IronFist

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edit: For the performance review scroll down to post 14, and another one at post 18.

I got my HP top portion header in the mail today

EX Only
DIY
Installation

Make sure the header is cool to the touch before you begin.



1. Remove the heat shield:
It's pretty straight forward. Sorry I don't have any pics, so I'll use the diagram above. Remove the three bolts that hold on the heat shield. These are both number 4's and number 5. The two 4's were easy, but 5 was a freaking bitch. Even using a long socket we still managed to pretty much round it off. It's also pretty hard to get to. We had to drive my car to a car place and ask them what they would do. A guy came out to take a look at it and tried a few different wrenches, none of which worked. Then he busted out the blow torch which I guess took off some of the rust, or made it expand, or something, but then he managed to loosen it and we drove back home and took it out and then removed the heat shield.

2. Remove the stock header:
After that take out the 5 bolts that are on the top of the header connecting it to the engine. The only one that should pose any difficulty is the right-most one, because it's a bit difficult to get to. You will need a 6" extension to reach it most likely. Loosen all 5 of those bolts, but don't take them all the way out yet.

Now you need to work on the bottom bolts. There are two. You must remove them from the bottom. They've got springs so they're kinda weird to work with. You will hear them creaking more than a normal bolt would. We didn't use jackstands or anything which makes it kind of a pain to get under the car at the right angle. I recommend having a friend helping you from above to make sure you've got the socket wrench squarely on the bolt. If you have access to a lift it will be easy to get these out, but since we didn't, it took longer than it should have. Before you completely pull them out, make sure you have something set up to support the exhaust pipe because you don't want it to fall onto the floor. With the exhaust pipe supported, take out the bottom two bolts. Now go back to the top 5 and take those out. Save them. Remove the header carefully to make sure you don't damage the gasket (part number 2).

3. Installing the HP header:
Before you install it, hook up a shop vac or something and blow it out. This ensures that it's clear. You don't want to have a packaging peanut or something hiding in the tube when you start up your car.
Pretty much just do the reverse of what you did to remove the stock one. You won't be using the heat shield so you don't have to worry about that. Make sure the gasket is in place. Attach the top 5 bolts first, and then the bottom two. Remember to tighten the top 5 a little bit at a time so that none of them gets too tight before the others. Once the top 5 are tightened, do the same for the bottom two. Again, if you don't have a lift you might want a friend to help provide a second set of eyes from above.

The torque specs (I think) are 23 ft/lbs for the top 5 bolts and 17 ft/lbs for the bottom two. If you don't have a lift, you might have to use a mirror to help you see the gauge on the torque wrench for the bottom bolts (depending on where your gauge is on your model of torque wrench).

Once you get it installed, do the typical ECU reset. Disconnect the negative terminal of the battery for 10 minutes (make sure you have the code to reset your radio). Reconnect it. Start the car and let it idle for 10-15 minutes. During this idle time, you might want to check under the hood for exhaust leaks. If you're going to touch anything, do it quickly as the header heats up very fast. After 10-15 minutes, go for a test drive.

Here are some pictures comparing the HP header with the stock header.

Top view:

IronFist

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View of the inlets:

IronFist

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Side view:

(notice how much smoother the bends in the HP header are)

IronFist

iTrader: (3)

Front view:

(By now you've noticed how much larger the HP tubes are)

IronFist

iTrader: (3)

Three more points:

1. The header was used when I got it, that's why it's not all shiny. Not like I care, though... pretty does not equal power.

2. The inlets on the stock header, while smaller than the HP ones, also went in a little bit so the inner diameter of the tubes is smaller than the inlet diameter. See the attached pic for a better explanation. The HP header does not go in like this. Just an observation I thought I'd point out.

3. The HP header is a bit heavier than the stock one.

03CivicEX03

nice.. Do you have to shave the motor mount?

IronFist

iTrader: (3)

I installed just the top portion. What you see in the pics is the only part I installed. I did not need to shave anything. I have an 02 EX auto, and I've heard that you need to shave part of the motor mount if you have a manual and you install the downpipe and all that stuff. But as far as I know, if you just get the top part it directly replaces the stock on and you don't need to shave anything.

pxboarder

do you notice a hp diffrence with the new header top end bottem end or both

IronFist

iTrader: (3)

I went for a test drive with my dad afterward. It seemed a bit quicker, but I'm used to driving my car with no other passengers so tomorrow when I drive by myself I'll post a more detailed review. But I figure if it felt faster with my dad in it, then it would feel even faster when I'm alone.

gearbox

iTrader: (95)

I'm jealous. Very detailed DIY by the way. I'll use it if I ever get a new header.

Silversleeper

iTrader: (5)

wow... looks a lot better than that stock header. i was really considering getting the HP header w/ downpipe. i have a axle back HKS, and wanted a tad bit more sound from it and figured the HP racing header would fill that void.

IronFist

iTrader: (3)

As for sound, I don't notice any difference at all. I have a stock exhaust, though. MY K&N FIPK II intake is still the same sound/volume I think. So I'm happy with that. I have heard, however, that headers will make an aftermarket exhaust louder. But like I said, I still have a stock exhaust.

Like I said, though, after I drive with it a little bit more I'll post a more detailed review.

gearbox said:
Very detailed DIY by the way

Thanks. I tried to make it as detailed as possible because unclear directions suck. The only thing I forgot was the size of the nuts. I think it was 12mm and 15mm but I forgot already. Sorry.

IronFist

iTrader: (3)

Hey mods, if you like my DIY please add it to the DIY section.

IronFist

iTrader: (3)

Performance:

Edit: I posted an updated performance review a few posts below this one. So, ignore this post and scroll down to find the updated review. Thanks.

For those of you who installed just the HP top portion header, post your opinion of it. Were your gains similar to mine?

GideoN

Wow, then the downpipe would make even more of a difference. I am thinking about getting this header/downpipe and your post has helped me out. Thanks.

IronFist

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More pics:

Jodster

iTrader: (8)

Looks good. I like it.

IronFist

iTrader: (3)

I like it cuz it performs well, not cuz it looks good.

IronFist

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Updated Performance Review

Another update (I have a lot of posts in this thread).

I think my ECU just finished adjusting to this mod. The other day I was driving after having it installed for about 200 miles and all of a sudden everything seemed faster. I'm talking about more power throughout the entire powerband! I hope it stays this way. This is strange, because I reset the ECU after I first installed it. Oh well. I like it better this way, anyway.

I also got 31mpg on my first tank of gas after installing this (probably 60% highway driving and 40% city driving, but lots of high revving the whole time )

GideoN

Sweet. I want w/downpipe now!

runner1738

iTrader: (2)

is the hp header street legal, i mean just the top portion? thats crazy that you still get 31 cause after just installing my aem intake i get like 28 city i guess most of the time its hard driving

obtix

Its like when an exhaust has to break in, you have to wait till it burns out (all the shinny stuff on the inside turns black). Reseting the ECU really wont do much for a mode like that.

Where did you get the header from?

IronFist

iTrader: (3)

Well, the header had about 5,000 or so miles on it (I was told) when I bought it, so there was nothing to burn out really. I got it used from Keigo (a member here) for $130 US. You can get them new on eBay for like $169 shipped.

runner1738, I hope it's street legal. I assume it is cuz you keep your stock cat.

Yeah, I got about 31 but that might change since it seems to have readjusted the ECU after 200 miles or so. I also have a K&N FIPK II.

Jodster

iTrader: (8)

It didn't change the sound of your exhaust at all?

HYPR DRV

iTrader: (2)

If any of you don't need to worry about emissions, then I highly suggest going with the full HP header, downpipe, resonator (hi-flow cat) set-up! I have an exhaust and an intake and it really doesn't make it much louder. Nice deep tone, if anything. And best overall performance you can get outta this mod. Two thumbs up!!!!

CrankinCivic

iTrader: (1)

HP huh ? so i am correct in thinking or reading from other posts, that this header top portion will fit on a LX as well ?

pxboarder

yes but its not legal because it removes the lx cat

civicskater

I have an LX...and was thinking about buying the top piece of the HP header and putting it on, then goin to meinike or some muffler shop and having them weld on a hi-flow cat past the stock midpipe or so....and put the 02 sensors there

Anyone done this? Know how much it'll cost all together, $300-400?

runner1738

iTrader: (2)

so its not legal on lx cause it removes that cat but what about on an ex? is stamped with a carb sticker on it like the dc one?

abmerop18

iTrader: (26)

did you ever do those 0-60 test with your G-Tech on it? i would like to see those.