Is 2.5" necessary? 2.5 vs 2 and 1/4

[Sidewinder]

I was just wondering if the larger size exhaust piping will actually make a huge difference in performance, especially later on with mods like ported intake and possibly headers.

I ask because I have a perfectly good dual exhaust system from a Monte Carlo Z34 I want to install, and I was wondering if I would even need to upgrade after that. I plan on getting a new downpipe made, along with removing the resonator. Eventually I want to get a high flow cat and two magnaflow mufflers as well.

This is off a 95 Z34, pretty sure its 2 and 1/4.

[sharkey]

sint the dual exaust just axle back??? if its dual 2 1/4, there then thats plenty. id run single 2 1/2" from the manifold to were it splits and it should be plenty big enough. i run a dual 2" headers back on my car and have no lack of flow

[SappySE107]

It splits in the rear. Get a mandrel bent exhaust if you want performance. I prefer the resonator as it mellows the exhaust out. 2.5 to the split and 2.25 after that is fine. I went as far as making it single exhaust. I like the exhaust even better through one muffler.

[Sidewinder]

Yeah sorry, it isn't a true dual exhaust, its a single split at the rear. I ask because at the moment I can't afford to get an exhaust done, so I was wondering if modifying the exhaust I have would be worth it. Otherwise I'm just going to get it put on with a new downpipe for now. I wanted to remove the resonator as well because I hear its a huge restriction. I guess it all depends on cost.

[IsaacHayes]

Resonator causes turbulance, much like how a flowmaster works. I go with straight through stuff for maximum flow. Without the resonator and my ultraflo muffler, the tone is fine. It actually sounds better with out the resonator on my setup than when I had it on. Hearing it bounce off K-rail's accelerating on the highway it sounds less raspy without the resonator. Go figure. It didn't get much louder but seems more even of a tone.

[Sidewinder]

Ok, well then I guess I will at least save money for a full exhaust system to go with headers when I eventually get them (I hope).

For now I think I will get them to install the (fake) dual exhaust and get them to axe the resonator. Thanks for the help