Help me figure out what diff I need to achieve a certain cruising speed

[MTD]

3.25LSD medium case in my car and its a riot to drive. dare I say... perfect. 1st gear is long enough to give you great traction off the line, second takes you to 70 indicated and 5th gear is useless unless youre above 70mph. I think the car is faster to 60 as well because of the better traction off line and eliminated 3rd gear change. I am happy to report better fuel economy as well. its fun dropping third on the highway and being able to rip it to 100..... I could go on and on

Oh wow, 3.25 lsd and it's still usable? What about skidding around? It's not something i do on a daily basis but i do enjoy it every once in a while. I would imagine it is much harder to pull a skid no?

[benz-tech]

After driving a 3.64 for the last few years, id say anyhing taller than a 3.73 is too tall. The biggest problem I have is the fall off between gears. It was horrible with a stock m42. The Franken motor does much better and I'm guessing its near, but not above, the 180hp mark. I just picked up a 3.73 LSD and look forward to running it. Ideally I think the 3.25 with an e36 g250 will be the best ratio combination. First gear would feel like a g240 with a 3.64 rear end(tall and usable), with the rest similar to a 3.90, if I did my math correctly.

[MTD]

Very nice, thanks benz-tech. 3.73 lsd seems like the choice to go. Still would like to hear from someone if it's still usable for some skidding around, nothing too intensive
EDIT: may i ask what you have done to get those 180hp?

[5Toes]

no skids in second gear, first gear does great but the 3.25 sucksfor drifting, period. when I get my ITBs on itwill be a nice match I think.

[benz-tech]

Very nice, thanks benz-tech.
EDIT: may i ask what you have done to get those 180hp?

http://www.r3vlimited.com/board/showthread.php?t=359475

I updated that build thread at the end so that everything was in one place.

[MTD]

no skids in second gear, first gear does great but the 3.25 sucksfor drifting, period. when I get my ITBs on itwill be a nice match I think.

Thanks. 3.73 seems perfect for me. I will begin searching for one

http://www.r3vlimited.com/board/showthread.php?t=359475

I updated that build thread at the end so that everything was in one place.

very nice. altering and adjusting the cams isn't a common thing in my country but you guys seem to do it a lot. Is there thread you can point me to, to read about the benefits and how to do it?

[Dj Buttchug]

I run a 2.93 and a 3.25 in m42 cars. Both are good for highway use 80+ MPH at 2700ish.

[5Toes]

^ been getting 31mpg combined receipts confirmed in my m42 sedan 80% highway at 65-80mph with 3.25

[roguetoaster]

^ been getting 31mpg combined receipts confirmed in my m42 sedan 80% highway at 65-80mph with 3.25

Last three tanks with a 4.45, 30.8, 31.6, and 28.4. Hmm, although much of that was with no spirited driving at all.