Author Topic: 3.64 lsd (Read 8552 times)

Marcp · « **on:** November 07, 2008, 06:11:16 PM »

Hi, I have a 3.64 LSD in the garage, and a 4.10 open on the car atm. I cannot find a 4.10 in the UK anywhere, and getting one from the US just seems like too much hassle, and too much money.

Has anyone ever driven a 318is with the 3.64? I love the buzzyness of the car how it is, but it really needs a LSD. I dont do trackdays with it really, maybe once a year, the car just gets used for running to work (some motorway, most town traffic) and backroad thrashes.

Thanks!

tjts1 · « **Reply #1 on:** November 07, 2008, 06:50:03 PM »

I put an open 3.64 in my car and it was best decision I've made for it. It's much more usable as a daily driver, more fuel efficient, quieter and quicker to 60 if you care about that kind of thing. I wish I could get a 3.64 LSD in the US.

vonkamp · « **Reply #2 on:** November 07, 2008, 10:57:18 PM »

Here's a 3.73 lsd on fleabay in case you are interested.

Marcp · « **Reply #3 on:** November 09, 2008, 04:03:20 PM »

Damn... missed that, and dont think they shipped to the UK anyway.

Did a sprint this weekend (basically what you guys call autocross I think) and being able to accelerate faster would have helped.

I just fear that the lack of torque will kill the car running a 3.64. I was coming out of corners in 2nd, and it was at about 2.5k RPM, so just below its sweet spot. With a 3.64 I dont know how much it would lower by...

How come 3.64 speeds up the 0-60 time from a 4.10? Does it feel any faster? If you wish to swap my 3.64 for a 4.10 LSD I'd be happy! lol

vonkamp · « **Reply #4 on:** November 09, 2008, 04:57:09 PM »

Here's a 4.10 LSD. If you ask, they may ship overseas. That's what you need right there.

bar73k · « **Reply #5 on:** November 09, 2008, 05:33:11 PM »

Quote from: Marcp;60286

How come 3.64 speeds up the 0-60 time from a 4.10?

It does not, by going down to a lower numbered ratio it will decrease acceleration,
increase top speed, the higher the number the faster the acceleration

Hodge · « **Reply #6 on:** November 09, 2008, 07:11:23 PM »

I have a 3.45 Variable Limited Slip in my car and love it.

It's still at nearly 4k at 80mph, but hey, that is what you get with a 1:1 5th gear!

Marcp · « **Reply #7 on:** November 09, 2008, 07:33:40 PM »

Quote from: bar73k;60290

It does not, by going down to a lower numbered ratio it will decrease acceleration,
increase top speed, the higher the number the faster the acceleration

I know it doesnt, but tjts1 said that it did, which is why i asked,

Boyracer · « **Reply #8 on:** November 10, 2008, 10:06:33 AM »

Quote from: bar73k;60290

It does not, by going down to a lower numbered ratio it will decrease acceleration,
increase top speed, the higher the number the faster the acceleration

It can speed up the acceleration from 0-100 kmh because you might need to use 1st, 2nd and 3rd gear to get to 100 kmh on 4.1 diff.

With longer ratio you might get away with only using 1st and 2nd gear, saving 0,5 secs (or something like that) because you do not need to go from 2nd to 3rd

But if you are not that interested about silly numbers on artificial tests, shorter ratio diff is usually better for acceleration.

xwill112x · « **Reply #9 on:** November 10, 2008, 10:34:52 AM »

why would you want a higher gear set?
i would have thought the more desired gear would be like a 4:27 or 4:45...?

tjts1 · « **Reply #10 on:** November 10, 2008, 11:50:58 AM »

Quote from: Marcp;60286

Damn... missed that, and dont think they shipped to the UK anyway.

Did a sprint this weekend (basically what you guys call autocross I think) and being able to accelerate faster would have helped.

I just fear that the lack of torque will kill the car running a 3.64. I was coming out of corners in 2nd, and it was at about 2.5k RPM, so just below its sweet spot. With a 3.64 I dont know how much it would lower by...

How come 3.64 speeds up the 0-60 time from a 4.10? Does it feel any faster? If you wish to swap my 3.64 for a 4.10 LSD I'd be happy! lol

With a 3.64 you don't have to shift to third gear.

tjts1 · « **Reply #11 on:** November 10, 2008, 11:52:52 AM »

Quote from: Hodge;60293

I have a 3.45 Variable Limited Slip in my car and love it.

It's still at nearly 4k at 80mph, but hey, that is what you get with a 1:1 5th gear!

The e36 has a different gear box without overdrive 5th. The differential ratios are not competable to the e30

tjts1 · « **Reply #12 on:** November 10, 2008, 12:02:49 PM »

Quote from: Boyracer;60356

But if you are not that interested about silly numbers on artificial tests, shorter ratio diff is usually better for acceleration.

Yup. In real world driving where you're not redlining the engine at every stop light, 3.64 diff will make for a quicker more comfortable daily driver because you wont have to shift as often. In 1st to 3rd gear you wont notice any loss of acceleration. 4th gear will feel exactly like 5th before the swap. 5th is a highway cruising gear. It will feel slower while accelerating but rpm will be about 12% lower at any speed.

Hodge · « **Reply #13 on:** November 10, 2008, 06:22:50 PM »

I know the E36 gear box is different.

Doesn't the E30 G240 have an OD 5th gear?

tjts1 · « **Reply #14 on:** November 10, 2008, 07:39:14 PM »

E30 has .8 to 1 OD. E36 had 1 to 1 5th gear. No over drive.

E36 318i/is/ti gears in the US. Other markets might be different. I don't know.

1991 E30 318i/is in the US.

The way I have mine setup now daily driver.

And autoX with slightly shorter tires 195/60 tires.

If you compare the second graph (E30/4.1) with the third graph (E30/3.64) in first gear, stock will get you to 30mph vs 34mph with the taller 3.64 diff. Its really not a huge difference in acceleration. What you will notice is that the engine isn't revving as hard to get you up to speed and you're not shifting as often to do so. But the really big difference happens on the highway where the cabin is much quieter.