I have a flowmaster 40 series (1 in- 2 out) on my truck right now. What can I do to make it louder?


2000 F-150 XLT
4x4
4.6L
Regular cab
Off-Road package

 

Take it off and run straight pipes. Scrap the cats and get some headers. Then you will be loud.



OR, you can get some high flow cats. This should make it a little louder.

 

Taking the cats off will mess with my oxygen sensors right?
So how do I get around that?

 

O2 simulators, or MIL eliminators. Get them in any auto. catalog. They screw into the exhaust pipe up by the motor exactly the same distance away from the motor that the cat. converter sensors were. They fool the computer to thinking that the converters are still on. No check engine lights or problems.

Remember also, running no converters is illegal, and could get you a nice set of fines for not having them. If you want a safe way to better converter options, go to ebay and look up Magnaflow hi flo converters. A pair of 2.5" converters ($115 shipped for both) should be a nice replacement for your stock cats. Run true dual straight pipes (no mufflers) off of those, you should be happy.

Good luck!

 

Isn't running no muffler illegal also?

 

Well actually if you read the law here in Florida, it states that altering you exhaust from the manufacturer setup is illegal. Basically, if your stcok muffler goes bad, by law you must replace it with a completly OE muffler. They do not enforce this very strickly however. They will just pull you over if you are too loud in there opinion. And since no stock muffler system is loud, they will always be within their right to fine you.

 

What about in Kentucky? or Ohio??

 

i don't know about kentucky or ohio,but here in tennessee we don't even have a db law.you can only get pulled over for like disturbin the peace or somethin.a better way to get around the o2 sensors(and cheaper) is to make your own mil eliminators.its easy as long as you can strip wire,and will cost you about a dollar.go to radio shack or somethin and get some 1/4 ohm resistors and put em in the signal wire of the downstream o2 sensors.it was the gray wire on my 00 but you might wanna get a wiring diagram for your just to make sure.if you have emission checks you don't wanna take the cats off comepletely so just gut em and throw the shells back on.

 

That's a really good ideal.

 

How do you go about gutting the cat. converters?

 

well,first you chop em off.all my friends,cousins,etc said you can take a pipe and ram it through the cat and get everything out.i tried that with a piece of thinner exhaust pipe,thick exhaust pipe,1/8 inch thick lead pipe,and barely dented it.then i broke out the 12"x 3/8" drill bit,drilled all kinds of holes got the crow bar and went to work on em.it may take some effort but the demolition is very therapeutic.then you can weld a piece of pipe inside the cat(what i would probably do next time) or just weld the hollow cats back into place.i completely removed the 2 front elbow cats cause i happened to have some mandrel bent pipes that fit the angle perfect.but you can also pie cut some exhaust and step it down to the right angle which is just about as good.then you'll need some mil eliminators.since i didn't feel like payin somebody 50 bucks for somethin a classmate of mine did to his dodge neon when he gutted his cats,i got a 1/4 ohm resistor(from him cause he had extras so i don't know how much they are,he said like a dollar at radio shack)and put one on each signal wire of the downstream o2 sensors(then ones after the cats) don't put any on the other o2 sensors or you'll defeat the purpose.what those do is give a lower reading coming from the o2 sensors back to the pcm making it think the cats are functioning properly.this will work on any obdII vehicle.if it works on a 98 neon and a 00 f150 i'd say it'll work onanything.

 

oops,i allready said like half that incoherant dribble up there,oh well.

 

The bad advice given in this thread is simply awe inspiring. This is a totally worthless thread and should be deleted. Gutting cats (which is a FEDERAL offense - it does not matter if you have a state emissions check), MIL eliminators (which are also a violation of Federal emissions laws)...

Hey, let's make changes to our trucks that violate federal emissions laws and pull out sensors so that our ECM can't make proper fuel adjustments to compensate for those changes. Yeah, that is all good stuff.

 

I agree. Changeing the exhaust can add power, fuel economy and a little smile on your face when you rev it up. But for god sake.. do it right. I have had so many people ask me why I didnt gut the cats or delete them altogether. They are there for a reason. I do plan to replace them with highflows, but with an ECM that monitors and makes changes contstantly based on airflow and such. I dont delete anything, I just replace it with better parts. Maybe why I have 177k on the clock and it actually runs better than it did when it was brand new.

Witey, we will discuss the best way to run an exhaust for one of these trucks after we see how long your motor last compaired to mine. Let me know when your over 150k and 8 years old. Lets see how it runs then.

 

first of all,did i say anything about messin with the upstream o2 sensor which is the one that actually monitors the engine,no.i would not do that because that is stupid.i'm not gonna chop off sensors that i need.i'm simply tricking that sensor into thinking the cat is still on.some people just want straight pipes for whatever reason is their business.some people aren't willing or don't have the money to waste on replacing cats when you really don't have to.like feds go around house to house tearing apart exhausts and seein if you messed with the cats or not.which,by the way,is the only way you could tell.and you know what when i hit 250 grand i'll come ram my bumper up your ***.i'm sick and tired of people tellin me i'm stupid when i know what the hell i'm talkin about and they don't know ****.the UPSTREAM o2 sensor is the one that controls mixture.and ps.i'll be at 150 grand pretty soon,i'm at 122 right now.if you wanna gut cats do it,if not shut the hell up about it.