Has anyone run there truck WITHOUT the cats? I have the resources to make another Y pipe, one without the 4 factory converters. I know that there will be a difference in the sound from my Gibson exhaust, but wonder about any improvements? All comments welcome!!!!

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1997 F-150 SC,4X4 OR,4.6, AODE.BLK. K&N GEN II, GIBSON SUPER TRUCK, SUPERCHIPS, B&M SHIFT CONTROL.

 

I believe it is illegal to run without cats. They are after all pollution control devices and the gov't tends to frown on that. Also it has sensors running to it, might affect how truck would run.

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97 F-150 S/C 4x4 ORP XLT 4.6 tow package
K&N , Flowmaster cat-back w/3" chrome tips. Bosch+4 plugs, Superchip.
Patriot fiberglass toneau cover, Westin chrome step bars.
Future mods: underdrive pulleys,4" lift, 16.5 wheels with 33's,ram air hood,and someday a supercharger.

 

I really doubt that you will feel any increase in performance by removing the Cats unless they are plugged. Also I am curios when you say "4 factory converters"? Are you sure that the ones located closer to the engine arent expansion chambers for the factory headers? They usually have these shrouded with sheet metal just like the Cats and removing them will restrict the flow.
I had a Crown Vic that was set up with duals an H pipe and 2 expansion chambers right at the end of the headers.
If it isnt too much of an expense to cut them off and run it without the Cats go for it.
Get some base line results on a Dyno before and after. Keep us posted.

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1995 F150 4x2 4.9L 5spd Twin I-Beam Front Suspension Gabriel Sport Ride 3 stage Nitrogen Shocks 3.08 rear axle, Autolite Platinum Plugs, Exact Wires. Goodyear Workhorse Extragrip Tires,

 

LAPEMPLOYEE -

You must keep in mind that many of the components on your vehicle - especially those in the emission control system report back to the computer. If you remove the 'cats', you're just asking for trouble. I don't think your truck will run very well, you'll probably get check engine lights on your dash, and you be breaking the law on top of it all. I don't you will see any advatage to removing the converters.

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Black '97, SC with 4.6, 3.55 gears, automatic, 2-4 Belltech drop kit, SnugTop fiberglass lid, 3 chamber Flowmaster muffler, billet bumper grill, fog lights, American Racing 17x8 wheels with 275-60 Goodyear Eagle GT II tires.

 

I recently had my exhaust redone on my '92 Flareside. Added headers, removed both cats and went with factory 2 1/4" pipes from headers to new 'Y' pipe with single 3" from there to a 50 series Flowmaster and exited in front of the rear tire. By keeping the factory pipes to the 'Y' pipe I could keep the O2 sensor plugged in. No engine problems whatsoever and very noticable power increase.



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'92 F-150 Flareside R/C "Electric Red" 5.0L
mods: K&N FIPK, Hypertech chip, Hedman Hedders, 3" exhaust, 50 series Flowmaster.

 

The two chambers that are mentioned above could be a resonator and a cat. I had a '87 and '94 F-150 and they both had that design. When I changed the cat on the '87, the new one was a combination of both. I wonder if the factory has a two chamber set-up until something goes wrong and then the aftermarket ones are a combination of the two.

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1994 F-150 XLT Supercab, Long Box, 302 EFI, Automatic, Royal Blue in and out, Captain Chairs. Chrome Rims 15x8's, Michelin LTX M/S 105S 235/75R15 (Summer), OEM Aluminum Rims 15x8's, Michelin LTX M/S 108S (Winter), Lightly Tinted, Soft Tonneau Cover, Ford Receiver Hitch Cover & Lock, Alpine CDM-7829 Head Unit, PPI 4800 Amplifier, Kicker 10" Solo Baric Sub with Custom Box and Kicker Impulse 6.1 Mid & Tweets.

 

Thanks for the replys, never thought about the resonator, expansion chamber design in this system. Could very well be what they are. What about any of the aftermarket header systems, little change or lots of change?

 

Yes those are all cats on the 97-99 f150. As a matter of fact the V8 models have 6 cats! One near the manifold and two in the longer housing downstream. That's 3 per side for a total of 6.
I try to keep up on the mustang mods to the 4.6L and it seems that the cats are worth 15 or so HP on the stang, which also has 6. The downstream O2 sensor must be fooled into giving the computer a nominal value for the OBDII sys to function in a drivable manner. I believe the 'stang guys wire a resistor in series with the O2 sensor but I have not found out what the value of the resistor is. If anyone knows where it goes and what the value is please post it!

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98 SC 4.6L stepside, Gibson headers, Gibson single exhaust, superchip, Intake mods, Piaa's, high end audio stuff.

 

hmmm,

I know for a fact that my truck has 4 converters or 2 converters and 2 expansion chambers if that is what they are. Either way there is only 2 somehtings on each side before the Y, then the muffler.

Could your truck be a California model, I think they add more emissions stuff on CA models.

 

For the older 302's you could buy an off-road H-pipe with threaded inserts for the O2 sensors. I don't know if it is available for the 4.6L or not. They did increase the HP bigtime. Don't forget that Ford has a very restrictive exhaust system to comply with EPA standards. I would recommend that you check with state/local laws before removing your cats, unless you are very good buddies with a state inspector. If you can duplicate the factory y-pipe with O2 sensor inserts, I say go for it as long as you can put the factory cats back on.

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stock 98 XL, Reg. cab,4.6, Auto, Tow package, 255/70R16 on styled steel wheels,3.55LS, Black with chrome grille and bumpers! MODS: custom stereo by me, building speaker box was a !@#$%. K&N air filter w/ airbox mod.

 

daveR, what year is your truck? Is it a late model? Did you get it new? the first cat should be the light off cat and as far as I can tell should be intact. It is of course very possible that ford found that it is not needed on some models and deleted the light off cat. Anyway mine has it, I took a good look at it when I installed the headers.

Chris

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98 SC 4.6L stepside, Gibson headers, Gibson single exhaust, superchip, Intake mods, Piaa's, high end audio stuff.

 

cujet,
I got my truck new. Its a '98 STX model, reg. cab, shortbed, 2wd, 4.6 5-spd.

I just went and crawled under to have another look. From the headers down the next "thing" is what appears to be a converter only because it has the heat shields. It is located at the bend, the inlet for them is coming in at an angle from the top, as the pipe comes down from the headers. The outlet goes out straight towards the rear, so these things kinda form the bend if you can understand what I'm explaining. Then it goes into what looks like a more conventional looking catalytic converter, straight through. After each one of those is a sensor then they Y together on the passenger side and go to the muffler.


Like you said I'm sure Ford has made different setups for whatever reasons/options in the past few years.


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'98 F-150 STX, 4.6L, 5 spd. reg. cab, short-bed, all black,... Line-X, Superchips, JBA headers. More to come.

 

LAPEMPLOYEE,

Removing the cats is a no no. But I Will not go into that. Your 97 has 2 converters, and these are three way converters. There is one on each side for a grand total of 2 converters. The heat sheilds at the bends in the pipe just below the manifole connections are just that heat sheilds. If the pipe is larger at this point it is probably to slow down the exhaust flow going into the cats to make them function in a more effeciant manner. Now if you remove the cats you should start with fresh pipe from the manifold back. This will save you $$$ in the long run because when you get caught and have to replace the system you will still have the OEM one. You will need to plumb the HO2 sensors in the new pipe, further down you will need to plumb the CMS. The CMS measures the variance in the oxygen level after the cat. You will need to find a way to change this reading or you will drive around with a code set. And that is where I leave you, looking for a way to cheat the system.

Kindest regards

Jean Marc Chartier

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On Order: 00 F-150 XLT SC Flairside 4x4 4.6 w/5spd
using: Wife'S 99 Explorer till arrival

 

I hear there's a $500 reward for providing info on anyone that has removed there Cats???

M

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'98 XLT, 4.6L, SC, 4x2, 3.08,
Black, SB, Flareside,
ARE Tonneau,
Lined, [img]//www.myf150.com/images/other/markg.gif[/img]
Tinted,
Deflected,
Mini-Disced,
Amped JBL 4x100,
Subbed JBL 2x12,
K&Ned,
B-B-B-M-F
Goin' thru tires fast
not Superchipped yet
not Supertrucked yet



[This message has been edited by Mark G (edited 10-03-1999).]

 

I talked with a friend at Ford and he said that you will see a power gain with the cats removed. The only problem you will have is the "check engine" light will come on. My friend also said that removing the cats is a federal no-no and does not condone this practice.