05-02-2015, 10:13 AM | #45 | |
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Just as it is with my RWD+LSD M235i and AWD Golf R
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05-02-2015, 10:19 AM | #46 | |
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It may also do so in full 'DSC off' mode, but without the steeling wheel position input, allowing the car to rotate around its axis without trying to correct it. I believe it still tries to match wheel spin rates.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi |
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05-02-2015, 11:09 AM | #47 |
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Well whatever it is, traction control, ediff, my tuned 135i sucked making 90 degree turns, car would pause and not really get moving until almost straight again. I added LSD and that helped tremendously with that aspect of the car, but did little to nothing for accelerating from a stop. The car could not handle the extra power of the tune and first gear was almost useless with second not much better. If I wanted to do burnouts I would have bought a mustang or camaro.
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05-02-2015, 11:37 AM | #48 | |
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I am glad the OP has made up his mind but I just had to address the "this guy" comment. Yes,I drive around on drag radials(NOT slicks) on all my cars without a problem ALL of the time except for Winter and why not? The Mickey Thompson ET street II, is a DOT approved tire and actually rides better than the stock tires as it has more side wall being a 45 profile-and looks better. They may not corner as well but they are fine for street driving. The only reason I just bought a spare set of rear wheels to mount them on is to save the thread for the drag strip. The fact is, a RWD M235 with sticky tires is fast as the AWD (if not faster) to 0-60,1/8 and 1/4 mile and will trap higher due to being lighter... and I have the time slip to prove it. [/IMG] I see you leave in Chicago so I suspect the weather is a bigger motivation for your AWD than you are letting on. First thing I am going to do if I ever move out of the Midwest to where it does not snow is ditch the AWD drive cars I have now. Last edited by olaosunt; 05-02-2015 at 11:54 AM.. |
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05-02-2015, 02:20 PM | #49 | |
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the eDiff program is only active on DSC OFF... it's just sometimes it gets confused with the DSC/DTC as they both brake wheels individually but eDiff won't cut any power and eDiff won't do anything to the front wheels while DSC/DTC will brake any wheel it needs to Also xDrive can't adjust torque side to side (like left wheel different from right wheel) it can only adjust torque front to back...at least last time i checked... |
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05-02-2015, 04:06 PM | #50 | |
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the RWD.) |
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05-02-2015, 06:07 PM | #51 | ||
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EDIT And the last 2 seconds of this one show side-to-side torque vectoring. Still looking for the old one showing it running through curves on ice with torque spread.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi Last edited by Zooks527; 05-02-2015 at 07:10 PM.. |
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05-02-2015, 06:26 PM | #52 | |
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05-02-2015, 07:38 PM | #53 | |
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Also I don't think you have torque vectoring for the front so you can't really do side-to-side there either in any case.... regular xdrive can't vary torque side to side It's not the xDrive that varies the break load, xdrive has nothing to do with brakes (if you had no brakes...xdrive would work exaclty the same)... it's the DSC that controls braking of individual wheels... put the DSC OFF and the car won't apply any brakes (apart from the rear from eDiff program)... it will just vary torque front to rear Last edited by pikcachu; 05-02-2015 at 07:44 PM.. |
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05-02-2015, 07:42 PM | #54 | |
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EDIT: The last 5 seconds of this video is showing variable torque on all 4, albeit without narration on a 5 series touring.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi Last edited by Zooks527; 05-02-2015 at 07:52 PM.. |
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05-02-2015, 07:46 PM | #55 |
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05-03-2015, 09:23 AM | #56 | ||
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"Torque vectoring" as used in the X6 is a hard system using an active clutch in the rear axle, positively adding power to a wheel. Torque shifting side to side in other iterations of xDrive is done using the brakes and an open differential, functionally the eDiff operation, and is typical across most non-clutch AWD systems. Can't find the video, but did find the press release (note: hitting the link will download a Word document press release to your computer, not open a browser window). https://www.google.com/url?sa=t&rct=...92291466,d.cWc Page 14, describing xDrive as implemented in a 3-series: "This interaction with DSC also provides a transverse lock function, forced distribution of power to the two front and, respectively, rear wheels by means of electronic intervention in the brakes: As soon as a wheel starts to spin without transmitting power, the brakes are applied specifically on that wheel, the differential in the final drive automatically feeding more power to the opposite wheel still maintaining its grip." This is pretty much what I said back in posts #46 and #51, and it certainly supports the proposition that non-DPC xDrive can vary power side to side. Quote:
Yes, it's tied to the DSC and the DSC function itself can be turned off, however (page 9): "Like on every BMW, DSC Dynamic Stability Control may also be deactivated on the all-wheel-drive models, enabling the sports-minded driver to enjoy all the dynamic driving qualities of his BMW in a controlled power slide by deliberately oversteering the car. The xDrive all-wheel-drive system as such cannot be deactivated." Which, again, is what I said in post #46 above.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi Last edited by Zooks527; 05-03-2015 at 10:24 AM.. |
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05-03-2015, 10:19 AM | #57 |
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Exactly, you were on map 7 with higher octane and boost, other awd guy was 93 octane map 2, yet you were slower to 60' and only equal by the 330 ft time. If awd car put your slicks on, added higher octane and went map 7, pretty much guarantee you wouldn't be even by 330ft. The rwd advantage takes over by back 1/2 of 1/4 as shown in higher traps. Enjoy your ride and nice timeslip.
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05-03-2015, 10:28 AM | #58 | |
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Say torque distribution front to rear at a given time is 40F - 60R So basically at the rear you have 30% torque to each wheel, now one wheel start spinning, what it will do (like ediff when dsc is off) is brake one wheel but the most one wheel will ever get is 30% while the other one will get 2 or 3% in a hope it gets traction...and the brakes is eating the other 27% torque It's not like you can send 57% out of the 60% available for the rear, to one wheel and 3% to the other.... it just sends 30% each, and you get 30% and 3%, wasting 27% through the brake pads If that's what you mean with vary torque side to side then you are right..... but it's really not varying anything... it's sending the same torque all the time to each wheel and then wasting the torque with the brakes You could use 2 LSD's (one front, one rear) if you wanted side to side torque distribution....like the subaru symetrical awd for example... |
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05-03-2015, 10:50 AM | #59 |
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xDrive in 2-series has no torque-vectoring, period. Some help in moving the car forward when wheel spin(s) comes from e-Diff, but the real thing - the mechanical closed differential - is only available for RWD. That's why I said that unless you live in a heavy snow area, RWD plus M-P LSD is the best way to go.
I'm talking from experience - did have a 5-series xDrive, do have M235i with LSD. Only the latter is a true bimmer by my books...
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just sold: 2013 F10 528i xDrive my AWD beater: 2015 Golf R mk7 DSG my RWD pirate & long-distance cruiser: 2015 M235i AT8, LSD Last edited by moldcad; 05-04-2015 at 04:39 AM.. |
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05-03-2015, 12:07 PM | #60 | |
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At the start, you have 30% of engine torque going to the road on the left, 30% to the road on the right, before a wheel starts to spin. Then, a wheel starts to spin. As it's an open differential, you now get 3% to the road on the left, 3% to the road on the right, 54% to rotational momentum of the right wheel. The braking function kicks in. You now have 30% of engine torque going to the road on the left, 3% to the road on the right, and 27% to heating the right brake pads. So, at the end case of your example, you have 10x as much torque being applied to the road on the left side of the car than on the right. You've moved 27% of the engine's torque from rotational momentum of the right wheel to force applied to the road at the left wheel. But you would like to quibble about the definition of "vary" in your force diagram. I'll go back to my last comment about talking past each other. Your point is that the car can't create more total torque on one side of the car than on the other. That's true. My point, that xDrive can vary side-to-side where the torque is applied to the road, is also true. I can't speak to Europe, but this is not true in the United States. The mechanical LSD is available for the M235xi here.
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Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi Last edited by Zooks527; 05-03-2015 at 12:17 PM.. |
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05-03-2015, 12:42 PM | #61 | |
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It's not that I like to quibble.... the wheels, from the drivetrain get exactly the same amount of torque....it's just that by wasting torque through the help of the brakes you get the impression that xdrive can "vary" torque side-to-side... I don't think you can put an LSD on an M235xi either... would love to see any link showing otherwise Last edited by pikcachu; 05-03-2015 at 12:47 PM.. |
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05-03-2015, 01:00 PM | #62 | ||
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Yes, that selectable value can't exceed 50% of the torque going to that wheel's axle. It can still vary from side to side on that axle, subject to the 50% limit. Now, had I said "increase" .... Quote:
Realoem also shows option for either the standard or MPerf LSD for the rear end: http://www.realoem.com/bmw/showparts...31&hg=33&fg=05 Both cars (M235i and M235xi) use the same part number for the normal differential, so there shouldn't be any valid reason why the LSD won't fit.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi Last edited by Zooks527; 05-03-2015 at 01:19 PM.. |
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05-03-2015, 02:27 PM | #63 | |||
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One thing is the be able to send different amount of toque to each will individually and another is sending the same amount and apply the brakes to reduce torque on some wheel I'm done with this, if you don't want to understand it, It's up to you. Won't waste more time trying to explain it. |
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05-03-2015, 03:08 PM | #64 | |
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But, look at the bright side. After insisting it didn't, you learned that the xDrive system does use the brakes. Think of it as a positive takeaway.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi |
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05-03-2015, 04:08 PM | #65 | |
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If xdrive could vary torque side to side why wouldn't BMW advertise it? You can't find any videos or info anywhere for a reason in the same way an eDiff is not even close to a mechanical LSD Yes i guess you always learn something new.... Can you show us any xDrive vehicle that has M perf LSD on? i didn't know that was posible... |
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05-03-2015, 07:36 PM | #66 | |||
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You seem to be unable to understand the word "vary". In your example in post #58 above, you posit a case where the wheel on the opposite side of a wheel that is spinning is putting 3% of engine torque down to the ground, and is then putting 30% of engine torque down to the ground after application of the brakes to the spinning wheel. If 3% going to 30% doesn't count as "varying", I don't think we're using the same definition of the word. Sure, you can't get more down to the ground than is being sent to the other half of the axle. So what? That doesn't effect the fact that the torque applied to the ground through the non-spinning wheel can be varied from the amount being applied by the spinning wheel to 10x that amount. It's coming back to the fact that you're fixated on torque being sent to the wheel, as opposed to torque being sent to the ground. Sure, the amount sent out each half of the axle is the same. What counts is that the useable amount applied to the ground can be varied so that each side is different. Quote:
Would you like me to speculate? Sure. If they advertised it since the DPC system came out, it would cut into their marketing effort to shill that. Is that the case? Beats the hell out of me. Ask them. EDIT: Whoops, there it is, on the main BMW site (as opposed to BMWUSA). Go here: http://www.bmw.com/com/en/insights/t...echnology.html Select the "How BMW xDrive Works" video. Watch it from 0:12 to 0:17. Notice the wheel torque graphic arrows. They'll be swinging side-to-side as the animation progresses. See below for two images cut from it. And a pig isn't close to an eagle. Again, so what? Where did I ever imply, let alone try to make the case, that an eDiff is close to a mechanical LSD? Perhaps you might want to dial the smug down just a bit. After all, in your post #53 above, you were clearly unaware that xDrive uses the brakes as part of its control system ("It's not the xDrive that varies the break load, xdrive has nothing to do with brakes (if you had no brakes...xdrive would work exaclty the same).."). I will confess that that particular omission did make me a bit less inclined to accept your technical analysis of the system. After all, if one wishes to opine on how the system works, shouldn't one, you know, know how the system works? Quote:
Regarding the LSD, I did give you a link to BMW USA's website, showing that it's available. I also gave you a link to a parts site that gave you the part number for it. If you don't believe two external sources, one of which is the manufacturer's website, I can't do anything about it. Now, I'll accept that you didn't know it was possible. But all that proves is that there's a number of things that you don't know about xDrive cars.
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2015 M235xi coupe, Black Sapphire Metallic, Black Leather, Fineline Stream trim, Steptronic, xDrive, ZPP, ZTP, ZCW, ZDA, ZDB, 5DP, hk w/BimmerTech amp, Enhanced BT
Prior 40 years: 67 BelAir wagon / 68 LeMans Tempest / 70 Mustang Mach 1 / 72 El Dorado / 78 Corvette / 81 Subaru GL wagon 4WD / 83 s10 Blazer 4x4 / 85 Bronco 4x4 / 96 Bronco 4x4 / 04 Passat 4mo / 09 BMW 335xi Last edited by Zooks527; 05-03-2015 at 08:30 PM.. |
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