I have done some searching and can't decide if there is really any reason to buy an aftermarket header on my AUTO 97 vtec Accord wagon? The stock exhaust manifold (some say) is supposed to be very well designed and powerful & strong enough to both provide good airflow as well as handling minor engine upgrades. I dont plan on turbo or anything big engine-wise anytime soon and my ride is a DD, but I would like a better cat-back exhaust and new/hi-flow cat. So if a header is say, $200-$350...will there be a significant enough improvement in sound and flow to justify slapping it on while I do a full custom exhaust, or should I spend the $$$ on other things??? Thanks!!!

 

Its really not worth it for a header.. Theres really no point in a high flow cat as most are pretty efficent and only produse 1 to 2 psi of back pressure (unless its cloged).. 2.5 exhaust will flow pretty nice.

 

OK, thanks. Kinda what I was thinking. I was thinking of a 2.25 catback, just cause its automatic and isnt due to see huge mods, BUT would it be better to get a 2.5? I want a very quiet, subtle sound...does the diameter of pipe matter, or just the muffler/ resonator? Is it cheaper to have it custom built or just buy ready-made catback? Thanks again.

 

I've got a 97 f22b2 and when I had my header I definitely noticed a difference, especially at the top end.

If you don't plan on going FI I would say go for it. Megan head would do you nicely, just stay away from OBX.

 

The F and H headers are very efficent and Im sure most of the diffrence was in your mind. I would just get a custom one made F series move alot of air and would benifit from the 2.5 over the 2.25. If you want a very nice deep tone run 2 mufflers or 1 nice resonator... I have run a 2.5 magna flow round muffler after the cat then a oval muffler by the rear bumper. It sounded so deep and was very quite..

 

^ I don't know that this guy is talking about.

An aftermarket is different from a factory manifold. With a header you'll slightly lose some low end torque but the upper power band becomes very smooth and improved. This will become even more apparent since you have vtec.

As far as exhaust, you really should max out at 2.25" on a naturally aspirated motor. 2.5 is really only necessary when going either massive motor build or forced induction. Hondas need backpressure which is another reason why you want to stick with the 2.25 exhaust at max. As far as a high flow cat, I would not waste your money. As another has said, they will only increase hp by 2-3 hp or so. When my cat becomes clogged or restricted i'll simply put on a test pipe.

If I were you and you have a very small budget this is how you should go:
Buy a no name $40 intake off ebay, throw away the filter and put a AEM or K&N on. Then, get a header - no names runs like $60 and Megan run like $120. Finally, for exhaust - get a cheap $99 stainless steel ebay exhaust, cut off the fart can, and have the muffler of your choice welded on.

Total cost would run about $400 or so.

 

Actually the headers are measured in Flow not because it has a smoother turns.. The stock (H and F series) Headers flow very nice and an aftermarket header will not out flow a oem header.. 2.5 will be fine for a F22 once again because the head Flows so well, H22's were seeing a 15whp increase from a 3 inch exhaust on N/a set ups with dyno graphs not just word of mouth.

I wouldnt buy a ebay exhaust, you can cut the muffler off and then cut it up into a bunch of sections and have it re welded as 90% of ebay exhaust dont fit correctly... or just get one made at an exhaust shop. Just get a magnaflow or vibrant muffler they sound pretty good.

 

The main factor in a header is getting the primary tubes to be of equal length.

I am not sure if you have had first hand experience with an aftermarket header for an F series header but an aftermarket header WILL provide more hp then the stock manifold. Simple. I've went from oem to aftermarket header and back to stock and have noticed a massive difference each time in both powerbands.

Finally, no way in hell is a 3 inch exhaust on an F series going to gain 15hp. That is beyond ridiculous.......I suppose you believe the $10 chips and Tornados work as well. Seriously, judging by your hilarious hp claims for either an F or H series simply by an exhaust upgrade I doubt you know what you are talking about.

With my original I/H/E upgrades (AEM sri, OBX header, Apexi WS2 catback) I probably gained a modest 10 hp on the high side but the upper powerband became AMAZINGLY smooth.


To HSP, listen to my advice and you'll be happy. I've got actual experience with a nearly identical vehicle. However, follow the price list I gave you - If I could have gone back I would have done that instead. Paying premiums for name brands is stupid when you can save quite a bit of money by using generic piping.

 

Awesome, thanks guys for all the differing advice, I love to get more than one perspective. I have so much more knowledge to base my build on now thanks to you !!! I'll prolly keep stock manifold for now, and maybe get Megan header some time later. I will keep it at 2.25 I think and get a really nice muffler. I want it QUIET, so do I get more than just a muffler, like resonator or whatever before the muffler? Or will a certain, particular muffler "muffle" the sound like I want? Magnaflow and Borla are all I have experience with... diff cars. MORE OPINIONS PLEASE! tyvm

 

Accord if you would of read what I said.. H22's were seeing those kind of gains google it. I have been building Hondas for I've 10 years and have a dyno that my bud own so I have seen what works and what does not. Headers are a waste of money and will not net you anything noticeable. I would be leave your claims if you had something to back it up other then a butt dyno.

 

LMAO...butt dyno...

 

So let me get this straight (besides bringing up H series which has nothing to do with an Accord), you say in a post "both F and H series manifolds are very efficient". Yet, you claim 15hp increase by replacing an already efficient manifold? Wooooow....that is hilarious! Or an exhaust? Seriously....if you really have been building Hondas for 10 years why are you referring to Google so much? Quite interesting....... So if a 3 inch exhausts creates 15 magical horsepower I suppose no exhaust would create 50!

HST - Seriously, this guy has no idea what he is talking about. 15hp from a header is ludacris on an H series motor. He is simply reading the false claims on eBay auctions. He thinks an oem manifold will outflow an aftermarket - FALSE. The hp gains from an exhaust, intake, and header are NOT created. They are FREED by removing RESTRICTION. HOWEVER, Hondas need a certain amount of backpressure or else you will do the opposite you are trying to achieve.

You've got 145hp from the factory and I was at 130 (f22b2). There is no need in spending a ton of money on some stupid custom header....letalone putting it on a dyno. Use the search feature and you'll see TRUE claims as to what hp can be achieved from I/H/E setups. Not some made up buddys customer header with a dyno story. Im not going to keep repeating myself so ill say it one last time - you will see a gain with the mods that I mentioned which will roughly equate to 10hp on the high side combined. The only other option for hp gain are going to be far more expensive and will not work well with a weak component (auto tranny).


Do it, be done, be happy, and enjoy the difference!