I am ready to order exhuast of my 93 hatch with a b16 and greddy kit

Now its going to be mandrel bent, no cat no resonator.

Is going 3 inch going to make a change?

 

There was a great article from a Garrett Engineer on here once....and he discussed the diameter of exhaust systems. The question is how much HP are you trying to gain....target HP? 2.5" is effective till 250HP and above that 3" is what you should install. If you decide to go with 3" for HP under 250 and all you get is more noise...you main gain HP up top....but its up to you...... Alot of people state that the larger is better...essentially yes, but not on a low HP vehicle....you sacrifice low end.....well this logic is only based on the Garrett Engineers facts....another option can be the E-Cutout which cheesefrog did on his B18 power EK. The idea is stock exhaust system welded to a 3" downpipe....and at a flip of a switch you run open downpipe......

 

i figure i will be at 10 psi. prolly under 250hp but I am hoping for like 230,

Maybe, I'll just go with the 3 inch for future upgrades

 

I'd go with a 3" system, especially if upgrades are a possiblity in the future.

 

how about 2.75" ??

 

https://honda-tech.com/zerothread?id=414433

 

3 inch