Just finished the exhaust on the 540 this weekend. I Ran 2.5" off of each header collector and replaced the cats with 2.5" X 18" resonators. Then we came off the resonator into a 2.5" to 3" Y pipe, and finally 3" Dinan. the final sound was a little louder than what I was shooting for, so I may stick another resonator before the Dinan.

These videos were taken with a weak camera, and I promise to have a great daytime video or start up and daily driving tomorrow, weather permitting. I am also planning on snapping some pictures with the car up on the lift, it looks GREAT.

Let me know what you think, I have my flame retarded suit on.

Reving with no load
http://s4.photobucket.com/albums/y147/turbo86/?action=view&current=540sound.flv

1st-2nd gear under load
http://s4.photobucket.com/albums/y147/turbo86/?action=view&current=540i.flv

Having some fun with a Formula on a 50 shot
http://s4.photobucket.com/albums/y147/turbo86/?action=view&current=formvsbmw.flv

Talk to you guys tomorrow!

Any probleams with runing no cats--Check engine, backfireing/brakeup etc?

vids arnt too bad...exhaust sounds good

that sounds sick man - very nice. any noticeable power gains?

Any probleams with runing no cats--Check engine, backfireing/brakeup etc?

+1 are you using emulators?

For the pre cat o2 sensors I used short style 'spark plug non fouler's from Autozone as bungs. For the post cat o2 sensors I used the longer style 'spark plug non fouler's from Autozone as bungs, as it raises the o2 sensor far enough out of the exhaust jet stream to keep the CEL from tripping. No CEL yet and I have put about 50 miles on the car since the cat deletes. If it does end up ticking off the post cat sensors, I will try screwing in another short style non fouler to get it even further up out of the exhaust stream, but I think I should be OK the way it is now.

As far as the power gain from taking out the cats, it is very hard to say. I really hate people that live by the butt-dyno. However, acceleration seems to have smoothed out, and the car feels like it pulls harder on the top end. Actually, before the cat deletes I was dead even with my buddy in that Formula from the 3rd video, but now I am able to put a car length on him in one gear. ???

Thanks for the compliments, guys! I was really expecting some serious hate on the exhaust sound!

awesome vids man...luv the sound of your 540i...what was the outcome of the race..looks like u hit the brakes 1st and u got on the gas 1st based on sound Im assuming u one..and what kinda speed did u hit?

Thanks! I JUST noticed my car barked 3rd gear!!!
We started from 40mph and shut down at about 95mph. I ended up about one car length ahead of him, but he did only have 600 psi of bottle pressure. We are going to try it again when his bottle is a little warmer and I get the Dinan reflash.

You guys think I should add another resonator? I can't decide if it is too loud or not...

Thanks.

It sounds perfect. Fairly quiet unless you really step on it, but you can tell it's a V8 for sure now. Very nice!

Flexall :D

Thanks, man!

beautiful sound.!

For the pre cat o2 sensors I used short style 'spark plug non fouler's from Autozone as bungs.I don't think its a good idea to use the foulers on the pre cat o2 sensors , since they will restrict the signal that feeds the DME and throw off your AFR readings during cruising/part throtlle(closed loop) also your MPG's going to be off
I would fit regular bungs for the pre cat sensors, now the post cat sensors are a different story

by the way the car sounds real good :thumbup:

I don't think its a good idea to use the foulers on the pre cat o2 sensors , since they will restrict the signal that feeds the DME and throw off your AFR readings during cruising/part throtlle(closed loop) also your MPG's going to be off
I would fit regular bungs for the pre cat sensors, now the post cat sensors are a different story

by the way the car sounds real good :thumbup:
Thank you!
FWIW, I did cut the precat non foulers down to the same thickness of the stock bung. Thanks for looking out!

went SS piping to my dinan muffler a few years ago - I loved it. But the first morning that I fired it up in our garage, it startled my wife so much that I was "forced to" add a small Magnaflow resonator to tone it down. My son-in-law has been urging me to drop the resonator again but ...............!!

The Dinan will be quite "raspy" on initial start up but sounds much better when the car warms up.

went SS piping to my dinan muffler a few years ago - I loved it. But the first morning that I fired it up in our garage, it startled my wife so much that I was "forced to" add a small Magnaflow resonator to tone it down. My son-in-law has been urging me to drop the resonator again but ...............!!

The Dinan will be quite "raspy" on initial start up but sounds much better when the car warms up.
:lol
That is GREAT! My wife made a poke at me the first morning I fired it up, but it was just a friendly jab, thankfully.

Just imagine your old setup without cats... :eyecrazy

Sounds good. Leave as it is, :buttrock

Thank you!
FWIW, I did cut the precat non foulers down to the same thickness of the stock bung. Thanks for looking out!
no problem, anytime

went SS piping to my dinan muffler a few years ago - I loved it. But the first morning that I fired it up in our garage, it startled my wife so much that I was "forced to" add a small Magnaflow resonator to tone it down. My son-in-law has been urging me to drop the resonator again but ...............!!

The Dinan will be quite "raspy" on initial start up but sounds much better when the car warms up.

:lol That is funny. My girlfriend gives me hard time when I let in run in the garage ( I back it in ). It vibrates the family room that has a door to the garage.

Flexall