Intake or 3in Straight Pipe Exhaust first? 07 Civic Si

I drive an 07 Civic Si and I don't know whether I should get an intake or an exhaust first, if i get one or the other I have to wait to get the second until I get some money together so I definitely want to get whichever is going to help my car out more until I get the second. And if I get intake should I get a cold air or a ram air? Not sure I know the difference in performance. Opinions would be great!

well man , its kind of a toss up. improving the exhaust flow is helpful and if you dont buy an e-bay crapper (like i did) it should sound alot better. remember sounding better doesnt necessarily mean faster. be sure to do the whole exhaust, including header and cat delete if you want any real performance gains. the difference between a cold air and a ram air is probably just configuration. ram air means literally ramming air into the motor via a scoop or vent and cold air setups are designed to pick up cleaner air, usually from down low close to the front bumper. the theory is that colder air compresses less and produces better combustion than warm underhood air. if you mean short ram not ram air, thats just an open filter style intake and you see alot of them in pics on here (look at my car, this is a short ram intake). with either of these mods remember that you are changing the air flow characteristics and your ecu may not like that. i had to buy a spacer for my o2 sensors so they would not throw a code. my buddys acura throws a code any time we get off the highway. you should expect better throttle response and maybe 5-10hp gains with these mods. only real advice i have is to stay with quality parts or end up with some whack ass fitment issues like i did. good luck and hit us up if you need more help.

I have a 08Si, I did the intake first-you can get away with the cheap ebay one for the intake. There is one that is a rep of the injen intake-the one I got- it won't throw engine codes like most other intakes. It's the best $50 I've spent on my car. You will notice an immediate improvement in throttle response and acceleration! Then picked up a used Race header and defouler, then Vibrant StreetPower exhaust. I installed both of these at the same time. Completely different car now! Warning with the header though!!! You HAVE to get motor mounts or torque damper of some kind or the header WILL hit the fire wall. Check out 8thcivic.com forums, there is a lot of info there! If you have any questions on the Si let me know, I've had mine for about 4yrs and have done all the mods myself.

Nice, yeah I wasn't planning on going to eBay for it but I might have to take a look, I was either thinking injen or aem for the intake and then I was just gonna go up to tristate muffler for the exhaust. So well see what happens

Def hit up ebay for the intake, check out the Injen and find the cheap one that looks just like it. The pipe will step down at the MAF sensor. I wouldn't use the filter that comes with it, I had a K&N laying around that worked on it. The rest of the intake is just an aluminum tube, just needs a good filter. As far as exhaust, 3" is a little overkill unless you plan on going SC or turbo in the near future. It will be a LOT louder with very little benefit over a good 2.5" exhaust.

Well for the exhaust I just want it to sound real, like loud but.not fart can loud and just sound legit. What do yo think I should do.in that department?

if you want to go 3" go with the Invidia Q300 or Full Race 3". Both are known to produce good power and not be too loud. Using a High flow cat will help keep noise down as well. I've got the Vibrant which is known to be fairly quiet, but not running a cat it can get pretty loud!

See I want loud though, just not wake the neighbors baby loud. I just don't want it sounding like a fart can where it's clear you have nothing under the hood backing your exhaust up and you have to make it obnoxiously loud to make up for it haha. I'm just completely lost in the exhaust department

A 3" exhaust on a NA unaltered engine is pointless. Unless you plan on building the engine(and i mean building not just slapping in some cams) than maybe, or a forced induction setup.

The great intake debate has been going on for years. some say short ram, some say CAI
it really depends on your goals. preferably i rather not have a vacuum in my bumper to clean all the water out of a puddle. it's in how you get the air to the engine efficiently and safely. but also remeber too much can hurt your performance gains. DO YOUR HOMEWORK! research.

K-Series engines are very responsive, but with the right combination of parts in a particular setup.

Lets say
exhaut $600
Intake $100 (for a cheap ebay junker)
Header $400 (for a non researched built header)

almost a grand for maybe 10-15hp? Not worth it. A properly built Header say Hy-Tech, Bisi, Endyn, etc, will provide 15-25hp depending on engine and maker. same goes with and intake. there is a reason some are exspensive, 1000's of hours of R&D went into the design. Same goes with an exhaust system.

In all my years of doing this i found if you buy junk you get junk or noisemakers.

RESEARCH, RESEARCH, and RESEARCH some more. you'll be happier in the end with the results.

i wouldnt put 3'' exhuast on that car. maybe 2 1/4 or 2 1/2 at biggest. you just dont need that big of pipe on there since its na, and im a apexi world sport fan, i love the tone that they give, and how they flow nice, and its not all ricey and raspy soundin.

but as far as intake goes, ive personnaly never noticed a difference when changing intakes on b series and d sereies hondas, im not sure about your car, maybe its just me.

whatever you do, make sure you use quality parts were you need too, i wouldnt reccomend using a cheaper header, i would go with a reputable brand that wont crack at the welds a few thousand miles down the road.

I do like Apexi, my buddy had one on his lude that sounded super nice. Now I'm gonna get laughed at for this I know, but is it absolutely necessary to get headers with the exhaust?

ForrySi wrote:

I do like Apexi, my buddy had one on his lude that sounded super nice. Now I'm gonna get laughed at for this I know, but is it absolutely necessary to get headers with the exhaust?

It all depends on what your looking for.

necessary no, will you get more of a benefit, yep. Think about it... if you leave one piece that restricts the flow of air, the air can only move as fast as that one restriction will allow. If you're just going for the sound or look of the exhaust- no, header will not give much benefit. If you head over to 8thcivic there are several videos of Si's with different exhausts that will give you an idea of what each will sound like. Check in the "8th Civic concurs the Dragon" threads, there are a few vids that have several different exhausts in the same video on the same camera. That'll give you a pretty good idea of what each will sound like.

ForrySi wrote:

I do like Apexi, my buddy had one on his lude that sounded super nice. Now I'm gonna get laughed at for this I know, but is it absolutely necessary to get headers with the exhaust?

Something else to take into consideration is that different motors will sound different even with the same exhausts. I love the sound of a world sport 2 on a H22, or the one mine has is the Tanabe G-Power medallion on a H23. But I've heard drive by's and vids of Apex-i and Tanabe's on the Civic Si's and didn't like the sound of either. Both are very expensive for what they are too. Apex and Tanabe are both 2 1/4" and over 6oo for either one. My Vibrant is a 2 1/2" and picked it up for 400 new. It's better made, looks better and sounds better than either of the Apex or Tanabe. But that's personal preference. Also, having not cat, it's louder than it would be if I had a high flow cat.

In that case I will.probably just get exhaust without new headers for now.and invest in headers when I can afford them

You are both great lol, keep it coming!

The other big expense with the header is motor mounts, without them it will cause issues. The other big thing to look into is flashpro. You will get results from flashpro without any boltons, it's that good!

i'd do exhaust first if u can cat delete that's even better. also running a straight piped car that's none turbo is bad for your engine since u will lack back pressure and its super super loud lol

Nah, the K20 loves running catless. Mine has been off for about 15k mi and it couldn't be happier. Problem with deleting cat on stock header and exhaust is the shape and length of the midpipe that contains the cat-it is long and odd shaped-can't just put in a test pipe. You would need to replace the entire downpipe, there are a few that are made but it is more cost effective and power efficient to get a header.

you could also get headers buy a after market muffler of your choice with the same diameter and get a exhaust shop to run a new pipe from headers to muffler they run hangers and all.. but you have to install the headers yourself.. that's how i got my 240sx exhaust done. don't see any gains in running a straight pipe it will just be loud as hell... you will have plenty of flow with headers, cat delete and a after market muffler but its your car you do what you want that's just my opinion..

Well I ordered the skunk2 universal 3in muffler, just came in yesterday, having it installed sometime this week. For now I'm just running stock pipes and headers up to the muffler. See I feel like if I have them dojust custom tubes it would throw a code unless I were to keep the resonator somehow. And headers are way out of my budget right now. Hmmm, what to do what to do

As long as you run a defouler on the 2nd o2 sensor, you shouldn't throw a code cat/HFC/no cat. LMK how you like the Skunk2, they are known to be about the loudest exhaust for the 8th. Should be a little quieter running stock manifold and piping though.

Ill be sure to let you know man, I'm hopming it sounds good

Trust me, youll be annoyed by a straight pipe.

I have a straight pipe and it's not bad at all