the other day i was looking under my truck and noticed that my exhaust system has these nasty rusting factory cats in between my headers and my flowmasters. I was woundering if it is illeagle to remove them and replace them with regular exhaust pipe piece. would that increase my horsepower any.

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1999 F150 REG.CAB BLACK 2WD SPORT 4.2 LITER V6

• FLOWMASTER SERIES 40 DUAL EXHUAST
• K&N Filter Injection Performance Kit
• MANIKS GRILLE GUARD
• PIONEER DEH-P4000 CD PLAYER WITH 4 3WAY SPEAKERS
• SPIDERGEAR BED WEB
• PROCOMP HEADLIGHT BLACKOUTS
• 1.75 INCH COIL SPACERS(gave me 3 inches of overall lift).
• 3 inch body lift
• 33x12.50R16(305/70r16) Procomp Mudders
• 16x8 American Racing BAJA rims

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JDsF150@austin.rr.com






[This message has been edited by JDm (edited 07-11-2000).]

 

It is Very Illegal to remove the cats under your truck. Especicaly since you live in texas, I do state inspections for this wonderful, **** as hell state. You can try it and hope not to get an inspector like me that might not notice it, but most probably would. Also you have a pre cat and post cat O2 sensor on your truck it would cause an engine light for the rest of the trucks life. Not to mention that you will not without a doubt never pass an emissions test without your cats (four of them). On your dual exhust is it a cat-back or true dual? On my truck I origonaly had a cat-back (added some power) but after I got a clue I had it chopped off and had the real true dual exhaust installed (what a diffrence that made). One more word of warning since I am a state inspector-Thoes blackouts on your headlights won't cut the bill either on the inspection!

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99 F-150 4.2L
True duals W/Magnaflows
Jacobs Ignition
K&N filtercharger
Custom programed chip
throttle body spacer
ported&polished throttle body
ported mass air flow sensor
Black Magic electric fan

 

f150freak,

Who did your exhaust work for you? I would like to know of a reputable shop with fair pricing here locally.

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2000 F-150 XLT Sport, Silver 4-door Supercab StyleSide
Short Bed (Only way to fit in the garage)
17" Sport Wheels with BFG tires, 3.55 R, 4.6l V8, Auto (First one in 20 years)
In-Dash Single CD Player, 60/40 Split bench dark graphite

Mods So Far
Fumoto Drain Valve, K&N Filter, Gatorback Spray-In Bedliner,
Llumar ProShield Window Tint, WMS Velocity Tube

Future Plans
Superchip, Upgraded Speakers/Stereo
FlowMaster Exhaust, Nerf Bars

 

do you have cats with your true duals.

 

Factory cats can be REPLACED after 5yrs/50K miles. There are several high flow replacements that will not impede your flow.

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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
Class III tow/Payload #3/Convenience pkgs.,
4-wheel disc/ABS,Chestnut/Parchment 40/60,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification,Superchip,
Dynomax ultra-flow welded 3" cat-back.

 

Yes, I do have all four factory cats on my truck. The shop that did my exhayst is "Kinney's Muffler Shop" They are in Beadford TX at 301 pipeline. I did a lot of resherch on my exhaust, asked a lot of questions and everybody told me that it is illegal to do true duals. Kinneys is the only shop that told me that it was legal cause of the arrangement of the cats on my truck. Also after all my reasherch I found one shop kept comming up as being the best arround and that was Kinneys. I will warn you it cost me $325.00 to have it done but if I had to do it over again I would get the excact same thing, it is just that good!

P.S. y2kXLTsport, since you live close enough I might be able to meet you so you can see for yourself on my exhaust.

[This message has been edited by f150freak (edited 07-12-2000).]

 

Florida just got rid of all emissions testing. Does anyone know if you can just get rid of all the cats on the truck after the oxygen sensor without hurting the engine? Would this help or hurt performance and milege?

On my Bronco, I just gutted the 2 cats out, so the shells are still on the truck. Only problem with this is that the larger cat makes a very tinny sound when the exhaust goes through it. Does kinda sound like it has a cam in it though.

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Boss™

Just Ordered 2001 F-150 Lariat Wht/Slvr medium graphite leather, 4x4, SC, SB, SS, 99L 5.4L, 44E tran, 7700# payload, Class III Tow, 3.73LS, Skids, Capts chairs, 4W disc ABS, shift-on-fly, keyless, HD everything
Planned Mods:
Westin Chromed Stainless Nerf Bars, ARE LS II bed cover, Bedrug™, Gibson Swept Side Cat Back, K&N filter w/airbox mods, Headman headers, Superchip, 3" body lift with at least 33's, alarm/pager/auto start system, stereo system

 

Hey Guys,

Removing the cats is illegal as long as they are functioning properly, that's federal law, but the real thing here is that you are not going to se any substantial power gain by removing them. Nor are you going to see any substantial gain by replacing good working cats with high-flow aftermarket units, UNLESS your engine has been heavily modified, and is putting out 350-400 horsepower or so.

Cats used to be a substantial source of restriction in the exhaust in the 70's and most of the 80's, but not anymore. For almost 10 years now, they only produce about 2.5 lbs. of backpressure, just to give you an idea.

And, as was mentioned quite properly in another post, trying to do away with O2 sensors or not putting them back in the same location will cause no end of problems, and is something else that should not be attempted.

Good luck to all,

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Info:https://www.f150online.com/rally2000/index.html