I know the differences between the two but is one worse than the other? Is it absolutely necessary to have the same width piping all throughout or is the minor restrictions caused by crush bending the pipe bad on a high compression motor? Your thoughts are greatly appreciated.

 

Honestly ive had both and i cannot really tell the extreme differences with crush bent or mandrel bent piping.
But ive never used any resonators or cats either.

 

Since pressure bending a tube deforms the metal, the inner dimension of the tube is reduced. A mandrel bent tube maintains the same inner dimension throughout the curve so it flows better than its pressure bent equivalent. The differences between the two become significant in a turbocharged application where you want as little back pressure as possible to spool up the turbo quickly. For normally aspirated engines, I would just save the cost of mandrel bends and go slightly bigger on the tubing diameter to make up for the pressure bending.

 

Okay, from what I have heard the exhaust for a GSR or ITR motor is stock ~2.5 inches, but in actuality it is about 2.3 inches. Therefore, if I put real 2.5 inch piping, I should be okay at the points where it is crush bent? Or does the 2.5inch piping need to be larger?

 

IMO, custom build it. order mandrel bend piping, make a temeplate, take it to a muffler shop and ask them to weld it for u. pretty cheap that way. thats how i did mine from my DP back. put a 2.5 flex with 2.5 all the way back.

 

well rule of thumb....gases that escape, escape with less turbulence when diameter is constant......any difference in diameter CAN result in slower escape and including crushes or irregularities can also hinder the speed of the gases escaping....so technically it does matter but to what extent depends on each situation......so basically i have solved nothing for you.....sweet

 

Where do you order mandrel bent piping? Are you referrring to someplace like Jegs, where they can get you the pieces for the project, probably about 10-15 different pieces, and then you have to weld it together? Or is the system coming from a shop, like it would if you ordered a Greddy Evo2 from Greddy, 3 different pieces.

 

http://www.kteller.com
just buy one of the piping kits and your choice of muffler
also a resonator wouldnt be to bad of an idea either