Around here about all you have to worry about is if they can see your cats. They don't hook you up to emissions tests of anything like that, so I'm wanted to hollow out my cats and just leave them on there. What do I need to do about my O2 sensors?

 

You'll have to get dummy sensors or MIL eliminators...
I think summit racing & jegs carry them.

 

WHAT ARE LOOKING TO GAIN BY REMOVING THE CATALYTIC CONVERTORS? NUMEROUS FLOW TEST AND DYNO RUNS HAVE PROVEN THAT A PROPER FUNCTIONING CONVERTOR HAS VERY LITTLE EFFECT ON THE FLOW OF THE EXHAUST SYSTEM. BESIDES, FLORIDA MAY DECIDE TO PUT VEHICLE INSPECTION INTO EFFECT. WHAT'S GOING TO HAPPEN THEN?

I HAVE A 2003 4.6 WITH ALL CATS IN PLACE, MODIFIED THE Y-PIPE INTO DUALS FOR DI/SO MAGNAFLOW. DYNO TEST HAVE SHOWN BOTH HORSEPOWER AND TORQUE IMPROVMENTS, ADDED X-PIPE IN FRONT OF MUFFLER AND PRODUCED EVEN GREATER H.P. & TORQUE.

THE EXHAUST EXITS BEHIND THE R/R TIRE SINGLE 3" TIP. LOOKS AND SOUNDS GREAT. HAS THAT 5.0 MUSTANG RUMBLE AND IS NOT LOUD OR ANNOYING AT CRUSING SPEEDS. HOWEVER, WHEN STOMPED IT LETS YOU KNOW THAT IT IS THERE.

 

I WOULD SUGGEST TAKING YOUR COMPUTER OFF OF CAPS SO THAT WE CAN ALL SEE CLEARLY

Id keep stock cats and just run true duals wiht magnaflow muffler into 2 tips. That would sound great!

 

97 Ford 4x4,

Saw 2 others that posted they did this ( the brute force way with a piece of rebar ), but they never posted any Dyno results if it did anything but make the truck louder ( and if it did anything to the xhst gas flow for TQ good or bad ).

It is that old wives' tail that Cats rob performance, for a correctly functioning cat

Unless you are going after Kooks Long Tube Headers, high flow cats, and true duals, don;'t bother the stock cats ( unless plugged ).

Start out with a True Dual kit, and see where you go from there, it might be Headers and high flow cats after that ( $$ )

TDS,
Please stop yelling, I'm half deaf now

 

I AM NOT YELLING AT ANYONE. THIS IS A FORD ROTUNDA KEYBOARD AT THE DEALERSHIP WHERE I AM THE SERVICE MANAGER. IT ONLY REPRODUCES CAPITAL LETTERS. THAT IS THE TYPE OF CHOICE FOR TECH LINE COMMUNICATIONS AND INTER-FORD CONVERSATIONS.

NO OFFENSE TAKEN, NO OFFENSE MEANT.

 

Here is my 2 cents.. and its from a friend of mines own experience.... He gutted his cats and ended up buring the hell out of his valves.... supposedly, and according to others on here.. you will generate extra heat that is usually trapped in cats and you will pay a big price in about 10 k....

he had to have a good bit of work done on his engine at only 27k and now faithfully had his cats in place....

 

I went home and brought the pc keyboard back with me. Its not as nice as FORDS and is not wireless but at least everyone will not think that I am SCREAMING at them.

If your catalytics are working properly and not clogged or deterioated, then why take them off? In wide open race applications - yes. For normal street performance and saturday night street racing - NO!

Could not resist the CAPITALS.

 

hey fellas . help me out! just had magna flow ceramic headers installed,long pipes cat backsand muffler. only one muffler on truck when i picked it up, dont you defeat the purpose by only putting one muffler back on?i had the truck dynoed before the headers were installed, had 406 at the wheels and 528 torque, took it back same day i picked up truck to mustang muscle for another dyno,horsepower remained the same,torque increased to 538, shouldnt i have seen greater numbers.wally

 

Long tube headers, high flow cats, and a Y pipe and a single muffler ?

I never would have thought about doing that, but it is a mod better then stock, and better then a cat back using the stock Y pipe. IF they used the Magnaflow Y pipe, I think that is dual 2.5" pipes into a single 3" pipe. It is better then stock by a long shot, which the stock Y pipe is more like a T pipe.

The TQ gain is the big part of doing the xhst. With alieving the backpressure and keeping the xhst gas flow going. This should be over most of the entire range, not just the peek TQ.

If you picked up 10 TQ Peek, take a look at the HP at peek TQ RPM, that should be up when compared to the first pull. ( TQ=HP*RPM/5252 ).

Peek numbers are a good indication of over all engine abilities, but when comparing the first and second pulls, you should compare the numbers over the entire range of the pull, to see where the TQ and HP for each RPM is at. With the formula, the HP should be up at the peek TQ area.
If you have the numbers electronically, over lay the 2 graphs to get a quick visual on the pre and post mod pulls.