zero hp gain
Super Member
Joined: Nov 2004
Posts: 570
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From: Los Angeles, CA
2006 BMW X5 4.8is and 2005 C55 AMG
I just picked up the car. The primary cats are back on, but the secondaries are still off. Just as a reminder, the car sounded AWFUL with all the cats off. The car sounds so much better now, but it still sounds a little like a riced out Civic under some WOT conditions. I'm probably going to put the secondaries back on, but I want my car back for now
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MBWorld Fanatic!
Joined: Jun 2006
Posts: 1,934
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From: Chicago
04 C32
I don't think it sounds riced out at all with the secondaries off and in idle the car still sounds stock very quiet. It does though give out a very healthy growl when you get on the throttle and has a deeper drone to it at cruising speeds, but that varies depending on rpm and how long you hold that rpm. I know my car is a V8 so the sound is different but the effect should be the same. Just so you know my car has a larger airbox, headers and the res removed.
I love the tone of the car with just the resonator removed. I wish I could have that tone, only a little louder. I was hoping that having the resonator and secondaries off would do the trick. I actually love the way the car sounds at idle with the resonator and secondaries off. It also sounds real good at part throttle, and at most WOT conditions. There are a few WOT conditions where that high tinney tone gets a lot louder, and that's the one part that I'm not too fond of, but it isn't that bad. I still like the way the car sounds. I'm not sure if it is worth the trade off. I like how the car sounds a little meaner without the secondaries, but the overall tone was better with them in there.
Don't get me wrong, the car is by no means loud, and it is still very quiet inside the cabin during normal driving. Under WOT, I'd guess that the volume is about 150% that of the car with just the resonator removed. With all four cats off, it was about 1000% louder (if not more).
Super Member
Joined: Nov 2004
Posts: 570
Likes: 0
From: Los Angeles, CA
2006 BMW X5 4.8is and 2005 C55 AMG
The only time I ever hear a tinney sound is when the car has been sitting awhile (more then a day) and is completely cold and I start it up. After that loud ignition kick for a few seconds I hear this tinney tone. Which I assume is the exhaust piping warming up. Once the engine is completely warm the car gets quieter, but not a lot and sounds pretty sweet.
Have you got the dyno results with just the the secondaries off? Any hp or tq improvement with them off?
Also, I'm a idiot, but what does WOT mean?
Have you got the dyno results with just the the secondaries off? Any hp or tq improvement with them off?
Also, I'm a idiot, but what does WOT mean?
Thread Starter
MBWorld Fanatic!
Joined: Jun 2006
Posts: 1,934
Likes: 1
From: Chicago
04 C32
There was no gain from removing the secondaries.
