Ken Gratton•4 Oct 2014

NEWS

Ford Mustang: A horse for all courses

What are the ingredients that will make the new Mustang a global success?

The Ford Mustang has always been agile and fast in equal measure – even back in the days of the GT 350 Shelby model. So finding the blokes to reveal all the nitty gritty for the new 2015 model – in the right context – was a matter of some importance.

At the Mustang's international launch last week two of the leading figures in the Mustang's development project were Lou Santora (we'll call him 'the chassis guy') and Adam Carter ('the engine guy'). Carter knows all there is to know about the 5.0-litre V8, but he was also well versed in the ways of the EcoBoost four-cylinder that will be the standard engine offered in the Mustang when it arrives in Australia during the second half of 2015.

First up was Santora, who neatly side-stepped the question of benchmarking the new Mustang against the car that is currently its closest rival, the Chevy Camaro. Camaro owes a lot of its engineering to Holden and the Zeta platform originally developed for the VE Commodore.

"Mustang's always had its own DNA," Santora replied. "As much as Camaro is a competitor... we are very careful not to let benchmarking a competitor lead us down a path that might take us away from what the DNA of Mustang is."

Media outlets in North America have conducted comparisons of Camaro and the previous model Mustang, offering the view that the Camaro provides a better ride/handling compromise than the previous generation Mustang, suspended by a live rear axle. Typically the earlier generation Ford would out-turn the Chev if it had the optional 'track pack' installed. But as a day-to-day driver the Camaro had the upper hand, American journalists reported.

Santora admitted that improving the new Mustang's ride/handling balance was a priority, whether or not it was a consequence of the competitor's strengths in that department.

"That's one of the things we were looking for as well," he said, "in the sense that we went and built the [previous generation Mustang] Boss – and that was a great handling, great steering car. You paid the price in the ride quality... because we were heavily constrained by the three-link axle and suspension set-up."

Santora says the internal benchmark for the new model was the (modern era) Boss 302's "lap times, handling and precision feel, while gaining a lot more ride quality."

"Over the base 'Boss', the GT Performance Package was a second quicker around the track."

The optional Performance Package suspension, as well as different spring and damper rates, adopts forged lateral links with "cross-axis ball joints" and stiffer strut top mounts at the front, with the cross-axis ball joints also specified for the toe links at the rear. These collectively eliminate compliance, benefiting power delivery and dynamic composure for the V8 models.

According to the chassis guru, without conceding ground on the dynamic front the Mustang's suspension is much more refined, soaking up bumps and irregularities much better than before, but also transmitting far lower levels of NVH (Noise, Vibration and Harshness) to the cabin.

"It gives you a much more matured, refined feel than Mustang's ever had."

One of the key KPIs for the project was to improve braking performance significantly, by ensuring the tyre contact patch was optimised under brakes. In the end, the development team settled on a 'double ball joint' MacPherson strut front end – a staple of BMW models from years ago.

As soon as Ford began playing around with an IRS system under a previous-gen mule, it was obvious the existing Mac strut suspension would now be the weakest link in the chain. The double ball-joint system immediately lifted the new car's rough-road ride quality and its straight-line stability, without detriment to the cornering power and handling that owners had quickly come to appreciate in the Mustang Boss.

Plenty of Mustang enthusiasts had denounced the IRS system as soon as Ford revealed it would underpin the new model. Many of those enthusiasts take their Mustangs to drag strips, and IRS systems have a reputation for introducing unwanted compliance and camber change that can diminish traction – as opposed to a properly set up live axle. Cars with IRS systems simply don't 'hook up' at launch.

"I think the customers are going to be pleasantly surprised at how good this car is in a straight line," Santora responded.

Santora says that serious drag racing enthusiasts will load up the new Mustang with all the right aftermarket gear for where the rubber meets the road anyway, but the IRS of the new model is better tied down, he claims, than the live rear axle of the very performance-focused Mustang Boss of the previous generation.

"If you compare an out-going Boss with a GT Performance Package, wheel hop in this car is far superior."

I subsequently discovered for myself that launching the Mustang V8 with even the standard suspension set-up would break traction, but didn't induce any sort of axle tramp. Remember Steve McQueen's Mustang GT in the film 'Bullit'? When he backs up to take off after the bad guys? Remember all that axle tramp?

A thing of the past...

"We tuned the previous car for the handling, and we got boxed in to where we had to trade off some wheel hop for the handling," Santora continued. "The amount of tuneability we had in the IRS really helped... give ourselves more options, less compromises..."

Santora stated that the Mustang's suspension was an entirely North American development project – and it's a one-size fits all application. Mustangs for Australia will ride on the same suspension settings as left-hand drive models.

"Our position right now is that our [suspension] tuning is actually global..." Santora explained. "Ford, taking on this 'One Ford' mentality... which is not an easy thing to execute... because markets are different... But Mustang DNA can be appropriated for all those markets."

On balance, that should be a very good outcome.

"We're firm believers that the harder you drive this car, the better it gets. You can really work the chassis hard, and if you start working it to the limit you get results with the throttle – especially in the V8 cars. It breaks away, it's progressive, it recovers well...

"I think this car rewards the driver a lot more... it makes me feel like a better driver than I know I am."

Next stop: The engine guy. Standing next to a 5.0-litre engine, Adam Carter was poised and prepared for any question, no matter how ingenuous.

The Mustang V8 is based on the same 'Coyote' engine architecture as the Miami supercharged V8s that will drive the upcoming Falcon XR8, and has previously squeezed into the engine bays of FPV models.

"The program for Falcon was almost lock-step with Mustang as far as timing," Carter revealed. "When we were developing this engine we were developing it with Falcon in mind at the time."

The naturally-aspirated 5.0-litre V8 was developed for the 2011 Mustang. For the 2015 model it has been largely carried over, but with the stronger conrods from the Boss 302 model and improved cylinder head flow commensurate with the Boss 302's. The difference there is that the Boss heads were CNC milled – requiring five hours to manufacture. Ford can build the heads for the new 5.0-litre "every 15 seconds."

Carter says that the new engine's exhaust camshaft was taken from the Boss 302 engine, and delivers 13mm of lift. The intake cam lifts precisely 1mm higher than that of the Boss engine.

According to the drivetrain expert, the 5.0-litre Coyote for the latest Mustang feels peaky, really turning on the taps above 4000rpm, but it is not an oversquare design such as the V8s of yesteryear.

"It's roughly square," he said, "it's 92.2[mm] bore, 92.7 stroke, so it's nearly square. Peak torque happens at 4250[rpm], and peak power is out at 6500. One way I look at naturally-aspirated engines... how good I rate they are, is the amount of separation between power and torque.

"For an old pushrod motor – and I know you guys [Australians] are big 'Cleveland' fans – usually 1000rpm separates peak torque from power in a pushrod engine."

The separation for the new 5.0-litre is up over 2000rpm, and power delivery seems appropriate for a relatively lightweight sporty coupe.

"Once it gets on the pipe," says Carter, "it's really strong all the way to fuel cut-out at 7000."

Both the V8 and the EcoBoost four-cylinder face increasingly stringent emissions regulation around the world in coming years. American legislation is broadly similar to Euro 6, which means an engineering equivalent to a hop, skip and jump to comply with emissions legislation on either side of the Atlantic (or anywhere else in the world, for that matter).

Internal combustion engines are at their 'dirtiest' during the minutes immediately after cold starting, and turbocharged engines can face even tougher challenges because the turbocharger actually insulates the catalytic converter from the warmth of the exhaust flow. Yet Ford has found ways of circumventing that problem with the EcoBoost engine for the Mustang.

"Fortunately, with direct injection we can do a stratified charge at cold start, and have better combustion stability," Carter explained.

"Your traditional spark timing you want to be around 30 degrees before top dead centre; these DI engines can run 10 to 30 degrees AFTER top dead centre. So at cold start they're basically at wide-open throttle. The throttle's all the way open. The spark retard is so aggressive that all of the energy in the combustion is actually going out the exhaust."

Carter says the V8 employs a similar strategy, but "not quite as retarded as" the direct-injected EcoBoost engine employing stratified charge. The V8 also runs 'mid lock' for its intake valve timing during the cranking on cold start. This reduces the time the engine spends cranking (in an Atkinson cycle mode for cold starting) and adds 20 degrees more retard "for even MORE Atkinson."

"That allows us to have better light-load fuel economy.

"That is what has allowed us to meet the emissions standard of the future."

It's an important adjunct to prolonging the appeal and viability of muscle cars in an era of climate change anxiety...

Fast facts

Engine:	Four-cylinder, DOHC, variable valve timing, turbocharged (EcoBoost)
	V8, DOHC, variable valve timing, naturally aspirated (V8)
Capacity:	2300cm³ (EB)
	4951cm³ (V8)
Bore and stroke:	87.5x94.0mm (EB)
	92.2x92.7mm (V8)
Power:	231kW @ 5500rpm (EB)
	324kW @ 6500rpm (V8)
Torque:	434Nm @ 3000rpm (EB)
	542Nm @ 4250rpm (V8)
Transmission:	Getrag six-speed manual or optional Ford six-speed automatic
Drive:	rear
Suspension:	Front MacPherson struts with double ball joint location; Rear Control Blade multi-link
Steering:	Electrically assisted rack and pinion
Brakes:	Four-wheel discs

Ford Mustang: A horse for all courses

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