ideal x-pipe positioning for performance gain?

[Turbo_Bimmer]

Originally Posted by TowX

Very nice. I tow my track car, and try to avoid driving offroad as best I can.

My '04 4.4 tows extremely well. When I was pulling my 911 on my open aluminum trailer it was no big deal to set the cruise at 75 and go for hours at a time comfortably.

Unfortunately my new enclosed trailer has max'd out the tow rating of the X5. By the time I load the car (2450 lbs) into the trailer (2900) and throw in 8 spare wheels and tires (350), tool chest (250) and spare parts (250), I'm at the tow rating. Sure, the engine has the power, but I can't come close to being able to see around the trailer. I've tried the aftermarket mirror extensions but at highway speeds they vibrate so much that anything along side is just a blurr. Too bad because the 4.4 pulls so well, and being able to leave the Steptronic trans in 5th at highway speeds is the perfect powertrain setup. I can pull at 70 pretty easily, just can't see. So sadly I'm now looking at changing vehicles- Yukon Denali or Infiniti QX56. Might just sell my 528 and keep the X5 as my daily driver though.

I whish I had an enclosed trailer! My open, steel trailer, with car, jerricans, extra tires is around 5000lbs, so it should be ok, even easy with the 4.4.

You say you use 5th gear. Is it you that forces it into 5th, or it downshifts by itself and stays there (assuming you have a 6speed).

Instead of selling the X, why don't you install 3 cheap backup cameras or RCA output surveillance cameras? One at the front left top of the trailer to cover the left side, one on the opposite side, and one at the back top. With some wiring and some imagination, it could be possible to have buttons or an electronic circuit that cycles through all 3 cameras continiously and send images on the screen (temporarely mounted on the console to the cigarette lighter). You already have 12V in the trailer... Just a thought.

[TowX]

My old aluminum trailer, full deck, with aluminum tire rack was just 1100 lbs, so when loaded I was usually pulling 4500 lbs. Easy to pull. But having the enclosed is so nice. After a 12 hour tow home, getting in at midnight, it's nice to just back the trailer in and lock it up. No need to unload the car, pull the tires off the rack, take all the tools, spare parts etc out of the X5. It's all locked in the trailer.

I pull the shifter over into manual mode and leave it in 5th on the highway for most situations. 3,000 rpm is about 72mph, just about perfect for towing. Leaving it in D or S, and the trans is constantly up and downshifting on grades.

Interesting thought about the cameras. But the real limitation of the X4, at least the E53, is the short wheelbase and unibody. There's a point where the weight of the trailer pulls the tow vehicle around, like the tail wagging the dog. A full size SUV will have a significantly longer wheelbase, and will be wider. Not nearly as much fun on a daily basis as my X5 with H&R lower springs, and lowered rear air suspension though. The only other thing I've considered is an Audi Q7 which has a 6" longer wheelbase, 6 piston forged brake calipers, and a higher tow rating.

[Papa13]

Very informative post. I have a 4.8is So, if I wanted to cut my resonator off why would I need to replace it something? Why can't I just straight pipe it all the way back to the muffler?

I love the sound but it sounds VERY restricted to me. I want to open it up. I am thinking about maybe cutting the 2nd cats (if there are 2nd cats like the e90 and e82) and cutting the res and just stright piping it back to the muffler. Though it could be the muffler that is sounding restrictive??

Any ideas? Thanks guys!