4" exhaust with or w/out cat.

[Big D.Wayman]

Hi folks,



Tomorrow I swapping a HX40 16cm turbo for the HX35 w/ 14cm turbo currently on the truck. I have a 4" downpipe but am wondering how the catalytic converter works with 4" exhaust. After that, I'll take the truck to an muffler shop and have them add BD's 4" exhaust but it's only cat. back as are most (all?) aftermarket exhausts.



Does the cat. have to stay? Will 4" exhaust bolt (weld) up?



Thanks,



-Darrell Wayman

Anchorage, AK

'95 3500

(First post - working on sig. line)

 

[nfox]

cat

In my opinion i would hang the cat out to dry, thats what i did when i installed my 4" jet turbo to tailpipe exhaust system. Oo.

 

[Boldt's Wagon]

The cat is 3 inch inlet and 4 inch outlet. The muffler shop can cut the 3 inch off back to where it flares out to 4 inch and weld on a 4 inch inlet.



Does the cat have to stay - do you have emissions inspections in Alaska? Even if no inspection, the muffler shop will still probably not install a system without the cat (federal EPA laws). You will probably have to neuter or remove the cat yourself.



To get the benefit of the new turbo, you should do something about the cat, rodding out or removal.



I have seen the cat plug up over the winter with cold operation and no pulling. The first trailer pull of the spring saw the first 3 long hard hills at 1050 post turbo instead of 850 post turbo until the cat was burned out again.

 

[Ben Rumson]

Peel it...

and gut out the insides.



If you've up'd your fuel, you'll risk pluggiing it up it you don't do anything with it.