What is fascination with N55 down pipe.

[Dackelone]

Originally Posted by BMW135pls

You definitely do, this is what I experienced when I went from OE N54 to 3" DP. Much better high end power that carries closer to redline though, so that's the tradeoff.

Back when my car was running the stock sw... the engine power fell on its face over 5,500 rpms. After I had my car flashed to run 14.5 psi(stage II) my car pulls to about 6,800 rpms. I was surprised it was all sw tuning.

Yes, the N55 mid pipes(on my N54) made more yop end power(AND noise), but it was the low end performance in DD mode that made me miss the stock N54 mids. I am happy, now with my factory N54 mid pipe(and cats intact) and my PE exhaust w/y-pipe(resonator delete). My PE sounds awesome - and everyone always tells me that when they are following me.

Dackel

[ayao]

Originally Posted by nachob

Thanks. I just had a pm that brought up another question. What about California smog test. Do you guys take them off for the test or will it pass?

N55 mid might not pass smog visual b/c of cat delete, if the inspector knows what to look for ...

[bdaddylo]

Originally Posted by Dackelone

Back when my car was running the stock sw... the engine power fell on its face over 5,500 rpms. After I had my car flashed to run 14.5 psi(stage II) my car pulls to about 6,800 rpms. I was surprised it was all sw tuning.

Yes, the N55 mid pipes(on my N54) made more yop end power(AND noise), but it was the low end performance in DD mode that made me miss the stock N54 mids. I am happy, now with my factory N54 mid pipe(and cats intact) and my PE exhaust w/y-pipe(resonator delete). My PE sounds awesome - and everyone always tells me that when they are following me.

Dackel

Interesting information. I did 5 dynos and the stock N54 mids and Berk on the stock tune and the avg. max HP and TQ on the N54 mids were 315 and 360 and on the Berk mids it was 322 and 359. The difference in max HP of 7 is deceiving as there are areas of the rpm band where the increase was up to a 15-20 HP difference.