TQ and HP limits of xDrive

M4TW · 09-22-2007, 12:18 PM

Owners of 335xi's like me may be concerned about how much torque and HP their xDrive components can safely handle before dropping in engine mods.

Does anyone have any insight?

The best description of the system that I've ran across is at bmw.ca.

Quote:

The multi-plate clutch distributes engine power between the front and rear axles as the situation demands. This process is both continuous and variable. If more power is needed for the front wheels, an electric servo motor applies pressure to the distribution unit, closing the plates. The plates in the clutch are closed using a special leverage mechanism: the greater the pressure, the more power is transferred via the chain-driven shaft.

If more power is needed for the rear axle, the clutch can be opened smoothly (continuously) and the engine output is transferred via the carden shaft.

I am assuming that the same components are used in all of BMW's xDrive lineup. The basis of my assumption is that my 335xi has HDC (Hill Descent Control) - an invaluable feature if you plan on taking your expensive BMW sedan or coupe to do some serious off-roading.

So anyway, the highest HP/TQ engine that xDrive is paired with presently is the X5 4.8i - a V8 with a 350/350 HP/TQ rating. Assuming a 10% margin of safety, the xDrive should be able to handle 385/385??????????

WilyB · 09-23-2007, 11:36 AM

I was discussing the issue of 4WD with the MB's AMG Product Manager last week and he told me the high torque of their engines was destroying the CV joints on their coupes and sedans and that they won't make a 4WD AMG for the time being. May be the next generation S600...

Of course that did not apply to the ML63s whose 4WD system is much beefier than for much lighter cars.

I had been considering a 535xi with engine mods, but not anymore!

808AWD325xi · 09-25-2007, 02:23 PM

MB/AMG experience doesn't apply. Likewise, just because an Evo's AWD system can handle 600+ awhp, doesn't mean it's in any way applicable either.

Unfortunately, until someone breaks something, we don't have any clue without data from BMW. Perhaps they don't know, but I doubt it.

09-23-2007, 11:36 AM	#2
WilyB Captain 19 Rep 671 Posts Drives: E92 335 Join Date: Jan 2007 Location: USA iTrader: (0) Garage List 1991 BMW 325iC [0.00] 2008 Porsche Cayenn ... [0.00] 1990 Ferrari Mondial T [0.00]	I was discussing the issue of 4WD with the MB's AMG Product Manager last week and he told me the high torque of their engines was destroying the CV joints on their coupes and sedans and that they won't make a 4WD AMG for the time being. May be the next generation S600... Of course that did not apply to the ML63s whose 4WD system is much beefier than for much lighter cars. I had been considering a 535xi with engine mods, but not anymore!
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09-25-2007, 02:23 PM	#3
808AWD325xi Ballin' out of control. 525 Rep 1,289 Posts Drives: 2009 335i Join Date: Jul 2007 Location: Moline, IL iTrader: (0)	MB/AMG experience doesn't apply. Likewise, just because an Evo's AWD system can handle 600+ awhp, doesn't mean it's in any way applicable either. Unfortunately, until someone breaks something, we don't have any clue without data from BMW. Perhaps they don't know, but I doubt it. __________________ Alpina B3 Flash/BMS OCC/ER CP/ETS 5/HKS BOV/M3 Control Arms
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