No Muffler??
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New User
Joined: Dec 2008
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No Muffler??
We have the V10 6.8L in our '03 Excursion and when we looked at the exhaust wand notice it wasn't welded . So we experimented by unbolting the last half of the exhaust so the cats are still on, and we like the sound better than the flow masters. And we went to radio shack and borrowed their decible meater. It was 98bd under the truck and legal is 92 bd, so as far as loudness goes we shouldn't have any probs for being to loud. So my question is how is the performance affected by having no muffler on the truck and what is it affecting, like horse power, torque, gas milage, and what ever else you can tell me. Thanks!!!
Elder User
Joined: May 2003
Posts: 818
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From: Mobile, AL
I am currently running with cats only on my 08. You will lose some torque because the engine is not tuned for the lack of backpressure. My MPG on highway improved, but in town MPG got worse. I intend to go back to Flowmaster with either a 40 or Super 44 after the first of the year.
Elder User
Joined: Mar 2005
Posts: 549
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From: chicago burbs
did that on my 2000 150 woth 4.6 lost 4mpg not sure on actual power with the exhaust and a k&n filter chirped tires going into 2ed in my auto.
was able to pull in front of coworkers import cars not that, that is hard
mpg may depend on how much you like to hear it.
was able to pull in front of coworkers import cars not that, that is hard
mpg may depend on how much you like to hear it.
Post Fiend
Joined: Jan 2007
Posts: 7,021
Likes: 4
From: Almost Heaven
I lost low end torque when I took the muffler off my 300. This might not bother you so much since you have a V10. Beast.
Why don't you look into the Cherry Bomb Extreme? It's a very small single chambered muffler. This might save you a little more backpreasure but still keep it loud.
By the way, scavenging is what gives you the most power, not backpreasure. But because you have cats on your truck it really doesn't matter. The best thing you can do is run correct sized pipe post cat. This in theory would inprove scavenging and help in both HP and TQ. Not sure how much though with both cats (don't you have four?).
Why don't you look into the Cherry Bomb Extreme? It's a very small single chambered muffler. This might save you a little more backpreasure but still keep it loud.
By the way, scavenging is what gives you the most power, not backpreasure. But because you have cats on your truck it really doesn't matter. The best thing you can do is run correct sized pipe post cat. This in theory would inprove scavenging and help in both HP and TQ. Not sure how much though with both cats (don't you have four?).
Elder User
Joined: May 2003
Posts: 818
Likes: 0
From: Mobile, AL
By the way, scavenging is what gives you the most power, not backpreasure. But because you have cats on your truck it really doesn't matter. The best thing you can do is run correct sized pipe post cat. This in theory would inprove scavenging and help in both HP and TQ. Not sure how much though with both cats (don't you have four?).
After writing this I found this...
http://www.zoomersexhaust.com/zoomers_technology.asp
Post Fiend
Joined: Jan 2007
Posts: 7,021
Likes: 4
From: Almost Heaven
I think I only have 2, my trucks at home I'll check tomorrow. After researching the scavenging effect it seems as though a 15" section of 2.5" pipe added to the end of my 3" would assist in scavenging. Additionally, wouldn't the addition if a forward facing scoop just before the rear facing tip create a venturi effect alowing for even greater scavenging? This configuration being with out a muffler obviously.
People will debate me on this. I'm not saying this is Exhaust Bible but it's the closest thing to an actual calculation I have come up with.
My personal exhaust system; EFI manifolds running into gutted cat into a baffled muffler with 2.50'' piping. Basically it's a mess. It does sound good at least.
Ideally, you want your manifolds to run into straight pipe the correct size. Like I said though it doesn't matter that much since you have cats. Your manifolds ought to take care of the scavenging. Just put a muffler on it you like the sound of.
Ps. I don't understand what you mean about the scoop. Could you please clarify?
Post Fiend
Joined: Jan 2007
Posts: 7,021
Likes: 4
From: Almost Heaven
Bump. I think you edited your post as I replied.
Zoomers Exhaust Works - Performance Exhaust Systems, Exhaust Tips, and Cat-backs
Dunno about this. I like to keep things simple. I would rather play it safe and use a thrush glass pack.
By the way, I've thought of glass pack type spools to help impove scavenging. Looks like someone already thought of it.
Zoomers Exhaust Works - Performance Exhaust Systems, Exhaust Tips, and Cat-backs
Dunno about this. I like to keep things simple. I would rather play it safe and use a thrush glass pack.
By the way, I've thought of glass pack type spools to help impove scavenging. Looks like someone already thought of it.
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Elder User
Joined: May 2003
Posts: 818
Likes: 0
From: Mobile, AL
We use eductors for dewatering on the boat, and one of the hazards is if no water is being drawn in, the eductor will suck all of the air out of the space. I figgured if this worked for water, it should work for air. My search was for venturi exhaust and Zoomers is what I found. Should be able to gain the tone and power I want with only some 2.5" pipe and a slight mod to my tip. But If I decide to go all the way with it I may look in to this company. The theory is sound, based on areodynamics compared to hydrodynamics.
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