Car and Driver Review (EcoBoost)

[Whiskey11]

C'mon man... you can't be serious.

I'm EXTREMELY serious. What this car offers me is added weight, added width (a problem in autocross, even more so in this amount), similar power and torque at peak, similar gearing, same weight distribution, same capability for tires (still limited to 285's in STU) and added ability to tweak rear alignment.

In the grand scheme of things, are the negatives in that going to outweigh the ability to tweak rear alignment and a reduction in unsprung weight? Answer for me is a resounding no. My home concrete is the Lincoln Air Park which while not Sebring International Raceway's bump every 6" mantra, isn't exactly without massive pavement heaves. Almost every course I have run out at LAP has taken "advantage" of several of these features in an attempt to throw off car's balance. That said, my car is extremely composed over these bumps.

While it isn't the "easy button" that an IRS is, a live axle can soak up bumps almost as well if you are willing to address the issues with it. On the S197 chassis the biggest complaint is the "feeling" of uneasyness over bumps at the back end of the car. Most reviewers attribute this to a live axle, I attribute most of it to the pan hard bar arrangement. Not only is the stock PHB controlling 300lbs of live axle, it does so with soft rubber bushings. Even if we eliminate the soft bushings entirely and run rod ends we still have a lateral displacement of the axle as the PHB moves because it is fixed at the chassis on one end and to the axle on the other. While that displacement is easily measured in the hundredths of an inch we are talking about moving a 300lb axle laterally any displacement. The force of this movement is going to really mess with the contact patch, hence the uneasy feeling in the rear axle.

So what is the cure? A watts linkage operates on a principle that virtually eliminates lateral displacement of the axle. This reduces changes in the contact patch drastically by eliminating a 300lb pendulum from under the car.

Not convinced about the PHB nonsense? Here is a watts link under my car, 265/40/18 Hankook RS3 summer tires, Lincoln Air Park's concrete, watts link, 275lbs/in rear springs and the stock GT 20mm rear swaybar:

[ame]

At 2.5" of rear axle travel (which is possible out at the Lincoln Air Park even with 275lbs/in rear springs) over a bump we are talking about 0.0745" (over 1/16th of an inch) of lateral displacement of the axle if the PHB is level at rest. That is no small number when you consider the effects that has at the contact patch with tire loading.

The rest of the issue comes with damping. There are some pimpy shocks out there that have huge blowoff curves for compression and rebound forces, some that even regress to lower values at higher shock speeds. That pays off dividends in keeping the tires on the pavement without shocking (punny, I know) the contact patch. My rear shocks aren't that pimpy but they do have a amount of digressive nature to their compression curve:



That helps blow off some of those bump forces and makes the rear more composed. Your average off the shelf shock doesn't do that.

Sure he could. If the course is pretty smooth, then a live axle can be dialed in to work very well. Frankly, people have been sorting the issues out of Mustang rear suspension for a long time, and depending on the class, you could potentially do a lot with it. I'm not sure about the specifics of what STX allows, I've been away from auto-X for a long time.

I don't interpret his comments to say that IRS is of no value. Rather, that dollar for dollar (or pound for pound), switching to an IRS isn't necessarily a better value than other potential mods one could make to the live axle set up. Considering that IRS adds overall weight (though cuts unsprung) and a lack of surface irregularities, for this narrow focus usage, I'd be inclined to believe him. But its still highly dependent on overall setup, driver preferences, class, etc.

I get to play on the Nationals concrete at Lincoln Air Park. It isn't perfectly smooth and have some large pavement heaves and uneven concrete pads but it is, for the most part, smooth. As for what STX (and now STU for pony cars) allows, it allows a lot actually, Watts link is legal, diff mounted or chassis mounted, torque arm for the S197 is legal (surprisingly), as are adjustable spring perches and coilover springs, rear swaybar (which I'm doing my damnedest to get RID of) and next year LCA's and relocation brackets are legal. Right now the only stock part of my rear suspension is the rear swaybar and the axle itself.

That said you have picked exactly what my comment was intended to mean. The cost of changing cars and developing a new car, pound for pound and dollar for dollar does not necessarily make a better car for my intended purposes. The "additional" alignment changes by going to an IRS isn't going to make the car appreciably faster for autocross use in the class I'm in. It certainly isn't the panacea magic bullet concoction that cures all handling woes. My S197 fights weight and tire width limitations (thanks SCCA! ) and not rear tire wear or rear grip.

Quite the opposite actually, I've had a number of people drive my car from varying levels of national competitiveness and they all have basically the same things to say about the car. Most notably is a.) It puts power down WAY better than they imagined a V8 powered car would and b.) it has way more grip then they ever anticipated the car having for its weight.

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[Rex Grant]

Has anyone heard what eb "base" car weighs vs the Premium?

Ford lists the curb weight for the EB/Automatic as 3524 pounds. So apparently the premium EB with the PP adds about 140 pounds?

 

[REX-RACER]

Ford lists the curb weight for the EB/Automatic as 3524 pounds. So apparently the premium EB with the PP adds about 140 pounds?

DAMN! :eyebulge:

Thanks for the info. I've heard the difference between the auto and MT6 isn't that huge, maybe like 25 lbs iirc but still 165 lbs is significant.

 

[Spartan]

Ford lists the curb weight for the EB/Automatic as 3524 pounds. So apparently the premium EB with the PP adds about 140 pounds?

Yep. You're adding a lot of stuff to it with the PP.

 

[FStephenMasek]

I have personally owned a number of turbocharged cars and they have NEVER, EVER, been kind to me at the pump.

My 1984 Pontiac J2000 Sunbird LE four door with the turbo package and manual transmission got excellent fuel economy, and I did not baby it. I was still shifting it at red line when desired up to when I sold it with 160,000 miles on it, and it was still running like new.

Our 2002 Mercedes-Benz C230K with a supercharged four also has good fuel economy.

Weight is the enemy, and a small engine struggling will never get good fuel economy.

The V8 in my 2014 Jeep Grand Cherokee will run as a four under light load. That and the 8-speed transmission allow it to provide 1 MPG better fuel economy than my previous vehicle, a 2006 Ford Explorer V8 with the two package, even though the Jeep weights at least 900 pounds more than the Explorer. I don't know why Ford resists cylinder shut-off technology, when Chrysler and GM (and others) have it.

 

[Spartan]

When you put a small turbo engine into a heavy car, the savings are generally not that grand.

This is the big thing that worries me about the EB in this 2015...it's going to put more strain on the EB.

Weight is the enemy, and a small engine struggling will never get good fuel economy.

I have a feeling Ford is going to trim some weight in the 2016 because every article is basically mentioning the weight gain. You can't have that and then have the EB be required to pull a heavier car.

The question is what can they do to make the 150-200 lbs back?

 

[REX-RACER]

This is the big thing that worries me about the EB in this 2015...it's going to put more strain on the EB.
I have a feeling Ford is going to trim some weight in the 2016 because every article is basically mentioning the weight gain. You can't have that and then have the EB be required to pull a heavier car.

The question is what can they do to make the 150-200 lbs back?

Time to take a page out the F150 playbook? ;)

 

[Spartan]

Time to take a page out the F150 playbook? ;)

Yah many of us wished that happened.

 

[stilesg57]

^^^ Doubly so now.

 

[REX-RACER]

Yah many of us wished that happened.

^^^ Doubly so now.

Ya do sort of wonder how using increased lightweight aluminum in the Mustang might impact the cost? In that regard the F150 is probably a good trial balloon given that people will buy them in great numbers regardless.

 

[Spartan]

Ya do sort of wonder how using increased lightweight aluminum in the Mustang might impact the cost? In that regard the F150 is probably a good trial balloon given that people will buy them in great numbers regardless.

They would easier recoup that in sales. And I'd pay an extra say $500-$1000 if over the course of the life of the car it's going to save me MPG every year.

 

[MUSThavaSTANG]

From the review:

"And yet there’s not much to complain about this EcoBoost Mustang other than it’s more expensive than the base V-6 while offering very similar performance."

"Ah, but what about the four’s acceleration? On the track, it lays down numbers almost identical to the last V-6 model"

Forget the HP and Torque numbers for a second, these 2 statements are based on DRIVING the car. For those of us who don't need a ton of creature comforts, I'm starting to wonder why there's any reason to buy the EB over the V6 other than it seems to be the cool thing to do.

 

[doulos4jc]

From the review:

"And yet there’s not much to complain about this EcoBoost Mustang other than it’s more expensive than the base V-6 while offering very similar performance."

"Ah, but what about the four’s acceleration? On the track, it lays down numbers almost identical to the last V-6 model"

Forget the HP and Torque numbers for a second, these 2 statements are based on DRIVING the car. For those of us who don't need a ton of creature comforts, I'm starting to wonder why there's any reason to buy the EB over the V6 other than it seems to be the cool thing to do.

MPG & performance package...two good reasons.

 

[MUSThavaSTANG]

MPG & performance package...two good reasons.

If you drive it like a nun you'll see better mpg. Anyone who wants a performance package won't be driving it like a nun.

 

[stangs-R-me]

MPG & performance package...two good reasons.

Although the better MPG would likely only be applicable on the non PP EB ... 3.55 gears, wider & heavier wheels/tires, and other weight gains associated with the PP are going to bring the EB MPG down closer to the V6 if not even below.

Put the optional 3.55's in the V6 and then maybe the EB PP would get the better MPG's.

However after driving a 2011 V6 / M/T with 2.73 gears for the past 4 years / 92k miles, I see no need for 3.55 gears and think I'd be perfectly happy with the stock 2015 V6 3.15's.

Off the line my car is fine and can even get the 235's spinning on a 5 MPH roll without touching the clutch pedal. Only time I wish I had lower (higher number) gears is when I go around a right hand turn in 2nd gear and want to get on it on the way out.

Doug

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