr. ix himself (Nando) has 4.10 diffs in his 5 speed swapped car.

[nando]

Not much difference (4.8%). People love to exaggerate the revs at freeway speeds - 75 is about 3500. Not bad at all, and no need to downshift since you're already in the meat of the torque curve.

[E30rider]

Not much difference (4.8%). People love to exaggerate the revs at freeway speeds - 75 is about 3500. Not bad at all, and no need to downshift since you're already in the meat of the torque curve.

Thanks Nando, I appreciate it! I'm going to do the swap soon and hopefully all goes well :) I was just worried because the guy I bought the swap set up from was being an asshole and didn't want to give me the manual diffs .. So let's see how this goes !

[4x4_e30]

I'm rocking 4.10s and a 5 speed, too. I think the biggest driving difference with gear ratios is how short 1st gear gets, in our case it makes for some awesome 6k rpm clutch dumps

[Kershaw]

Yeah, no. Don't do that. Great way to blow up the spider gears in your front diff.

[nando]

I've done it probably 150 times, lol.

[Kershaw]

I used to, not anymore.

On snow tires it's ok, they spin a bit before they get traction so the drivetrain doesn't get shocked too bad. But the direzza star spec IIs just have too much grip. They don't spin at all. I was in the pouring rain when the diff I sent you died. 3 of my tires moved several inches around my rims (I had them marked) and the spider gears ate it.

I'm not sure I'd order these tires again, they provide traction far past the speeds of my driving skill. I haven't had too much fun with them.

[nando]

I usually did it on hoosiers, the light wheight i think helped. Under 20lbs per corner.

[Kershaw]

The tire alone or the tire and wheel combo?

[nando]

Tire and wheels

[Kershaw]

Seriously?

My BBS RS and SSIIs are around 31lbs and I thought that was light. What rims do you have? Dropping 11lbs of rotating mass per wheel would be huge.

[nando]

14" stock weaves are super light and so are hoosiers. I could lift them up onto the hub with one hand.

The downside is they are narrow and the sidewalls are huge.