I've been told the cold air induction systems such as K&N really don't give any real world enhancement. But would something like this help with high altitudes, especially for towing?

Are there any ways to improve high altitude performance?

 

An after market intake will help in no way, shape or form at any altitude.

What exact problems are you having? Which engine, what gear ratio, trailer size and weight, what cab, which transmission, what is the tire size, what altitude, how often, steep inclines, etc?

Only way to get any real improvement is to get a tune and use a higher octane gas.
You may be able to re-gear, long tube headers, exhaust, good tune up, etc, but without knowing a starting point, hard to say.

 

No problems yet. We won't be buying our trailer for several more months, but intend on traveling to and through the mountains.

I have an '03 F-150 SuperCrew 5.4 auto V-8 2 WD with 3.55 gears and SWB. The trailers I have been looking at are on the heavier side and so I assume with a fairly low geared rear end that long in lines and high altitude will leave me struggling a bit.

I figured I'd start with a programmer to give the engine a bit more output, but wondered if an intake upgrade might help get more oxygen into the combustion chambers.

I have been considering a rear end swap, which is part of a question I have another thread asking about. The idea was to help with long inclines and looking through my manual it shows an increase in GCWR. Changing to 4.10 gears would increase my max towing by 2000 lbs?

 

3.55 to 4.10 is about a 20% change ............ so if your motor is turning 1800 RPM now at road speed, you will increase to 2160 RPM at the same MPH ( ground speed).
You can accomplish that at running speed by dropping down a gear... What the 4.10 does is basically give you better torque at the bottom end to get the trailer rolling and accelerate onto the highway. Shift points will be a little lower MPH / closer together and make it easier to maintain speed.

 

So it doesn't change the GCWR? I'm curious why the exact same truck but with 4.10 gears has a higher GCWR rating. What else is different?

 

The Supercrew never had 4.10 gears, so changing yours to 4.10 will not change the GCWR.
The F250 LD/7700 has a 4.10 option, but has a higher GCWR to start with. That is the one that has the higher 15,000 lb GCWR.
Changing from 3.55 to 3.73 or 4.10 will make it pull a trailer better, especially from a start, but overall cruising will not be much different, and if going up an incline, you would be turning the OD off anyway.

 

My manual shows the SuperCrew and SuperCab with the 3.55, 3.73, and 4.10 gears for the F-150 and 5.4 V-8 2WD. This is strictly an F-150 manual.



Looking a bit closer I missed that the max trailer weight only improved by 600 lbs with either the 3.73 or 4.10 gears. Is the suspension different to increase the truck's capacity that much?

 

Only the 7700 (that comes with a 10.25 axle) had the 4.10 option from the factory.
3.73 was a rare option on Supercab/Super Crew, usually on FX4 models, but I believe it is standard on the 7700 (that did not come as on option on the Super Crew).

The manual is confusion though. Having the 2 models listed together makes it harder to understand.
Notice the 3.55 option has 2 weights listed? The first one is for the Supercab. The second is the Super Crew.

Look at this website for a little clearer understanding of it.

Regardless of what gears you put in the truck, a 4x2 Super Crew with a 5.4 has a max trailer weight of 8,000 lbs and GCWR is 13,000 lbs.

 

What is the 7700 you mention? Looking at the link of options it shows the Lariat SuperCrew came with a 7700 payload, which is the truck I have.

*EDIT*
Reading further it says it's an option and comes with the 4.10 rear end, which mine does not have.

 

The 7700 is a heavy duty F150 option (was called a F250 LD from 1997-1999). It was never an option on a Super Crew, only Supercab or regular cab.
It has a beefier suspension, better transmission, larger rear axle and 7 lug rims.

 

So the difference really comes down to the axle handling this additional weight?

*EDIT*
Late response...

 

There is more to GCWR 'engineering' than just the axle ratio, trans and engine size.
You cannot make a greater GCWR by just changing a few items.
If your concerned enough, a Diesel is your needed level in an F250.
Good luck.

 

A F250 LD/7700 has a better axle, gearing, suspension, transmission and I believe a reinforced frame.

 

I was merely interested in the gear swap for better accelration and pulling uphill, especially in the mountains. But when I saw what appeared to be the same truck but with those gears and it showing a heavier GCWR I wondered if it opened trailer options, as there are a few others that were close to max with no fresh water, which wouldn't be cool if you are boondocking. An extra 361 lb gives me full water tanks and would keep me away from the max, which had the light shining bright. Oh well on the additional weight...

I've had two guys with similar truck's and the same rear end tell me they pull heavy trailers in the mountains without issues as long as a slow vehicle doesn't get in front. Maybe it's not as bad as it seems it'll be...

 

My truck just has 61k so a new one is later down the road. But I'll think more on what I can pull next time for sure.