I have a 04 F150 4x4 STX Supercab with a 4.6L. It has 3.73 gears with limited slip and FX4 18" wheels with 275/65-18" tires. My current performance mods are a Corsa cat-back exhaust, K&N cold air intake kit, and a Diabo tuner. I just ordered a Edge programmer so I will be ditching the Diablo tune as soon as the Edge arrives.

In retrospect I should have got the 5.4L, I bought my truck used and liked it better than any 5.4 I found in my price range. I am trying to decide if I am going to keep the truck or sell it and buy a 5.4L. I love my current truck but I am pulling heavier trailers more often than I planned and I am dissapointed with the towing performance of the 4.6L. Are there any other mods that you recommend, or should I just get a 5.4L?

I normally pull a trailer at least once a week. I pull a jetski & sailboat overall weight approximately 1500 pounds, a 6x12 enclosed trailer approximately 4000 pounds when loaded, a 20' boat weight approximately 3200 pounds and a open car trailer that is 2800 pounds empty, plus 2000-4000 pounds for whatever car is on it.

I am satisfied with the performance without a trailer. However when I am pulling a trailer, acceleration sucks, it does seem like it can almost always gain speed at any time. The strange thing is my jetski/sailboat trailer seems to cripple the truck as much as the loaded car trailer. I always tow with overdrive off, and the few mods I have done increased performance significantly.

 

have you done an AAL?

power wise, you could re-gear but thats 1500 bucks for front and rear.
turbo set up
headers

thats all i can think of off the top of my head. just remember selling your truck to get a 5.4 you will lose money obviously but the truck market sucks right now as well.

 

as stated above a turbo would be your best choice, however it can be pricey as there are mods to any kit to make it fit your truck.

long tube headers, 24# injectors (for more part throttle torque), e-fans and a dynotune would work,

4.10 gears would almost be a better choice

 

First off you should have got the gryphon, second it dosent seem that you would be happy with either engine, you are going to have to go slower when towing it is that simple.

 

I haven't done an AAL, my truck seems to handle tongue weight nicely though. I attached a picture with the car trailer connected, the rear is sagging 1" at most with approximately 500-600 pounds of tongue weight.


I was planning on regearing, I have a friend that is experienced installing gears and will do it free, so I only have to pay for parts. I did think my truck had 3:55, and was planning on going to 4:10. Now that I found out it has 3:73 I don't know if will be worth the hassle to upgrade them. I don't want to go any taller than 4:10 though since the truck sees alot of highway miles unloaded.

I am not a fuel injection expert, but I do not see how 24# injectors would increase part throttle torque, please elaborate. My understanding is unless your injectors are at consistently at 100% duty cycle and you are still running lean, then there is no benefit to larger injectors. I would be suprised if I am close to 100% duty cycle with my minor mods.

How much HP/TQ do you think I will pick up with a good set of headers? If ti would make a fairly noticeable difference, I will give it a shot. If it will be a marginal difference at best, I don't think I mess with it. I am assuming it will take more than a set of headers to wake up this truck's towing potential. A quick search at Summit Racing showed several different options in the $150-$300 range.

I was looking for a supercharger for the truck, but obviously didn't find any kits for this truck/engine. I didn't look into turbo chargers much at all though. I will do some research and see what turbo kits are available. I think a turbo is a viable option if it would require only minor modification to the kit to get it working properly. I don't really want to get into doing major mods to a turbo kit. The truck is a daily driver and needs to stay reliable.

I bought the truck in December 07, and got it way below market value at the time, it was probably equivalent to the current market value of the trucks. Judging from other ads, I "should" be able to sell my truck without taking much of a hit, if any. If I did pick up an 5.4L, I would transfer any of my current mods that crossover.

 

I should have done more research on the programmers before I bought the Edge. I was researching towing on this site and everyone kept mentioning how great the Edge was so I placed an order for one. About an hour later while doing more research I saw the Gryphon mentioned for the first time. Since I bought the Edge already, I think I will try it first, then most likely send it to get the Gryphon upgrade/custom tune.

I probably should make my towing goals more clear. The truck is able to maintain speeds that I tow at (60-70mph depending on trailer), it feels like it could get going faster, but for safety reasons I haven't tried. Acceleration is pathetic though with any trailer behind it, it feels unsafe trying to get up to speed on the highway. The 04 F150 is my 2nd full size truck, my first was a 95 F150 ext cab/sb with a bone stock 351w. The 95 had similar HP/TQ ratings (which may have been underated) but it pulled so hard, it felt like you could just yank my jetski and sailboat off their trailer. With the 04, it is very sluggish with the same trailer and load (no more than 1500lbs), almost as sluggish as when I pull 6-7k pounds. I can understand being sluggish with a heavy trailer, but it seems a light trailer with minimal wind drag should pull easy. If I could improve the acceleration while towing I would be thrilled with the truck.

The Corsa exhaust, K&N cold air intake and Diablo programmer did seem to improve the towing performance significantly, I am hoping the Edge/Gryphon towing tunes will improve it even more.

 

Mike Troyer explained it to me, something about the larger injector being able to shoot more fuel onto the valve, my truck gained like 30hp on the top end with the larger injectors and tune

Long tube headers is where you will gain better towing ability, shorties will just gain you some noise

a remote turbo system (similar to the STS) can bolt up in place of your muffler and then run the boost piping forward

or any 2 valve 4.6 mustang turbo kit, you'd need to modify the piping to clear your truck but might be easier

here's a supercharger that I've been looking at for my gutless 4.6 https://www.f150online.com/forums/su...0-what-if.html

 

you can trade your edge in for a gryphon. contact power hungry performance. its about 75 bucks i believe.

headers- you will want long tubes. shorty's dont gain you any power. long tubes i think you will pick up about 25-30hp but i would verify but you will pick up a decent amount of power.

you would probly pick up about 35-40 rwhp with the long tubes and gryphon i would assume.

 

What other mods did your truck have when they recommended the larger injectors?

 

I think I will definitely do that. It is $25 for the tuner conversion and $50 for each custom tune. I should have bought the Gryphon in the first place, but it could have been alot worse. As it is, it will cost an extra $25 if I get 3 custom tunes, but I will most likely just get 2, so I will actually save $25.

I found a couple sets of long tube headers, but I haven't found any mid-pipes that can be used with long tubes for our truck. I definitely don't want to go hacking into the Corsa exhaust. I need to do some more looking and see what I can come up with.

 

Not sure if the 4.6 will be the same, but the 5.4 in my Expy responded very well to headers, high flow cats and a Flowmaster cat-back exhaust in addition to an electric fan conversion.

For comparison - my Expedition at 150k+ miles was about 1.5 truck lengths faster getting to 60MPH than another bone stock (5.4) Expy of the same year with less than half the mileage...

I'd have to imagine the 4.6 would see at least a comparable difference with the same mods, especially with the difference I've seen it make on my Mustang (with the 4.6, of course).

 

efans will be your cheapest performance mod at this point

 

pulleys, shift kit, cat back and a cai

 

With the 4.6, it's peak power is in the upper rpm range to begin with. So, you have to find stuff that'll get you more power in the lower rpm range if that's what you are looking for...

When I go on the hwy on ramps from a stop, I have to wind out my 189,000 mile 5.4 pretty good, but it gets up to 60 mph pretty fast, considering the 'brick' I have on the back.... I expect it to be slower on the acceleration side, just because of what I'm asking it to do at that time..

I also tow a 4x8 utility trailer and can load it up to about #1500 max... I can certainly feel it back there and it still takes my truck some extra time to accelerate with it..

"Towing performance" is very subjective IMO and I might drive your truck with any of your various trailers attached and think it's fine... I think my rig is fine, but if you were to drive it, you might think it's crap...

Again, for you, I'd be looking for any kind of 'low end' improvements and if you happen to need to rev up past the 4000 rpm mark, just know that's where your motor is at it's best power... If you don't like 4000 rpms, then you need a diesel!! ha, ha!

Mitch

 

I got the Edge tuner yesterday and loaded up the level 3 performance tune. It really seemed to wake the truck up and move the powerband down lower. I was surprised how big of difference it made over the Diablo. I haven't tried the level 2 yet, but will switch to that before I tow. I will be pulling my 6x12 enclosed trailer Sunday and Monday, so I will know by then how much it improved towing.

I also bought an E-fan kit from another member of the board, those will be here Monday so I will install them early next week.

I agree towing performance can be very subjective. I am definitely dissapointed with the "performance feel" while towing with the truck. With my 00 Explorer Sport V6 it seemed to pull my jetski/sailboat trailer with ease. My 95 F150 felt like I could hammer it and the stuff would fall off it would pull so hard. The 04 F150 just slowly accelerates. It does get there though, and hasn't refused to do one thing I have asked it to

To be fair, the 04 F150 is heavier than all the other vehicles I have towed with. We just had it on a recently certified scale yesterday it was 5860 with less than 1/8 tank of fuel. It would be pushing 6000 with a full tank.