I have an 08 Reg cab 4.6L. I have a K&N drop in and I know I didn't pick up any power but it does seem to respond better. Well, now I am looking to buy an intake and magnaflow exhaust. Has anyone experienced a decent gain with these two? I know they both have outrageous claims of power gains but what can I expect in the real world? Gas mileage and power?

One more, would you go with Roush legal or Magnaflow SI/SO exhaust?

 

More free flowing filter will always suck down a little more air.

I would take the Roush Off-Road personally, but I think I would take the Magnaflow SI/SO because it will be a little louder if done right. Single 3" exhaust with a 4" tip.

 

First, a tuner is going to give you the most performance gain. It will add about 15 to 20% power plus improve shifting. The intake and exhuast, maybe 5 to 10 hp. But if you can, the best solution is all three. S&B or AF1 intake, a Roush Offroad exhaust, and a Gryphon tuner would be my choices.

 

Oh yeah a tuner is definitely in the future. I want a gryphon (is this pronounce griffen?) but for now I have to do something to the truck and I cannot make my mind up on wheels so I am going to wait on them till tax time or maybe Christmas. My main concern now is freeing up the exhaust and intake for a little better mileage. Atleast that is what I told my wife. Lol. Other than wheels, these two things and the tuner are the most expensive I have planned so I want to do them soon. I will be buying my tuner in about a month. Will the intake and exhaust make my truck run lean even if I reset the ECM?

 

I do not know if the 4.6 has the same propensity to run lean as the 5.4. The 2004 and 2005 5.4s would definitly run lean with a higher flowing intake. Here is the order I would use. Exhaust(because I have to hear it), the Gryphon, intake and then wheels. That way, you can run the canned tunes until Bill gets your custom tunes to you. You can get a custom tune that will incorporate the intake you are getting. You will already have your tuner when you get the different wheels and tires, thus enabling you to reset the odemeter for the new size.

That would be my plan and order of things. I just don't think you take advantage of an intake without a tuner with a custom tune, plus you run the risk of running lean.

 

Just to say it another way, if I had to give up mods, the very last one I would give up would be my tuner. It does more for the truck than all the others.

 

Good point. I guess I will have to buy all three at once. Thanks. That helps alot. Although my wife would probably not like your advice.

 

They do tend to not see the necessity of these things.

 

A less expensive mod you might consider, a Ground Force 2" shackle kit to drop the rear a little. If it were mine, I would remove the STX stickers, but that's just me. I hate stickers.

 

whats that got to do with power and milage?

personally, I think that lowered trucks are just way below me.

 

Lower trucks use less gas and the decal removal cuts wind resistance and weight. Good grief!

 

I will be removing my spare tire, and door handles in efforts to decrease weight even more. The sticker never even crossed my mind. NICE CATCH!

 

Actually, I have already raised the front with an AS and removed the decals. Pics are in my gallery. I added a whole bunch of stuff. New headlights, grille, AS, ez down, hood deflector and HID's. I wanted it leveled and the wife said no lowering so I went up. LOL.

 

Looking good!

 

This will no doubt be a minority opinion but here's another way to approach it. the fact that you are thinking about the Roush Legal makes me think you are not looking for a giant noise maker. I put the Roush Legal on my 2006 5.4l and think it's as loud as I'd ever want to be. I also tried the roush intake but found it to be unpleasantly loud and droning apparatus. It did however flow better and the truck ran much better than stock. Instead I put a AEM dry drop in filter and frankly it seems to flow just fine and without the noise.

I don't doubt a custom tuner would be an improvement but is this idea of $450 exhausts and $350 intakes plus $400 tuners really worth it...and then we need electric fans and underdrive gizmos??

Maybe I'll go for a tuner down the road but for now I've got a nice mellow exhaust tone, I'm getting 19+ MPG at a steady 65-70 mph and it runs better than stock. I'm just going to leave it alone a while and see if I really feel the need to go further.