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LS1 powa!
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Discussion Starter · #1 ·
I'm doing some research and pre-planning and want to know if what I have right now will be sufficient. I currently have the Flowmaster force II cat back, the pipes measure 2.5" OD. Will this be too restrictive, or good to go?
 

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I am also interested what others have done.

I am thinking a Dynomax VT 3 inch single all the way back or 3 inch in a dual 2.5 out. Its a daily driver so max HP is not a issue.

Anybody done either one of these ??
 

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It's a 4. something
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I have true dual 2.5 mandral bend no cats with sanderson shorties and borla pro xs mufflers. It's good but I think a tad large for my stock internal, stock tune 4.8. I wish I would have went 2.25 into a single 3" exit based on what I've seen. I dunno. I'm no expert, that's just my 2 cents
 

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Yeah I am torn between the big single or duals.... both out the same side or one to each side.

I dont carry a spare under the truck so I have plenty of room.
 

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LS1 powa!
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Discussion Starter · #7 ·
I plan to keep it a single outlet, not a big fan of duals. The plan is to have roughly 400 HP and I'm worried that my exhaust will be too small for that.
 

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Bowtie Til I Die
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I have 2.5 with a y to 3" through a HUGE dynomax super Turbo muffler with a 3" outlet where the stock exhaust is...plan to put a cut out on after I build the 6.0
 

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I will be doing 2.5" off of each manifold to a single 3" through some sort of turbo muffler out the factory exit as well.
 

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SOmething i read on ls1 forums . This is information written by someone else take it for what its worth . the replies on the thread was that this right on the money


"Hey guys I just got done reading a good article in the May 2005 issue of Popular Hot Rodding Magazine. The article was written by David Vizard who seems to be one of the most accredited and respected people in the automotive performance world. In the article he stated that CFM is a great way to help develop a zero loss exhaust system. For zero loss a exhaust must flow 2.2 CFM per horsepower(This means less than 1% of total power produced by the engine is lost due to back pressure.). From reading the article I think that a lot of people that see gains when going from a 2.5” exhaust system to a 3” dual system see them because the muffler on the 2.5” system didn’t flow enough for their application. David stated that per square inch of exhaust tubing there is 115 CFM of flow. So plugging some numbers into the good ole TI-89….. ((3.14 * radius^2)*115[*2 for a dual exhaust system])/2.2 = Max hp supported with zero loss

A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…

Now these numbers are assuming that everything else is set up perfectly. The muffler must flow as much as the open pipe or more to get zero loss at the listed hp levels. He also states that using a muffler with a larger inlet/outlet diameter than your exhaust pipe is a great way to get more out of a smaller diameter system since the muffler flow will be able to match the straight pipe flow. Now there are many other things to consider when designing an exhaust system but I figured this would give a great foundation to build on."
 

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true duals 3" with cats an h-pipe and two dynomax 3" vt mufflers
 

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I have shorty headers with a Borla XR-1 muffler on a mostly stock LS1. Not a camaro but this should give you an idea of what that combo sounds.It is relatively quiet at idle and low speed but punch it and it screams appropriately.

?????

Cant hear a thing,that sucker is quiet.:haha:
 
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