I have a 96 F-150 with a 5.8 litre. I have had the muffler chopped out of the exhaust but the catalytic converters muffle the sound. The muffler shop told me that if I took the cats out that it would screw up the power of the engine because of the placement of my O2 sensors. Is this true?? And if so is there anything I can do about it????? I want it straight pipe loud.

 

I don't know about that, if your province is like mine, they have started the checks on vehicles for emmission testing. This would mean that if your vehicle doesn't pass then you have to get it fixed before you get your next licence tag for the plates. So, if Alberta has this, you may want to think twice about your decibel level that you wish your exhaust to be. Others have talked about running flowmaster 50 series (loudest) and you would still be environmentally friendly like the government wants you to be. Myself, I wish I could get rid of the cat. too and put on a much better flowing system BUT like everything else in this world the damn government is sticking it to us again !! Personally I am looking at a true dual system with freer (sp?) flowing cats. and a set of mufflers exiting behind rear wheels. Still checking to see on dollar figures though.

Have Fun & Keep on Truckin'

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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 6.5 Mid & Tweets.

 

I have true duals on my 89 f-150 with a 302. They removed the pre-heater and the cat, and ran true duals with turbo mufflers. During WOT the "check engine" light comes on, but then goes away. No biggie.

I wanted to run straight pipes, but since it still has manifolds, it wouldn't have enough backpressure. If you do choose to run complete straightpipes make sure you have headers. I would think a 351 would have more backpressure than a 302 with the same setup. Although I am not sure. Ford-man: any thoughts?

 

Before you do anything, take a look at where all your O2 sensors are. Many, maybe all? OBD-II machines (96 and later, maybe even 95 in Cal.) have O2 sensors ahead of, and BEHIND the converters. OBD-II looks for Oxy content also after the converters, not just in front of, like they used to be. If it tries to adjust for poor/no converter performance, you will have more problems than just a check engine light on. OBD-II is a big change from what was before. So keep your gas-cap tight. No kidding!

 

get some headers but don't bolt them on too tight and then finish off the system with some glasspacks
thatll sound sweet
jb

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Built Ford Tough
Check out my truck at <A HREF="http://www.geocities.com/fattron/jb.html
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The details are that my O2 sensors are after each cat. All I want to really know is if I can cut the cats out and put shorty blue bottles in my split dual exhaust. I know for a fact that I can't have true duals because my O2's run at the specific temperature my exhaust is at that point in the exhaust. Maybe if I moved the O2 sensors to holes in shorty headers for an older 351 engine??? In response to PASTMASTER I had an 88 ford 302 and I ran true duals with shorty headers and glass packs and had no problems except the cops.

 

I have straight pipes on mine '88 302, with dummy dual coming out the back. Not only does it run incredibly awesome, but sounds as good also.

 

I just got my "Y-pipe" with the inline cats off and had the muffler shop run me true dual 2.5 inch exhaust angled down halfway down the bed of the truck. All three O2 sensors are in the pipes (generally where they should be). So far no check engine light and the performance is A LOT better! The sounds is GREAT, but i imagine it gets kinda loud when I really floor it. So i'm still debating getting some aggressive LOW rumbling but still loud mufflers put on. I have a O2 sensor simulator in the mail just incase the check engine light comes on... then i'll plug it up to the 3rd rear sensor. I hope the performance increases even more when I get my new K&N FIPK installed.