Yes, when it comes down to using a truck as a commuter vehicle, you know plenty

Seriously, as I said before, it's pretty frickin' useless to discuss improvements of X percent, unless we know where they started from or how the previous model compared. I mean, right now, I could act like the Ford fans in this thread and claim that I'm stronger than any other poster because I increased my bench press by 50%. That's maybe true if I started at 350 lbs, but if I started at 100 lbs then I'm just blowing smoke (and if we're talking about the current F150 frame, we're definitely not talkinig about a linebacker physique). Without any other supporting info, this is a statement that simply cannot be proven. You folks are getting suckered by marketing hype.

Additionally, a 900% improvement in rigidity does not automatically translate into huge improvements in ride quality, or any performance metric that's measurable without lab-quality instrumentation. Yes, there's a relationship, but it's not easily quantified and therefore I wouldn't get excited to the point that I'm shouting 900%!!! every time I talk about this truck.

Oh well, I'm sure everyone in this thread is already dead-set on what they think. It sure is amusing to see the effect of pseudoengineering in marketing, though.

 

"Yes, when it comes down to using a truck as a commuter vehicle, you know plenty "

I've got a 150 page specification for a PARKING BRAKE system in front of me right now.

I'm willing to bet that 99% of the folks who buy cars never considered that someone could actually write 150 pages of specifications on a PARKING BRAKE.

I understand that you make shifters or associated components, tell our firends here what a GM shifter specification (SSTS) looks like.



"Seriously, as I said before, it's pretty frickin' useless to discuss improvements of X percent, unless we know where they started from or how the previous model compared."

Excellent point.



"It sure is amusing to see the effect of pseudoengineering in marketing, though."

The truly scary thing about it is that these little nuggets are passed along by automotive writers as things they actually understand (they don't) and then parroted by their readership as gospel.

I guess I am coming to the realization that part of the trick to marketing a vehicle is to get the propaganda machines tuned up and running in the direction you want them to - regardless of whether or not what you are saying actually makes sense.

That entire concept is a difficult one for an engineer to grasp. I think we're tuned to the idea that an engineering solution is better or worse than another purely on its ability to accomplish a given function and that opinion relative to limited information on function is irrelevent.

This is a considerable shift in thinking on my part... I'll have to chew on this one for a while and try to get my arms around it.

 

PacerX, you don't seem to be too familiar with the concept of Ad Hominem. Basically, attacking the premise, not the person.

Anyhow... your reading skills are also pretty lacking; and you just wasted quite a bit of time because of it. Read my first statement, that even YOU quoted.

You spent your entire time trying to tell me that weight does matter- but if you'll read down you'll see that I acknowledged that. What my arguement was, is that it doesn't matter all that much in terms of the effectiveness of the frame itself.

 

This thread is hilarious.

I have a degree in engineering, and I own an advertising agency, so I know both sides (engineering and marketing) very well. I know how specs are translated and "tweaked" into things that appeal to the general public. And believe me, once they've gone through the marketing spin, you would never recognize them.

How do you think that each successive generation of cars gets 50-900% stiffer each time they're redesigned? They measure it IN A DIFFERENT WAY. Ot at ONE SPECIFIC POINT. I mean, after reading about 4 generations of 50-900% improvement, the only logical conclusion was that cars of the 70s and 80s had frames made out of overcooked pasta, and that cars of the 60s really didn't have any spine at all but crawled over the road like big slugs.

Hint: PacerX and Eric Bryant are engineers. This is what they do for a living. They make MONEY doing this. From previous posts, they both seem to have an excellent grasp of what they do.

I think I'd be inclined to listen to what they say.

 

For some reason that quote cracked me up.

It stands to reason that if cars keep getting 900% stronger with each new generation, we should very soon be able to drive them through brick walls or jump them over the Grand Canyon without loosening a nut. Gotta love marketing!

 

For what it's worth, I'm not trying to say I know more than any of the engineers here. But also along that same line, I don't think that simply because I am not an engineer, my opinion should not be voiced. My 'dumbass' comment to PacerX was not in regard to frame specs or to any other engineering related discussion; it was related to the fact that he conveniently compared the smaller V8s rather than Ford's new 5.4... then when asked to compare the other two he started in with the "well the 6.0 would own the 5.4" and even went so far as to incorrectly claim that the 1500HD (the smallest truck you can get a 6.0 in) was a 1/2-ton, so it made for a perfectly valid comparison. That's what my dumbass comment was directed to; beyond that we have moved to a completely different subject that he seems to be giving quite a bit less biased and more objective information, and I have never discredited him for that.

Furthermore...

Some of you are acting as though I and/or the Ford marketing team's claim of the 900% increase in torsional rigidity is becoming common place these days.

It may be worth noting that this is the first time I've ever seen a 900% increase in torsional rigidity claimed.

Also, only a 30% increase in bending rigidity was claimed with the new F-150.

Matter o' fact I'd dare say that most ground-up redesigns that I see either don't mention their increased chassis rigidity, or if they do, it's usually claimed somewhere in the range of 15-40%.

It only seems to be this latest generation of full size trucks that are making these huge claims, and the key element in every singe one of their redesigns was the addition of hydroformed frame rails.

I'd suspect if you checked previous generations of these same trucks, various late-model unibody redesigns, and quite possibly the ground-up redesigns that will succeed these current generation full sized trucks, you won't see anywhere near the same gains in rigidity unless we see the advent of yet another technology such as hydroforming.

 

"PacerX, you don't seem to be too familiar with the concept of Ad Hominem. Basically, attacking the premise, not the person."

Kind sir, the concept that you are going to educate me on the finer points of debating decorum is flawed. Let me assure you, and put all of those little doubts you have in the back of your mind to rest, I can learn very little from you in this area.



"Anyhow... your reading skills are also pretty lacking; and you just wasted quite a bit of time because of it. Read my first statement, that even YOU quoted."

I read it, and its wrong. That's why I tried to enlighten you, which has become an exercise in frustration.

You did NOT understand the structural concepts I had to re-iterate concerning torsional rigidity. I'm pretty sure you still don't. In truth, I only scratched the surface and kept the content and terminology to a minimum for those who read and are not mechanical engineers.

If you want to be buried in it, I can start the explanation that EVERY torsional rigidity test in the vehicle is really a combined torsion and bending condition, which either requires iteration to correctly solve for in the SIMPLEST of cases.

Now, add the following:

First, we're not dealing with the simple cases that we all used in college as engineering students. The frame in question is a "thin-wall section" structure, which means we had better start looking at crippling and buckling or we can get into big problems very quickly.

On paper, a thin-wall section structures will look like it works just fine without considering this, and then a section will collapse unexpectedly and WHAMMO! - catastrophic frame failure. The next few years of your life will be spent talking to attorneys and explaining why little Jimmy went rocketing through the windshield and hit an oncoming bus due to YOUR frame failing. I had to testify for a case once concerning a brake failure that resulted in the death of a child - I NEVER want to do that again, and I wasn't even the responsible engineer.

Second, we have to understand the true load path, and realize that the cab and bed structure are going to have a significant effect on our outcome. This is even MORE COMPLICATED, as the cab structure is very complex assembly of very thin-walled stampings with spot-welded joints. If some of the spot-welds are not as strong as they should be (which is a very common occurance - US manufacturers ALWAYS overkill the number of spot welds or mig welds, with the understanding that some number of them may not have adequate strength) bad things start to happen.

Now figure in that the spring, tire, wheel, suspension and sway-bar system is a pretty complicated mass-elastic system subject to vibration considerations and there's another whole level of complexity.

Third, where torsional rigidity really figures into things is when a wheel hits a bump. This is a dynamic occurance, not a static one. All of the "manual" methods for calculating the rigidity of the structure are really static calculations. It is simply too cumbersome to calculate the dynamics by hand.

So now I've got to run out and hire a finite element analysis expert to run a simulation for me or spend the rest of my career (and quite a few calculator batteries) braining this out. Alternately, I can build LOTS of frames and test them, but this is time-consuming and expensive.

Fourth, even if I hire the best finite element analysis computer-jock on the planet, his/her calculated answer STILL HAS TO BE TESTED - preferably by someone who knows what he/she is looking at. So now I write a document called a DVP&R (Design Verification Plan and Report), which details every test I'm running, why I am running it, and what the results are.

Fifth, I better start looking at contingencies now. Early on I wrote a document called a DFMEA (Design Failure Mode and Effects Analysis) just in case I screw something up. Sometimes (bless their little hearts...), manufacturing folks don't do things EXACTLY the way I specified them unless I hit them over the head with the idea that a given requirement is ABSOLUTELY CRITICAL by calling it a KPC (Key Product Characteristic). Sometimes, hitting them over the head doesn't help much either... so I better figure out what happens if they still make a mistake (PFMEA - Process Failure Mode and Effects Analysis).

You do NOT understand, in real terms, what the effect of excess weight is on a vehicle globally. You do NOT understand that the frame is part of a SYSTEM that satisfies numerous requirements.

Instead, you want to parrot marketing catch-phrases.

Simply put, you don't know what you don't know, and are choosing to enter into a debate concerning structural considerations for automobiles with an individual who makes a living on related subjects (actually... I'm stronger in mechanism design, but structures are structures).

Whatever your job is, I can assure you that I would never presume to know more about it than you do - for instance, I'll never tell you how long the fries need to stay in the fryer, or what the proper amount of ketchup is for a Quarter-Pounder.

I have attempted to reasonably explain to you what you do not know, you don't want to listen.



"You spent your entire time trying to tell me that weight does matter- but if you'll read down you'll see that I acknowledged that. What my arguement was, is that it doesn't matter all that much in terms of the effectiveness of the frame itself."

You're wrong. See the above.

My point was that you literally have no clue WHATSOEVER as to what the effects of excess mass in a vehicle truly are, and have ZERO knowledge as to how much it does or does not matter. The entire statement you made was a complete waste of electrons.

End of story.

Now, let's say this gentle rebuke of mine is coming from the wrong source and you'll never accept it. OK, that's fine... but a word of advice... there are many others here who are fully as knowledgeable (or more so) than I am. If you can manage it, I would advise you to keep your unsupported opinions to yourself and let those others educate you then.

 

What makes the new F150 600 lbs heavier? Is it the frame alone, or the OHC motor, or just a combination of things? Did I read somewhere that 4-doors are now standard? If so, that artificially increases the weight, when compared to the previous model

Ford didn't just add 600lbs without considering the consequences. We're missing something here.

 

Good point. I can't find 2004 F150 curb weight specs anywhere... but the 2003 F150 comparably equipped is actually lighter than the Silverado.

Furthermore, when I was looking for curb weight specs I noticed that even the 3/4-ton 1500HD 6.0 that PacerX tried to use as a defense for the new F150's 5.4... it's still a bit shy of the 5.4's power.

Where are you getting your curb weight specs PacerX? And since you think you're so unbiased and objective in your comparison of the new F150 to the Silverado, why have you still not mentioned how the 5.4 stacks up to the 5.3?

 

My engineering expertize is limited to the mechanical odds and ends I did on my '85 Mustang years ago, so when threads like this come up, I sit them out but keep up on them (gotta learn someplace, right?).

Just the same, I tend to take claims on structual rigidity with a grain of salt, for just the same reasons you brought up. After years of hering claims of improvement in the 100s++% range, I came to a conclusion long ago that either the claims were bogus, or the measurements kept changing. Glad to see this non-engineer was right.

Many other interesting bits here (especially the summary on why the IRS of the Explorer & Expedition doesn't seem to perform as advertized) and the continued engineering lessons.

Carry on! This CamaroZ28.com bootcamp is very interesting.

 

FWIW I drove my g/f's parents 03 Expedition (Eddie Bauer 4x4) the other day. I thought it rode smoother and quieter than their 02 Tahoe (LT 4x4), and I like the interior (dash especially with the exception of the guages) 10 times better.

But I didn't like the motor nearly as much. Not as smooth in power delivery, and not as 'confident' feeling. I wonder if they'll put the 3-valve 5.4 into the Expedition for the 04 model year as well?

 

First of all, I'm way late to this thread but I enjoyed reading it. Like others, I have passed liquids through my nasal cavity on some lines. The one that got me was Proud Pony's statement about waxing the big Ford truck resembling an Amish barn raising.

Now let me get on to my generalized points.

600lbs a small difference???? that's the equivalent to 4 average adults riding along. That 600 lbs cuts fuel economy quite a bit, requiring a bigger tank, requires more brake to stop it (or living with longer stopping distances), makes it less responsive to steering input, etc. etc. etc. 600lbs is fantastically overweight IMO.

900% increase in structural rigidity. I have to ask, is there a point of diminishing returns to this stat? Hypothecially, say I produce a truck with 30,000% increase in torsional rigidity. Exactly what does that gain me over 10,000% increase in rigidity? At what point does the benefit gained not justify the added cost/weight and not produce any quantifiable gains in ride quality and performance?

 

I still think we have quite a way to go in this area. Even my 00 Silverado with hydroformed frame rails, while noticably taughter than my friend's 98 Silverado... it had quite a bit of very noticable unnecessary flex over irregularities in the road.

 

But I doubt you can quantify torsional rigidity by simply riding in a car. Human bodies are notoriously bad measurement devices for heat, distance, weight, anything you want to measure.

Do you really think you can feel a 10-fold increase in stiffness by riding in a car? We're not talking a little stiffer, we are talking 9 times more stiff than it was before. It may be impressive as hell to a potential buyer...some guy that is going to haul hay in it and drive his wife to church on Sundays...but in terms of actual performance what does that do?

I'm no engineer, far from it actually, but I'd have to doubt any automotive structure could realistically be stiffened 900% without it being a true 1-piece machined block of steel. The only conclusion I can draw is that its a marketing gimmick and as others have said, they derived the stat by changing the way it was measured or flat out made it up.

I'm sure its stiffer, but 9 times stiffer? I always thought trucks needed a certain level of flex due to their length and the disconnect between the cab and bed, plus the intended usage.

The engineering effort to make a 100% increase in rigidity to a full frame vehicle has to be pretty major, not to mention 900%.

 

First, the gain isn't 1 to 1. The largest amount of gain is most likely seen very early in the testing. When you apply a load to a structure, there are four clear zones along the stress/strain curve.

Stress = exactly what it says - a measurement of internal shear, tension or compression on the the part itself. Stress is usually measured in thousands of pounds per square inch (ksi - English) or MegaPascals (MPa - metric). Note that the units are identical to those for pressure - so you can look at it that way if you like.

Strain = how far the part moves in response to the load.

Load the part up and you can measure stress vs. strain. The curve you get is called a stress/strain curve.

For all metals, you get the following zones, in order:

1) Preloading, an area on the stress/strain curve where you are getting movement without any (or very little) stress. In a riveted assembly, this is where the gaps between the rivets and the other parts are being taken up.

2) Elastic deformation. This part of the curve is a straight line. For metals, as long as the stress does not exceed the "elastic limit" and enter the next zone, they'll snap right back to their original shape (minus movement due to preloading). The actual slope of the curve is known as "Young's Modulus". Steel has a "Young's Modulus" three times greater than aluminum, and twice that of titanium.

3) Plastic deformation. After the elastic limit is reached, you enter a non-linear part of the curve with a much more gentle (and variable) slope. In this area you can remove the load, but the part won't snap back to it's original position. This is called taking a "permanent set". You've bent it, permanently.

4) Breakage. Well, keep throwing load on it and it breaks. Obvious enough.

Steels are really nifty in that they ALL have the same slope to the elastic part of the curve, but stronger steels extend that slope farther. So, for any two steel structures that are geometrially identical but made of different steels, as long as you never exceed the elastic limit, they have identical stiffness. Pretty cool, huh?

Now, a 900% increase in torsional rigidity could be accomplished by limiting preload losses (perimeter welded instead of riveted joints), changes in shape to crossmembers (closed-section hydroformed pieces instead of open section stampings) and extending the stress/strain curve by using a stronger steel.

K, that's all cool...

To make a 30,000% increase? Well, make it out of granite which would have a steeper slope to the stress/strain curve early on - nearly vertical, but no elasticity - when granite exceeds the elastic limit it shatters. Load up, ride the vertical part of the curve, BOOM! - shrapnel, end of story.

Granite is heavy too...



Now, what do you really get?

Well, you can keep the tires more square to the road, but at some point square is square - the tires move around anyway.

You can drop spring rates some - but not by 900%.

The vehicle will behave more predictably over bumps and with a load, but not 900% more predictably - whatever that is anyway. More "linearly" might be a better way to describe it.

In short, you get the springs and suspension to do what they were designed to do without interference from undue body/frame distortion.