4.0 SOHC Off Road "Y" Pipe with Legal High Flow Cat or Cats???

[Blown]

I currently am running my own cat back with turn down before the rear axle. I cut the pipe off behind the cat and added a 2.5" pipe with 2.5" small welded chamber muffler. I know that helped flow considerably as the pipe behind the last cat used to keck-down to 2".

I did a quick search, looked at a few pages of results but I did not find what I want and it's got to have been done??? I want to legally increase flow if there are gains to be had. The stock set-up looks to be restrictive with multiple cats???

 

[adsm08]

Cats, even multiple ones, aren't really as restrictive as you think. Years ago they were but since systems have been designed from the ground up with cats in mind for 40 years that has been fixed.

Most people think a cat is restrictive because it has stuff inside of it, which would be a valid train of thought if the cat wasn't 2-4 times the diameter of the pipes going in and out. This, plus the spacing of the catalyst matrix means that the flow rate through the cat is about the same as the regular pipes.

 

[AllanD]

As an example I have a factory made "test pipe" that bolts in place of my Ranger's
1993 pattern explorer catalyst...

To be brutally honest I feel the truck runs better with the actual cat installed.
than it does with the test pipe...
Especially just doing my average running around...

The test pipe does slightly better IF I'm blazing around everywhere Wide Open Throttle though not enough to really miss it when the cat is installed...

And this is on a '93 Explorer engine with Borla Headers in a gen1 supercab (5sp and 4.10 gears)...

So If there's extra power from "losing" the catalytic converters I've been unable to find it....

THE difference between running with and without the cat amounted to fewer complaints from my mother that her feet were cold in the winter with the cat. and fewer complaints that her feet were hot without it in the summer.

Since my mother passed on last year, this difference hardly matters any more

AD

 

[adsm08]

So If there's extra power from "losing" the catalytic converters I've been unable to find it....

THE difference between running with and without the cat amounted to fewer complaints from my mother that her feet were cold in the winter with the cat. and fewer complaints that her feet were hot without it in the summer.

Since my mother passed on last year, this difference hardly matters any more

AD

And people say I have a way with words.

Allan, the way you word some things just leaves me in awe sometimes.

 

[AllanD]

Glad to hear of something else I didn't lose from suffering a stroke...

No "old jokes" please, I'm only 54

 

[Blown]

Ok guys

My condolences, my folks are in their 80's....and a stroke jeez. Very heavy next to my little question. I am fitty2

Are you two considering I am running about 6 lbs of boost and would like to put some bigger heads on it??? (then there is likely a rebuild and forged rotating assembly and more boost)

I got to keep it legal and want to do so, it's my daily driver.

 

[mp3deviant721]

I agree with those two guys. You'd be better off ditching your chambered muffler for a straight through like a Magnaflow or a Dynomax Ultra Flo. That's just my opinion though.

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[Blown]

ahhh it is a high flow, Thrush, welded, chamber, muffler 2.5" inlet and outlet, similar to a flowmaster 40 in size and construction.. The muffler flows great. The only thing that might flow better is a strait through glass pack which would be too loud for me. The restriction is in the cats and bends in the "Y" pipe and what I call restriction is not a problem for an N/A Ranger.


I am going to measure the tubing size behind the exhaust manifolds and compare to aftermarket off road "Y" pipes and call my local guys for emission requirements. If it looks doable I will report back. Doable? I want to DIY, it's got to be legal, and there has to be a gain in performance or it won't get done.

I may have to go all mustang on it to get bigger pipes and cats.