My stock downpipe was rattling and I was annoyed. Never really planned on upgrading the exhaust manifold just because by looking at the stock one, it looks to flow fairly well. And I'm not building this motor.

So I ended up with the DC Sports 4-2-1 one peice because I heard that the 4-1 may hang lower and with my car almost 2" lower than stock, I didn't want to risk it.

Header came in today and I opened it up eagerly only to be disappointed. By no means is the quality of it terrible, but looking at the piping size, I really wasn't expecting any power gains. Looked like a better looking replica of the stock cast manifold. The piping appears slightly larger going into the cat though.

Installation was a breeze, took about an hour and a half, including putting the car on jack stands. Suprisingly, I didn't even need to separate the stock manifold apart to remove it. Just dropped down from the bottom with a little manipulating. The one peice went in more easily since it was smaller, lighter, and didn't have heat sheilds adding mass to it.

Took the car out for a spin and had the biggest **** eating grin on my face. Not because it was stronger. It actually felt the same, maybe a hint more oomph in the midrange. But I was happy because that annoying rattling/buzzing at 3500rpms was gone. Hooray!

So a 4-2-1 on a basically stock GS-R (Intake/advanced timing/exhaust) is not going to net you anything noticeable. I drive and flog this car 60 miles a day, I know her pretty well. If you don't have to worry too much about ground clearance, give he 4-1 a try. I'm kind of wishing I had, but since this is the daily driver, I'm not regretting it all that much. I'll put it on the dyno and see if the torque curve changed.

I figure this writeup is pretty pointless to most of the folks on the forum, but with the annoying "what header should I get" posts every week, I'm hoping this may answer a few questions.

 

DC or jdm ITR 4-1

 

I have a rattling noise caused by my exhuast manifold... when I got some work done the mechanic forget to put a bolt on and it caused a small gap to happen, and the thred for the bolt is no gone, which means I need a new exhuast manifold. If I just took it all out, and put on a DC header (probably 4-2-1 cause of the clearance issue) would it elimate the noise and everything?? My problem seems simliar to yours cause it starts to rattle around 3500 rpm or so, tho it's an LS. What do you guys think??

 

[QUOTE]My stock downpipe was rattling and I was annoyed. QUOTE]

Same here.

 

Wow.. good post! I wish everyone could be this thorough.
Thanks for the info. Let us know if you ever get a dyno, I still am somewhat undecided on 4-1 or 4-2-1..

 

4-1 Design

 

You know why your manifold was rattling???? There is actually two layers in the stock manifolds... If you go and smash the stock header a few times with a hammer it stops the noise.. for a few says. then it comes back. AHAHAHA

I know this cause my car was doing the same thing.. The muffler guy got under the car, beat on it, sent me on my way.. It just kept coming back so i splurged and got the 4-1.
Anyways, this is pointless, but just if you were curious as to what the noise was its the inner pipe on your stock downpipe that makes that noise once it gets old or has been hit or welded fro some reason..
later

 

actually, there was a dyno day done over at the Type R forum, they had like 8 different Headers all dynoed on the same car, under the same conditions.

all of the headers were within a 8hp range, and the good quality headers were all within 3hp, regardless of 4-1 or 4-2-1.

I personally have the comptech header, I like the way it looks. Search for a quality unit first, and then decide what looks best.

of course, if you are running with a built motor and are pushing 250 to the wheels, NA, you should disregard what I said, but if you are at that point, you already have headers, and you know which ones you need.

anyway, choice of which header to get isn't as hard as it seems, just get one that is of good quality and you feel comfortable with.

 

hittin your header with a hammer, that's a new one. if your exhaust rattles around 3500-4500 rpm it's the a-pipe. the idiots at honda welded them so that the two collector pipes touch. dealership will sell youa rebuild kit for only 565 dollars(a waste if u ask me). i'd rather spend the five hundred on a new exhaust and header setup, granted it amy be a little more but hey think of how much better the car will run sound and GOOOOOOOOOOOOOOOO!!!

 

Sounds like the same situation I ran into with my '94. I was debating between the 4-1's and 4-2-1's and the ground clearance issue was the breaker. I'd be willing to bet that a 4-1 with a smashed underside flows much more poorly than a 4-2-1.

 

Ya my noise I found it is coming from where the A pipe and B pipe meet. So basically, I was told it was the exhuast manifold... they said I need a new 1 and I asked what if I got a whole new header and they said "Umm, I don't know". Will a new header fix the problem? Or I am not realizing the obvious that I just need a new exhuast manifold and then add a new header anywayz. Well any help guys?

 

The aftermarket header is a replacement for the stock exhaust manifold. See the front side of your engine where the exhaust manifold comes out? See where it goes underneath the car and connects to the catalytic converter? Those are the parts that will be replaced with the header. So yes, a header will fix your 3500RPM exhaust buzz.

 

Thanks mercury! That's all I needed to hear... I appreciate it greatly!! Time to go out and BUY!