straight pipe
 

Hi Guys,

i have an 01 X5 4.4i and was wanting feedback from anyone who has replaced the standard resonator with straight pipes? I know a few people have on this forum and been happy with it, but any problems such as droning inside the cabin or loss of power?
thanks
frank

I cut my resonator out and replaced with straight pipes and I don't have any noticeable difference in cabin noise. When the front windows are down I can deffinitely hear more a growl though. I like the straight pipes because its not overwhelming like a B&B TriFlow or an Eisenmann...its more subtle. I had a TriFlow on my old M3 and even though I loved it, it was a bit obnoxious. At least once a week I had random people off the street telling to take my car in for service because the exhaust must be broken...that's when I would jump in the car rev her up a little and blow them across the street :-)

I just had this done on Friday....At idle, it's still fairly quiet, although it doesn't sound as clean as with the resonator on. At full throttle though, the thing roars. I'm guessing there was a *slight* gain in HP resulting from a little less backpressure. As for cabin noise, I noticed the exhaust was slightly louder, but nothing unbearable.

Don't think you get any gains from reduced back pressure.

If it was that easy BMW would of used bigger pipes.

The whole system was computer designed and the run by your on board computer.

It's already been noted ad nauseum that X5 exhaust modifications yield insignificant changes in HP. Owners modify their exhaust more for aural benefits. It's been discussed before, in fact, you were involved in the discussion. You do remember your statements stating exhaust modifications creates nothing but noise pollution, don't you? That was the post that you called everyone a bunch of angry rednecks.

I haven't forgotten...

Cocoabrova talked about gain in hp.

Still question the wisdom of doing this if you don't get more hp, but what ever turns you on.

But can't be a red neck can you?

I'm still undecided between this nad the X pipe.... but I'm sure one spring hits, I'll be doing one or the other.

by doing the X-pipe it sticks more to the original stock set up compare to the straight pipe. My 05 4.4 has the x-pipe mod and I really like the sound, not too loud and yet not like the stock.

I took a look inside the resonator after it was cut off. I noticed that when looking down the 2 pipe, one pipe has drilled little holes that takes up half of the resonator length wise and the other half of the pipe is solid.

The same goes for the other side but the one of the pipe has little holes on the top half and the other pipe has the holes on the bottom half when looking for down from one side..