PDA

View Full Version : 540i running No Cats, Performance ???


bk540sport
12-05-2004, 04:27 PM
Hello, i have a 98 540i auto sport with dinan intake, and stage 2 ecu and tranny software, i am going to be doing a custom exhaust, dual universal remus, with no resonitaor and a custom x pipe, i do not have to worry abouht emissions, i was wondering if anyone thinks i would get a big gain, running no cats, and some sort of o2 sensor, bypass, and does anyone know where i can find something to trick or bypass the o2 sensors, thank you

tpham
12-05-2004, 06:46 PM
Hello, i have a 98 540i auto sport with dinan intake, and stage 2 ecu and tranny software, i am going to be doing a custom exhaust, dual universal remus, with no resonitaor and a custom x pipe, i do not have to worry abouht emissions, i was wondering if anyone thinks i would get a big gain, running no cats, and some sort of o2 sensor, bypass, and does anyone know where i can find something to trick or bypass the o2 sensors, thank you

Not worry about emissions? You gonna get a huge power surge but running w/out cats is illegal & unfriendly to environment.

Cheers,
TP.

bk540sport
12-05-2004, 09:08 PM
Hello, ment as far as track use and for street go back to the high flow cats

rph74
12-08-2004, 07:18 AM
My car has no cats, but it trips the "service engine soon" light. It runs a little rich at idle, but that's the only adverse effect. Other than that it's perfect.

bk540sport
12-08-2004, 07:56 AM
Thanks for the response, what i am wondering is do you feel alot more performance with no cats, and is it alot louder, at cruising speeds and guess all around, thanks alot

LmtdSlip
12-08-2004, 10:00 AM
...i do not have to worry abouht emissions

Taking off your cats is a Federal Offense.
And bad for the environment.

Is 2-3 HP worth that? :dunno:

SoCaLE39
12-08-2004, 11:19 AM
Man you guys......he's just asking a question about the performance gain.....hell he would probably still be running cleaner w/o the cats than half of the rice burners running huge turbos and only pushing 200hp on their hondas...lol. However i do have to say....what difference does the sound make at "cruising speed" if its going to be used for track. If indeed this car is going to actually be used on the street just run the high flow cats.....you'll get the added exhaust flow w/o worrying about the emission control systems.

justin

rph74
12-08-2004, 11:51 AM
Thanks for the response, what i am wondering is do you feel alot more performance with no cats, and is it alot louder, at cruising speeds and guess all around, thanks alot

I actually wouldn't know, because I bought the car that way. I'd actually prefer to have cats on the car on it so the light would turn off, but I haven't gotten around to it yet.

540 M-Sport
12-08-2004, 07:13 PM
I have yet to see much performance benefit on most cars from the removal of cats (unless the cat was plugged or defective). You do run the risk of "check engine" lights too.
I'd leave it on...

jensenh
12-09-2004, 12:54 PM
I have yet to see much performance benefit on most cars from the removal of cats (unless the cat was plugged or defective). You do run the risk of "check engine" lights too.
I'd leave it on...

AA track pipe on M3s puts up some decent power gains: S50 = +26 WHP, S52 = +13WHP
but then again, a 540 is not an M3.

http://www.activeautowerke.com/exhaust/exhtrackpipe-e36.cfm