m52/zf trans + 2.93 = too low?

[jrdeamicis]

with a 3.15 on the same setup in my m3 with the SAME tire size, a 3.15 was right on the border of too low.

I had access to a S2.93 and a S3.73 and decided that 3.73's are

1)Easier to come by if I explode one
2) Going to be major fun on the roads that I drive on.

[rThor432]

...and if only our cars weren't shaped like bricks (what is the average E30's coefficient of drag, anyway?).

It's .330.

[evil_twin]

This is my teaser...






I think I am going to pick up the 3.15 open also :)

[rThor432]

This is my teaser...

Lol it's an eta diff.

[Bmjpv]

3:15 Lsd

My 3:15Lsd came out of a z3. Did any car with a 3:15 come with an open diff? Am I correct in thinking the 3:15 only came on late cars like the z3 ? Joe

[evil_twin]

hahahahahah i tricked you guys lol.

bmjpv - 315s came out of z3, and 325s came out of e28s. I typed it wrong, Im going to pick up a e28 (325) diff. also.

[JeffRR]

I'm running the 2.9lsd behind my ZF, I'm also running a stock-ish OD size tire ~ 23.7" for now.

I'm planning on going 5-lug and with that a little taller tire, I might look at the 3.25 with the taller tire.

Oh ya, its 100% street driven where I want 1st and 2nd. Track is another story.

[evil_twin]

Im going to be drifting my car. I was going to put the 293 in my car, but I pulled the back cover off and found that there was sheered bolts from the LSD. Another reason why welded is better :)

Since I am going to be drifting, I'm thinking the 293 might be too low, but will be good for when I turbo? Currently with the 373 at 60mph is at 3k RPMs in 5th gear. I run the gears out wayyyy too fast with it.

[e30polak]

I used to run a 3.25lsd in my s52 with the ZF and it's the ideal DD gear. However, I wanted something that was a little more aggressive in 3rd and 4th, so I found a 3.46lsd and am currently running that now.

With the 235/40/17 tires I'm running now I crank 65mph @ 3k, which is a little too high for my liking. Luckily i'm not on the highway too much, but I'd love to get a 6spd.

For now the 3.46 is a little torque monster in the streets! 3.73 is way to short of a ratio with the ZF. When I supercharge my car I will get a 2.93 for sure.

[evil_twin]

Nice... So the range of 293-315 is good.

[a_thomasmr23]

It's .330.

.32 with is lip .35 with normal lip as per car and driver

[rThor432]

^^I just went for the known average, because he asked for the average. There are too many different spoiler packages and I dont know the CD of each particular combination :).

But good info ie. thanks for posting the exact numbers from that article. If I remember right that was from an article on the early (diving board) cars back in the late 80's. Right?

[Uber E30]

you sure about that, i read the e30 m3 was .33

[rThor432]

No, I havent wind-tunnel tested one myself. Not positive a bit. ^^His post said .32 and .35 from the Car and Driver article, so I'd say it's close anyway.

[m3_eater]

It's awesome to see technical data back up the fact that my E30 feels so much better at highway speeds when I have the "is" lip on than with none. The difference is VERY noticeable, particularly at 80+ MPH.