i just installed a SI/DO flowmaster 40 on my 4.6 2004 heritage f150

it sounds nice and deep, but it's not nearly as loud as i thought it would be. is it because of the cats? i know this truck has 4, should i tear 2 off?

will an x pipe make it louder???

 

Yes, the multi-cat setup makes it quiet. You have to get a really loud muffler to make much sound. Besides being against federal law, I wouldn't personally rip the cats off a brand new 2004 truck. An x-pipe isn't really going to add the loud sound that you're after. An extremely small muffler will increase the sound. Many members run straight pipes in areas where inspections are relaxed. Getting 2 high flow cats will increase the sound, but they will likely have a shorter life span.

 

Louder than 40 Series Flowmaster = straight pipes.

Make sure you got the original 40 series and not the quieter Delta Flow.

 

well, i'm pretty sure that it's a regular 40 series.

the part number was something like 430402 or something around there. is that the correct number?

hell, it was 50$ brand new on ebay, so i figured it was the original

 

straight pipes is the way to go, they sound awesome. Run true duals off the factory cats with 2.25" pipe all the way out the back with tips, it sounds awesome. Ive got a buddy here at school wtih that setup on his 4.6 and it sounds mean as hell. Sounds alot louder than my cut out muffer/dual tailpipes setup.

Cant wait till next summer---hi flo cats, true dual straight pipes on my 4.6 Should ROAR!!!

 

but will it still sound deep and throaty or will it be loud and clappy?

 

It sounds more "mean" like a Mustang than deep / throaty. I don't think F-150's can achieve that deep throaty sound that the Chevy's get for whatever reason...maybe it's all in the cat setup. I am running straight pipe with a flowmaster "Y pipe" to replace the restrictive stock unit and have done as far as having it turned down before the axle, AND a 3 1/2" tip added and it's still not nearly as loud as half of the other trucks on the road. I'd like to do away with the pre-heaters all together and see how that works.

 

Another choice would be to do electric cutouts. That would be loud! Do a search on here, there are a few companies that make and sell them.

~Colby

 

I have flowmasters of my 2000 5.4 flareside and they sound great, loud, and deep. If you want yours deeper and louder, replace your 4 stock cats with 2 free flow cats on each side. That will increase the velocity of the exhaust to your mufflers which equals louder and deeper exhausts. If you add an X-pipe on top of that if will deepen up even more. I dont suggest going with straight pipes, I had them on mine for a will, they sound great in the low RPMs but they crack, and pop in the higher RPMs which I dont like. But if you like that sound, which some do, straight is the way to go.

 

i'm looking at magnaflow hi flow cats. which series do i need?? 53000? 54000? do i need ones with oxygen tubes??

be a little more specific because i'm going to order them.

 

Crawl under there and take a look...no oxy. tubes.