E Diff swaps.

[BMW BMXER]

A local e30 guy here doing a turbo project wants to trade my 2:93 LSD for what I think is a 3:93 LSD ( I know for a fact tis LSD just forget the ratio)

What will happen if I swap to a larger ratio diff? Higher top speed or better accel?

It wouldnt cost me anything to do straight swap. He says its a good upgrade (currently has an eta motor) but if anyone else could elaborate on what differance I would feel that would be great.

[DEV0 E30]

Yes. Your car will accerlerate faster but your top end won't be as good. I'd find out exactly what it is first, if you don't go for it you could always give it to me.

Since it's free, I'd say do it. I'd wait for other people to chime in with their info though.

[Jand3rson]

Don't put a 3:93 diff in an eta, you will hate it. Go to a 3:25 at the most. As eightyfoure said, you will get better acceleration, but you'l be at screamingly high revs (oxymoron for an eta, I know :D ) while at speed, like highway driving.

[BMW BMXER]

I am going to find out what ratio it is, might be lower than I thought.

I'll let you guys now.

I cant give it to you id have no diff then. :P

[BMW BMXER]

The diff is a 3.73. How can I crunch the numbers?

[bwanac]

"bmw unix nerd" -> google it and find his gear calculator

[BMW BMXER]

I am a bit of an idiot when it comes to math, a bit meaning a lot, and idiot meaing dumbass. I found these stock e numbers.

1st 3.83:1
2nd: 2.20:1
3rd: 1.40:1
4th:1.00:1
5th:0.87:1

Axle Ratio: 2:79:1
Fina Drive: 2:26:1

Using that dudes gear calculator where do I put my diff number?

His calc is here

http://www.unixnerd.demon.co.uk/revs.html

I will be running 205/50/r15s

[Jarvis]

I think RedBaron had a 3.73 on his ETA. Chipped, it was redline-limited to about 120-125mph.
An easy way to think about it is that a manual 325i/is comes with the 3.73. Go drive an 'i" but always shift before where an ETA redlines (4800rpm?). A 3.73 equipped ETA will probably be a bit quicker than that experience, considering the ETA's broader torque. If top speed and gas mileage aren't huge concerns for you, get the 3.73. It'll make an ETA a hell of a lot more fun to drive.

[Brew]

Just did the calculation on this site: http://www.sjdsm.com/tech/gear_speed.htm

Looks like you'll be doing 105 at 5k rpm in 5th gear.

Go with a 3.25. You'll still be able to hit 115-120ish chipped, and you'll cruise at relatively low revs on the highway.

[James Crivellone]

You have zero top end with a 3.73, your always shifting and boom your out of the power band.

I had a 3.73LSD in my car, it sucks on the highway.. in city was fun though.


I have a 3.25LSD in my car now, kicks ass

[BMW BMXER]

105km is 168.98 km/h.

Highways around here (canadia) are 100 max.. I normal go 120.. 140 ish on cruises.

Hmm.. it'll be tight. Free things never work out right.. damnit!

We will see what I do. I want a car thats more fun to drive (so bored of my eta its not even funny), but I do a decent amount of highway driving.

Apperently Fil (Eurostyle on max) ran a 4:10 in an eta.. I don't know if he was telling the truth or not.. or why?

[WeDgE]

105km is 168.98 km/h.

Highways around here (canadia) are 100 max.. I normal go 120.. 140 ish on cruises.

Hmm.. it'll be tight. Free things never work out right.. damnit!

We will see what I do. I want a car thats more fun to drive (so bored of my eta its not even funny), but I do a decent amount of highway driving.

Apperently Fil (Eurostyle on max) ran a 4:10 in an eta.. I don't know if he was telling the truth or not.. or why?

Some go up to 110km/h posted...but they're usually the divided ones... :)

[Mystikal]

Just install the chip, you'll be satisfied with the car for a while after that. :D

[Eurostyle]

105km is 168.98 km/h.

Highways around here (canadia) are 100 max.. I normal go 120.. 140 ish on cruises.

Hmm.. it'll be tight. Free things never work out right.. damnit!

We will see what I do. I want a car thats more fun to drive (so bored of my eta its not even funny), but I do a decent amount of highway driving.

Apperently Fil (Eurostyle on max) ran a 4:10 in an eta.. I don't know if he was telling the truth or not.. or why?

I ran a 3.91 in my old car...Right now my frend is running a 4:10 in his chipped 86...I drove the car and the take off it amazing! Top speed is about 190Km/h...

[Bimmerfanatik]

Shit - the SETA is going into the vert and I just realized - I have a 3.73 LSD in there.

Did the SETA come with 3.73's or 2.93's? How bad is this gonna be? I do a lot of highway driving...