Limited Slip Diff choices...
05-17-2002, 10:38 AM
#1
Out Of Control!
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Limited Slip Diff choices...
Hey guys!
Just out of curiosity anybody on this forum upgraded or changed their Limited Slip Diff? And if so what are the choices? I've heard of anywhere from 3.07 to 3.15? What are the differences? Any insight to this would be appreciated.
Thanks!
Just out of curiosity anybody on this forum upgraded or changed their Limited Slip Diff? And if so what are the choices? I've heard of anywhere from 3.07 to 3.15? What are the differences? Any insight to this would be appreciated.
Thanks!
05-17-2002, 06:58 PM
#2
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E55, F550, S600 Ducati 999
Jam55
This would increase torque at rear wheels by 10% in a given gear. Since the car already has 5 speeds, I don't think it really makes much difference in higher gears.
Because your gearing is lower (numerically higher), you will change to the next gear earlier, ie instead of changing to 3rd at 70mph you may change at 60, which reduces somewhat the perceived advantage. I am not stating that it will not improve acceleration, but there is no guarantee of improvement as the only real advantage is in 1st gear where traction can be the limiting factor, not gearing.
Don't know about you, but I have chronic wheelspin in non supercharged 55 using full throttle below 25mph. Leaving ESP on just causes the car to cut the power.
0-60mph esp off 4.7sec esp on 5.1 sec.
I changed LSD in bmw 750il from std to 3.91 out of 735iL. Car would then smoke up from standing start and was much better off the line, but wasn't really any quicker 30mph plus.
MB is very torquey motor, don't think this sort of change is suited to it. i have seen on this board that Sleestack has had diff change. With that much power on street tyres don't see the use as traction in lower gears would be limitation on acceleration, not gearing. This also hurts fuel economy and car becomes noticeably louder cruising. (engine is spinning 10% more for given road speed). The best way to increase performance is not to lower the overall gearing, but change the gear ratios in the box to "tighten them up", which does genuinely improve performance. Sounds like a project for someone like Renntech etc.
Sorry for the long winded reply.
This would increase torque at rear wheels by 10% in a given gear. Since the car already has 5 speeds, I don't think it really makes much difference in higher gears.
Because your gearing is lower (numerically higher), you will change to the next gear earlier, ie instead of changing to 3rd at 70mph you may change at 60, which reduces somewhat the perceived advantage. I am not stating that it will not improve acceleration, but there is no guarantee of improvement as the only real advantage is in 1st gear where traction can be the limiting factor, not gearing.
Don't know about you, but I have chronic wheelspin in non supercharged 55 using full throttle below 25mph. Leaving ESP on just causes the car to cut the power.
0-60mph esp off 4.7sec esp on 5.1 sec.
I changed LSD in bmw 750il from std to 3.91 out of 735iL. Car would then smoke up from standing start and was much better off the line, but wasn't really any quicker 30mph plus.
MB is very torquey motor, don't think this sort of change is suited to it. i have seen on this board that Sleestack has had diff change. With that much power on street tyres don't see the use as traction in lower gears would be limitation on acceleration, not gearing. This also hurts fuel economy and car becomes noticeably louder cruising. (engine is spinning 10% more for given road speed). The best way to increase performance is not to lower the overall gearing, but change the gear ratios in the box to "tighten them up", which does genuinely improve performance. Sounds like a project for someone like Renntech etc.
Sorry for the long winded reply.
Last edited by stephens; 05-17-2002 at 07:03 PM.
05-17-2002, 08:02 PM
#3
Out Of Control!
Thread Starter
stephens
Thanks for the good information. What i'm after is i'm trying to find out what the differences of the LSD gearing? I think sleestack is using a 3.07 and i heard someone saying that there is a 3.15 also available. How do you find out which one best suits your need? 3.07 or 3.15? Or something else??
Thanks!
Thanks for the good information. What i'm after is i'm trying to find out what the differences of the LSD gearing? I think sleestack is using a 3.07 and i heard someone saying that there is a 3.15 also available. How do you find out which one best suits your need? 3.07 or 3.15? Or something else??
Thanks!
05-19-2002, 10:47 PM
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E55, F550, S600 Ducati 999
JamE55
I think there is also a 3.27 available. Which one is right? That's a matter of personal preference. To give you an idea, putting a 3.27 rear end is like removing 5th (4th becomes 5th) and adding a much lower (higher numerical) 1st. Actually all the other ratios would be moved closer to 1/2 a gear down. Haven't the guys at Evosport got experience in this?
I think there is also a 3.27 available. Which one is right? That's a matter of personal preference. To give you an idea, putting a 3.27 rear end is like removing 5th (4th becomes 5th) and adding a much lower (higher numerical) 1st. Actually all the other ratios would be moved closer to 1/2 a gear down. Haven't the guys at Evosport got experience in this?
05-20-2002, 12:38 PM
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Volvo V90 CC
The way I learned about diff gears going to a lower gear such as 3.15:
Pros-better 0-60 mph and quarter mile times (if you can get the extra torque to the ground and not spin like nuts.
Cons-Engine revs faster at cruising speed (example at 75 mph), gas milage get affected a little bit down,
Worst con is top speed get greatly reduced
So you have to consider, do you want to be faster off the line and don't care about top speed? go for 3.15.
Personally if I were to put the supercharger on my E55 I'd like to go to a higher gear (lower number) to avoid so much tire spinning.
Pros-better 0-60 mph and quarter mile times (if you can get the extra torque to the ground and not spin like nuts.
Cons-Engine revs faster at cruising speed (example at 75 mph), gas milage get affected a little bit down,
Worst con is top speed get greatly reduced
So you have to consider, do you want to be faster off the line and don't care about top speed? go for 3.15.
Personally if I were to put the supercharger on my E55 I'd like to go to a higher gear (lower number) to avoid so much tire spinning.
