any negative effects runing no muffler?
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Elder User
Joined: Jun 2008
Posts: 574
Likes: 1
any negative effects runing no muffler?
i have been pondering getting an exhaust system for my 07 for many months now
i have finally come to the idea of just staying with my stock exhaust
BUT
im putting an electronically controlled exhaust valve from a racing boat in just before the stock muffler...
is there any negative effects in running just pipes
im going to use enough stock pipe to get plenty of back flow
i just dont know if theres something im not thinking of....
thanks
i have finally come to the idea of just staying with my stock exhaust
BUT
im putting an electronically controlled exhaust valve from a racing boat in just before the stock muffler...
is there any negative effects in running just pipes
im going to use enough stock pipe to get plenty of back flow
i just dont know if theres something im not thinking of....
thanks
Laughing Gas
Joined: Oct 2005
Posts: 1,058
Likes: 1
From: South Jersey
Before I fabricated my exhaust on my 2005, I ran no exhaust, just the cats for about a month and it sounded like it had duels already on it. The stock system is very restrictive, and isn't too loud without the muffler on back removed. If you choose too do that, you will still need to have a tailpipe put on it so you don't get any exhaust fumes in the cab.
Senior User
Joined: Jun 2005
Posts: 375
Likes: 0
Huh, did you say somthing? Could not resist! No backpressure means loss of low end torque IMHO. My 05 sounded better with a Magnaflow but it did loose low end, left my 08 alone. Open exhaust is better for WOT not low end grunt.
Posting Guru
Joined: Aug 2007
Posts: 1,714
Likes: 1
From: Canton, IL
Most of the restriction comes from the cats, removing the stock muffler will make almost no difference. Increasing to the next size pipe will help the upper end RPM but should only minimumly affect the low end because the main restriction is still present. If i were to remove the 2nd set of cats on my 04, it might run better. I think the 06 and up only have 2 cats total. whereas i have 4.
Posting Guru
Joined: Aug 2007
Posts: 1,714
Likes: 1
From: Canton, IL
Gotcha on the 4 cats on the 06's. Didn't know for sure.
On my 04, the secondary o2's are between the first and second cats. the first ones are further up stream. I could easily remove the 2nd cats.
On my 04, the secondary o2's are between the first and second cats. the first ones are further up stream. I could easily remove the 2nd cats.
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Elder User
Joined: Feb 2007
Posts: 866
Likes: 1
From: Michigan
Are all the trucks like this? Cause the only o2 sensor I have seen was betweent he two cats. Well thats on my 04. I was thinking of gutting the rear two cats. I didnt see any sensors on them though.
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From: Southern California
i have run numeorus post 1974 vehicles with no muffler past the cats and have had no loss of power (because the restriction is at the cats and that isn't changing). The one issue that I do see with running a cut-out is, I am wondering if the ECM can respond fast enough to the bypass of the muffler (in terms of the slight fuel mixture change) that will occur. Because these engines run so very lean, and although we are not looking at greater than a 1-2% fuel mixture change, I think if you were in a mode of other than idle, floored, or decellorating, would there be a change of an momentary overlean condition during a partial accel to cause damage?
Posting Guru
Joined: Aug 2007
Posts: 1,714
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From: Canton, IL
there are two more ahead of the first cats on our 04's. These are the ones that the engine uses to measure and calculate from. The secondary o2's are for the emmission system to make sure the catalyst is working. I drove along time on one of the secondary o2's being bad. Truck ran fine, no loss of MPGs. or power, just a dash light and a code.
New User
Joined: Jul 2009
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When replacing the stock exhaust with a flowmaster super 44 I had to run into town to pick up more piping to finish the exhaust and decided to run it with no muffler. It seemed to me to have way less power and didn't sound very good at all. I got tons of looks from people though and I am I sure annoyed a few of them. 
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
i have run numeorus post 1974 vehicles with no muffler past the cats and have had no loss of power (because the restriction is at the cats and that isn't changing). The one issue that I do see with running a cut-out is, I am wondering if the ECM can respond fast enough to the bypass of the muffler (in terms of the slight fuel mixture change) that will occur. Because these engines run so very lean, and although we are not looking at greater than a 1-2% fuel mixture change, I think if you were in a mode of other than idle, floored, or decellorating, would there be a change of an momentary overlean condition during a partial accel to cause damage?