I recently talked to my freind about my 97 accord ex and he thought i shouldnt buy headers rather he said bore out the catcher(dunno if thats the right terminolgy). i also thought maybe just keep keep my stock manifold and buying a high flow cat converter. Which way is most approbiate for my sitiuation. And Do those high flow cats work good.?

 

5th gen EX headers are as good as they get. I think you mean port matching, ie making sure the header is properly matched to the size of the exhaust outlets. You could do it, but it'd be a lot of money for nothing, really.

I wouldnt get aftermarket header for a 5th gen EX at all.

 

take your cat off. take a big pipe, and a big hammer... drive the pipe through the cat. put the cat back on.

as cheap as freeing up power can get... because its free. (not sure if you can do this since your car is obd2)

 

i dont beleive that pounding out a cat is gonna make much power sicne it seems to me it would cause real turbulence and poorer flow....

 

and a cat restricts things...

 

IMO the best "bang for the buck" when it comes to power is getting your throttle body bored out for $100 http://www.maxbore.com and I am sure you would see great throttle response, higher flow of air and a bigger inlet into the intake manifold.

https://honda-tech.com/zerothread?id=771875 <==more info

Basically when it comes down to exhaust side of things the ex header flows the best even out of most cheaper header brands. Exhaust will run you a little more (300-500) for a decent cat back w/mandrel bends....but once you open up what the engine receives you typically see better results.

 

I don't where the myth got started about the EX exhaust manifold but I've seen dyno sheets where even a DC header will give a 2-4hp improvement over a stock EX 4-2-1 manifold...

The DC freed up alot of mid & upper range power as well...

The EX manifold is decent but not good by any means...

Any lesser priced header brands will probbaly be comparable... but the DC is NOT all that bad and better than alot of the lower priced headers out there... Pacesetter for example...which is pure ****...

 

Take TOAB's advice, big pipe and hammer. I did that and it seemed to help some with my cat-back bolted on... I've been researching this for a while to figure out what to do in my situation and I'll be cutting off the collector pipe and welding a 2.5" pipe from it straight to my exhaust (might use flexpipe also) Then I will be ordering the O2 sensor simulator (for the obdII) from kteller or ebay or wherever I can find it for the cheapest. You just have to find a shop that will do an illegal mod like that.
From what I've seen, DC headers do not make a difference for the EX and I've seen and heard of many DC's tending to crack. dc gets a from me
Good luck, hope this helps a little.

 

Or buy my stainless resonator with 02 bung welded in. direct fit.