Hello all,

I have a 2008 F-150 FX2 Sport (4.6L V8). And im looking to get a dual exhaust system on my truck. Ive come to the end of getting flowmasters , however im stuck on the setup. Would a True Dual setup or a SI/DO 3in/2.5In piping sound better on the smaller 4.6L? Just curious

THanks

 

If it were me, I would go with the single in dual outlet setup. There is a certain smoothness that results from the exhaust combining into a single stream. It smooths out much of the roughness, and creates a venturi effect, as well as a bernoulli effect, both of which enhance the scavenging of the engine, which is good for low end torque, and can be beneficial to fuel economy. I like the sound of dual outlet mufflers as well, they tend to be very deep, and to project the sound smoothly. Dual outlet mufflers are louder than single outlets, and I have heard some that were louder than most true dual setups due tot he fact that there is only one muffler instead of two.

Whichever way you wanted to go, you vehicle is compatible. You vehicle has two independently monitored exhaust banks, which means that running duals is made simple, much simpler than dualing a system with only a single exhaust bank. However, there is a fuel tank that is kinda in the way a little, so the safest way to route the duals would be to bring both pipes on the same side and then route them where they need to go after the rear axle. This makes one side longer than the other, which can effect the sound, possibly in a negative way. The dual outlet muffler on the other hand will have a smooth tone, with maybe nothing more than a volume difference of a couple decibels between the two, but both will have the same tone.

The dual tailpipes with as single muffler is less expensive as well. I have not seen enough concrete evidence to show that true duals have any advantages other than sound to convince me that it is worth any extra money or the added weight. True duals work well on high RPM performance modded engines, but I'm just not convinced they have any real advantages on a street vehicle.

 

I would go with a SI/DO 2.5" pipe.
Big pipe size and true duals and you could lose bottom end torque!

 

Alright i have decided to go SI/DO Super 40 Flowmaster, what other add-ons could i put on that would increase the loudness if im not happy with what it comes out with. Was thinking a KN air filter, any other opinions would be good.

 

Avoid K&N, go with AFE or AEM dry type filters. K&Ns ruin the MAF sensors, which in turn hurts fuel economy and performance.

High flow cats may make it louder, though your vehicle should still be covered under the factory emissions warranty, and it is illegal to replace the OEM cat with an aftermarket within that period.

 

ruining the MAF is caused by a person over-oiling the filter, not the filter itself

if your getting a dry filter, i would probably go with the volant powercore, its dry and volant intakes come with an enclosed filter box rather then just a heat shield

 

Then I guess K&N over oils them from the factory because my first MAf failure on my Mazda occured only 3,000 miles after installing the K&N. I took peoples advice not to over oil them, but despite that, I have subsequent MAF failures every 5,000 - 10,000 miles since. I replaced the K&N with an AFE ProDryS and the problem went away. I have had the same MAF sensor ever since.

Volant does make good filters, though I do not have any experience with them. the thing I would be concerned about with the Volant is the price tag and when I was looking at them, I didn't see anything about them being washable.

 

Oil from a K&N is not going to make a MAF fail and have to be replaced. If oil gets on it clean it with MAF cleaner or contact cleaner. Of all the years I've been using K&N I've never found a spec of oil in the intake or on the sensor. I clean my MAF once a year regardless. I run one of K&Ns pre filter wraps and it helps keep the filter clean.

 

LOL, I know quite a few mechanics who absolutely despise K&N, though they don't mind replacing MAF sensors. You may like your K&N, I ran them for years too. And they did the same thing in every vehicle I've used them in. If the vehicle had a MAF sensor, it ruined it. I have not had a repeated MAF failure since I switched to a dry filter.

Also according to the Spicer article, the K&Ns let a lot if other crap through too. The whole point of an air filter is to remove everything from the air which could damage the engine. Any filter that fails to do that is not worth the space it occupies. In the Spicer tests, the K&N was the absolute worst filter for removing dirt from the air, unless the wrap was also used. Even then it ranked poorly. The K&N let more dirt past the filter in 15,000 miles, than the OEM filter did in 72,000 miles by over 1,000:1. AFEs ranked pretty well in comparison. I find that sad that the K&N prefilter wraps are a better filter than the filter itself. They also take away much of the performance gains.

 

Sounds like your better off using a dry filter anyway because you don't know how to properly use a K&N. A K&N isn't the best for very dusty enviroments. I have never had any intake dust problems as I check regularly or any MAF or oil problems but your filter may be closer to the MAF than mine.

Geez, an air filter is for filtering air, who would have thought.

Show me some dyno info that the prefilter robs power. Just sounds like your normal spew of hot air.

Also why would someone waste the money to put anything on a Mazda with over 500k miles on it. The MAF was probably on its last leg to begin with, if it had a MAF at all. I know Ford switched to MAFs on their trucks sometime in the early to mid 90's.

 

It didn't have over 500,000 when I got the new filters, besides, I have nothing against putting money into a car that continues to perform and function as well as my Mazda does. Every time I invest into it, it returns the favor by continuing to operate relatively trouble free. I had the tranny rebuilt just prior to turning over 500,000, the engine still runs strong, though it has started to burn some oil. It passes smog really well, and it hauls heavy loads when I need it to. I've hauled over a ton before, and while the suspension doesn't like doing that, the vehicle overall handles it just fine.

Seems to me that you have automatically decided that everything I say is wrong simply because I do not agree with you. Heck even when I agree with you I am wrong, and you will pick that apart and put your twist on it.

 

Well it just seems a lot of what you post is ridiculous. Like a K&N completely ruining a MAF after 3k miles, single platinum plugs only lasting 15k miles and etc. You give a lot of false information and slam a lot of products along the way. You have to expect people to question, thats just the way it is.

 

Hey, this is my experience. It is true whether you choose to believe it or not. With my MAf it didn't actually ruin the MAF, I was able to clean it and restore full function with ordinary throttle body cleaner. But the symptoms were unmistakable. The engine would start pinging, and it would loose throttle response, like it was leaning out. When I cleaned the sensor, performance returned. So fortunately I have not had any of these symtoms repeat since I changed to the AFE filter. One thing that also made me made, is the K&N cost me $62 bucks back when I got it. The AFE only cost $46.

 

You were saying the oil from a K&N will "RUIN" the MAF and implying it has to be replaced, Now you say it can be cleaned. Get your story straight. Several posts back I said the MAF will not be ruined and can be cleaned to correct your misinformation.

 

It will foul the MAf sensor, and if I didn't remove it promptly, it would have permanently ruined the MAF. I know on the Ford MAF sensors that it does bake on almost immediately, so cleaning the Ford sensors has less success as it did on my Moms van which also had a K&N, though it took somewhat more miles to do the damage, her MAF was a little farther from the filter, which is probably why it took a lot longer to foul out. But no amount of cleaning it restored function.

Since this is a Ford forum, and this information pertains to Fords, the I stand by my original stance, that is that the oil or crud that comes off the K&N filters ruins the MAF sensors, and they might clean up, but will most likely need to be replaced.

Look why don't you just say it. You automatically thin that anything I say is wrong and that you think that I am an idiot.