first, yes ive searched and found some good information. with that outta the way, my jdm header is getting scraped up pretty badly, and im positive its takin out a ton of power.

I know I can get a type one, mugen, JUN, toda, an-r, or JG modded header, but those are all over $500, with that being on the low side.

Im curious if anyone has taken a (type r maybe? since my setup is w/ the itr header) 421 and had a 2.5 custom collector welded on there. this ground clearance is killing me.

i am not an autochrosser so i dont care about what you have to say about 2.25 collector, unless you are stating that the company's design is to be used with a 2.25 collector and putting a 2.5 collector on it would actually lose power...but I think that the dyno chart on that JG modded on proves that theory wrong.

please let me know what you guys think, im in a pickle, and sort of low on funds right now, but if i can sell my dc jdm for relatively cheap I could probobly piece together the money for a new header. Im in no rush, just want some opinions and ome advice from people that have done this first hand, or have dyno charts. cut the bullshit, i dont want any my brothers friends cousin, just the real deal. thanks for your time.

peece

 

So do you mean put a 2.5" collector on a stock ITR manifold?

 

not stock, but aftermarket, like a DC, Rs*R, JG, Apexi, Greddy, but just in the type r form ( length, whatever )

 

I dont' see any reason why you couldn't do it. I don't think you'll see any gains on headers designed like DC sports or Greddy. Now the good stepped primary headers like JG you should get some gains off of.

Have you considered the JDM ITR 4-1? Fastline Performance makes skid plates for them, that bolts right up. The JDM ITR sits a little higher than the DC JDM header as well.



http://www.fastlineperformance.com/skidplate.htm

 

i figure if i upgrade, i want something i don't have to be fretting about every 12 seconds. the b17 sits lower than any other engine ( i believe ) so the dc is practically dragging its ***** all over the place...i've been really careful and it was doin good, but one pothole killedit--

plus the 421 w/ 2.5 design makes better midrange and good high end. im just contemplating my ideas. I will probobly just stick with my dcjdm until i have enough money laying around ( literally ) to just buy another one and not worry about it, but that wont be for a while.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">plus the 421 w/ 2.5 design makes better midrange and good high end. im just contemplating my ideas.</TD></TR></TABLE>

Those 4-2-1 w 2.5 designs are not the same as a DC 421 with a larger header. The secondaries are much further down, around where the collector would normally be, and the collector is also further down. You need a shorter catback in order to fit those.

I don't have any proof, but I do think it will decrease power. You are going to have a rapid increase in diameter. The final pipes are only about 2.25" after the secondaries, and they taper down to 2" at the collector. Seams like it would be very inefficent.


Modified by StyleTEG at 5:41 AM 5/21/2003

 

i have no problem extending my exhaust and cat forward, but what you said about the rapid decease in diameter is what im worried about.

does anyone have a dc SS 421 for a type r? i think they would have larger primaries than the normal dc 421s, but i cant be sure. i think importbuilders.com does a 2.5 mod for the dc 421 (type r) but the only thing i ever get out of them is that dam misleading dyno chart thats been posted a thousand times and "the JG is better"...sweet..nice information. anyway, anyone with any advice please pop their head in.

 

Well I dunno if you could extend the header in the way the hybrid headers do

check out this spoon


The secondaries are not till the very end of the header, almost at the collector, where the DC 4-2-1 are right near the exhaust ports.


Modified by StyleTEG at 5:41 AM 5/21/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StyleTEG &raquo;</TD></TR><TR><TD CLASS="quote">The primaries are not till the very end of the header, almost at the collector, where the DC 4-2-1 are right near the exhaust ports.</TD></TR></TABLE>
Maybe I have this all wrong but I thought the primaries were the four pipes that connected to the head. And the secondaries are the two larger pipes that connect to the collector. Can you tell me for sure which one it is?

 

You are correct, I wrote it backwards I am going back to fix it to avoid any confusion.