3" or 2.5" turbo back?

[jdmawd]

Originally posted by Knuckles2.0
well spending 500-800 bucks on an exhaust sounds fun and all but what about building your own 3" exhaust with say a dynaflow at the end... any one have any luck with that ??

Well building your own exhaust sounds fun and all but i have better things to do with my time. Then make some shitty carp exhaust in my backyard, becasue im to ####ing cheap to buy a quality exhaust system. anyone have any luck with that

 

[pickens]

I'm happy with my "crappy" 3in custom press bent cat back. It sounds better than 90% of the dsms I heard around here. I paid about $240 for everything including all the flanges and muffler.

 

[jdmawd]

Should custom and press bent even be used in the same sentence:laugh:. Some things are just worth the cost, a well built exhaust system is on of them.

 

[jbillakdsm]

I've built two exhaust systems for my DSM before I went out and bought a 2.5" RnR turbo-back. I probably spent twice the time, money, and effort trying to save myself the money of buying an exhaust system and I even have access to a machine shop and professional welding services for free. I can't tell you how worth it it is to just buy one that is made by someone who has hundreds of systems under their belt and has every dimesion and turn right. Besides, my entire exhaust with a SS muffler and high flow cat. was 650 shipped. Not bad for an entire turbo-back.

 

[Cirus_93TSI]

what everyone seems to be failing to realize is that a 3" press bent isnt really a 3" exhaust, if its press bent then the 3" pipe will be crushed in every bend, and the interior diameter will only be 3" in the staright sections, u will expirance similar power loss with a press bent to having a 2.5" cat in ur 3" exhaust
thats the whole point of mandrel bending, so that the inside of the pipe is actually 3" in diameter all the way back, if u press bend a 3" pipe it will be about 2.75" in every slight bend, and about 2.5" inside every drastic bend, that means if u have a 3" press bent all u really have is a 2.5" exhaust that gets bigger in the straight sections, and that will mess up the flow of the exhaust, which is y a 2.5" mandrel bent exhaust with a test pipe will out flow a 3" press bent with a test pipe
with that said, unless u have access to a mandrel bender ur not going to be able to build an exhaust worth putting on ur car, try and press bend it urself and u will end up ruining the first pipe u use because u didnt plan out the bends correctly and u will end up crushing the pipe down far too much for it to flow good enough to give u any power, then u try again and end up with a 3" exhaust that is crushed down to 2.5" several times, which is what u will get if u buy a press bent exhaust for a dsm, they dont flow good enough to be worth the money they cost or the time and money it takes to make it urself
all i can say is being cheap makes u slow, spend the money and get a good 3" mandrel bent ehaust from someone who knows how a dsm exhaust should be made, a custom exhaust shop can make u a mandrel bent exhaust, but it wolnt flow as good as a name brand dsm turbo back exhaust, and wolnt cost that much less, what u think is saving u money now is really making u waste money later down the line buying the same part again when ur not happy with the junk u bought for a cheap price

 

[doug]

I've gotten to where I don't even read your posts any more, they're so badly composed. Please put a little more effort into spelling and punctuation.

 

[Sotarts]

Originally posted by Cirus_93TSI
what everyone seems to be failing to realize is that a 3" press bent isnt really a 3" exhaust, if its press bent then the 3" pipe will be crushed in every bend, and the interior diameter will only be 3" in the staright sections, u will expirance similar power loss with a press bent to having a 2.5" cat in ur 3" exhaust
thats the whole point of mandrel bending, so that the inside of the pipe is actually 3" in diameter all the way back, if u press bend a 3" pipe it will be about 2.75" in every slight bend, and about 2.5" inside every drastic bend, that means if u have a 3" press bent all u really have is a 2.5" exhaust that gets bigger in the straight sections, and that will mess up the flow of the exhaust, which is y a 2.5" mandrel bent exhaust with a test pipe will out flow a 3" press bent with a test pipe
with that said, unless u have access to a mandrel bender ur not going to be able to build an exhaust worth putting on ur car, try and press bend it urself and u will end up ruining the first pipe u use because u didnt plan out the bends correctly and u will end up crushing the pipe down far too much for it to flow good enough to give u any power, then u try again and end up with a 3" exhaust that is crushed down to 2.5" several times, which is what u will get if u buy a press bent exhaust for a dsm, they dont flow good enough to be worth the money they cost or the time and money it takes to make it urself
all i can say is being cheap makes u slow, spend the money and get a good 3" mandrel bent ehaust from someone who knows how a dsm exhaust should be made, a custom exhaust shop can make u a mandrel bent exhaust, but it wolnt flow as good as a name brand dsm turbo back exhaust, and wolnt cost that much less, what u think is saving u money now is really making u waste money later down the line buying the same part again when ur not happy with the junk u bought for a cheap price

STFU !!! Everyone knows disadvantages of press-bent system! No one needs to read it for the 89723487234872384723847th time!!!

Go back and read my las post!

I've gotten to where I don't even read your posts any more, they're so badly composed. Please put a little more effort into spelling and punctuation.

Amen.

 

[johnnytsi]

It is actually pretty easy to build mandrel systems in your garage, just order a stick of straight tube and a few 180 degree mandrel bent pieces (www.jcwhitney.com ) Cut each angle you need from the 180, use a tail pipe expander to flare the end of the next piece of pipe. adjust each piece and tack them together with a wire-feed (you can rent them). once you are satisfied with the fit, weld a bead around each joint.

I have built both IC pipes and exhaust system this way. The only down side to this is that my welds aren't very pretty.

This is a cheap, efective way to get a mandrel system , I have even seen flex pieces for sale to build down pipes.

Cheers,
John-

 

[laza101]

2.5" should be plenty unless you're planning on making lots of power (>350hp)...If you're not planning on extensive mods, it wouldn't hurt to have some back-pressure, as this will reduce your chance of getting boost creep (I got crazy creep on a 16g w/2.5" press-bent exhaust, had to enlarge the wastegate) and the car will be more torquey down low.