What about all the guys that changed to steeper gears and didn't notice any real difference in mpg? We are talking modulars here not a 460 or PSD. What about all the power (among other things) Ford left on the table with the stock tuning? Auto engineers for the most part do what they are told to do and what parameters they have to work within and what requirements they have to meet.

Well your 250 will probably weigh a bit more than your Expedition. It probably has the enemic 3.73 gears too. The stock tune from the factory is sluggish and laggy. A tuner with a good custom tune can help the truck feel quicker and add some power even on 87 octane gas. It costs around the $400 mark if that is something you would want to try. A gear change will cost quite a bit more than the tuner.

 

Another one who feels my remarks are uncalled for because I disagree with them.

My "uncalled for" remarks suggested that there are reasons that these trucks are geared the way they are. Certainly they aren't perfect for every scenario out there but making the statement that they "wont change the fuel economy and may actually help" is flat out wrong unless the truck is operated in a certain manner or with certain aftermarket equipment.

I challenge anyone here to find an engineer who will agree with the statement that taller gears will never hurt fuel economy. And for those who think moderators can't participate in discussion you can always find another forum to take part in. That's not the way we do it here, and I can voice my opinion just as much as anyone else.

 

He wasnt talking about MPG's...that I noticed

Regearing will get you more "power"...but it will cost you gas

Unless

You are running oversized tires. Going to deeper gears will get you back to near factory design ratios. The Engineers design these rigs for Power and Economy in certain RPM's. My PSD is sucking a bit right now with my 35's...but I plan on fixing that with 4.88 gears and 37" tires. My driveline ratios will be near factory

I've had several 5.4 3v vehicles. I would never call them gutless. My 08 Expy was similar weight to a SD and it would gyddy-up and go on demand. No problems yanking a small trailer around either

I'm betting the OP has larger than stock tires. A small change like upsizing tires will really hurt performance

 

They are, but for a number of reasons that might not have anything to do with real life. Like in CA, towing at 55mph as the max speed limit, 4.56s or 4.88s might be best (and might gain MPGs) because who in their right mind imagines towing at that awkward speed? Grapevine@55 + 5.4 + 3.73s = headache, and maybe a roasted trans. An extra 20mph of airflow over the coolers and 20* lower ambient temps can make a huge difference between towing a 6% grade in CA versus towing a 6% grade in Colorado.

A guy over at PSN runs something like 3.31s behind a GearVendor and 6.0, but I feel undergeared with 3.73s and wish I had gotten 4.10s from the factory. Yes, steeper gears in this case would mean less MPGs, but being able to hold 70mph with a trailer and not get raped by semi's on I-10 pays for the costs.

Costs and benefits to everything, which is why forum-facts are all relative. Kind of like how how an auto would have automatically been better when you tried to get your manual GT out of an icy dealership parking lot

Ignore the flamers, you hold 6.7L together

 

That's enough of flaming moderators.

Perhaps those of you flaming Tom for his post haven't been around FTE long enough to realize that moderators are allowed to participate in the forums here. Even the Super Moderators and Administrators are allowed to participate.

If you have an issue with the information he posted as it pertains to the subject at hand, fine. Debate it as you would with any other forum member. If you have an issue with moderation, this is addressed in the Site Guidelines (link in my sig). Issues with moderation are handled as per the instructions in the guidelines, not in open forum.

The fact that he is a moderator is immaterial here and there will be no more criticism of moderation in open forum, period.

 

The good thing about FTE ...we promote and want the Mods to be involved, they are the ones that see the "negative" stuff coming !

 

A lot of the problem might be the "fly by wire" setup on the gassers. A tune from Mike at 5-star would help it a LOT according to many who've tried it with a fly-by-wire engine.

Much of the lack of power you think is there is the computer not opening the throttle according to how fast you mash the pedal. Also, you're talking about a truck that is much heavier than your Expedition, so there really is (almost) no point in comparing.

Find out what gears you have.

Also, if you didn't buy this truck new, go over everything that can affect power - fuel filter, clean the MAF, and ... even check your tire pressures. You'd be amazed what a difference that makes.

Also, not to muddy the waters here even further, it's been my (and many others') experience that the Ford modular motors do NOT pay a heavy price in fuel mileage when you regear lower. Especially in in-town driving and towing. And even on the highway, going from 3.73's to 4.30's has historically not made a big difference on the Ford modulars - that's the 4.6, the 5.4 and the 6.8 V10.

I once regeared my '96 t-bird that has a 4.6L from 3.27 to 3.73. I went from 23-24 MPGs on the highway to 26. Yes, you read that right.

I can't say your 5.4 will respond the same way, but power-wise regearing is a huge benefit.

--

Side note: It's been FTE's policy here that moderators are allowed to have their own opinions. Even when they disagree with other moderators

 

I think the tuner would probably be the best improvement for the money, but the OP hasn't been here since 2/16.



ON edit: I've never regeared a modular truck, but both my last two Powerstroke trucks as well as my Mustang have had the tallest gears available. Not by choice but that's just how things ended up. My fuel economy was always 1-3 MPGs lower on the highway than those with lower gears running the same speeds. My Mustang is incapable of achieving it's 26 MPG EPA rating even at 55-60 MPH, but some are seeing 27-28 with 3.31s. Of course this is subjective, but there are two things that lower gear ratios do for highway cruising. Less RPMs mean less parasitic losses due to friction, and the increased engine load means the throttle plate is open further and therefore suffers less pumping losses. This is negated in most cases at or near WOT as the PCM commands a richer mixture to give the power you're demanding.

 

To go even further off on a tangent, most if not all Fords stay in closed-loop at WOT these days, so they are still running at stoich, not richer

As for the parasitic losses, intake vacuum, etc, it's all a toss-up. If the vehicle has a high enough aerodynamic profile, the gears can actually help. In my '96 t-bird, that highway mileage was running 70-75MPH. I might have actually LOST mpgs if I was doing only 55

ANYway...

 

 

Huuh...makes sense I guess. I know that many GM vehicles emit a thin cloud of soot when they punch it, but I've never noticed this from a Ford.

Would love to hear an explanation as to how aerodynamic profile has anything to do with efficiency of taller gears.

 

I'll jump in the stew with you guys...

I have an 08 F250 4x4 Crew gasser with the 5.4. I traded in an 07 Expy Limited EL with the same engine, the 5.4. Both 5.4s are the 3v engine. The difference between them is the honest 6-spd trans in the Expy and the extra 1200 or so lbs in the SD. My Expy wore 275-60-20s and my SD is wearing 325-60-18s.I know my SD is running 3.73s and I *think* my Expy was also. I was getting about 11-11.5mpg around town in the Expy and I'm getting 10 in the SD with the same driving.

As far as power goes, the SD feels a little more sluggish to me if I'm easy on the throttle. The Expy was much quicker around the same throttle points than the SD feels. When you really got into the gas on the Expy, it got up and went for you. The SD isn't quite as quick but it'll move out pretty well if I really get into it. The problem with getting into it like that with the SD is the mpg. If I get into the SD as often as I did with the Expy, it throws my mpg right down the toilet.

IMHO, I wouldn't say the 5.4 is underpowered. It could use some enhancements and a little help, but it's not bad. I'll add the tuner and see how that works out this summer.

It all comes down to personal preference though. Had I been driving a PSD for a couple years and then gone to the 5.4, it would probably feel much different to me. As it is, I'm not upset at all with the power I'm getting out of my 5.4

 

Ford changed that when the 3Vs came out and they will go into open loop at WOT.

 

I have a 2003 5.4 which came with less HP than yours because its a 2V, and the way i have it right now, it actually gets up and goes. I have an SPD y pipe, dual exhaust, k&n filter and SCT x3 from mike @ 5 star on the 87 performance tune. Drove around with a few of my buddies yesterday (one who has a 6.0 and a tuned 4.6 mustang) and they both said its definitely more powerful. so try tunes...

 

It takes a certain amount of torque to push through the air (and push the tires) - the higher (numerically) the gearing, the easier (for the engine) to push through the air. But, the higher the RPM at the same time. If the planets are aligned just right, you can offset the higher expected fuel usage rate by the lower load, overall using less fuel. Or at the very least, equal it out.

The original 2-valve Ford Modulars were a perfect example of this. I haven't seen any evidence, anecdotal or otherwise, for the 3-valvers.

Oh well, off to pick nits somewhere else