I just realized that the 206ft/lbs of torque is measured at the crank, so obviously it's a different ballgame at the wheels. Anyone know what all the e46's put down at the wheels, or how to calculate it (i.e. how much loss there is)? Thanks.

And I've already been looking at this site: http://www.bokchoys.com/differential/GearRatios.htm

 

15-18% loss from the crank to the wheels. "approximately"

 

It's not necessary to get software with a diff swap but it's definately beneficial. Raising redline from 6500 to 7000 will help make shifting a little more comfortable and alleviate the top end decrease due the shorter final drive.
As far as an LSD, you're going to find it hard, if not impossible, to find a one under $1000 being as though the only way to do it is a custom job.

 

Grrrr... I didn't know this before I got my car... I guess I just assumed that like with the E36's it was going to be easy to do. Oh well, it's just a daily driver . I'll make due :thumbup:

 

Grrrr... I didn't know this before I got my car... I guess I just assumed that like with the E36's it was going to be easy to do. Oh well, it's just a daily driver . I'll make due :thumbup:

Yeah, unfortunately we can't just swap in an M3 diff like on the E36 platform

 

I doubt you can find an limited slip unit for less than $1000 because you need to pay for the limited slip unit and the labor for it to be installed. The cheapest LSD you can get is the Qualife ones. As for the torque increase, you are right, it is about 18%. Good luck!

I have an LSD right now and the difference between a LSD and an open differential is so huge. Like you said, the LSD just makes the car hug the corner! If you want the best LSDs contact Jim Blanton at Performance Gearing. Excellent person to deal with! :thumbsup:

 

I doubt you can find an limited slip unit for less than $1000 because you need to pay for the limited slip unit and the labor for it to be installed. The cheapest LSD you can get is the Qualife ones. As for the torque increase, you are right, it is about 18%. Good luck!

I have an LSD right now and the difference between a LSD and an open differential is so huge. Like you said, the LSD just makes the car hug the corner! If you want the best LSDs contact Jim Blanton at Performance Gearing. Excellent person to deal with! :thumbsup:

At the cost of getting an LSD for an E46 I'd rather just hold of until I buy an E46 M3 in a couple of years (still a poor college student afterall ).

 

Going from a 2.93 to a 3.46 is an 18% change. Will also raise all your revs by 18%. I would wager that 95% of people would find that much of an increase in revs unacceptable. Basically you wil make 1st gear almost useless and effectively turn your car into a 4-speed.

 

Going from a 2.93 to a 3.46 is an 18% change. Will also raise all your revs by 18%. I would wager that 95% of people would find that much of an increase in revs unacceptable. Basically you wil make 1st gear almost useless and effectively turn your car into a 4-speed.

no doubt, i am in 1st gear for like a second before i am at 6500k, and i have to shift (5 spd, 3.46) you might be better off with a milder 3.15 or 3.07...

 

3.15 rear axle is the best compromise for the 328I.

 

Isn't that the same gearing though in a 328i w/ a 3.46 as a 323cic/325cic?

If they came from the factory like that, then is it really that bad?

 

Isn't that the same gearing though in a 328i w/ a 3.46 as a 323cic/325cic?

If they came from the factory like that, then is it really that bad?

Well, the 3.46 came from the factory on 323 and 325 steptronic cars. We all know that steptronic slows the car a bit. As for first gear being useless, try being boosted. The revs fly even faster. I think a 3.46 is better suited for a 6-speed because for me at 80mph, I am at ~3k.

 

on a 323 its not so bad because the car is actually kind of gutless. On a 328 there is more power and I agree that 3.46 is too big of a change.

 

4k rpms @ 80mph for me...

 

So does everyone here recommend that I stay away from 3.46? It seems like it's going to be real hard to find a 3.38.

 

So does everyone here recommend that I stay away from 3.46? It seems like it's going to be real hard to find a 3.38.

I think for a 5-speed, you should stay with a 3.15. A 3.46 and 3.38 has less than 3% change. You will still be at about 3500 @ 80mph. If you don't cruise much, then the 3.46 is fine. But once you start doing lots of cruising, it would most likely reduce your gas mileage.

 

Ha ha no **** dude? I bought a 328i back in August and I had to replace my rear diff mount too. Son-of-a-*****.

 

Ha ha no **** dude? I bought a 328i back in August and I had to replace my rear diff mount too. Son-of-a-*****.

Did it actually fix anything for you when you replaced the rear mount? Did you have a clunk before that?

I really don't think that I would mind doing 3500RPM at 80MPH. I actually don't do any long distance driving. The Bimmer is my daily driver for getting around the city. I usually try to own two cars so that I have another car for any long distance driving that I have to do... it's likely that I'll pick up an E30 or a Honda or something soon.

Can anyone with a 3.46 in a 328i or 330i actually tell me that they regret doing it?

 

It's hard to suggest which you'd like better. You say it's a daily driver..so leeds me to say 3.15..but you also are coming from an E36 M3 and say you want acceleration. Then I easily say 3.38. What size wheels you running and do you expect to swap them out in the future? If stock 16s, go 3.15. With the 3.15 you also won't be "craving" the software(Shark)download.

 

How poorly does it actually affect gas mileage? I have the stock 17" sport wheels; I run 225/45/17's. I plan on possibly getting some 18" or 19" CSL replicas one of these days, but I'm fine for the time being with the stock wheels.

I feel like the gears are really tall coming from the M3, but maybe I'm just imagining things. What would it take to get an 328i geared like an E36 M3?

Also, wouldn't I actually only be doing about 3658RPM's at 80MPH vs. the stock 3100RPM's. That's an 18% increase, but it doesn't seem that ridiculous to be doing that at 80MPH. Is this bad for the motor?

 

For a daily driver you don't want anything really higher than 3.15 on your 5-speed. With the 3.15 ratio, you can achieve a speed of at least 60-mph without the need for a 2nd to 3rd gear shift.

 

How poorly does it actually affect gas mileage? I have the stock 17" sport wheels; I run 225/45/17's. I plan on possibly getting some 18" or 19" CSL replicas one of these days, but I'm fine for the time being with the stock wheels.

I feel like the gears are really tall coming from the M3, but maybe I'm just imagining things. What would it take to get an 328i geared like an E36 M3?

Also, wouldn't I actually only be doing about 3658RPM's at 80MPH vs. the stock 3100RPM's. That's an 18% increase, but it doesn't seem that ridiculous to be doing that at 80MPH. Is this bad for the motor?

I was looking into the 3.46 diff swap for my 328 also, but changed my mind due to the fact that a) high RPMs, worse gas mileage b) constant shifting c) loss of cruising ability and d) loss of really high end speed.

I was thinking about going 3.38, but they are hard to find and cost a bit more. Also, it isn't that much of a difference over the 3.38.

I recently read about someone installing a 3.23 diff in their car and am in the process of finding one. If that doesn't pan out, 3.15 here I come.

 

i'd like to go 3:15

 

I lose probably 1-2 mpg by going to 3.46 diff. I can still get 27mpg on the freeway.. cruising probably 70ish.

 

How poorly does it actually affect gas mileage? I have the stock 17" sport wheels; I run 225/45/17's. I plan on possibly getting some 18" or 19" CSL replicas one of these days, but I'm fine for the time being with the stock wheels.

I feel like the gears are really tall coming from the M3, but maybe I'm just imagining things. What would it take to get an 328i geared like an E36 M3?

Also, wouldn't I actually only be doing about 3658RPM's at 80MPH vs. the stock 3100RPM's. That's an 18% increase, but it doesn't seem that ridiculous to be doing that at 80MPH. Is this bad for the motor?

going to heavier wheels will probably kill your gas milage a little. My heavy breytons cause me to lose about 1mpg in city driving.

The slight increase in rpms shouldn't be bad for motor. it was really that bad... BMW wouldn't put 3.46 diffs on manual tranny 323/325CICs.