Here's one potential setup - DC Sport 4-2-1 into Random 2.5 cat into custom 2.5 B-pipe into ITR muffler.
Pros and Cons compared to...
JDM 4-1 ITR into Random 2.5 cat etc...
Finally
JDM 4-1 GSR etc...
I know I need the Random (or similar )hi-flo cat into the custom b-pipe, and I already have the muffler on.
Which will give me the best improvement across the powerband without killing torque down low?
I'm also thinking $$$. I'm not made of money, so I'd like to keep it reasonable, but I wlso want to see an improvement. How about Spoon compared to the JDM unit?
OK. just wondering how I'm going to spend my X-mas bucks.
Thanx!

 

aftermarket 4-2-1 = weight savings is great... not much hp though
jdm 4-1 = hp and weight savings, but is $$$ when you consider a cat is needed.

Import Specialists... yup--> Carlex has a good deal on the DC JDM 4-1 and cat.....
~check out the best buys forum I think its in there.

I have an Apexi 4-2-1 and cannot wait to get my Spoon JDM 4-1 on the car.... I have dragged with a buddy in a barely modded GSR (oem header) and he was just as fast, so to a USDM aftermarket 4-2-1 compared to our newly available and now-its-cheap JDM 4-1 headers I say get JDm 4-1!!!!

 

If you are running a GSR or ITR don't even think about getting any of the "bolt on" headers out there. You need the ones with the larger collectors. If money is tight then go with the JDM ITR header and a good cat. If you can't afford that right now, still don't buy the "bolt on" one and just save your money.

 

I like SMSP's plan. I'm a patient guy, so I won't waste a few hundred bucks on a pretty piece of stainless that won't get me anywhere quicker than I cab already get there!
I figure a new cat is needed to get full use out of this system, so it's in the budget anyway. The big question was which header. Concensus says JDM ITR. I doubt I can afford Spoon or Toda, although either would be nice.
How much can I expect to spend on the JDM unit? The 4-1 with a 2.5" collector (I think that's the righ size, isn't it?).
Thanx guys

 

...$400 new.

 

Where do you get that price? And does that include the cat? They're not too much thru Nopi, maybe $150.

 

What do you guys think about the CTR exhaust manifold with 2.5" collector? I am pretty sure it's 4-2-1 like most stock manifolds but should be better.

 

good question . curious myself on how that would be ?

 

Are you sure the CTR has a ~2.5" collector (or at least the same size as 98+ Spec jdm ITR)?

Why not get the jdm dc 4-1? better value

 

Am pretty positive the collector is the same size as the ITR. I do belive that JDM GSR manifolds are bigger than USDM ones.
I don't have the cash, and the manifold looks stock and you can bolt on a heatshield.

 

So the CTR with the 2.5" collector may offer the same performance as the JDM ITR, for less $$$?
This is a stong possibility, if true.
How's the quality?
And how much?

 

CTR?
might not fit becaue the CTR is a B16B which is a shorter block compared to a B18C.. so the header may be too short and in essence hit the oil pan if bolted to your GSR motor......

never heard anyone mention a CTR header. never.
JDM ITR can be had at jdmhondaparts.com pretty cheap... or at Import Specialists cheaply too.

 

I don't think they give out the same performance. If they do then honda would have used that for the ITR as well. And it's a 4-2-1 not a 4-1.

quality? how much? i don't know, i don't have one yet but will be tracking 1 down soon.

 

https://honda-tech.com/zerothread?id=73438
On that thread, it is said that...

the B16B block is a P72/GSR block stamped with B16B on the frontside. They used high compression pistons as part of its 'R'ness...

 

Good point...
Seems like the cost wouldn't be too much different. Might as well go JDM ITR 4-1. That really seems like the best setup. If anyone has this, add some commentary. I'd like to know how it drives.
Thanx!
PS Just read the WRX wagon vs RS-X S comparo in SCC. Interesting read. I haven't driven a WRX yet, but they look like fun.

 

I had a Comptech header which only gave me like 4.6 whp over the stock manifold. In the mid range it only gave me 1-2 whp over stock, which I did not feel at all. The biggest difference was after 7500 rpm. In my opinion, all the aftermarket 4-2-1 headers are a waste of money!! Weight savings VS. the stock manifold is great though. I saved like 15 lbs! After installing the JDM header, the car seems to pull much harder at VTEC and all the way to redline! I will get my car dynoed this weekend so I will be able to tell exactly how much it helped vs. the Comptech.

 

ya i have the DC 4-1 headers and i get about 5hp!! im really considering the JDM 4-1's

 

1fast: I'm very interested in that dyno, please post the results asap

 

just get a SMS header and run no cat. You'll like it very much. trust me

 

I would definately go JDM ITR 4-1. jdmhondaparts.com has it for $400 plus $25 for the flange, $25 for the gasket, $70 for the heat shield (upper and lower seperately), or $130 for the pair. I think I would also recommend the upper heat shield, it's a little more sleeperish.

 

I wonder, do I need the flange? I guess it's not welded to the collector, as in from the factory? What's the deal with that?
2.5" collector, 2.5" cat, 2.5" custom b-pipe, ITR muffler. All should be kosher, and a gain of about 8 whp?
Sound good to you guys?
Sounds good to me!

 

chair: Follow the link below to see what my GS-R gained. The only power mods done to the car are those listed in the link.
https://honda-tech.com/zerothread?id=74611

 

Those are some impressive numbers! I really dig the torque increase. I basically have the same mods as you (ie hardly any), but this is a good place to start.
So I'm sold on the JDM! Once those X-mas checks start rolling in, I'll start drooling and babbling...
Thanx for the input.

 

chair: n/p, let me know how it turns out.

 

why buy the JDM OEM unit? why not look for JDM aftermarket 4-1 w/2.5'' collector insted rembember these are the same units that alot of japanese guys most likely have setting in there garage collecting dust because they swapped out for a better unit. I read in SCC the JDM apexi unit makes the most power of all.