I have a 99' GS-R and I'm in the market for a good header and exhaust system. I've been having some trouble finding good information on the true differences between a 4-1 header and a 4-2-1 design. Right now I'm between the DC 4-1 header and the comptech 4-2-1, as well as both companies cat-back exhaust systems. The cat-back needs to provide power(duh), but not sound too loud and reedy. I would appreciate your opinions and experienses with both of these systems as well as other possible options.

Just so you guys know I plan on going further with the motor in the near future, with cams, ECU, fuel system, etc. But I/H/E is first.

 

I'm judging by your posts that you are fairly new to this board. If you are then let me be the first to tell you that there is a search button in the right top corner. Let it be your friend and click on it and type in header or exhaust. These topics have been covered numerous times on here and you should be able to find much information.

 

then 4-1 is like the ITR header design. The 4 pipes go straight into one pipe. Hence 4-1.... the 4-2-1 is more like a two peice header. The 4 pipes are joined to 2 pipes then joined up to 1 pipe. I hope that it makes sense at all. But i had the 4-1 header its great, but if your car is slammed low close to the ground like mine then your gonna end up smashing the bottom of the header, when you bottom out on a speed bump, etc. HOpe it sheds a little light....

 

I've been around performance cars all my life and I know a significant amount about muscle cars and carburated, large displacment aplications. I'm not as educated on imports. Comptech tells me that a 4-2-1 design's power is throughout the power yet no real gains come till about 4500 rpm according to their dyno graphs. And the 4-1 design seems to be better from my standpoint but there are an overwhelming number of people out ther running 4-2-1. I'm just trying to find some information on how much of a power gain and where at b/t these two systems.
THX

 

The 4-2-1 design is going to basically get you more lower to lower mid range power. A 4-1 design is more of a mid to high end power. Its up to you where you want your power gains at. I personally have the DC CC 4-2-1 header design.

 

In general, 4-2-1 headers provide more power (& torque) throughout the power band, 4-1 headers provide peak power.

There's some exceptions (Hytech, Toda, Spoon, etc), but you won't be able to buy them for less than say $700 (But they're worth it). All the high dollar headers are 4-2-1, but that's an entirely different design.

If you plan on going on to cams & etc, I'd recommend a JDM DC 4-1. It posts power gains similar to the high dollar headers because it has a 2.5" collector. The downside, obviously, is that now you need a 2.5" cat and a 2.5" exhaust.

No real power comes until 4500 RPMs because well, its a Honda.

 

yea that really sucks. i have actually scraped my oil pan
i have the dc 4-1 and it RULES!! oh and the DC 4-1 makes dyno proven power. That comes from an unbiased dyno owner who doesnt sell any parts, its just what he has seen. he has actually seen a mugen header make a type-r LOSE HP.
later

 

i've got plenty of power down low...he he he hee

 

What do you guys think of the exhaust systems? Are they loud, deep, or reedy? I don't know anyone that has either so i can't hear them in person.

 

I know both are relatively quiet, but I haven't heard either in person.