Author Topic: LSD large vs small cases, ratios (Read 11199 times)

nickmpower · « **Reply #15 on:** December 29, 2006, 12:00:12 PM »

Quote from: Vladi;16406

what does the length of the gear have to do with weight of flywheel? Nothing, the lightweight flywheel just makes your engine rev faster. :confused:
Bentley quote for E36 Getrag 200/250 gearbox (left) and Getrag 240 gearbox (right)
1st 4.23 1st 3.72
2nd 2.52 2nd 2.02
3rd 1.66 3rd 1.32
4th 1.22 4th 1.00
5th 1.00 5th 0.81

So the 1st gear in the E36 gearbox is actually shorter than the E30 one.

yes but with my 3.46 it will be longer. Also i thought first gear was too short already and with my engine work and the lightweight flywheel it would go through it even faster

romkasponka · « **Reply #16 on:** December 29, 2006, 12:14:18 PM »

dont use first gear

kevo__ · « **Reply #17 on:** December 29, 2006, 06:58:10 PM »

well i've just taken my 3.64 lsd (rebuilt with ford clutch pack) and replaced the gearing to a 4.45 out of a e34 520 and it's a hoot now, much more rally car like. whats this about gearbox swapping? does the e36 318is box have different ratios then? does it fit? kev

romkasponka · « **Reply #18 on:** December 30, 2006, 06:54:06 AM »

Quote from: kevo__;16432

well i've just taken my 3.64 lsd (rebuilt with ford clutch pack) and replaced the gearing to a 4.45 out of a e34 520 and it's a hoot now, much more rally car like. whats this about gearbox swapping? does the e36 318is box have different ratios then? does it fit? kev

yes it fit perfectly.

kevo__ · « **Reply #19 on:** December 30, 2006, 05:34:59 PM »

hmm magic that'd give me...

1st - 23mph
2nd - 38mph
3rd - 58mph
4th - 80mph
5th - 97mph.

imagine that in the lanes...

kevo__ · « **Reply #20 on:** December 30, 2006, 05:35:48 PM »

btw how'd you get it to rev to 7200rpm??? and what does 4 bolts in the sump mean?
cheers
Kev

romkasponka · « **Reply #21 on:** December 31, 2006, 01:05:47 AM »

I have chip for 7200.

http://www.m42club.com/forums/showthread.php?t=594
5 bolts

Quote from: kevo__;16486

btw how'd you get it to rev to 7200rpm??? and what does 4 bolts in the sump mean?
cheers
Kev

kevo__ · « **Reply #22 on:** January 01, 2007, 02:00:39 PM »

sorry i meant 5 bolts, is the engine happy to rev to that standard then? mine is 180,000 miles old and still original so she's tired, what else have you done to your's to get the extra 1000 rpm? and what is the significance of 5 bolts? i don't understand what you mean?
thanks for your help
Kevo

kevo__ · « **Reply #23 on:** January 01, 2007, 02:05:22 PM »

ah just read the writeup now on the bolts explanation, could have been nasty.

mikko · « **Reply #24 on:** January 10, 2007, 06:26:55 AM »

i tried 3.73 diff on my iS, gear ratios were never right so i changed 4,27

long ratios on little engine, no no

only thing on that 3.73 diff was that lock kept 110nm, on 4,27 keep only 50nm

by the way, how much stock lsd slip nm is?

dino245 · « **Reply #25 on:** January 10, 2007, 09:16:58 AM »

I have a small case 3.91 LSD from a 84-85 318i that had the M10 engine. These are hard to find but they are out there and bolt right up and dont weigh as much as the medium case diff's. If you go to metric mechanics web sight and look at there diff page there is a brake down of the ratios and torque handaling of the different ratios.

mikko · « **Reply #26 on:** January 11, 2007, 01:38:04 AM »

whoaa... nice website! thanks dino245

tjts1 · « **Reply #27 on:** May 24, 2007, 02:49:20 AM »

I was just reading through some of the threads relating to diff ratios and trying to decide what I'm going to do with my car. I have 2 sets of wheels. One with 195/65R14 and another with 195/60R14 Falken Azenis tires for weekend fun. I crunched some numbers in a gear ratio calculator with both tire sizes combined with every gear ratio that might have the remote possibility of making sense. I still haven't decided what I'm going to do but I thought others might find these useful. Keep in mind that the speedometer is inaccurate and it won't correspond with these numbers. Starting from the shortest ratio to the tallest.

What I have on the car right now.

My stock tire size and differential.

E36 318ti Final drive is almost identical to our 4.1.

tjts1 · « **Reply #28 on:** May 25, 2007, 04:58:09 PM »

Just for comparison sake, my beater NEON ratios. This is a base SOHC 2.0, no PS, no AC, etc, about 2300 lb. The neon is just as quick off the line but has longer legs in any given gear.

Right now I'm leaning toward this ratio as a good middle of the road option.

josephb983 · « **Reply #29 on:** March 25, 2008, 03:54:25 PM »

Quote from: tjts1;26582

Just for comparison sake, my beater NEON ratios. This is a base SOHC 2.0, no PS, no AC, etc, about 2300 lb. The neon is just as quick off the line but has longer legs in any given gear.

What program did you use to generate these nice charts?

EDIT: This is the calculator I have used: http://www.unixnerd.demon.co.uk/revs.html