i've been reading around in the archives and people have been comparing it to the DC Sports JDM 4-1 header. in comparison, the DC JDM 4-1 has slightly better gains than the JDM4-1, but it hangs lower and does not have mounts for a skid pad (which i think i would want). it was pointed out that the welds on the JDM 4-1 are inside (thus, reducing the inner diameter at those points and hindering some of the flow).

anyone know if it would be possible to port those welds without having to re-weld the pipes? is it something i could do myself? i've never ported anything before, so i'm pretty much stupid to this and would appreciate any input.


the plan: jdm 4-1 w/ carsound cat .. haven't decided on cat-back yet (maybe skunk2? apexi n1?).

the alternative header would be the DC JDM 4-1.

 

oh ya... thats no problem, guys do it all the time!

port the inside, but i do highly suggest putting a weld bead around the outside!

lemme try to find an article

edit - here ya go http://www.sandmracing.com/m_e02_jdmheader.html

 

on an off-shoot of this question... My car is gonna stay relatively tall (dropping less than 1"), so would the JDM DC4-1 be better for me since I won't have to worry about clearance as much?

 

another good question. anyone know how much lower the DC JDM 4-1 hangs?

and thanks skunkintegra ... reading up now :D

 

For reference: I have the JDM ITR header on my Teg and I'm on ProKits, which isn't too low of a drop and I scrape over the speed bumps at the new Fry's in Plano off of Central and 190. Although I think the speed bumps there are taller than usual because I can generally get over others with no probs.

I liked the gain alot with my GSR engine with CTR cams/JDM header. I wanted to get the Skunk2 IM with the setup before my wife hydrolocked my engine. doh!

 

I have the JDM 4-1 on mine. It doesnt hang very low. Ive only scraped once and that was pulling into a steep driveway really quickly to avoid debris. Im liowered 1.5" and i dont scrape on speed bumps or anything like that.

 

for searching

 

actually the dc header he welds are def not on the inside, the inside is completly flush and flat. I just got mine 3 days ago

 

TODA

-Ace

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SleepnCiViC &raquo;</TD></TR><TR><TD CLASS="quote">actually the dc header he welds are def not on the inside, the inside is completly flush and flat. I just got mine 3 days ago</TD></TR></TABLE>

i know. thats why the DC JDM header has slightly more gains thatn the JDM 4-1 (which is the one w/ the welds on the inside)... but the only thing that concerns me about the DC one is that it hangs lower than the JDM. so i'd prefer it if i can get the JDM 4-1, have it grinded and rewelded, and (after reading that one article) having it painted.. then i'd be one happy fucktard.

 

here's my honest opinion....

save your $$$ for a few months, and then treat yourself to a sms, toda, hytech, etc...

if you really want to do this all motor honda thing....
you gotta go all out

my 2 cents!!

 

also the honda 4-1 header is not a TRUE 2.5in collector it has 2 layer tubing the inner layer is about 2 3/8 inches, the dc sport is true 2.5in collector.

 

I just picked up a JDM 4-1 yesterday and it looks nice, but the welds could definitely use some work!

BTW, so if I get a 17" long, 2.5" Carsound cat from hybridgarage.com with flanges, it isn't going to bolt up to my stock '01 GSR B-pipe because of the piping diameter difference???

Someone told me that the length is fine, but the stock exhaust b-pipe(about 2") must be cut... and a 2.5" flange has to be put on that too! If this is true it sucks because you could never bolt the stock cat and header back up withput cutting it again and so on.

 

not sure but why bottle neck a the jdm header and hi flow cat, gte some bigger cat-back piping

 

You might not have to b/c the 3-bolt flange bolt pattern and spacing might be compatible.

But, even if you could do that, you shouldn't. Big bottleneck.

Use a 2.5" to 2.25" or 2" transition 3-bolt header flange. You can find them at Jeg's, Summit, and JC Whitey. Measure your B-pipe OD to determine what size to buy.

 

i believe the DC JDM will bolt up to a stock cat converter .. not sure though. will it bolt up to an aftermarket one .. like carsound or something?

 

It won't bolt up to the stock cat.

 

isn't there an adapter for it?

or is it basically, if i get a header, i'll need a new cat to go w/ it?

 

You can use the stock cat, you just have to replace the cat flange where it mates to the header collector.

For example: You can get a 2.5" to 2.25"/2" pipe reducer (whatever the OD pipe size is on the cat) for $2.49 from Pepboys and then a universal 2-bolt 2.5" ID flange w/ 4.75" bolt spacing from Road Race Engineering. Cut the flange off the stock cat, weld on the reducer pipe, put on the flange, flare the end of the 2.5" reducer, and bolt everything up.

 

hahah.

ok. its probably easier just to get an aftermarket cat. now.. another question.. will the aftermarket cat bolt up to the rest of the stock exhuast pipes? or should i just get a full catback system w/ the header and cat?

 

Depends on the bolt pattern on the 3-bolt flange.

If you really don't care to mess with trying to come up with the pieces for yourself, I'd just call Dave at SMSP and tell him what application and parts combination you're working with and he can probably supply you with whatever cat and transitions as needed. You may need to give him some measurements off the diameter of the B-pipe and length of cat you want to use.

Don't expect it to be cheap tho.

 

stock jdm 4-1 flange..


after welding outside and grinding out the inside..


Thank S & M Racing for the pics