mandrel bending allows more flow and reduced backpressure right? isnt a problem for our cars that most cat-backs reduce backpressure which reduces low-end torque? i found a place that does custom mandrel AND crush bending.... would it be better to get a crush bent cat-back and get more flow while keeping back-pressure? tia

when we're nt we need backpressure, when we go turbo, we like the big pipes with free flow

mandrel bent is always better.. period. a 2.5" crush bent pipe wouldn't allow as much power as a 2" mandrel bent pipe.

Mandrel bent exhaust pipes are always better, but press bent pipes are much cheaper. If budget is a problem then go with a larger press bent pipe than you'd normally get if you wanted a mandrel bent pipe.

For example, let's say you wanted a 2.5 inch mandrel bent pipe but it cost too much, then get a 3 inch press bent pipe instead. It's better than nothing. One friend has a 2.5 inch press bent setup from an exhaust shop. It's good quality work, the hangers were welded in perfectly, and it cost something like $300, not bad if you're on a budget, even though mandrel bent piping would have been better.

Remember that there are really 3 types of pipe bending. You have Mandrel, Press bent, and crush bent. Press bent pipe is the most common that muffler shops use, its better than crush bent, but not as good a mandrel. Crush bent pipe has many ripples in the bend, reducing the cross sectional area of the inside pipe, more than press bent.

I'm guessing your non turbo. If this is the case then there really isn't any reason to get new/larger tubing. The only thing our cars will benifit from when we are non turbo is a GST muffler. Which are cheap to buy. Our tubing is just right.

yeah, if you are even considering boosting later down the road, mandrel is the way to go. If not, then any other type of bend will do.

mandrel = same diameter throughout the bend, expensive as hell.
press = pressure put on the center of the bend and the pipe is stretched around a die. thins the walls, and changes(reduces) the diameter of the over all bend, the ends retain the pipe size
crushed = causes the ripples in the inside of the bend on a pipe. if you look at some of the tailpipes coming out of trucks(i.e. chevy silverado, etc) those are crush bent pipes.