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(NEED ADVICE) New Exhaust setup UPDATED


08292014, 04:38 AM  #45 
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Thank you I see it more clearly now.
Right now all I have is a Vibrant Ultra Quiet, a glasspack, and a Remus muffler. Since I added the Vibrant it's at the perfect tone for me now (not too loud, not too quiet) and minimal drone. The only problem is that it barely fit under the car, sits about 2 inches lower than the belly of the car, I scraped on a speed bump today . I have to find a new spot for it soon, but its something I had to do, it was the quietest thing around.
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08292014, 02:41 PM  #46  
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It's your car, your money, and ultimately your decision. Just know you're wrong. 

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08292014, 04:59 PM  #47  
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08292014, 05:42 PM  #48  
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I recall a member criticizing you for your intake dyno comparison before it was done. He went from mildly flaming you to later donating his intake for your cause, which has been a HUGE help to a lot of forum members who consider different intake options. So let's put the arguments aside and try to help each other out here. Everyone is entitled to their own opinion, even if they're completely blind to the facts. I'm not taking sides here, but do your best to help people out with information. What they do after that is their decision, no need to get upset about it. Moving back to topic, keep us updated on how the exhaust turns out! 

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08292014, 06:11 PM  #49  
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08292014, 08:48 PM  #50 
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Found this site with some good basic information on exhaust pipe sizing.
http://www.exhaustvideos.com/faq/how...pipediameter/ Here's the table from the site. Of course these numbers are just estimates, but still some useful info. I am really interested in finding what the best option would be for our cars. Not just for one setup, but say finding the right diameter depending on each set of mods or combination of mods to help out the diversely modded community. Of course there are infinite combinations, but these are the ones I think are most common. (Muffler deletes can be considered as "aftermarket muffler" in my descriptions) 1.) Stock headers + stock secondary cats + stock resonator + stock muffler (STOCK /// Examples: 90% of 3series vehicles ) 2.) Stock headers + stock secondary cats + NO resonator + aftermarket muffler (AFTERMARKET MUFFLER WITH RESONATOR DELETE /// Examples: BMW PE, magnaflow etc.) 3.) Stock headers + high flow secondary cats + NO resonator + aftermarket muffler (AFTERMARKET HIGH FLOW SECOND CAT EXHAUST /// Examples: Supersprint high flow catted midpipes, Afe high flow catted midpipes, etc.) 4.) Stock headers + NO secondary cats + NO resonator + aftermarket muffler (AFTERMARKET STRAIGHT PIPE TO MUFFLER /// Examples: BMW PE w/ second cat delete, supersprint catless midpipes, AFE catless midpipes, etc.) 5.) High flow catted headers + high flow secondary cats + NO resonator + aftermarket muffler (AFTERMARKET HIGH FLOW CATTED HEADERS WITH HIGH FLOW SECONDARY CATS /// Examples: AFE high flow catted headers paired with AFE or supersprint high flow catted midpipes, etc.) 6.) High flow catted headers + NO secondary cats + NO resonator + aftermarket muffler (AFTERMARKET HIGH FLOW CATTED HEADERS WITH STRAIGHT PIPE TO MUFFLER /// Examples: AFE high flow catted headers paired with AFE or supersprint catless midpipes, etc.) 7.) Catless headers + high flow secondary cats + NO resonator + aftermarket muffler (AFTERMARKET CATLESS HEADERS WITH HIGH FLOW SECONDARY CATS /// Examples: Supersprint headers, AFE headers, Because racecar! 8.) Catless headers + NO secondary cats + NO resonator + aftermarket muffler (FULL ON CATLESS STRIGHT PIPE TO MUFFLER /// Examples: Supersprint catless headers, AFE catless headers, paired with AFE or supersprint catless midpipes or second cat delete etc.) These combinations are the main ones I thought of. Since there may not be enough of a difference in exhaust flow in options 24, those 3 options can be grouped under one size piping, 56 under a second size, 7 under a third size, and 8 is an animal of its own of course. Lets find the perfect size hole for our cars! 
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08302014, 03:41 AM  #51  
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08302014, 01:08 PM  #52 
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I actually used that dyno on a similar discussion a while back, I lost the source and the actual follow up dyno on the exhaust. If OP wants to be ignorant (and make no mistake, he/she is) I'll let them. For instance the exhaust manifolds secondaries are around or under 2" diameter, but he's going to mate them to 2.5" pipes per bank Which is a greater cross sectional area than a single 3" pipe. If you want to lose velocity and power, that's the perfect way to do it.
Anyhow, that chart is meaningless because it doesn't match up with reality  http://forums.vwvortex.com/showthrea...tbacktoback VR6 2.5 vs 3.0 exhaust http://forums.clubrsx.com/showthread.php?t=583274 Bolt on RSX S (2.0 4cyl) dyno 2.5" vs 3" 
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08302014, 03:14 PM  #53 
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Yea, Amini77, you have to realize what TheAxiom is suggesting is ONE 3 inch pipe going all the way back. You're doing TWO 2.5 inch pipes which is more surface area, as he said.
So upping the sizing a small amount on a dual set up can increase surface area a lot more than upping sizing the same amount on a single setup since the same amount of gas is passing through the pipes in both situations. Lets do the math and see. Let Rd be radius of pipe for "dual" exhaust piping setup. Let Sd be the surface area of pipe for "dual" exhaust setup. (*NOTE: We have to multiple Sd by 2 when we get the answer for one pipe, because there are two pipes.) Let Rs be radius of pipe for "single" exhaust piping setup. Let Ss be the surface area of pipe for "single" exhaust piping setup. So the radius of a 2.5 inch diameter pipe = 2.5/2 => 1.25 = Rd And the radius of a 3.0 inch diameter pipe = 3/2 => 1.5 = Rs Equation for dual 2.5 inch setup: Surface area, S = pi(R)^2 => 3.14(Rd)^2 => 3.14(1.25)^2 => 4.91 = Sd (*From NOTE) Sd*2 => 4.91*2 => 9.82 cubic inches = Sd total for both pipes in dual setup Equation for single 3.0 inch setup: Surface area, S = pi(R)^2 => 3.14(Rs)^2 => 3.14(1.5)^2 => 7.07 = Ss 7.07 cubic inches = Ss total for pipe in single setup From the results, you can see that there is less surface area in the single 3 inch pipe than there is with dual 2.5 inch pipes. In other words, single 3 inch piping is actually "smaller" than two 2.5 inch pipes. So Amini77, when you say that 3 inch piping is "too large", you are mistaken. UNLESS, you misunderstood that TheAxiom was telling you to go with two 3 inch pipes. That in fact would be too large! How relevant are those graphs to our cars considering the different engines? 
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08312014, 05:51 AM  #55  
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Dual piping>Resonator(inlet 2, outlet 1)>Single pipe for the rest of the exhaust. He's talking about the entire exhaust being 3 inches all around. And I'm saying 2.5 inches all around. Basically half the midpipe is dual pipes and the other half is a single pipe.
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08312014, 05:53 AM  #56 
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Nothing wrong with that lol
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09012014, 04:50 PM  #57  
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