03 Ford 5.4 260 HP Vs 03 Lincoln 5.4 300 hp

[DAMN_FORD]

If the only way to rate the peak HP at a higher RPM would be to re-tune so the peak torque occurs at a higher RPM. (Hp = Torque x RPM)

The 2500 RPM torque peak is low compared to other engines except diesels. I think the GM Vortecs peak torque is around 4000 RPM.

Low end torque gives more throttle response and towability. But, you don't get that strong mid and high range pull when you stomp on it. The X has a great low end, but that's about it.

 

[Guest]

Torque better describes the FORCE utilized to propel. What's the old racer's addage? "Horsepower sells cars, torque wins races."

I'm no automotive engineer but I do know torque is actually the force applied to the wheels to propel or pull. Though torque and HP are intimitately related I would say for pulling and acceleration torque is more important. Case in point. The new import's v6 I recently read about develops 260 HP much like the 5.4 L X. But nowhere near the torque (read available force at the wheels).

Carl, as you stated Hp = T x RPM...actually Hp = T x RPM / 5252.118

The Tahoe's 5.3L develops 285 peak Hp at 5000 rpm. Thus:

285 = T x 5000/ 5252 or

5252 x (285/5000) = T or

T = 299 ft-lbs at peak Hp

The X develops 262 Hp @ 4500 where:

262 = T x 4500 / 5252 or

T = 306 ft-lbs. at peak Hp

So at peak Hp in the 4500 to 5000 rpm range the X is still delivering more "force" to the wheels for propelling the vehicle or pulling a load.

Conversely The Tahoe develops peak TORQUE at a much higher rpm. 325 ft-lbs at 4000 rpm to be exact according to Chevy. From that point on either side of the curve (higher or lower rpm) the Chevy is developing less torque than 325 ft-lbs.

The X OTOH dvelops it's peak torque at 2500 rpm! This is remarkable considering it's peak torque is 350 ft-lbs. From this point either side of the curve the Ford develops less torque as well.

However, this is where the X beats the Chevy hands down. From that point (2500 rpm) all the way out to 4500 rpm the X is developing more torque than the Chevy dropping from 350 to 306 over 2000 rpm The Hoe on the other hand doesn't even hit it's peak until 4000 rpm and drops from that (325 ft-lbs) to less than 300 ft lbs in 1000 rpms.

If you plot this on graph paper you'll see the X has a much wider torque curve. And even though the X doesn't generate as much Hp it is developing a considerable amount more torque than the Chevy from 2500 all the way out to 4500 rpm, and probably from 0 - 2500 rpm as well.

From my understanding this is the whole object of truck powertrain design. An engine that develops peak torque at low rpm and can maintain that torque across the rpm spectrum creates more actual useable force at the wheels.

Cody

 

[Guest]

I was curious as to what the calculated Hp of the X would be at 5000 rpm. So I used the formula above and rearranged the equation using these variables:

X - peak Hp = 262@4500 and 306 at 4500 rpm

Also we know that the torque falls 44 ft-lbs from 2500 to 4500 rpm. This translates to 1 ft-lb loss in torque for every 45 rpm increase over 2500. That's assuming a linear relationship. Most of the torque curves I've seen are pretty flat decline from the peak on up. Confused yet?

So extending the rpm of the 5.4L out to 5000 rpm means an increase of 500 rpm. 500 rpm / 44 ft-lbs loss per rpm = 11 ft-lbs loss at 500rpms or roughly 295 ft-lbs.

So assuming the 5.4L X is developing 295 ft-lbs at 5000 rpms we can now plug back into the formula:

Hp = 295 x 5000 / 5252 = 281

Theoretically the X 5.4L should be developing roughly 280 Hp at 5000 rpm....theorectically...hehehehehe

Ramblings of a maniacal number cruncher.

Cody

PS: But you know what happens when we "assume"

 

[DAMN_FORD]

Holly buckets! There's some thought there!

When I was shopping for my vehicle, I used the exact same methodology to pick. I tow 7500 lbs. I decided that to get the same pulling power of the X, in GMC I needed at least the 6.0. 'Cause at 65 mph with 3.73 gears, the RPM is 2500. To get equivelent torque at this RPM I needed the 6.0 (still short) or 8.1. These engines are available only in the 3/4 ton. 5.3 is no comparison. I don't want no stinking rough riding 3/4 ton just so I can tow a trailer once a month. Leaf spings are for busses!

 

[Guest]

Holly buckets! There's some thought there!

Yeah well like I said, it's all theory and number crunching. But it should be a fairly resonable approximation of how the two really compare.

And those numbers are conservative. Chevy actually rates the 5.3 with 285 Hp@ 5200 rpm....not 5000 rpm like I guessed. So the numbers would be even more in favor of the Ford 5.4L. Because at 5000 (like I thought the Hoe was rated) the calculated Hp would be something on the order of 275 or 280 Hp ...not 285. And the resulting torque would be more like 290 ft-lbs not 299.

That's all a bunch math and hocus pocus. But the proof is in the pudding. When I drove the Hoe then immediately drove the X, I intially thought the Hoe was slighty"peppier". But the more I drove my X and then drove my friends new 5.3L Hoe I realized the X actually was performing just as "peppy" as his Hoe....if not more so, the difference I was detecting wasn't in the feel but the sound. The Hoe made a mean noise when I wound it up. The X did not and now I know why. The X simply rides quieter. I think it is insulated better and is heavier. Now that I've driven the two head to head extensivelyI'm convinnced there isn't a lot of real difference in Hp between the Ford 5.4L and the Chevy 5.3L. But there IS a significant torque difference and I can feel it when accelerating.

Whad' you think when you test drove the new 5.3L Hoe?

Cody

 

[Guest]

I decided that to get the same pulling power of the X, in GMC I needed at least the 6.0.

Actually you STILL wouldn't get there. Even though the Escalade is touted as the "most powerful" full SUV on the planet it still AIN'T rated as high as the ol' X for payload and capacity.

Escalade specs (from cars.com)

Curb weight 5641 lbs. (The X is 5686 lbs)

Engine horsepower 345-hp @ 5,200 rpm

Engine torque 380 lbs.-ft. @ 4,000 rpm

But get this:

Payload 1,359 lbs.

Max. trailer weight 7,800 lbs.

In comparison the ol' X has a payload of 1,651 lbs and max trailer wt. of 8,650!

How can that be when the Escalade develops more torque and weighs the same?

Probably because the Esc doesn't create as much low end torque and from 4000 to 5200 rpm it probably falls on it's face like it's cousin the Hoe. Or could it be something with the independent suspension on the X? I'm not sure what all determines payload and max trailering weight. You?

I'd love to see all the test data GM and Ford have. I bet it's real interesting.

L8R

Cody

 

[DAMN_FORD]

I thought the 5.3 felt fast. But it had to rap out to get the pull. It is not responsive like the X. Almost bought an LT 3/4 burb with the 8.1. This had excellent throttle response. But, I expected it to pull harder when you romp it. It still wouldn't spin the tires. This would would have easily met my towing needs. However, it got less than 10 mpg, it had a rougher ride than I wanted (still not bad), the tail end sticks up high in the air even though it had autoride (doesn't make sense to me), and the best they could do was 44K. I did not like the fit and finsh of the interior. I did not really need that size either. Then I read on the internet that they are having piston slap and high oil consumption problems with the 8.1. That was it for me since I didn't think the 6.0 would do the job.

I wouldn't mind seeing a torque curve with the 5.4 against all of the vortecs on the same chart.

 

[DAMN_FORD]

"I'm not sure what all determines payload and max
trailering weight. You?"

I read somewhere that these specs are determined in a meeting room with a bunch of engineers. There is no set formula.

 

[Guest]

Surely somewhere out there in cyberspace we could find a plot of torque and Hp for the 5.4 and the 5.3/6.0L GM junk. I'd love to see it. If I find something I'll post back here.

Concerning payload and max trailer weight...I know one sure fire way to find out. Get a trailer with some heft. Then tow it up a hill with the Tahoe and do same with the X and see how they respond.

As a matter of fact I might do a little experimenting. My best friend has a new Hoe with a 5.3L. He tows a competition ski rig that weighs about 5,000 lbs. Next time we go to the lake we'll test 'em.

L8R

Cody

 

[Mustang71Lover]

engine Question

I know the Navigator is DOHC and puts out more power from the same 5.4L as the Expedition, but how interchangeable are the engines? Could I buy a Navigator's engine and put it in the Expy to get a nice power upgrade of about 65 Hp? And thats not to mention all the upgrade I could do from there.... But I guess my question is, would the Navi's engine fit in the Expy?

 

[Guest]

Re: engine Question

Originally posted by Mustang71Lover
I know the Navigator is DOHC and puts out more power from the same 5.4L as the Expedition, but how interchangeable are the engines? Could I buy a Navigator's engine and put it in the Expy to get a nice power upgrade of about 65 Hp? And thats not to mention all the upgrade I could do from there.... But I guess my question is, would the Navi's engine fit in the Expy?

Yes you can. There is a guy on fordtruckworld who is in the process of doing this swap. It isn't as easy as it may seem as there are several things that have to be changed. You would be better off to add a turbo or a s/c to the motor you have now. It would be cheaper and less of a headache. Just my .02

 

[DAMN_FORD]

There is a consumer reports issue that races the Sequoia, the Yukon and 03 X pulling a 5000# trailer 1/4 mile. The X came in last. But, the X has the highest tow capacity.

I figured this is because when you floor it, you are in the 4K + RPM range which is well out of your peak torgue. As far as regular driving, the X will have more driveabilty because you have the highest torque in the RPM range you are driving.

The YUK and the Toy have peak torques in the 4K range.

 

[Guest]

Having peak toque that high in the rpm range is ridiculous. No one tows at those speeds and if they do the tranny won't last long.

 

[DAMN_FORD]

You can feel the low end in the X, especially when pulling a trailer on a hill. Other vehicles go into second right away on an incline. The X will hold third much longer. The down side is that if you do nail it and it down shifts while towing, you don't accelerate much more than if you running 3/4 throttle in 3rd. It just makes alot of noise.

This is kinda how diesels tow. You don't really accelerate harder when its on the floor down shifted.

So basically, the X tows great from 0-65 mph. After that there's not much there. But, you generally don't need to go much faster than 65 when towing a big load. I think this is why the X has such a large tow capacity.

Are there any Ford Engineers out there that could comment on this thread? It would be quite interesting to hear what they say.

 

[Guest]

Guys guys Guys,

What Consumers Report is NOT telling you is Critical!!! The Tahoe had a final drive ratio of 4.1. The Expedition only 3.73!!!

Think about it people!

 

[Guest]

Having peak toque that high in the rpm range is ridiculous. No one tows at those speeds and if they do the tranny won't last long.

No doubt. The sad thing is the Hoe's peak T was 325 at 4000. I'm guessing at around 2500 (HWY cruising speed) the damned thin only has about 275 Ft-lbs. And when you hit a hill with that little T you've got problems. I don't think consumer's did a good job of evaluating the tow capabilities of these trucks.

This is kinda how diesels tow. You don't really accelerate harder when its on the floor down shifted.

So basically, the X tows great from 0-65 mph. After that there's not much there. But, you generally don't need to go much faster than 65 when towing a big load. I think this is why the X has such a large tow capacity

Yep exactly. I just towed 6000 lbs to Nebraska with a F350 Powerstroke. it's peak torque is in the 2500-3000rpm range. A Yukon will obviously smoke this thing in a 1/4 mile race. But towing ....hahahahahahaha...it ain't even a match. That 350 doesn't even feel 6000 lbs. I set the cruise at 75 and it's rock steady....never even shifts gear even when climbing a big hill. Also consider this Powerstroke only has 235 Hp but develops something like a whopping 425 ft-lbs of TORQUE. When pulling torque is everything.

This is how I imagine the X tows compared to the Hoe. It simply is under NO stress because it has so much low end torque..

What Consumers Report is NOT telling you is Critical!!! The Tahoe had a final drive ratio of 4.1. The Expedition only 3.73!!!


Now this makes sense. If the X had a 4.11 (not even offered) what would it do then. It's common knowledge the Tahoe comes with either 3.73 or 4.1 rear end ratio. No doubt Chevy probably hedged their bet when they sent consumer's the test vehicle. They gave 'em a Tahoe with a 4.11 rear ened knowing Ford doesn't even offer one. Now that's not really apples to apples is it?

Cody

 

[Guest]

I found out that the Sequoia comes in two final drive ratios for the 4.7 L. 3.91:1 or 4.10:1. This would be a HUGE advantage over the 3.73 in the X especially regarding 0-60, 1/4 mile times and TOWING.

I can't figure why Ford doesn't have a 3.90 or 4.10 optional rear end for the X.

Cody

 

[DAMN_FORD]

I was wondering that myself when I was shopping. GM offers a 3.73 and a 4.10 as well. I was wondering if lower gears are available for the X either from Ford or aftermarket.

I bet that would be a pricy retro-fit.

 

[Guest]

Actually I've a call in to www.ring-pinion.com. They seem to think there is aftermarket gears available for the 03 X.

I checked on gears for my 4x4 Ram 1500 and the gears with all gaskets, seals, shims, and install kits would cost about $600. My mechanic said he could install them for about 4-500. So I'm looking at $1000-1100 to re-gear my Ram.

The guys at ring-pinion said the new X wouldn't cost much more than that, so I'm guessing $1000-1500.

Cody

 

[DAMN_FORD]

I don't think consumer's did a good job of
evaluating the tow capabilities of these trucks.

In this artical they compared the Honda Pilot, the Sequoia, the 03 X and an 03 Tahoe. It was supposed to be a full sized SUV blow out. They said that Honda held just as many people, that is why is was in the running.

They talked highly about the features of the 03 X but complained about power, fuel economy and engine refinement.

Yeah, I wish it had more power too, but I think Ford put it where it counts.

CR picked the winners in this order:

1 Honda
2 Sequoia
3 Expedition
4 Tahoe

They had much more complaints about the Sequoia, yet they picked it over the X.

They did the drag race with the trailer. This is not a good way to see how good a vehicle tows. F350s can tow a city, but I doubt if it would win drag races (Like someone said). They need to come up with a different measure of towing capability.

The X came in last but they threw out the Honda 'cause it had only a 3500 lb tow cap. (What a joke)

Consumer reports used to be informative but I think they are bias toward Japaneese and smaller vehicles. Why else would they have the Honda in this comparison. The even the Durrango would be a better choice than the Honda.

I lost alot of respect for CR after this article.