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Ok, so its probably a little late for this topic since I already purchased the TRD exhaust (Got it for $320 on eBay, BTW), regardless, here goes nothing. I measured the diameter on the TRD exhaust tubing and it is 2.5". I have looked around on the 'net and most of the catback systems are 2.5" as well. So my question is, why are they any better? I am assuming that since the tubing on the TRD portion of the exhaust is 2.5", that the cat to axle portion is 2.5" too?
 

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Originally posted by TrueRedtC@Oct 13 2005, 08:09 PM
right... I guess I am asking what is the point of purchasing the whole thing if it uses the same diameter pipe as stock?
the reason is because most stock exhaust piping on cars has unneccessary bends in it which rob horsepower during exhaust..although some, not all, cat-back exhausts use the same diameter piping as stock, but the difference is the piping itself..take a look under ur car if u can and look at the stock piping and then compare it to a picture of a full catback exhaust and youll get what im saying..most likely the catback exhaust will have less bends in it and it looks prettier too haha..with more straight forward design piping it causes less back pressure..but like courier11sec said, bigger isnt always better..meaning that some back pressure is needed in the exhaust or that to can cause loss of horsepower..
 

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a lot of the time the factory system uses cheaper "crinkle bends" (the inside of the curves on the pipe has a wavy section on it) the inside of the pipe is not smooth around the curves and doesn't let air go as efficiently. most aftermarket system use mandrel bending which keeps the pipe the same size and smooth the whole way
 

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BS. The factory bends are all mandrel bent. It's cheaper in volume to do it that way anyway.

The biggest gains to be make are simply because the cat is gone. I have yet to see a significant power loss from a few turns. If that were the case, cylinder head ports would not be the curved things they are, they'd figure out a better configuration to get a completely straight shot. They don't.

It never ceases to amaze me how much magazine horsepower is out there. It's a lot like stickers. Magazines said it made more power on the dyno so it must be good. What a crock.
 

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Great pic! And what does CC say about the hp improvement?

How could that be with all those power robbing bends in the pipe? Sorry, I'm being sarcastic, but this whole thing about straight being better is so overblown (sic) it isn't even funny.
 

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ok, my bad. i heard somewhere that the tc muffler is supposed to "open up" or something for more power at the higher rpms. any truth to that?
 

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Stock muffler does have a valve on a spring, that's why all these aftermarket "free-flowing" mufflers don't really do anything besides make noise.
 

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Originally posted by lo bux racer@Oct 14 2005, 07:47 PM
Great pic! And what does CC say about the hp improvement?

How could that be with all those power robbing bends in the pipe? Sorry, I'm being sarcastic, but this whole thing about straight being better is so overblown (sic) it isn't even funny.
I know you're joking, but I'll answer anyway.

CC has a dyno showing 12HP gains. SOmeobody here has a dyno showing 3-5HP gains.
 

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i would like to get in on this as well. i am looking at axle backs at the moment mainly i want a little something and don't have the cash for a full cat back and frankly don't see the point. i want to keep my cat because i HATE ricey sounding exhausts. i may loose the resonator at some point but who knows. Then again ONLY if it will make some type of power gain. ANy is more than none. please forgive the ignorance but wouldn't a less restrictive muffler over all the garbage that goes on inside the factory muffler one make some sort of gain other the db level?

edit: here is a link i found with dyno runs with 2 axle back systems. i would think it is safe to assume this will be an average gain for any axle back system. input?
 

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Originally posted by C!ph3r@Oct 24 2005, 10:55 PM
i would like to get in on this as well. i am looking at axle backs at the moment mainly i want a little something and don't have the cash for a full cat back and frankly don't see the point. i want to keep my cat because i HATE ricey sounding exhausts. i may loose the resonator at some point but who knows. Then again ONLY if it will make some type of power gain. ANy is more than none. please forgive the ignorance but wouldn't a less restrictive muffler over all the garbage that goes on inside the factory muffler one make some sort of gain other the db level?

edit: here is a link i found with dyno runs with 2 axle back systems. i would think it is safe to assume this will be an average gain for any axle back system. input?
A) no link
B) cat-back means after the cat, so you do not lose any catalysts.

-Ed
 

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OPPS. =) here is the LINKAGE

Yeah i know what a cat back exhaust is. I am just wondering are there really going to be that significant of gains to be had from a cat back versus an axle back? Every one talks about how great the piping is and outside of the lack of the resonator i don't see how that much more power is to be gained from a cat back system over an axle back. From the cut away images i have seen of the stock muffler this seems to be the most restrictive part next to the cats. i could be wrong and if i am i definitely want to be corrected. Thanks for the help guys.
 
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