My mods: MPG/Performance

[Jackpine]

An exhaust change is not going to do anything for your mileage, but it CAN change the sound. A couple of the other Mods on this forum (cleatus12r and 88Racing) know more about exhausts than me though, as does Bill. I'm really only "parroting" what I've learned from them. (I think I've got it right.)

If your ties have a more "aggressive tread" they probably have more rolling resistance. Cold inflate them to the max pressure shown on the sidewall. That may help some.

- Jack

[Jackpine]

Originally Posted by ArtieWag

I know this is a "Power Hungry" forum, but... I just wish to deal with adults here, and not someone who wants me to drive a different kind of vehicle. I own two f150's. Because they 'fit' me.

Does anyone have any good information on bed covers, air dams, wheel covers, etc. that have improved mpg? I have installed soft bed covers on my trucks, but they seemed to reduce mpg slightly. They have made the trucks more useful, so I have kept them on.

Yes, I have searched the internet on this topic, and all I can tell you is that other people hate F150s and we as their owners are obvious morons. I hope that is not the case here.

More Power, applied correctly, less drag, more MPG.

You won't find any F150 "haters" here, but you MIGHT find some that prefer the bigger cousins.

I'm a little surprised that a bed cover (tonneau style) would reduce your fuel efficiency. I would expect efficiency to improve or at least remain constant. But you might be getting a slight increase in skin friction drag over the bed with a soft cover, compared to a "hard" tonneau).

I'd think a "smooth" wheel cover would reduce some drag in that area, but I have no data to back that up. I doubt the difference would be significant though.

I don't think an air dam will help at all. I see it as increasing the frontal area of the truck, which is already a major factor in creating drag.

I think if you lower the truck, it might help some with fuel efficiency, but you'd reduce the truck's utility.

- Jack

[Longshot270]

Originally Posted by ArtieWag

I know this is a "Power Hungry" forum, but... I just wish to deal with adults here, and not someone who wants me to drive a different kind of vehicle. I own two f150's. Because they 'fit' me.

Does anyone have any good information on bed covers, air dams, wheel covers, etc. that have improved mpg? I have installed soft bed covers on my trucks, but they seemed to reduce mpg slightly. They have made the trucks more useful, so I have kept them on.

Yes, I have searched the internet on this topic, and all I can tell you is that other people hate F150s and we as their owners are obvious morons. I hope that is not the case here.

More Power, applied correctly, less drag, more MPG.

Dont worry about Ford bashing here. PHP only does tuning on Fords so a Chevy guy would be outnumbered quite a bit and any brand bashing could be removed if it didn't have any logical basis in the conversation. BUT I dont find the new F150s to seem all that aerodynamic (an example of logical connection)

I do not have any solid numbers but I can give you plenty of opinions based on observations I have made.

Theoretically a bed cover should improve your mileage but the difference would be less noticeable than that of comparing cheap gas to top quality gas, something that I have found to be one of the largest differences in my truck. Also, you are adding weight when you compare the two conditions? When you compare before and after, is it empty bed before/empty bed after?

Air dams, you could possibly see an improvement. If it blocked the majority of airflow over the grille then you would most likely see higher operation temps. If you still have the coldest possible air coming in, and a higher temp engine, again theoretically you should see an improvement under responsible driving conditions. Some factors that might inhibit this would include higher engine temps causing the fan to engaged more often, a noticeable drag on the engine. I do know that it does have an effect on top speed but I'm not sure if it would have a large enough effect on the constant operation to improve mileage. If you are nearly 100% driving above 60ish mph (the point where wind resistance is said to start taking its toll) then it may help. I do find it interesting you mentioned it because one of the major car brands (can't remember which) has an air dam that automatically deploys to cover the grille area when it reaches highway speeds. It supposedly increases efficiency. I do not know if increases speed efficiency through a smoother wind profile or engine efficiency of warmer under hood temps. May be both may be neither.

Wheel covers, if you can get it to come down around the fender to cover the tire/rim then I'd imagine it would. You just run into a major problem in the front. Turning would be nearly impossible because the tire extends outside of the body profile. Back fender shouldn't be a problem though. I have seen that used on earlier "eco" cars. Just make sure it would be removable in case you have a flat or something. If you are talking about the fenders that come out like fender flares, I'm willing to guess that they would make mileage fractionally worse by decreasing aerodynamics. The front would form a pocket that could cause slight vacuum and the back portion would act as a dead end air scoop and form a slightly pressurized pocket, both pockets would act as resistance. The fender pockets would not be major pressure points so it is hardly a drop in the bucket from a practical standpoint.
***Note: I'd be willing to bet that putting a fiberglass belly covering that resembles the lower shielding on rally cars would greatly improve aerodynamics by reducing drag from all the stuff hanging down underneath. Fiberglass would be easy to form, easy to fix, weigh very little and be relatively cheap. You will just need to consider flexing (suspension and frame), heat and moving parts.

As Jack said, you could lower it but you lose some of the utility traits, I don't fully agree. In the case of heavy pulling or moving over rough terrain it may be accurate but I can tell you that lowering the truck makes it a much easier to load and unload things from the bed. Adding a 2.5" leveling kit to the front actually brought my tailgate down a little bit (see-saw angle effect). When I'm not hauling kayaks or fishing equipment I use my trail bike for around town commuting so my truck ALWAYS has something in the bed that I am putting in and taking out. After 2+ years since putting that on I am still glad for the slight drop. It lowered my tailgate about an inch so that is one less inch I have to lift everything. Or in other words, lowering may improve efficiency and utility.

[Longshot270]

When I put fuel quality I was meaning by brand, if you run premium with the truck tuned for 87 the majority of the fuel properties are not being taken advantage of. Raising the timing a few degrees would help. As the price of gas has gone up I have switched over from the cheapest fuel to brands like Shell. Already my mileage is improving along with overall performance like a smoother idle. When I see a 5 cent difference I really see (.05/3.xx) or less than 2% cost increase. The switch to higher grades will probably be coming because it will be more cost effective to use them as the % price difference narrows.

I dont think they make the wheel skirts for these trucks because it would not be very "popular" and the wheel covers may help if you find some that still have openings because like you mentioned the brakes need to be easy to cool.

Air dam under the bumper I was thinking you were talking about a grille cover. I'm sure the skirt would help.
I figure those rally cars see more gravel, mud and dirt in one race than you do in a month. If you leave openings it should help some of it come back out. It also doesn't have to be a full covering. You could stop at the tranny.

My AC doesn't do much at idle, guess I need to recharge it. But that is part of UDPs. They lower the gear ratios for the accessories.

For gears, do not go below 3.55 if you want to keep any useful towing capacity.

You should look into lowering shackles in the back. It will not make the truck useless because you can still tow somewhat lighter loads with them. If you still need to tow heavy trailers you can look into helper springs, air bags, etc. I've seen them put on trucks and it brings the back in line with the front. It also lowers your tailgate a few inches.

Overall, your driving style has much more say in mileage than mods. If you are on the highway, drop it down to 65 rather than 70. If you are in the city, both Jack and I have found that giving it more gas to get up to speed then backing off to maintain improves mileage more than granny driving it with turtle slow acceleration.

[Jackpine]

I'll add a couple of things. I think an air dam under the bumper is somewhat problematic. (And I thought that was what you were talking about, although I didn't understand you were talking about fender skirts - shades of the 50s)! An air dam is going to increase your frontal area. This increases the "flat plate" air drag on your vehicle. But, it reduces the airflow under the vehicle which is quite turbulent. It would possibly be a "wash", but my gut feeling is that it would increase overall drag.

Fender skirts would help a little bit, I suspect, but I would not be able to stand the "look".

I would NOT go to a reduced gear ratio. Yes, the engine will cruise at a reduced RPM, but the engine load is increased. You reduce the effective force (against the ground) that the engine can exert to get you up to speed and keep you at a cruising speed by doing this. The only way to get that "required" force back is by giving the engine MORE fuel at the lower RPMs.

Your Wife may "coast" for a longer period when coming to a stoplight or other stopping situation. Any way you can reduce the use of brakes is going to help your mileage, while possibly making people behind you angry. Interestingly, Janet uses her brakes more than me, and it drives me crazy to ride with her.

Lowering/leveling would probably help. Again, it has the effect of reducing the overall frontal area effect.

I assume you are using a "high-octane" tune if you're using premium fuel? If not, you are wasting gas. You MIGHT try increasing the timing ever so slightly if you have that capability in your programmer. My understanding is the CS/CTS platforms don't give you that option (and I've never looked for it on mine). But, if you can, try +0.25 degree increments and TEST!

- Jack

[Longshot270]

Hajek Sets Three Production Truck Land Speed Records At Bonneville - Dragzine.com

Jack, I tend to wonder about the front dam. Every modified "production" vehicle to run at high speeds, including the F250 link I posted above and most NASCAR style race cars, put one on. The idea is to force air around the sides rather than beneath for greater handling at high speeds. NASCAR is an endurance race more than anything so every mile you can get without stopping puts you ahead. Top speed just makes the miles go by quicker. If the airdam styling had hurt mileage they would not have used them.

Artie, when you raise timing you increase mileage quite a bit. When I was running canned tunes, just a .5 degree increase gave me 1 mpg in the city.
The gotts mod increase higher flow rate efficiency (above 2100ish) but has no noticeable effect below that.

Also, I installed a vacuum guage a while back (something you may want to look into) and the cruise control will consistenly lower the vacuum a few (inches/Hg) as compared to my foot. You can get them online for around $15 and you just hook a hose up past the throttle body. My truck actually had an extra lead in the vacuum system that I plugged directly into.

I'm thinking 4wd regearing will never pay for itself.

Find that guy who turned his couger into a bugatti clone. He is pretty dang good with fiberglass and making good body stylings.

[Jackpine]

Originally Posted by ArtieWag

...<snip>... As far as octane ratings, I don't have any tunes yet. And yes, when I take a long 750 mile jaunt, I do burn premium. I understand from these posts that I will even like it better than I do now after I install my tuner - Yeah! ...<snip>...

ALL RIGHT! Now I'm understanding things a bit better. By putting "premium" fuel in your truck without being able to increase the timing to compensate, you are hurting your gas mileage! So called "premium" gas has octane boosters in it that really do nothing more than inhibit ignition under conditions of pressure and temperature (what you get on the compression stroke) and, they cause the flame front to advance at a slower rate (slow down the burn).

Premium gas was developed for high compression engines that would cause the fuel/air mixture to ignite PRIOR to the spark (pre-ignition, or spark knock). Our engines are not "high" compression, so premium is not needed. But, the slower burn component of the fuel was designed to provide the greatest expansion at the optimum time in the power stroke, given an earlier (advanced spark) ignition point.

Without a tune, your ignition point is too late for that fuel. It is the same as retarding the spark using 87 octane gas. You lose power, because the burn is starting and completing too late. It's probably completing in the exhaust manifold, and possibly working against the piston during the upward part of the exhaust stroke.

I've said this before - "premium" gas is NOT "better" gas. The additives it contains do not contribute to the energy content.

- Jack

[Jackpine]

Originally Posted by Longshot270

Hajek Sets Three Production Truck Land Speed Records At Bonneville - Dragzine.com

Jack, I tend to wonder about the front dam. Every modified "production" vehicle to run at high speeds, including the F250 link I posted above and most NASCAR style race cars, put one on. The idea is to force air around the sides rather than beneath for greater handling at high speeds. NASCAR is an endurance race more than anything so every mile you can get without stopping puts you ahead. Top speed just makes the miles go by quicker. If the airdam styling had hurt mileage they would not have used them.

Artie, when you raise timing you increase mileage quite a bit. When I was running canned tunes, just a .5 degree increase gave me 1 mpg in the city.
The gotts mod increase higher flow rate efficiency (above 2100ish) but has no noticeable effect below that.

Also, I installed a vacuum guage a while back (something you may want to look into) and the cruise control will consistenly lower the vacuum a few (inches/Hg) as compared to my foot. You can get them online for around $15 and you just hook a hose up past the throttle body. My truck actually had an extra lead in the vacuum system that I plugged directly into.

I'm thinking 4wd regearing will never pay for itself.

Find that guy who turned his couger into a bugatti clone. He is pretty dang good with fiberglass and making good body stylings.

Longshot, I think the front air dam is there more to reduce the "lift" that airflow produces on a fast moving vehicle, rather than as a "drag reducer". As you say, this improves handling at high speeds (an absolute necessity). Other methods involve wings and spoilers that force the vehicle down onto the road. Without these devices, the vehicle can become negatively stable at high speeds, resulting in total loss of control.

And, wings and spoilers also create drag. It's a price you have to pay for control.

Now, if you were able to create an air dam that looked a bit like the "cow catcher" on the old steam engines (only solid) then you might reduce drag a bit by moving the air aside in a less violent manner than the flat front of our trucks. We actually develop a "stagnation area" at the front where there is very little air movement. At the boundaries of this area, the air flow is very turbulent.

We also, of course, have a big stagnation area behind the truck, due to the "vertical" planes there. I think we could improve fuel economy by creating a bed cap that would taper from the cab down past the current tailgate to a "point". Kind of a "teardrop" back end. It would look absolutely horrible, the truck would lose most of its utility, and it would be far too long to fit in any parking space.

- Jack

[Longshot270]

If you want to build a dam yourself there is a material I know that works very well. It is tough and flexible and designed to last long. Look for hay baler belting or repair belting. To attach it to anything for this purpose you would use a small metal bolt with a wide waster and crank the bolt down tight. You could probably put it on the bumper since you can get it up to 10 (maybe 12) inches wide. It is made of a very tough rubber with 1+ nylon ply. I'm building a rudder system for my kayak out of it so after much exploring different materials I picked it as being the cheapest/most effective/longest lasting alternative. You may want to look into it for repairing your RV.

Here is a link. I found it at Tractor Supply Co just because I used to work there so I know what they have. Any co-op or ranch supply store should have it.
Replacement Baler Belting, 10 in. Wide-2 Ply-210# Nylon/ft. - 1420017 | Tractor Supply Company

I suspect that if you put it on the bumper in one piece will angle it towards the truck and make it more rigid so going over stuff forwards shouldn't be too bad. Backing over obstructions, however, will. If you do strips hanging from the bumper there shouldn't be an issue but it will probably not be as effective.

As for the rims, see if those cheapo clip on rims from walmart will work. Most of them are designed to look like dinner plate wheel covers and they will at least have openings for air circulation.

[Longshot270]

Interesting, the stuff I have is stiffer than the actual plastic under my front bumper. It could be that I got it from a store that is too far out of the way for any baler to go to for repairs. I'm willing to bet that the stuff I got is over 5 years old and has been sitting inside for that time. If you got some that was newer it would make sense to be more flexible.

Also, 75 miles is not very far to calculate average fuel usage. That is the distance I usually use to confirm that my tire size is dialed in. What method are you using?