• Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.

DC headers

Do you mean in terms of build quality or overall horsepower gain? or both?
In the Civic world, the DC sports headers do not have the best reputation. But from what I understand, they are cheap and work well. (I think the main complaints are quality and durability)

As far as the NSX world, I have no idea.

NetViper -= 100% Stock EBP 2000 Civic Si =- Still looking to get an NSX, but at least I can live life at 8,000 RPM!
Here's my thoughts on the available headers in the US. Obviously I sell the DC Sports & Comptech headers, however, I am trying to provide an unbiased opinion...

First, a note about the header systems on NSXes: There have been 3 exhaust plumbing configurations during the years, 91-94, 95-96, and 97+. These changes are largely due to two things: change in the flex points of the headers and OBDII modifications including the addition of a after-cat O2 line in 95.

On the early cars, 1991-94, Honda used a braided steel reinforced flex joint. In 95, Honda shifted to using spring loaded bolts with ball-joint couplers that allowed flexing at these joints. A much better design, IMO, because the later design does not require the use of flexible tubing that is prone to cracking. This can be illustrated by viewing this link:
http://www.carparts.com/parts/newsearch2.asp?reflink=0-0-0-0- 0&sourceid=2&parttypeid=&itemid=6475&autoidsearch=NO

The upper is 91-94, the lower is 95-96. Note the ball socket on the lower header.

The RM Racing header uses a slip joint, the DC Sports a flex joint, and the Comptech and Fujitsubo headers a ball joint.

RM Racing
Build Quality: 5/10
$1499.00 (91-94 only)
Similar to the exhausts, the welding is very poor on these headers. Often, big gloops of excess flux can be found on the internal walls of the headers. These headers have been dyno proven to be slightly better on the top end than the DC Sports headers, probably due to the larger internal diameter (not verified, just going off memory). These were the least expensive headers until SoS arrived on the market. One good aspect is these headers use sleeve joints instead of the flexible coupler, however, these headers are known to leak on the joints, just like the exhausts. Not CARB legal.

DC Sports
Build Quality: 7/10
$1299.00 from ScienceofSpeed
Quality is good for the price IMO. Under high heat scenarios, the flex joint has been known to crack over time. Covered under warranty, but it's something that has to be addressed if you are running a forced induction car or one that is tracked often. These are the least expensive currently on the market. CARB exempt.

Build Quality: 9/10
$1749.00, $1616.00 from ScienceofSpeed
Excellent build quality even on Japanese build-quality standards, however, also the most expensive in the US (but decent on Japanese header system standards). Only headers made for all years of the NSX. Originally manufactured by DC Sports up till about 96 I believe. Older ones are the same as the DC Sports. The newer design uses a ball joint coupler, which makes these headers very reliable. These are the headers I recommend. Although they are a little more, the quality dictates that in the long term, they may be the better investment. These headers are also most often in stock, which is a big plus.

-- Chris

[EDIT]: updates


www.ScienceofSpeed.com - Click for more info

[This message has been edited by ScienceofSpeed (edited 17 November 2001).]

[This message has been edited by ScienceofSpeed (edited 19 July 2002).]
www.optauto.com (Options) Sells the DC headers for all years for- $1216 and the Comptech for- $1669. Best price I've found so far...

We are top 3 for NSX Porterfield Pad Sales!
92 NSX White #745
91 NSX Black #644 sold
I've been running dc stainless headers since 97 and have had no problems.they are compatible with ct bypass pipes.my only advise on headers for obd-2 cars is to make sure the o2 sensor bolt hole is well positioned and allows the bolt plenty of room.
I had the DC Headers installed on my 1995 NSX last weekend...car runs like total shit now...incredible stumbling and hesistation...getting 10mpg or WORSE.

I'm changing the O2 sensors tomorrow and hope this fixes everything. I've checked everything on the car...all connections and vacuum hoses, etc...O2 sensors looked fine, but may have been damaged in the swap. The car was running strong as stink before the headers went in.

Stay tuned...

Andie - depressed all week

don't be too upset it sounds like an o2 sensor or just a bad connection between the wire and the o2 bolt.my first header had the bolt aiming at the fire-wall behind the gas tank.during hard accel the wire was torn because of engine torque.the lights and gauges went dead but the car still ran .once turned off the car would not start.dc was appologetic and sent a redesigned header.that was 35k miles ago.
Originally posted by docjohn:
don't be too upset it sounds like an o2 sensor or just a bad connection between the wire and the o2 bolt.my first header had the bolt aiming at the fire-wall behind the gas tank.during hard accel the wire was torn because of engine torque.the lights and gauges went dead but the car still ran .once turned off the car would not start.dc was appologetic and sent a redesigned header.that was 35k miles ago.

The new O2 sensors should be in today...so I'll put them in after work. I'm just upset because one tech blamed it on bad gas (been through 3 tanks of gas since then...not the gas), the second tech blamed it on bad plugs (brand new plugs installed just 2 weeks before the headers, and were running strong up until the header install), and another tech blamed it on a poor header design - said the primary tubes were too long...so I'm not upset so much about it runny poorly...I'm upset about peoople trying to blow smoke up my ass. :-(

My started doing this also after I installed headers and exhaust and removed the cats. It doesnt happen all the time and it is usually only when I havent driven the car for a little while. I'm interested to see if the O2 sensors fix it. keep us posted. thanks
I've never heard of headers affecting performance in this way. Long collector pipes? The length of pipe behind the collector is the same diameter as stock, I don't think your tech knows what he's talking about. Sounds like he is trying to cover for damaging the 02 sensors.

-- C


www.ScienceofSpeed.com - Click for more info
Well, I bought and installed the new O2 sensors (not cheap), and the car does the same thing...it runs like a wounded snail.

So, I had the entire fuel system drained and cleaned and reassembled. Then I had the ignition system checked out. Well...6 hours later, and mucho bucks later...nothing. So I had the EGR disconnect, just in case it was stuck open and recirculation too much exhaust gases...didn't change. Tried a new MAP sensor...nothing.

Finally...decided to just pull ALL O2 sensors out to force the computer into MAP mode...car runs fine and strong...tuned out the default rich air/fuel map with the APEX-i...and the NSX is strong again. However, when you let off the gas and are in neutral, it almost dies and then surged back up to a good idle...no feedback from the O2 sensors about idle, so it is sloppy with shutting off the injectors when the engine is not under load.

Anyhow...I'm going to work with what I have, and try to solve the idle problem... This is the first 1995+ NSX with this problem...so it's frustrating.

I'm going to dyno the car this weekend, hopefully, and see if it actually makes decent power with manual air/fuel tuning and no O2 sensor feedback to the ECU. I suspect that the O2's are sending a shitty signal to the ECU and/or the ECU is damaged...no idea how...


I suggest reading the O2 sensor voltage using multimeter or air/fuel gauge. Also, if they have a wideband O2 sensor at the dyno, that should help you read out what kind of air/fuel ratio you are running. Did you have the AFC before you did the header install? Maybe you should disconnect it to see if that changes anything? I'm sure you'd thought of all that already...hope you'll find out what's wrong
Have you considered the possibility that the problem is the new fuel management computer you installed, or the higher-than-stock fuel pressures you are running? Perhaps the injectors are damaged?

-- Chris


www.ScienceofSpeed.com - Click for more info
We already checked everything...with and without the AFC...every possible combination...voltage is fine...

So we'll wait...have a theory, but I won't spill the beans until I test it out.


We removed and cleaned each injector already...disconnected the fuel compouter...fuel pressure regulator was taken apart as well...we literally checked EVERYTHING. :)

Basically, the car was running strong as stink before the headers, and after the headers, it runs like shit. So ---> the ONLY thing that is different NOW is the headers...nothing else changed.

hey andie i took your advice to go to a forum to see if anyone waned to sell their calipers so here i am. i happened to find you here... (MCA MOTORSPORTS yellow type r)