Okay, this is the deal. I have a '98 F150 Supercab shortbox, 4wd,Lariat trim, with the 5.4, auto, and 3.55 limited slip. The only mod I have done is the overload springs, Hellwig 25's.

Now, I love the way this truck handles, unloaded...and it's mpg. I am towing a race car on a trailer, so my max tow weight, including the trailer is 6500 lbs (2000 lb trailer, 4500 lb car). More likely, with my race car (2800 lbs), I'm looking at 5000 lbs including the trailer. But, I often carry spares in the bed of the truck, like engines, trannys, rear ends, ect.

I am also running 17" tires on factory Ford rims.

I want this truck to pull better, stop better, and all around perform better, but not really mess with the mileage. Here are my thoughts, please chime in if you have some ideas...

Toss the overload springs and go with some Air Lift air bags. Ad a rear sway bar. Go to 16" rims and a light truck tire in the D or E rating, like a 265/75-16.

For the brakes, I'm thinking of better pads and a professional brake bleed.

But, for more power....? I have had problems with the K&N gooping up my MAF. What about 3.90 gears...or greater? A tranny shift kit?

Could my truck be modified to match the tow rating of the F-150 with the 7700 package? I really am not ready to buy a new truck yet, so, for the time being, this is what I have to work with. Like I said, the K&N wasn't good in my application, but maybe a better exhaust system coupled with gears will make the difference I'm looking for. I have decided not to go with a chip, mostly because of the premium fuel issue.

The rear suspension is my biggest issue really, it sags quite a bit, even with the overload springs. Is there a company that sells heavy duty springs, maybe 4 or 5 leafs, that would bolt into my truck? Without raising the back end by 2 inches or more?

Let me know, my other option is going with a V10 Superduty...and I'm not ready to step up just yet, the mileage is really a big deal to me.

 

I believe your GVWR is 12,500 pounds with a max trailer weight of 7500 pounds, according to the 03 owner's manual. I had a 99 Lariat Supercab 4x4 5.4L and it was also around 7500 pounds.

To improve performance, though, intake, exhaust will help. If you don't want a full intake kit, then at least a K&N drop in. People seem to get better mileage with that; I did on my 99. Doesn't help a lot with power, though.

Gear change is an option, but expensive because you have to change both the front diff and rear (4x4).

Get some Powerslot rotors and some ceramic brake pads for the front of the truck. Please tell me your trailer has electric brakes and you are using a brake controller. That will make a huger difference.

For your tires, there are LT rated tires availible to fit the 17" rim. Something like the Goodyear Wrangler AT/S or BF Goodrich TA All-Terrain KO. You may be able to downsize your tire to effectively increase the axle ratio. That would be cheaper and easier to do than a gear swap.

 

I have already tried the drop in K&N, got WORSE mileage and the MAF got gummed up (twice) by the oil on the filter, and I used half what was recommended. I might go the exhaust route and an full intake, as long as my mileage doesn't suffer, a few extra hp would help.

And yes, my trailer has electric brakes and I use a Tekonsha brake controller. My brakes have been "soft" for some time now, since a pad change, not sure why, the system was never opened, so it was never bled.

I'm not really lacking in power, it actually tows pretty well (except for the occassional big hill that slows me down). Perhaps a shift kit too?

My biggest problem is the rear suspension. It's just plain too soft. I have those overloads, and they're okay, but they "clunk" quite often. Could a welding shop maybe recurve my leaves, maybe add one or two? Or, what about the springs from another model? My other option is air bags, and I have no experience with them.

Thanks for the input...

 

Well, you usually have to “give up” something in order to “get” something, and MPG is usually the sacrifice, but not always……..

We have pretty similar setups. I have LT265/75/16 load range C tires, 3.55 gears, and tow about a #4500 travel trailer. While I’m less weight then your trailer, I probably have more wind resistance to deal with while going down the road, so power is of concern for me as well.

I’ve not had any MAF problems with my K&N, other then the rubber gasket peeling off, so I’ve taken it out (can’t tell any difference from the paper one at all either……). I do have a 3” “cat back” exhaust. The tail pipe is from a Gibson Swept Side system, but I’ve since replaced the muffler with a Flo-Pro. That all by itself was a huge difference in my low end! With the Gibson muffler, and towing on a stretch of highway, I’d have to downshift into second to get up certain hills. With just the Flo-Pro muffler swap, and driving on the same stretch of highway, towing the same trailer I can now make the hill in third!! I’ve noticed that it gets moving easier too. Don’t have any numbers to prove it, just on the road experience.

If you are wanting more ‘get up and go’ especially from a stop, then a gear change to 4.10’s would really help the most IMO. You might even see a slight increase in city mileage, as the motor won’t have to work as hard to get you moving. Highway mileage might suffer some, due to the increased rpm’s you’ll be running to maintain the same speed….

Adding more “power” to the engine really only goes to creating more heat in your tranny IMO….. And most times, if you are achieving this with just bolt on parts, the power increase is only in the peak rpm’s. What you really need is torque to get you out of the hole. HP will get you speed.

As far as your spring choice, I have the Hellwigs and they don’t make a sound….. They actually ‘cured’ the ‘clunk’ I had (the one where you come to a stop and then take off again and “CLUNK”……) and stopped the wheel hop I had on slippery roads. They also made the truck handle and just overall drive better too. I don’t have any experience with the air bags, other then I didn’t want to mess with them. Have you tried to put some more tension on the U bolts on the overloads?

You should probably flush your entire brake system. I did and it made a huge difference in the pedal pressure. I used a hand operated vacuum pump to suck out the old fluid in the reservoir. Filled with fresh brake fluid. Moved to the right rear wheel and opened the bleeder valve and attached a rubber hose to it that went into a large jar. Press the pedal, close valve. Release pedal, open valve. Repeat until clear fluid comes out. Move to left rear. Repeat. Keep an eye on your fluid level in the reservoir!! Right front, repeat. Left front, repeat. All I can say is WOW! What a difference it made in braking. But, your trailer brakes are what you need to make sure are working properly to have better on the road braking performance. Can you lock up your trailer brakes by just hitting the manual slid bar on your controller?

Good luck!

 

AIR BAGS

 

Are using weight distributing spring bars on the hitch? If you are not, its the answer to your problem. It will level out your ride by distributing the weight across the front and rear axles.

 

Dont we all. lol


Just buy an F250 or 350.

Honestly, how much money are you going to spend making your truck a wanna-be 3/4 ton?

There will always be a substantial difference.

 

I would recomend firestone airbags. I put a set on about 2 yrs ago on my truck (pretty much the same as yours) and love them. My trailer when loaded weighs about 6500lbs, plus I usually have the bed full(dirtbikes, gas, water) and can have the truck completly level and rides great. When empty, I pressure the bags down and it rides as if stock.

 

Air bags can hide real problems!

If your truck is on the overloads and still bottom outs, you are overloaded. Even though the air bag levels the truck, the axle is still overloaded - only now you may no longer be as aware. That’s not good.

Like dbossman says, get the weight distribution hitch. It takes weight off of the rear axle and puts some back on the trailer axle and some on the front axle. This may sound hard to believe, but I've tested it at the truck scales. It really works.

Also, don't just look at the tow rating for your truck, look at the combined (CGVW) limits. I'll bet both you and john dardis are overloaded.

With my truck (rated to tow 7,700lb) and my 5,700lb RV, I am 2,000lb under the tow limit but only about 500lb under CGVW once I put in the kids and every thing needed for a week of camping.

Even though I don't have overloads or bags, I use husky weight dist bars and the ride is smooth.

Hope this helps!

 

I totally agree about the weight distribution hitch. It not only redistributes some weight to front end, but also help the truck and trailer ride smoother. I also agree that on said trip I was about 1200lbs over on my gcwr and about 1100 over on my truck gvw. I was only stating how well the airbags help out. It would've been impossible without them.

 

misteramx,

Two things that I did to support a slide-in (pop-up) camper.

1) Dropped tires from LT265 down to LT245/75R16E. Got a tiny bit more torque, but more importantly, I run 55lbs of air which improves cornering. Load range E tires are usually rated for 80psi.

2) Had a suspension shop take the springs apart and add a leaf between the 1st and 2nd leafs.

These two changes made an incredible improvement in ride and cornering with the camper on.

Good luck finding more power.

 

I dont claim to be a expert in this field but from what I have researched in hitches lately, I would recomend a equalizer hitch The link is self explainatory and really increases a vehicles towing capacity There is lots of different styles to choose from but all do the same basic principle:
Sway bars
Reese

Good luck, hope this helps