M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: JoeDellio on August 06, 2009, 06:34:41 PM

Title: Calculator shows only 102mph @ 7K with a 4.45 rear diff?
Post by: JoeDellio on August 06, 2009, 06:34:41 PM

for the E36, I was using these numbers and this is what came up with a 205/55/16 tire.

1st 4.23, 2nd 2.51, 3rd 1.67, 4th 1.23 and 5th 1.1

I dont see how anybody could drive on the highway with the 4.45 if this holds true, it would be screaming at 80mph!

Im about to buy one (Im on a buying spree, engine, M20 FW/clutch, and now this), but I have to drive to FL soon and I dont want to kill my car on the way at 5K for 20 hours.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: tjts1 on August 06, 2009, 07:40:49 PM

5 speeds had a 3.45 differential. Automatics have 4.45. Why would you put a 4.45 on a 5 speed? The gear ratios are already too short. You can't even get to 60mph in second. Go taller.

(http://farm1.static.flickr.com/210/535781129_bc708ba002_o.jpg)

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: JoeDellio on August 07, 2009, 06:26:52 PM

Its the only LSD with a small case available locally for $300 that will bolt on my E36.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: tjts1 on August 07, 2009, 06:34:13 PM

Can you fit a large case? I don't know E36 very well.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: JoeDellio on August 07, 2009, 11:53:24 PM

Quote from: tjts1;76512

Can you fit a large case? I don't know E36 very well.

A large case from a M50 will fit, but it requires me to also swap in the rear axles and cups, plus the rear section of the driveshaft. Then we are talking big bucks for an already expensive rear diff. I may just have to hunt for a locked 3.45.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: Hodge on August 08, 2009, 06:57:59 AM

Like I told you in the other thread, a 4.45 will absolutely suck for everything but city driving. Even then, it will probably suck since your gears will be so short.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: JOMARO on August 14, 2009, 03:12:04 PM

i have it on my e30... and it pulls really hard in every gear .. i dont even have to shift down sometimes while passing others.. but it really sucks on highways ..top speed 125 on 14"basket weaves with 185/65   and it over heats if i stayed there for a while . really sucks if u ask me .. the only thing that made me use it , is the fact that i m going to autox my car.... but i m seriously thinking to go for something lower ... where i can hit 60 in sec gear ..

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: Hodge on August 14, 2009, 05:31:29 PM

3.45 LSD in my E36 and I still can't hit 60mph in 2nd. I kinda wish I went 3.23 or thereabouts. WOuld hurt acceleration but would allow me to not shift as often.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: tjts1 on August 14, 2009, 11:02:24 PM

E30 and E36 transmissions are completely different. You really can't compare the two when speaking about the same diff ratio.

Title: Calculator shows only 102mph @ 7K with a 4..45 rear diff?
Post by: Danny707 on August 15, 2009, 12:13:11 AM

Take both diffs apart and put the clutch packs in the 3.45