I just thought I would share my expensive adventure with my 2001 F-350 4x4 extended cab longbed. I have always tricked out every vehicle I have ever owned but learned a valuable lesson when I bought my V10 a year or so ago. Shortly after buying it I took the stock exhaust off and put custom y-pipe and 3 1/2 inch exhaust with flowmaster (I think 70 series) muffler and side exit in front of the rear wheel, K&N intake and SCT X4 with a few five star tunes. Now I understand why everyone says keep it stock and be happy! I basically gained a super loud droney exhaust along with losing gas mileage and when towing I had to turn the stereo up loud so the exhaust noise didn't drive me crazy. I just removed the flowmaster and put a stock diesel exhaust on my truck and it is quiet like it was before. Going to put the stock intake back on and try to regain some of the mileage maybe 1 or 2 mpg's I lost but realizing that these aren't gas savers by any means. I'm going to keep the tuner because I do like the changed shift points for the tranny but just wanted to throw my opinion out there if anyone is contemplating any of these upgrades. I do believe in upgrades to vehicles and I think these forums are great if you read and heed everybody else's bad experiences so you don't have to live them too.

 

I have gibson exhaust on my 6.0 very quiet. Friend has a flowmaster I think on his dodge and it will drive ya crazy. His wife rode for about 50 miles with us and loved quiet. I have oem air filter as they have shown no need for AM until in excess of 500 rwhp.

They have shown that AM intakes can help but a lot of mpg lost due to tuners and heavy right foot!

 

Flowmaster=DRONEmasters. I will NEVER install another on any of my vehicles. Last one was on my old F150 4.2. Sounded good outside the truck, glad I had a loud radio inside! Wife and kid hated to ride in it.


Y-pipe and tuner were the most bang for the buck for me. I have a CAI with dry AEM filter. Filter looks good, sounds good when I put my foot in it, but no noticeable gain in power or mpg's.


BTW, in economy tune, I can get 15-16mpg on hwy @ 70mph. Although,I keep the truck in performance tune (12-13 mpg) so I can wear a BSEG when I drive it! Besides, these trucks can't pass a gas station anyway!!

 

I did a Magnaflow on the stock piping, with headers and it's pretty quiet when not really gunning it.

 

The majority of your problem is in the exhaust. Too large tubing killed velocity and wrong exit location. Stock manifolds with the stock y-pipe is not too bad but the combination of the stock manifolds and aftermarket y-pipe gets really annoying.

I have Doug Thorley headers, K&N FIPK, Dynatech cat, stainless Flowmaster ForceII (with FM70 muffler) and 5 star tuning. I lost NO mpg and gained noticeable power throughout the rpm range. The headers are the key to having a good sounding truck that makes mor epower, the stock manifolds are utter garbage on the 99'-04' trucks and the root of a lot of problems.

People put together bad exhaust combinations an then blame the Flowmaster muffler when in fact they are the only ones to blame. I had in front of the rear wheel exit on my truck for a while with a Dynomax ultra flo, my dad had the same setup but with a Magnaflow and the SPD ypipe. BOTH were loud, annoying and had drone.(dads truck with stock manifolds was worse)

 

Your right DKF I've always been a diesel guy and this is my first big gas engine so learning what works sometimes can be painful. Wish I would have done the headers first but now with the 3 1/2 inch stock diesel exhaust and the Y-pipe its the perfect amount of peace and quiet and it isn't sluggish by far with the tuner on 91 performance. On all my other trucks I used magnaflow so never really dealt with flowmaster. I definitely think exhaust diameter makes all the difference in the world because when I hear of people going 4 inch on these V10's it sounds way oversized to me. All in all though the test will be when I tow here shortly and I don't have to put ear plugs in!

 

Exhaust systems on gas vehicles can be more fickle. A 3.5" tailpipe would be ok IF the exhaust exited in the stock location, before the muffler it would be the stock 3". The exhaust gas cools down and slows down enough by the time it exits the muffler that the larger 3.5" tailpipe won't hurt anything and can actually help. Matter of fact some of the 3V trucks came with a some 3.5" pipe on the stock system.

Turbo diesels and even turbo or supercharged gassers are not as picky with using larger exhaust pipe sizes, you can actually see nice gains by going quite a bit larger.

With a set of headers like the Thorleys that changes the headers and y-pipe, they change the sound of the exhaust quite it bit. I ordered the Force II exhaust kit the day after the headers were put on. In front of the rear axle exit and a packed muffler sounded very bad. I learned through trial and error with my V10 and my dads V10 trucks. He bought his first one in 98' so I got to know a little bit what works before I bought mine but I still made some mistakes and wasted some money.

 

I was losing some mpg so I put a in an Airaid CAI and a Flowmaster exhaust ................disappointed, didn't seem to help. Someone on this forum said to stick with the stock air intake, that the Airaid was the problem. So I took off the Airaid and put the stock air filter back in. Still have the Flowmaster on and it can drone sometimes under load but not too bad. I'll monitor and see how this goes. I still have the stock exhaust up in the attic. Haven't gone to 5 star yet, that could be another option.

 

These trucks and virtually every other come from the factory with a CAI. Those aftermarket variations with their silly non effective heat shields are not a CAI. There is no performance advantage to them, in some applications they can actually rob power.

Might be the biggest waste of money in aftermarket parts.

 

Yes, thanks! Although I did do a CAI and tuner on my Mustang and it really seemed to make a difference. Not so with the 6.8. I've also heard that the plugs on the 3v get easily
fouled and that that could be a problem in regard to the lack of performance.

 

I have an 09' 250 with a Magnaflow catted Y-pipe-into 3" piping. The 3" goes into the Flowmaster 70 in the stock location with 4 inch MBRP piping after the muffler which exits in the stock location. I also did the Airaid intake, and the 5 Star Tuner(which was the best upgrade for the truck by far) and it will pull anything I put behind it with ease. I will likely run the factory intake box in the summer and run the Airaid in the cooler parts of the year. Although the Flowmaster does drone a little and would be too "loud" for the taste of others, I love the sound it produces with the 3v V10. I have gotten plenty of compliments since I ditched the Banks exhaust and went with the 70 series. I went with 4" for the tail pipe shearly for sound depth, which is exactly what it did. About the only other thing I will do as far as performance is the BBK throttle body, and tune update. I love this truck! Can't wait to haul the next trailer of firewood! These V10's sound awesome under a load.

 

I have an 01 with a y pipe and 4" mbrp catback and engine sings nice and throaty no drone