straight pipes
Elder User
Joined: May 2007
Posts: 936
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From: Carlos, MN
I agree on a new truck like this straight piping would be a bad idea, and cause you to lose power due to back pressure. Now if it were a diesel I would stay straight pipe away, all you can do is gain power. You should be able to delete the muffler and be ok, but don't remove the cat that's where all you back pressure is. If you delete that you will have no power if the truck will even run. The problem with a gas truck is they require back pressure to run especially the new ones.
Last edited by RogueSpear2023; Oct 23, 2007 at 09:35 PM.
Freshman User
Joined: Mar 2004
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I guess I don't understand the whole back pressure thing either. I thought back pressure only came into play on 2 stroke motors not 4 strokes. Maybe I'm way off but why do drag cars and roundyround cars run open exhaust if they need back pressure?.
Post Fiend
Joined: Jul 2005
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From: 21791
They have so much exhaust velocity that the size of the actual exhaust pipe is the restriction.
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Postmaster
Joined: Oct 2005
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From: Clarksburg WV
"Back pressure" is a myth.
The engine needs exhaust velocity, not back pressure.
I fail to see how removing the muffler from the stock exhaust will "kill" all your power. It's still the stock exhaust, and the stock muffler sucks.
Considering the number of people I see that cut out their stock muffler for sound, and leave everything else stock, I'm sure you'll be fine.
However- is the truck 5.4's programming anything like the Mustang's was from '05 & up? I know on those things, you have to get a PCM flash and some other crap just to put an exhaust on the thing because it creates a lean condition (kinda like a motorcycle I guess)
The engine needs exhaust velocity, not back pressure.
I fail to see how removing the muffler from the stock exhaust will "kill" all your power. It's still the stock exhaust, and the stock muffler sucks.
Considering the number of people I see that cut out their stock muffler for sound, and leave everything else stock, I'm sure you'll be fine.
However- is the truck 5.4's programming anything like the Mustang's was from '05 & up? I know on those things, you have to get a PCM flash and some other crap just to put an exhaust on the thing because it creates a lean condition (kinda like a motorcycle I guess)
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Joined: Sep 2000
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From: Stephensville WI
A little back pressure is good.
What you do by varying the backpressure is (to an extent) move the powerband of the engine up and down. A less restrictive exhaust system will move your power band up in the RPM range. This also will reduce power in the lower RPMS.
IMO: A cat-back pipe will be fine on a 5.4L V-8. Keep your cat to provide a bit of restriction and you;ll be fine.
What you do by varying the backpressure is (to an extent) move the powerband of the engine up and down. A less restrictive exhaust system will move your power band up in the RPM range. This also will reduce power in the lower RPMS.
IMO: A cat-back pipe will be fine on a 5.4L V-8. Keep your cat to provide a bit of restriction and you;ll be fine.
Junior User
Joined: Mar 2007
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i took my muffler off my 03 250 5.4 and its not to loud it sounds good until about 5k RPM then it kinda high pitched but still ive been running it like that for 3 - 4 months now no problems and as for power i still have power i dont think that back pressure is a issue esp when the cat is still there
Freshman User
Joined: Sep 2007
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Originally Posted by arcatek
i took my muffler off my 03 250 5.4 and its not to loud it sounds good until about 5k RPM then it kinda high pitched but still ive been running it like that for 3 - 4 months now no problems and as for power i still have power i dont think that back pressure is a issue esp when the cat is still there
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Joined: Apr 2004
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From: Georgia
There is a big difference in straight piping and running a cat back. The original post said straight piping. Leaving the Cat will give some backpressure which should run ok but no restriction at all really sucks on a 5.4. I ran mine down the road with nothing but pipes just for the heck of it when I was installing my muffler. It was loud and like Redford said it had no bottom end power. But go ahead and do it if you feel the need. Just don't say I told you so when you hate the outcome.