2 1/4 or 2 1/2?

[1PhatCX]

just wondering whats better, 2 1/4 inch exhaust or 2 1/2 inch exhaust for a ZC? i wanna help it breath a bit better and flow better too and i can get a good deal on exhaust right now so whats better?

[d16a6crx]

For N/A, you want backpressure. I would go 2" or 2 1/4"

[badboyzkustumz]

as long as you dont plan on putting a turbo or nething on there the largest u should go is 2 1/4, thats what i have on mine and it makes a huge difference over the stock.

[1990civicdxhb]

2 1/4 u need that backpressure---

[91civicDXdude]

please stop spreading misinformation.

you do not EVER need back pressure. BACK PRESSURE IS BAD ALWAYS. 100% of the time. not 50% of the time, 10% of the time, 99% of the time. BACK PRESSURE IS BAD AND YOU DO NOT WANT IT.

please learn what the hell you're talking about before you go spouting off some bullshit that redneck bob told you about his camaro mufflers.

1phatcx: to answer your question, i would go with a 2.25" mandrel bent exhaust, and if you cant get that, then 2.25 crush bent

[BigBearWest]

you man i got a DOHC ZC with 2.5 piping and it work well. i am planing to turbo it this winter. i say get 2.5

[SiZ]

2.25!!!

D series WAHHHHH!

[1PhatCX]

sounds like 2.25 it is i can get a 10 foot straight length of pipe for 24 bucks and those mandrel bent u pipes like JC whitney sells for 25 bux hehe cheap free flowing exhaust here i come!

I'm gonna turbo my car but have no money currently, and hell, its only like 50 - 60 bucks i'm spending so i figure why not? same price for the 2.5 as well, maybe a buck or 2 more tho no biggie

[91civicDXdude]

if you're going to turbo it in the future, put atleast a 2.5"

[d16a6crx]

Originally Posted by 91civicDXdude

please stop spreading misinformation.

you do not EVER need back pressure. BACK PRESSURE IS BAD ALWAYS. 100% of the time. not 50% of the time, 10% of the time, 99% of the time. BACK PRESSURE IS BAD AND YOU DO NOT WANT IT.

please learn what the hell you're talking about before you go spouting off some bullshit that redneck bob told you about his camaro mufflers.

1phatcx: to answer your question, i would go with a 2.25" mandrel bent exhaust, and if you cant get that, then 2.25 crush bent

You say you dont need backpressure, but then agree with the size of piping? Backpressure is needed for n/a power.

[civicwithawankel]

[quote=91civicDXdude]
"you do not EVER need back pressure. BACK PRESSURE IS BAD ALWAYS. 100% of the time. not 50% of the time, 10% of the time, 99% of the time. BACK PRESSURE IS BAD AND YOU DO NOT WANT IT.
please learn what the hell you're talking about before you go spouting off some bullshit that redneck bob told you about his camaro mufflers."

hey dude you should take your own advice, you really think you don't need backpressure? loosen or unbolt your exhaust manifold at the head and then fire it up. then stop spreading your misinformation.

the only time backpressure isn`t needed is in a high powered race setup or something going for a land speed record. a civic that doesn't have turbo/supercharger will need *some* bp to idle and run smoothly. unless you plan to drag race your car with serious mods you should keep at least a high flow performance resonator/muffler on a straight 2 inch whatever pipe to keep it street legal, possibly a cat if emissions are a problem...

[badboyzkustumz]

without back pressure your cars dies at idol under 2000rpm. so put a 3 inch exhaust on your CIVIC (not CAMARO) and sit at a light in traffic for a few minutes and see how long you keep that engine running dork knob....

civic tuning 101- 2 and a 1/4 inch pipe is the HONDA recomended sized pipe used for NON-ASPIRATED vehicles (see definition below) for advanced tuning. pulling numbers out of your arse and actually doing research and talking to HONDA certified mechanics are two different things. ANY d series engine should have 2 1/4. B series or larger is recomended 2 1/2 inch pipe do to the larger output. large amounts of back pressure IS bad but you do need SOME b/p.

NON-ASPIRATED- a non turbo or non supercharged vehicle (most of our civics)


-side note- you are going to need at least 14 feet of pipe to replace to the stock position and at least 11 to retrofit the exhaust to the right side. i know because ive done both and measured it out.

[91civicDXdude]

you do not need backpressure. say it with me. YOU DO NOT NEED BACKPRESSURE.

what you DO need is exhaust velocity. the size of the piping dictates the exhaust velocity of any given setup. too big of a pipe makes the engines exhaust have little to no exhaust scavenging at lower rpm, which is why i suggest 2.25" piping. I run 2.5" exhaust on my car; my header collector is 2.5". Honda must not know about "needing backpressure" and 2.25" exhaust becuase their integra type R has a 2.5" collector on the header.

btw, i've run my car open header MANY times, and the idle is fine. OMFG MY CAR MUST BE MAGIC! IT WONT IDLE WITHOUT BACKPRESSURE!!@#@@

backpressure is a force acting against the pistons effort to expell exhaust gas, which in turn leads to loss of power. Just like removing friction from the engine will free horsepower, removing all restriction (i.e. BACKPRESSURE) will free up horsepower.

civic tuning 101- 2 and a 1/4 inch pipe is the HONDA recomended sized pipe used for NON-ASPIRATED vehicles

Non Aspirated huh? you might mean NATURALLY aspirated, because non aspirated would mean the engine takes in *NO* air. but maybe you'd know this if you didnt pull numbers out of your arse and actually have common sense. dumbass.

Please do ME a favor and learn what the hell you're talking about before trying to act smart newbie.

[RedRacerCivic]

Go for 2.25" if you are n/a. 2.5" if you are going to run a turbo or a all motor beast.

[Masta]

Originally Posted by 91civicDXdude

btw, i've run my car open header MANY times, and the idle is fine. OMFG MY CAR MUST BE MAGIC! IT WONT IDLE WITHOUT BACKPRESSURE!!@#@@

=.

ok i'm not here to flame or anything, but that guy was talking about unbolting AT the head. So your tellin me that your car will start up with out a header period? From what i'm reading in your post, i'm guessing your just didn't have the header bolted on to the cat, which would be running open header.