Found this on Honda-Tec.com

Spades SOHC upgrades

First things first, enabling the engine to breath; after all, engines are nothing but air pumps.
Intake Path: To start off, we look at the filter and piping. Cold Air Intakes (CAI) although some assume just relocate the air filter into the front bumper, are actually acoustically tuned to the engines they are made for and allow for a rather comfortable bump in the mid-range horsepower. K20s (RSX-S for this example) have been dynometer (dyno for short) proven at +20 whp (wheel horsepower) with a CAI as apposed to the 5 whp with a "short ram" design. The AEM V2 although costs more is also designed and tuned for both mid and upper RPM acoustics. If you don’t have to worry about water, get a CAI made with acoustic testing. (Read: AEM)

Following the air flow we come to the throttle body. This is more of a throttle response upgrade than a horsepower upgrade. UNLESS the stock throttle body is too small to allow all the air the piston chambers can pull in at wide open. Basically, adding a larger throttle body allows you to be a "full throttle" faster because of the larger volume of air. Any throttle body for an H series B series or D series are interchangeable, with one catch; you need to pay attention to where your IACV (idle air control valve) is. For example, the D16Y8 (96-00 EX) has different mounting points and uses a 2 wire IACV. On the automatic, the IACV (which is a 3-wire) is mounted on the throttle body and the manual has the IACV mounted on the back of the intake manifold. The later model VTEC B series and B20 (CRV) throttle bodies are all 60mm in size. Except for the ITR, this is 62mm. The H22 is also a 60mm throttle body, while the Civic gets a puny 56mm. Make sure when you add the larger throttle body that you port match (make the holes the same size) the opening of the intake manifold.

Next in line is the intake manifold. For those of you who want OEM, you want the D16Y8, often referred to as the Type R manifold for the D series. It has somewhat short and fat runners and a large chamber to allow the air to distribute to each cylinder properly. The Y8 IM has the common horizontal throttle body. Here is a link Courtesy of VTC_CiViC with a complete how-to: http://www.makuragi.s5.com/civic_99/Y8maniswap/ NOTE: This will not work for the D17's. Honda had the bright idea to make it a return-less fuel system. Recent research has developed aftermarket IMs for the N/A SOHC. Edelbrock is at the top of the list on this one. Not only does it fit better than the Skunk2. You do not have to raise the fuel pressure to get more power on the Edelbrock IM like you do have to with the Skunk2 IM. Lastly, there has been a recent interest in taking motorcycle Individual Throttle Bodies and attaching them to an OEM intake manifold cut at the runners. Find an example at http://www.homemadeturbo.com

In my personal experiences, I had a AEM short ram intake when I was asked by Edelbrock to test out their Intake Manifold. So I needed a before dyno. With a AEM short ram, DC 4-2-1 header and a 2.5" Cat-back: The D16Y8 put down 116whp. Once we had the Edelbrock Intake Manifold installed, peak horsepower jumped to 121whp, with the only loss in power being 2whp just before VTEC crossover for a simple 25rpms. Once that was completed, the car was loaned to AEM for design and fitment of a CAI. After a week of research, the CAI was designed and not only did it add 10whp with the "AEM HUMP" (a term used for the mid-range increase in HP) but added another 5whp overall! This brought the total to 126whp! To put this into perspective, a stock Civic EX puts down 109whp.

Exhaust: Lets start off with the exhaust manifold (header). There is not a single OEM exhaust manifold out there that doesn't need work. But, for those of you who want to budget a used aftermarket manifold for the EX is where you want to go. There are a lot of people out there who by the time they can swap have already put a header on there D series and now need to sell it. If you have a DX, LX, or HX, You will have to relocate your catalytic converter under the car to use this header configuration (which happens to be illegal in some states). There are two different designs for a header. The 4-2-1 (or Tri-Y) and the 4-1. It is said that the 4-1 costs you low-end torque to give you more power up top. However, if you follow this link http://www.automotiveperforman....html you will see that some 4-1's have better low and mid then the 4-2-1. Header designs on stock engines are so good that this is more a preference thing until you start building. One advantage of the two-piece 4-2-1 is that you can remove the lower half when you need to pull the oil pan, instead of pulling the entire header. There are some new designs for the SOHC headers as well, they are all well designed but also tested and designed for built engines. I suggest speaking to each company and seeing what the recommend before deciding. Bisimoto is one of these designs. Available through http://www.exospeed.com The HF (all Civics other than the EX and SI) exhaust manifold can be modified to add a turbo. Then you don"t need to spend the extra money on a turbo manifold. See http://www.homemadeturbo.com for more information.

Following the exhaust stream out, we come to the Catalytic converter. Unless yours is old, don't worry about it. For those of you who can afford to upgrade the cat, tests have shown that a 3" free flowing cat is close to the flow rate of a 3" test pipe. In fact some people were shocked at how well a free flowing cat works (and it's legal but only on OBDI vehicles). Or go with the $10.00 test pipe from Home Depot (NOTE: Test pipes are not smog legal and you face a $3,000 fine). That's right, people have even made there own test pipes with minimal effort.

After the catalytic converter, is the Cat-back. Most people recommend using a 2.25" sized exhaust for the little 1.6L. And a lot of the aftermarket exhausts are 60mm or 2.3 inches. I believe that you should actually use no less than 2.5 inch. My dyno results proved that it adds more power than the 2.25 and I gained another 1 whp throughout the power band when I removed the silencer from the muffler. But, you also want to make sure you get mandrel bent piping and straight through designs on both the resonator (if you have one) and the muffler. If you don't get the straight through designs, you will loose power, it's that simple. However, with straight through designs also comes sound volume. A good compromise has is an exhaust that comes with a silencer. You can remove them for track days and leave them in for daily driving, as stated before, only losing about 1whp on a stock engine. NOTE: I seriously recommend a resonator. Who likes sounding like a bumblebee???? Exactly, the resonator will get rid of the sound and actually deepen the tone of the exhaust.

Transmission/Flywheel/Clutch: Remember this, the shorter the gears the better. It is easier for the engine to push/pull the car. The VTEC engines have always had the shortest gears and it is a "bolt on" part. The 96-00 transmissions will bolt on a 92-95 Civic. One small thing to consider is that the 96-00 transmissions have steel shifter forks instead of the aluminum forks that are in the 92-95 transmissions. For you cable transmission guys, there are the Hasport kits that convert your Cable to Hydro. And, SSR offers a 4.7 and 4.9 Final drive for the D series Hydro transmissions. HX/VX/CX owners, upgrading the transmission should be the first thing you do, this is a HUGE difference. Once you get the shorter geared transmission or already have one, a limited slip differential is a great option for FWD cars that are putting down decent amounts of power. I recommend Quaife because its gears, not a clutch and it comes with an unlimited lifetime warranty. A lighter flywheel is also a recommendation. Not only do they increase throttle response, t

 

no, I don't like stealing other people's content and reposting it without their permission. If the user wants to come here and post it, then we'll talk.

 

ok i got a little lost in the intake manifold part what is the best intake manifold for my 2002 ex?? either a honda oem or aftermarket

 

The Z6 manifold proves better in every dyno comparison on this page, both top and bottom end.

http://www.hadamotorsport.com/tech/r...chip/index.htm

 

thats a great find very informative

 

the z6 in your dynos are the exhaust manifold im looking for the best INTAKE manifold

 

In that link, the use of a Z6 manifold is inferred whenever the words "Y8 intake manifold" do not appear.

As for what manifold you should use, I'm not sure on a 2001+. Pm Chimera. He should be able to tell you.