MKB sport differential
#26
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Originally posted by Sleestack
His statement regarding only being able to change the diff. on manual transmissions is wrong. You do have to make modifications to the ECU, however, the MKB differential is a complete package.
His statement regarding only being able to change the diff. on manual transmissions is wrong. You do have to make modifications to the ECU, however, the MKB differential is a complete package.
#27
...............For Ben or anone from Evosport regarding the MKB sport differential. MKB apparently has signed an exclusive contract in the US for the next 2 years with Renntech. We all know what that means as far as prices go. Are you aware of this contract and does it have a bearing on your ability to continue to sell the MKB sport differential?
..............Secondly, since you sell the MKB differentials and the EGS controller, do you have any info regarding the issues being discussed on this forom? Specifically, any numeric info from KB in germany regarding improvements in 0-60 or quatermile times if any? Thanks.
Ted
..............Secondly, since you sell the MKB differentials and the EGS controller, do you have any info regarding the issues being discussed on this forom? Specifically, any numeric info from KB in germany regarding improvements in 0-60 or quatermile times if any? Thanks.
Ted
#28
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CLS350
Originally posted by JBrady
What is your tire size?
What is your redline?
What is peak HP at what RPM?
What is peak TQ at what RPM?
I can calculate for 3.27s but you may want to go a bit higher... other ratios available?
What is your tire size?
What is your redline?
What is peak HP at what RPM?
What is peak TQ at what RPM?
I can calculate for 3.27s but you may want to go a bit higher... other ratios available?
221bhp@5700
232 lb-ft@3000
redline is 5800
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Originally posted by Ted Baldwin
...............For Ben or anone from Evosport regarding the MKB sport differential. MKB apparently has signed an exclusive contract in the US for the next 2 years with Renntech. We all know what that means as far as prices go. Are you aware of this contract and does it have a bearing on your ability to continue to sell the MKB sport differential?
..............Secondly, since you sell the MKB differentials and the EGS controller, do you have any info regarding the issues being discussed on this forom? Specifically, any numeric info from KB in germany regarding improvements in 0-60 or quatermile times if any? Thanks.
Ted
...............For Ben or anone from Evosport regarding the MKB sport differential. MKB apparently has signed an exclusive contract in the US for the next 2 years with Renntech. We all know what that means as far as prices go. Are you aware of this contract and does it have a bearing on your ability to continue to sell the MKB sport differential?
..............Secondly, since you sell the MKB differentials and the EGS controller, do you have any info regarding the issues being discussed on this forom? Specifically, any numeric info from KB in germany regarding improvements in 0-60 or quatermile times if any? Thanks.
Ted
#30
wuz the EGS controller and kb?
.........KB=mistake. Should be MKB
........EGS controller as I understand it is the electronic unit that controls traction, wheelspin etc. It turns out that changing the diff on your Mb is the easy part. Reprogramming the EGS controller so that ESP and tractyion control can understand what happened to your car is the problem. Otherwise ESP goes nuts and thinks that your car is spinning out of control. Therefore rear differential adjustment in in earlier MB's without traction control is no problem. Since the advent of traction control, this has becopme more difficult. I spoke with the people at Bergwerks yesterday and it turns out they have abandoned their rear differential adjustment project on newer Mb's because they can't figure out how to reprogram the EGS controller. The only people I know in the USA that can ACTUALLY ACTUALLY change your diff and reprogram your EGS controller or sell you a new one are outfits affiliated with MKB.
Ted
.........KB=mistake. Should be MKB
........EGS controller as I understand it is the electronic unit that controls traction, wheelspin etc. It turns out that changing the diff on your Mb is the easy part. Reprogramming the EGS controller so that ESP and tractyion control can understand what happened to your car is the problem. Otherwise ESP goes nuts and thinks that your car is spinning out of control. Therefore rear differential adjustment in in earlier MB's without traction control is no problem. Since the advent of traction control, this has becopme more difficult. I spoke with the people at Bergwerks yesterday and it turns out they have abandoned their rear differential adjustment project on newer Mb's because they can't figure out how to reprogram the EGS controller. The only people I know in the USA that can ACTUALLY ACTUALLY change your diff and reprogram your EGS controller or sell you a new one are outfits affiliated with MKB.
Ted
#31
Others here are making excellent points regarding tuning issues. From a straight mechanical perspective... here are the calculated numbers for your car.
Tetza supplied data:
245/45/17
221bhp@5700
232 lb-ft@3000
redline is 5800
gearing 3.95,2.42,1.49,1.00,0.83 diff 3.07
max test speed for each gear is: 38,62,100,131,131
Understand that I am using a mathematical model to calculate the following information. Also, I do not know what the factory tire size is. I don't know if the above is stock or aftermarket. Using the above supplied size I calculate 25.68" tire diameter. Now, size can vary from tire model to model and this is for a new tire, if they are worn by 1/8th inch the diameter is 1/4 less. Any slippage is also not calculated.
So, with the above lawyer like disclaimer (I am not a lawyer ) Here are the calculated speeds:
3.07 gear, 5800rpm
1 = 36.5mph
2 = 59.6
3 = 96.9
4 = 144.3 (unlimited)
5 = 173.9 (unlimited)
3.27 gear, 5800rpm
1 = 34.3
2 = 56.0
3 = 90.9
4 = 135.5 (unlimited)
5 = 163.3 (unlimited)
Rear Wheel Torque, in pounds feet, using 20% drivetrain loss. In each gear, first number is at torque peak of 232tq @ 3000rpm, second is torque, at power peak of 204tq @ 5700rpm.
3.07 gear
1 = 2251 1979
2 = 1379, 1212
3 = 849, 747
4 = 570, 501
5 = 473, 416
3.27 gear
1 = 2397, 2108
2 = 1469, 1291
3 = 904, 795
4 = 607, 534
5 = 504, 443
RWTQ increase going from 3.07 to 3.27 gears in this application:
1 = 146, 129
2 = 90, 79
3 = 55, 48
4 = 37, 33
5 = 31, 27
Honestly, for this relatively small gain, I would think a better choice for improving your 0-60mph times would be an increase in torque converter (TC) stall. A 500rpm increase is quite reasonable and would IMO give a better result. I can't say for certain how the ESP would react but it should be tolerated. On a car with a locking TC there is very little tradeoff. The Lexus croud is almost unanimously happy with a TC change. A TC change would cost about $500 for the stall change and the R&R labor (probably about 4 hours) total cost around $1000.
Tetza supplied data:
245/45/17
221bhp@5700
232 lb-ft@3000
redline is 5800
gearing 3.95,2.42,1.49,1.00,0.83 diff 3.07
max test speed for each gear is: 38,62,100,131,131
Understand that I am using a mathematical model to calculate the following information. Also, I do not know what the factory tire size is. I don't know if the above is stock or aftermarket. Using the above supplied size I calculate 25.68" tire diameter. Now, size can vary from tire model to model and this is for a new tire, if they are worn by 1/8th inch the diameter is 1/4 less. Any slippage is also not calculated.
So, with the above lawyer like disclaimer (I am not a lawyer ) Here are the calculated speeds:
3.07 gear, 5800rpm
1 = 36.5mph
2 = 59.6
3 = 96.9
4 = 144.3 (unlimited)
5 = 173.9 (unlimited)
3.27 gear, 5800rpm
1 = 34.3
2 = 56.0
3 = 90.9
4 = 135.5 (unlimited)
5 = 163.3 (unlimited)
Rear Wheel Torque, in pounds feet, using 20% drivetrain loss. In each gear, first number is at torque peak of 232tq @ 3000rpm, second is torque, at power peak of 204tq @ 5700rpm.
3.07 gear
1 = 2251 1979
2 = 1379, 1212
3 = 849, 747
4 = 570, 501
5 = 473, 416
3.27 gear
1 = 2397, 2108
2 = 1469, 1291
3 = 904, 795
4 = 607, 534
5 = 504, 443
RWTQ increase going from 3.07 to 3.27 gears in this application:
1 = 146, 129
2 = 90, 79
3 = 55, 48
4 = 37, 33
5 = 31, 27
Honestly, for this relatively small gain, I would think a better choice for improving your 0-60mph times would be an increase in torque converter (TC) stall. A 500rpm increase is quite reasonable and would IMO give a better result. I can't say for certain how the ESP would react but it should be tolerated. On a car with a locking TC there is very little tradeoff. The Lexus croud is almost unanimously happy with a TC change. A TC change would cost about $500 for the stall change and the R&R labor (probably about 4 hours) total cost around $1000.
#32
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ones too fast according to CHP!
Originally posted by Ted Baldwin
...............For Ben or anone from Evosport regarding the MKB sport differential. MKB apparently has signed an exclusive contract in the US for the next 2 years with Renntech. We all know what that means as far as prices go. Are you aware of this contract and does it have a bearing on your ability to continue to sell the MKB sport differential?
..............Secondly, since you sell the MKB differentials and the EGS controller, do you have any info regarding the issues being discussed on this forom? Specifically, any numeric info from KB in germany regarding improvements in 0-60 or quatermile times if any? Thanks.
Ted
...............For Ben or anone from Evosport regarding the MKB sport differential. MKB apparently has signed an exclusive contract in the US for the next 2 years with Renntech. We all know what that means as far as prices go. Are you aware of this contract and does it have a bearing on your ability to continue to sell the MKB sport differential?
..............Secondly, since you sell the MKB differentials and the EGS controller, do you have any info regarding the issues being discussed on this forom? Specifically, any numeric info from KB in germany regarding improvements in 0-60 or quatermile times if any? Thanks.
Ted
2nd - working on it (problem is the info we have gotten from 3rd parties is not real)
#33
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CLK55 Cab
If this mod was installed on a 55 engine with the limiter still intact, would I actually see a drop in top speed or no, since the 55 can easily attain 155 anyways. Also, assuming there is no loss in top speed, would the car be slower in any points in the powerband, affecting(slowing) quarter mile or 0-100 times?
#34
Originally posted by trock3155
If this mod was installed on a 55 engine with the limiter still intact, would I actually see a drop in top speed or no, since the 55 can easily attain 155 anyways. Also, assuming there is no loss in top speed, would the car be slower in any points in the powerband, affecting(slowing) quarter mile or 0-100 times?
If this mod was installed on a 55 engine with the limiter still intact, would I actually see a drop in top speed or no, since the 55 can easily attain 155 anyways. Also, assuming there is no loss in top speed, would the car be slower in any points in the powerband, affecting(slowing) quarter mile or 0-100 times?
The rate that a vehicle accelerates is a function of the amount of force acting upon the resistance to that force. By changing gears you will have more force (torque) available in each gear BUT (assuming no change in redline) that gear will max out at a lower MPH.
Example. If you car previously hit 37mph in 1st gear and after the change will redline at 34mph in 1st gear... your car will be quicker from 0-34 but SLOWER from 34-37mph. Same applies from second, third, 4th and 5th gears. Using the previous data I listed it would be: 0-34 quicker, 34-37 slower, 37-56 quicker, 56-60 slower, 60-91 quicker, 91-97 slower, 97-131 quicker (speed limiter) Over all the car is quicker, no question, feels stronger, has more force for 94% of the range.
#36
.................For an upgrade that costs$5K, it is too bad there isn't adequate infor mation from the vendors. Nonvenbdors seem to have more info and even then the information so far can be summarized as..........."if you get the sport differential, your car MIGHT go faster." Obviously, this is not enough info with which tp dish out $5K. I am certain that the vendors will sell more of these sport differentials if they provide more like is traditionally done for other performance products.
Ted
Ted
#37
Ignoring the discussion of shifting points, all this talk is about how lower (shorter) gearing will increase acceleration. It is certain, however, that there is a point where lower gearing will cause a car to be slower, not quicker (e.g., my truck is much quicker in its normal gear range than it is in "low" range; you can imagine that a powerful car with a 10:1 axle ratio would not be nearly as quick as it would be with a "normal" differential). I think there is a fine balance between power and gearing that needs to be struck in order to optimize acceleration. Intuitively, it seems that greater power requires lesser mechanical advantage. Can any of you comment on optimum gearing? It simple has to be a function of power and weight, but I do not have the engineering acumen to figure it.
#38
Super Member
RWTQ increase going from 3.07 to 3.27 gears in this application:
1 = 146, 129
2 = 90, 79
3 = 55, 48
4 = 37, 33
5 = 31, 27
- Taking published test values for acceleration (from Car & Driver), measured torque curve, and known stock gear ratios, I created a spreadsheet relating speed to time to RPM at 100 RPM increments; interpolating torque @ each increment.
- Then calculated an altered force @ the wheels with shorter gears [yes, taking into account also that the car hits redline sooner ].
- Then from that calculated the reduction in time it would take to get through each previous rpm/speed increment with the increase in force @ the wheel, using basic physics calculations [formula evolved from the "Physics of Racing", aka 'PhoRS', text floating around out on the net ... and don't forget mass is in slugs not pounds if you try this yourself! ].
The end result was a realization that I'd reduce 0-60 time by only about 0.2 seconds. I was entering into this hoping it would prove to be close to a second.
It didn't seem worth the $4K-$6K at the time. But I'm beginning to think about it again. It would help if it was a limited-slip rear. Maybe that, plus a K&N filter, plus maybe even a chip ... that should spruce things up.
#40
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Originally posted by c43amg
The end result was a realization that I'd reduce 0-60 time by only about 0.2 seconds. I was entering into this hoping it would prove to be close to a second.
The end result was a realization that I'd reduce 0-60 time by only about 0.2 seconds. I was entering into this hoping it would prove to be close to a second.
I think you could shave a second off you 0-60 for less then $5k.
I want to change the rear diff because the gearing doesn't feel right through medium turns, I hit redline before the end of the turn in second, third is to high, I bog then have to rebuild momentum. Just not getting optimized power applied at the right points.
#41
Originally posted by c43amg
I agree. I did what you did, but went a bit further with my method of calculations for whether I should go to 1:3.46 gears on my C43AMG (stock is 1:3.07).
- Taking published test values for acceleration (from Car & Driver), measured torque curve, and known stock gear ratios, I created a spreadsheet relating speed to time to RPM at 100 RPM increments; interpolating torque @ each increment.
- Then calculated an altered force @ the wheels with shorter gears [yes, taking into account also that the car hits redline sooner ].
- Then from that calculated the reduction in time it would take to get through each previous rpm/speed increment with the increase in force @ the wheel, using basic physics calculations [formula evolved from the "Physics of Racing", aka 'PhoRS', text floating around out on the net ... and don't forget mass is in slugs not pounds if you try this yourself! ].
The end result was a realization that I'd reduce 0-60 time by only about 0.2 seconds. I was entering into this hoping it would prove to be close to a second.
It didn't seem worth the $4K-$6K at the time. But I'm beginning to think about it again. It would help if it was a limited-slip rear. Maybe that, plus a K&N filter, plus maybe even a chip ... that should spruce things up.
I agree. I did what you did, but went a bit further with my method of calculations for whether I should go to 1:3.46 gears on my C43AMG (stock is 1:3.07).
- Taking published test values for acceleration (from Car & Driver), measured torque curve, and known stock gear ratios, I created a spreadsheet relating speed to time to RPM at 100 RPM increments; interpolating torque @ each increment.
- Then calculated an altered force @ the wheels with shorter gears [yes, taking into account also that the car hits redline sooner ].
- Then from that calculated the reduction in time it would take to get through each previous rpm/speed increment with the increase in force @ the wheel, using basic physics calculations [formula evolved from the "Physics of Racing", aka 'PhoRS', text floating around out on the net ... and don't forget mass is in slugs not pounds if you try this yourself! ].
The end result was a realization that I'd reduce 0-60 time by only about 0.2 seconds. I was entering into this hoping it would prove to be close to a second.
It didn't seem worth the $4K-$6K at the time. But I'm beginning to think about it again. It would help if it was a limited-slip rear. Maybe that, plus a K&N filter, plus maybe even a chip ... that should spruce things up.