M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: Marcp on November 07, 2008, 06:11:16 PM
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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!
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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.
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Here's (http://cgi.ebay.com/ebaymotors/BMW-325is-3-73-1-Limited-Slip-Differential-E28-E30-Z3_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1163Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem320316175523QQitemZ320316175523QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories) a 3.73 lsd on fleabay in case you are interested.
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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 :D
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Here's (http://cgi.ebay.com/ebaymotors/BMW-E30-E28-325i-535i-M3-Z3-4-10-LSD-DIFFERENTIAL_W0QQcmdZViewItemQQhashZitem290273627258QQitemZ290273627258QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories) a 4.10 LSD. If you ask, they may ship overseas. That's what you need right there. :D
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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
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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!
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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,
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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.
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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...?
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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 :D
With a 3.64 you don't have to shift to third gear.
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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
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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.
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I know the E36 gear box is different.
Doesn't the E30 G240 have an OD 5th gear?
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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.
(http://farm1.static.flickr.com/210/535781129_bc708ba002_o.jpg)
1991 E30 318i/is in the US.
(http://farm1.static.flickr.com/231/511886664_d1dc947c06_o.jpg)
The way I have mine setup now daily driver.
(http://farm1.static.flickr.com/190/535665000_6513535d9f_o.jpg)
And autoX with slightly shorter tires 195/60 tires.
(http://farm1.static.flickr.com/220/511927171_c4857d3774_o.jpg)
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.
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I really dont know what to do now.
I can get a 3.91 open and put my LSD pack into it, I just think that the M42 (well mine at least) doesnt really have the torque to lug it around with a 3.64, in some ways I like the rev happyness of the car and the twisty backroad fun you can have. Maybe im just lazy and dont like the idea of 5th being so tall, with the 4.10 if im doing any less than 60 I need to change down to make real progress. Cant find any vids on youtube of 318's running 3.64's. Does the exhaust have to come off to shorten the prop for a medium case?
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Well I also have no PS, electric cooling fan, 22# injectors and CAI so I'm probably sending slightly more torque than stock to the wheels through the 3.64. The decision is up to you. LSDs always seem to sell well so I would go for that. If you don't like it you can always resell it. Swapping diffs from one housing to another is a complicated project.
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Been trying to sell this diff for ages, no one wants it (in the UK anyway)
Dunno. might just give it a go I guess, cant take too much time.
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Sorry to be a complete pain... but did your car "feel" any slower after you swapped? Sometimes it doesnt matter how fast im actually going, just the car feels fast from picking up with quite a shove in 1st, 2nd gear.
Slow cornering, that sort of thing, does that mean now changing down again? Some of the roads I go on are 2nd gear corners, to keep the car in its power zone, would I notice this too much?
Gone dizzy now... been looking at your graph too much!
Thanks for your help
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If you are flooring it in first and second gear and your butt dyno is very very in tune with the car, then yes, it will feel exactly 12% slower. In normal driving where you're not flooring it all the time, you'll accelerate just as quickly the car won't feel any slower. The only thing you'll notice is that the engine wont rev quite as far to get to the same speed and you'll be able to take second gear all the way past 60mph when accelerating onto the freeway.
Get really well acquainted with the procedure to swapping the diff. Theres some really good writeups on the other E30 forums. Once you're familiar with it, you'll see that its a 2 hour job the first time you do it, and a 1 hour job the second time. The whole diff is held in place with 4 bolts to the sub frame, 1 to the trunk floor, 6 allen screws to each axle and 4 bolts to the drive shaft. Its really not a big job. You might want to have a second pair to help you lift the new diff into place. If you're not happy with the diff, you can always try something else.
http://www.pelicanparts.com/bmw/techarticles/JF-Tech/BMW_E30_3_Series_Limited_Slip_Differential_Swap.htm
http://www.e30eta.com/ecdiff.htm
http://www.emotors.ca/Articles/7.aspx
good luck
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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.
Marin Pride,
I bought my Alpine White 3, 318i in spring of 2007, around the same time I think you bought a gray 318is? Anyway, I read your diff. swap posting with interest - wanted something a bit quieter at highway speed and a little better gas mileage. I must say it was the best mod I've done, besides completely overhauling suspension (lowering car about an inch). With a conforti chip, the car at 180k runs like a champ and second gear to 60 if I want it. Best of all, is fourth gear at 70 and passing with power, something I couldn't have done before. I hope you read this, because it really is a great improvement, even if there is a bit of initial loss of power - it's more than made up for with first gear to 30....
- Dru
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Well I did it this weekend, fitted the 3.64.
And as far as I can tell, it drives identical to the 4.10 lol! I really have no idea what ratio this is now, im running 195 50 15 tyres, standard UK spec IS gearbox (not sure if its a different ratio to the US) and it is now doing about 65mph to 3000 RPM..... This is GPS readings, not speedo.
When I counted the crown wheel, there was 40 teeth, didnt count the pinion, cause I forgot.
Anyway... kind of wished it was a 3.64, was warming up to the idea of quiet crusing. But my god.. isnt LSD fun?
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Marin Pride,
I bought my Alpine White 3, 318i in spring of 2007, around the same time I think you bought a gray 318is? Anyway, I read your diff. swap posting with interest - wanted something a bit quieter at highway speed and a little better gas mileage. I must say it was the best mod I've done, besides completely overhauling suspension (lowering car about an inch). With a conforti chip, the car at 180k runs like a champ and second gear to 60 if I want it. Best of all, is fourth gear at 70 and passing with power, something I couldn't have done before. I hope you read this, because it really is a great improvement, even if there is a bit of initial loss of power - it's more than made up for with first gear to 30....
- Dru
That sounds like an excellent setup. I'm glad it worked out. I'm actually on the look out for a 3.73 LSD right now. My 3.64 open diff isn't cutting it anymore after my first autoX. I really think these 2 ratios are the ideal for our cars. Shoot me a PM if you're ever in San Rafael and I'll buy you a drink.
cheers
Justin
Well I did it this weekend, fitted the 3.64.
And as far as I can tell, it drives identical to the 4.10 lol! I really have no idea what ratio this is now, im running 195 50 15 tyres, standard UK spec IS gearbox (not sure if its a different ratio to the US) and it is now doing about 65mph to 3000 RPM..... This is GPS readings, not speedo.
When I counted the crown wheel, there was 40 teeth, didnt count the pinion, cause I forgot.
Anyway... kind of wished it was a 3.64, was warming up to the idea of quiet crusing. But my god.. isnt LSD fun?
Using a quick online gear ratio calculator and the info you provided about your tire size and assuming you have the same 0.81 overdrive 5th gear, my powers of deduction tell me that you in fact have a...
Are you ready for this?
3.91 differential!
It didn't sound like you were looking to reduce RPMs for highway driving or anything like that so this might be a perfect setup for you. And yes, LSD is awesome in more ways than one :D
Enjoy the ride
Justin