I finally installed the DC header this morning. I took my sweet time during the entire install to take pictures and got it done in about 3 hrs. If I had to do it again, it should only take 1.5 hrs.

Tools needed:
floor jack
jack stands
12 mm wrench/socket
14 mm wrench/socket
ratchet with long extension
O2 sensor socket or 7/8" wrench

Tools highly recommended:
ratchet box-end wrenches
breaker bar (your best friend)
WD-40 for exhaust rubber hanger

Removing the stock manifold and A-pipe:
Everything can be removed from the bottom of the car. Note: remove the O2 sensor and connector first to avoid damage. Also pay attention not to damage the exhaust manifold gasket, as it will be reused for the header.
Tip1: Use WD-40 on the exhaust rubber hanger and the A-pipe will slide off much easier.
Tip2: When removing the bottom bolt to the heat shield cover, use double-wrench method unless you have very long wrenches. See pic below.
Tip3: The heat shield will come out the bottom by rotating it upside down and it will slide out.

The manifold is mounted by two nuts (top) and three bolts (bottom). You can access all the nuts/bolts from the top (stand on a chair) except for the bottom right corner, which can be easily accessed from the bottom. Once the manifold support bracket is removed, the manifold will drop straight out through the bottom.

Installing header and A-Pipe:
The header can also be installed through the bottom of the car.
Mount the header onto the manifold top studs and install all three bottom bolts. Stand on a chair and install the top two nuts. If you have a 14mm ratchet box-end wrench, you can tighten all the nuts/bolts from the bottom of the car. Just follow the enclosed instructions to install the A-pipe.

Driving impression:
If you guys remember my write-up on the K&N CAI installation, I said I can't notice any gain. I was not kidding and the dyno will show why. I believe the lack of gain from the intake install is due to the relatively new and tight engine (it only has 1500 miles). However, when I took the car out for a drive after the header install, I felt it! The engine revs easier and more responsive to the throttle input. I then took it to the same dyno and it proved my butt dyno was right! I believe once the engine is loosen up, a few more hp and tq is very possible.

Okay, some pics from the header installation. Enjoy!

A pipe comparison


Manifold comparison


Stock 4 into 1 collector


Double layer manifold gasket


Double-wrench method


Ratchet box-end wrench for tight spaces


Excellent ground clearance!


Header installed


Dyno result


I like how the header provides some nice gain across the entire power band especially after VTEC!

 

Other then the header, what are other mods you have on your car. If none, that's a pretty good gain for a part under 300.00, IMO

 

JTso, It looked great! How does you feel power when you drive? I I am glad that you are satisfield with gain hp from DC sports header from dyno test. I am sure that your TSX will feel more power and smoother. Dyno looked good! Can you make a new picture of your engine with new DC sports header? Thanks bro

 

OK, I'm a little slow, so you have the K&N CAI. Did you have that or stock set-up for the dyno? Any noticeable changes in noise with the header installed?

 

The first dyno run was done with just the K&N. I know the result looks like stock. That's why I started this thread to see how engine mileage affects performance. I'll dyno it again after a few more thousand miles to see if there's any improvement.

I noticed a slight increased of engine sound perhaps due to the thinner exhaust header and lack of heat shield cover.

 

you have an auto correct?

 

I have a MT. The dyno was done in 4th gear. That brings up another point. What gear did you guys use for the dyno?

 

What altitude do you guys sit at in WA...rough estimate if you don't know. Was the noise any louder than the intake noise itself at WOT?

 

Those gains are totally worth the money ... I guess I out to buy the DC headers now...

 

According to my GPS, it's 136' at where I'm at. I can't hear any other noise except the intake during WOT. I only hear a slight increased of engine sound during idle with the hood open and me standing in front of the car. It's hardly noticeable inside the car with the windows rolled up.

 

very nice.

 

Thanks for the awesome writeup JTso. I already have a Comptech exhaust and really don't want any more noise in the car. Do you think the header will add to the noise, or will the exhaust's noise muffle that of the header?

 

I think you did a great job to us all by sharing this.

Thanks...

 

If you already have an aftermakert exhaust, you won't notice anything from the header at all.

 

You're welcome. It costs me almost $100 for the dyno runs. Ouch! Well, I guess I took one for the team! LOL.

 

Awesome, thanks.

*Sigh*. Another mod to add to my to do list.

 

Arg, I thought I was done after doing my suspension mods. I guess I can squeeze a header in before I take a break from the modding.

 

there will NEVER be a break from modding.

NEVER

 

exactly!

when i first got the tsx, i said to myself no more modding. before the car even arrived, i already had the springs and body kit sitting in my living room

 

so what are the downsides of ceramic coating? that it might crack or something? is that a real concern with the DC header or are they high quality.

 

Okay so what hp, whp and torque gains are we lookin at with this header alone, and header/intake together?

 

The downside is the header is made out of mild steel. If the ceramic coating is damaged, the exposed metal can rust. This usually happens when the car is bottomed out and the header hits the ground. However, this particular header has very high ground clearance. You probably never have to worry about damaging the header.

 

just one question, have you done your suspension yet? if so, what kind?

would you still call it safe if after 1" drop?

i believe DC header is the only header available at this point, am i right!?

thanks

 

comptech makes a stainless header

 

Dani, my car is not lowered yet, still waiting on strut/shocks. There shouldn't be any clearance problem even it's lowered 2". The oil pan and cat converter will get damaged first before the header. Just look at the clearance pic again and you'll see what I mean.

Here's another clearance pic.

 

where did you set the jack stands at? Also, did you reuse the original gasket?

I have a 2003 accord and the setup is mostly the same, even the exhaust manifold looks the same. The main problem with stock setup seems to be the restrictive looking 4 to 1 collector. Why honda did that, I have no clue.

 

JTSO.......nice work man! and thanks for taking one for the team on the dyno!

looks great man!

any plans for an exhaust?

 

The jack stands were at normal spots where you would position the scissor jack. Yes, I reused the original exhaust manifold gasket.

 

Thanks, I don't have any plans for an exhaust at this point. However, I'm seriously considering the Hondata gasket and TB coolant bypass mod. In fact, the TB coolant bypass mod is done.

 

For the slow guy....what is a TB coolant bypass mod?

 

and where can i get it at?

also, is the heat gasket out yet?

 

The TB mod is to bypassing the hot coolant lines running through the bottom of the throttle body. By design, the coolant lines are there to prevent the throttle plate from freezing under cold temperature. Because of this, the throttle body receives the same coolant temp running through the engine, which also heats up the intake temp. Therefore, this mod is usually done along with the Hondata heat gasket to further reduces intake temp.

Pros: The TB mod is cheap and easy to install. It costs approx. $1.50 for a fitting and 20 mins of labor after removing the intake tube.
It's very effective. The throttle body is no longer hot after driving even in hot weather. It will be warm due to under hood heat but no longer heated by hot coolant.
It's easily reversible back to stock.

Cons: It's not recommended if you live in very cold/freezing area, as the throttle plate may become sticky.

 

Do you have a link or post of a "how to" on this mod? Thanks for the info!

 

The Throttle Body sounds interesting and easy after putting a CAI on already. Where'd you get info for this? I'd bite in a sec. if its that cheap, who cares if it freezes here

 

Can't you adjust the throttle cable too for a bit of a gain or something?

 

I'll post a how to in a few minutes.

cmf: nothing can be gained by adjusting the throttle cable. All you can do to the cable is to make sure the adjustment is within spec.

 

hey JTso

just wanna make 100% sure here, so the only thing you do is to replace the stock header with DC's, nothing else right?

it should turn out just fine by leaving everything else unchaged, true!?

thanks!

 

Dani, I'm not sure I understand your question. What do you mean by leaving everything else unchanged?

 

sorry for being unclear, what i meant is...

everything should just work out fine by simply taking off the stock header and putting on the DC's right!?

there's no need to enhance other parts of the engine (or whatever else) due to the new header, correct!?

hope u got my question, ...just wanna be 100% clear here (havent done or heard anything about a header mod...so...hehe)

 

No problem, the DC header is a direct replacement and uses all factory mounting hardware and location.