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Drivetrain loss on AWD
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04-15-2011, 09:35 AM | #1 | |
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Drivetrain loss on AWD
What will be the drivetrain loss on AWD? Is it more of less compare to RWD?
Does type of tranmission effect the loss? Is 15% or 20% rule really work? This is a really interesting topic. Let the discussion begin. Quote:
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04-15-2011, 10:53 AM | #2 |
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For E90 ix steptronic, what is the est. loss number? 10% maybe?
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04-18-2011, 02:48 PM | #3 |
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For reference, on a local Dynojet that uses a full correction factor on turbo cars (read: peak numbers appear "inflated"), the RWD 335i's up here seem to put down an extra ~15+whp or so more than the AWD 335xi's. So yes, there is an additional drivetrain loss associated with having 2 extra drivewheels, and it's fairly significant.
That's the price you pay for additional traction in inclement weather.
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04-18-2011, 04:16 PM | #4 |
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Back in 2007 my buddy Jason and I both dyno'd on the same dyno, same day, same conditions. Both cars were about 3 months old with a couple thousand miles on each clock. He was RWD, me AWD and he was consistenly between 22 and 23 HP higher than my uncorrected numbers across the three pulls.
So I'd say approximately 20 hp is a good number to reference for this comparison. Last edited by forza1976; 05-13-2011 at 02:54 PM.. |
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04-18-2011, 10:39 PM | #5 | |
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Have you seen the thread where xi owner's want to disable the front portion of the awd by pulling a fuse so they can do power slides and donuts? German engineers must just die when they hear this. The whole point of these sophisticated drive trains is to prevent loss of traction. They do exactly what they are designed to do. If AWD wasn't superior, World Rally Cars would be 2WD. |
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04-19-2011, 01:04 AM | #6 |
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I dyno'd my STOCK 08 E92 335xi a couple months ago
put down 255whp moments later a E90 sedan put down 272whp Now i have a jb4 and cant wait to get dyno'd =)
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04-22-2011, 07:33 PM | #7 |
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My 335xi got 255whp on dyno as well. I feel good now!!!
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08-04-2011, 06:23 PM | #9 | |
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08-05-2011, 07:39 AM | #10 | |
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Maybe in comparison to other AWD vehicles it isn't, but against the i without lsd, it is superior. Now obviously the handling aspect is negated by the additional weight and the higher stance for a stock xi. But lower the car with good coils and reduce about 50lbs of unsprung weight at the wheels and you will have a vehicle that handles very nicely. |
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08-05-2011, 07:46 AM | #11 | |
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X-Drive actually is a pretty good balance of performance and inclement weather capability. Looking at how x-drive is engineered, it is pretty close to how Nissan's ATTESA-ETS works. DPC makes another leap towards performance, but simply adding a LSD to the rear will make a more than capable AWD system at the track. We'll see if there will be a trickle down from the x5m, x6m, and future m5 x-drive to the 335. |
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08-13-2012, 03:10 PM | #13 |
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08-19-2012, 03:30 AM | #14 |
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Damn -- I figured there'd be more drivetrain loss, but 255whp is still a little disappointing. That being said, I anticipate some crazy JB4 results!
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08-19-2012, 03:46 PM | #15 |
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There's a lot more going on than drive train loss. I recently went from a 2007 E92 328xi to a 2008 M3. The weight of the awd, tire wear in front, really heavy steering, all add up to a totally different feel, and a lot of stuff to push around.
Also, the 325 and 328 versions of the xi have slightly different final drive ratios: the i has a 3.73, and the xi has 3.91. The 330, 335 i/xi have the same ratios, all 3.73. |
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08-22-2012, 08:58 PM | #16 |
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Yup, I have a quaife with my xi. Grip is ridiculous, even with FBO+Meth+E85 I can do a brake torqued launch and not even chirp a bit. I will be honest and say that I haven't slid the car at all (I can't, even in the rain, 275 supersports at all corners) but I am very excited to get some narrower rubber to see how the car feels when traction is lost. My car in its existing form will easily run out 2nd gear on an oiled, water covered skidpad (with smooth driving).
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08-23-2012, 09:40 AM | #17 | |
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