Yes, I realize that the collector on the JDM 4-1 is larger than the inlet on the USDM cat, but they both share the same 2-bolt configuration that should line up. Being that it's only a 1/4" difference, it seems like it would still fit. Has anyone tried to bolt these two together?

 

I did it once, with my SMSP to my stock ITR cat. Itll work.

 

Isn't the JDM collector just a bit longer? I know mine didn't mate up all the way - had to drive home open header (ouch), and then to the muffler shop to get my Jeg's cat welded up to fit. That was a while ago, don't recall the details

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Splat &raquo;</TD></TR><TR><TD CLASS="quote">Isn't the JDM collector just a bit longer?</TD></TR></TABLE>

Yes, the JDM header is approximately 1" longer than a USDM header. There's some play in the exhaust hangers, so that might not be a problem, though I've never tried it personally.

ebelp - Out of curiosity, why would you want to bolt a JDM header to the stock cat? If you don't plan on upgrading to a larger, higher-flowing cat, you'd basically do just as well to simply buy a quality USDM-sized header.

 

Come to blacksburg y0, and we can figure it out.

 

Hey man im doing almost the exact header install this weekend. I'm having to drive to the exhaust shop with the DC JDM 4-1 on the stock cat so they can replace with the high flow. Rguy has good input on this

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">There's some play in the exhaust hangers, so that might not be a problem, though I've never tried it personally. </TD></TR></TABLE>

That must have been our problem - some play, but not enough. I could only get the cat and header halfway lined up

With stretchier (worn) exhaust hangers, you might be able to get it to line up.

 

so, to bolt it to the stock cat you need a flange and donught gasket correct? Or just the gasket? I'm planning the same install this weekend and don't want to run into any problems. I've searched, but no clear answers. bump

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bryce &raquo;</TD></TR><TR><TD CLASS="quote">Hey man im doing almost the exact header install this weekend. I'm having to drive to the exhaust shop with the DC JDM 4-1 on the stock cat so they can replace with the high flow. Rguy has good input on this </TD></TR></TABLE>

why go through that, just give dave at SMSP a call and he can get u set up with a nice cat that will fit...BIG to Daves work!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98Itr-0448 &raquo;</TD></TR><TR><TD CLASS="quote">so, to bolt it to the stock cat you need a flange and donught gasket correct? Or just the gasket? I'm planning the same install this weekend and don't want to run into any problems. I've searched, but no clear answers. bump</TD></TR></TABLE>

The clear answer is a JDM style header is longer than a USDM header and requires a shortened cat to bolt up properly. You CAN bolt a USDM cat to a JDM header but them the cat will be too far back to bolt to the USDM B pipe. You need an aftermarket cat and while you are at it you should use a 2.5" in/out cat to utilize what the advantages to a JDM header are.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">ebelp - Out of curiosity, why would you want to bolt a JDM header to the stock cat? If you don't plan on upgrading to a larger, higher-flowing cat, you'd basically do just as well to simply buy a quality USDM-sized header.</TD></TR></TABLE>

I guess I'm just impatient. I have the JDM header just waiting to be installed. I hate looking at it everyday just sitting there doing nothing. I haven't purchased a high-flow cat yet, but my stock cat was turned into a high-flow by the previous owner , I know it'll flow a bit better than stock.