2.25" Or 2.5"

[Newcivic]

Ok need some help here guys, don't know much about these kinda things so need some advice.

1. Im buying an exhaust system for my civic and i think (correct me if i'm wrong) the pipping for it for a catback system should be 2.25" ?

But the exhaust i want to buy comes with a 2.5" Pipping straight through.

And the question i want to ask is what is the differnce if i get a 2.25 and a 2.5 .. Do i lose any power at all? Or anything

Thanks in advance! :D

[Zdster]

Stock exhaust piping on all civics if I am not mistaken is 2.25. In regards to your other questions I did see a post a while ago on a similar topic. Try searching the 'technical' forum.

[lloydbanks]

Yep, 2.25 is the way to go... 2.5 will result in a slight loss in torque. It's like a garden hose. If it was really fat, there'd be no pressure at all, & it would just dribble out... At least, that's what I was told when I bought my exhaust. Plus, I bought a 2.25, & I was VERY impressed with the results :thumbsup:

[Terry]

If is SOHC.......2" ...2.25"....and 2.5" are much about the same..........i suggest to save some $$ to get header:D

[XOXO]

2" or 2.25" is best. I think 2.5" is too big for a Civic. Stock civic pipe is 2" from cat to resonator and 1.75" from resonator to muffler.

[iceman_vti]

lol damn u XOXO thats what i was gonna say.. i've got a 2.5" on my civic... sounds good, and awesome performance while quick shifting.. i notice the car doesnt lurch when i pop in the clutch

[tRipitaka]

Stock exhaust piping on all civics if I am not mistaken is 2.25. In regards to your other questions I did see a post a while ago on a similar topic. Try searching the 'technical' forum.

stock is something like 1.8" or so..

2.25 will give you good all-round performance through the rev range..
2.5 will give you better high range performance, sacrificing low end..
but think about it, if ur using it as a daily driver, how often do u go to high revs ?

[lloydbanks]

if ur using it as a daily driver, how often do u go to high revs?

Um, as often as I can... :rolleyes:

[Tu88y]

2 1/4 for a civic is good for daily driving...

2 1/2 for top end...

Its all depending on what you want to do

[lloydbanks]

Do i lose any power at all? Or anything

I think everyone agrees so far, that "yes", with a 2.5 you'll lose a little power down low...

[_CiVIC_]

2.25inches bro!! i made the mistake of putting 2.5 before and it felt like a slug... to think that only 0.25inches made such a big difference.. woaah now im back to my original 1.8inch piping, running much better than 2.5..

[Setanta]

2 1/4 MAX! A full mandrel bent 2inch system would actually be better for a SOHC to maintain a good all-round result. 2 1/2 on a SOHC is a complete and utter waste.

Put it this way - my DOHC B16A SiR will not be getting more than a 2 1/4 Mandrel bent system, as it came with a 2 1/8 inch system standard. I want the car drivable but with better gas movement (OEM is pipe bent not mandrel). Having run more than a few modified NA cars over the years, I know that overdoing the size is a waste and can adversely affect the drivability. It's about the gas flow, not about size

[Newcivic]

Great guys thanks for that ! i think im going to custom a 2.25" pipe because the exhaust system that i'm getting they dont make 2.25" :( They only make 2.5" . And yep if you guys say its better on the bottom end then that's what i need it for :D Thanks alot for the help ..

Another question if i were to have like say a VTi-R engine or Type R .. would i be looking at 2.25 still or 2.5?

[sivic]

its for a cxi right? go 2". on this engine the 2.25" prob wont give you anymore gains than a 2", maybe just before redline but thats it. and you said you want bottom end power. 2.25 will give you less in that range than a 2".
on a D16A8/ZC which is DOHC and develops more power up high a 2.25 still only makes marginal gains just before redline over a 2" system

[jimmeh]

2.25in is perfect cos if u look at all the big names that make honda exhaust spoon,mugen,5zigen and buddy club all make 2.25in

[Chi]

2" or 2.25

Stay away from 2.5

[Setanta]

2.25in is perfect cos if u look at all the big names that make honda exhaust spoon,mugen,5zigen and buddy club all make 2.25in


And they make them for B series motors, not the D series that comes in a CXi or Vti.

Applying intelligence over mag-racing is possibly the better way to go hmmm?

[bennjamin]

just slap on a 2inch cat-back exhaust system and be happy.

I have had a 2.25 inch cat back system on my stock ZC/d16a8 (1.6)- and i can say even on a 1.8 or maybe 2l 2.25 is possibly too big.

[ekslut]

It all depends on what engine you have, but when I was looking at japanese branded exhausts, I found most of them were a bit under 2.5" (All about 60.5cm).

But on most cars I think 2.25" is enough, its only when start making more power I think there would be a need for 2.5".

[sivic]

yeah all the big names use 60mm piping (between 2.25 and 2.5) because as Setanta said they are all made for b series. d series doesnt even get a look in japan. so you cant say, oh they big names use this it must be the best. its the best for the intended application which is not a d series.
but anyway, you said you wanted low to mid range. in that case 2" is perfect. it will be superior to 2.25 all the way through the range except for MAYBE just before redline
2.5" is just silly for a d unless its turbo

[pgclee]

if your car is kinda STandard, go for 2.25"...no point to go 2.5"....Vtec is abt flow...

[blu3illusion84]

aww.. crap wat rong wif 2.5... geez wat am i guna do now.. i just order Cannon catback muffler from oversea.. is 2.5 manrel bend.~ omg!! ish dat bad? HELP!!!