Would this yield anything? has anyone does this before? I was thinking about it and it kind of seems iffy since the stock midpipe later turns into a single pipe than splits again at the axleback section. Any thoughts?

 

Well, I have an F, but the similarity of the two, V engines in the same chassis, that I feel I can answer this. What I did, was to eliminate the secondary cats, and substitute an X pipe as you want to do. I then continued into two glasspack resonators and on into the stock mufflers. IMHO, it sounds better, but is still quiet, and puts out more power. It cost me about $450.00 for my conversion from a from a two into one into two exhaust system to a full dual system

Lou

 

Well...my exhaust removed a pair of the Cats, but its a H pipe.

 

Put it this way-

Axle-back systems on the IS350 gain about 7 hp.

Full, removing the 2nd cats, exhausts, add 12 hp.

Full, replacing the 2nd cats with aftermarkets, adds 10 hp.

So just removing the 2nd cats entirely makes a difference roughly somewhere between 2-4 horsepower.

Less, I imagine, on a 250.

Modern cats are pretty efficient.

Plus that whole it violates federal law to remove em thing.

 

To answer your question...

(Connect the lines)

This below layout will not be effecient for gains...

l l
X
Y
l l

This lay out will..

l l
X
l l
l l

 

nice...i would like to do this mod and eliminating the "y" pipe the hks hi power connects too

 

Thanks for the info fellas, that makes enough sense as well, JoeZ

Now I'm thinking about cutting up my stock midpipe and tanabe to create a true dual setup... :\

 

I did it to mine with 2.25" 304ss true dual all the way from primaries with magnaflow mufflers, with an x-pipe in place of secondaries. I love it, and it sounds pimp!