[DeTomaso] New Ford GT Twin Turbo V6

[Charles McCall]

Chuck - fascinating reading. Thanks for taking the time to share

-----Original Message-----
From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of cengles at cox.net
Sent: viernes, 16 de enero de 2015 16:53
Cc: detomaso at poca.com
Subject: Re: [DeTomaso] New Ford GT Twin Turbo V6


Dear Forum,

                In a coincidence, there is an interesting article in the 
new Road and Track about turbocharging modern engines in modern sports 
cars.   FWIW.


                Full disclosure:  complete article is Rare Forced Air on 
page 27-28 in the Feb 2015 Road&Track by Jason Cammisa.

               These are my selected highlights from that article. 
Complete disclosure: I am not a fan of turbos.  I prefer normally 
aspirated engines for a number of reasons and this article supports my 
opinion.  While the new Ford GT has a twin turbo Ecotec V-6, I would 
prefer it to have a normally aspirated Coyote or the new flat crank V8.

 From Jason Cammisa:

“We don’t like the turbo,” said the  man with an Italian accent, “but it 
is the right way to reduce emissions without sacrificing performance.”
A rare moment of honesty, then a graceful slingshot into the same turbo 
spin we’ve heard from all corners of the globe.
The fact is, every car company is being forced into forced induction, 
for the exact reasons our Italian friend gave.  Since neither he nor the 
company he works for, Ferrari, can come out and say it, I will: Turbos 
aren’t the best solution, especially for high-performance cars, and they 
don’t always provide the benefits that carmakers claim they do.

Turbos, which are powered by exhaust energy that is otherwise wasted, 
increase engine output by forcing extra air into the cylinders, 
prompting the fuel injectors to provide more fuel for combustion.  More 
combustion, alas, means more heat.  To keep the engine from overheating, 
turbo engines inject excess gas under boost.  It seems counter 
intuitive, but this “rich mixture” cools down combustion and reduces 
exhaust temperatures.  It is also a double whammy fuel economy killer, 
because burning that extra fuel doesn’t help the engine make more power, 
it actually reduces output.

….out in the real world, riding that big, effortless wave of boosted 
midrange torque means burning extra fuel—and creating even more CO2.  So 
much for reducing emissions.

Performance, in this sense, refers solely to acceleration.  The Ferrari 
California T’s turbo 3.9 liter 553 hp V8 easily outmuscles the old 
California’s naturally aspirated 4.3 liter 483 hp v8.  Mission 
accomplished.  Except there’s more to an engine’s behavior than going 
fast in a straight line.  The way the engine generates power –its 
personality, if you will---is just as important as the numbers.    For 
the entire history of the marque, Ferrari’s engines have delivered 
urgency and drama in lockstep with revs, creating a festival of sound 
and fury as they raced toward a redline.  Ferrari engines love to rev, 
which is one of the main reasons we love Ferraris.

Once there’s a turbo impeller muffling the screaming glory of that 
prancing horse, you’re talking about an entirely different animal. 
Engines with turbos big enough to provide boost throughout the operating 
range produce peak torque at low revs and then gradually run out of 
steam, like turbodiesels do.  To combat that, gas-powertrain engineers 
artificially create broad torque plateaus by limiting boost at lower 
engine speeds.  That electronic trickery helps the engine more closely 
emulate a naturally aspirated one, but even that isn’t enough for 
Ferrari.  The California T’s computer also looks at gear position and 
limits max boost in lower gears to encourage its driver to revel in the 
gears.

Turbo lag.  Ferrari claims the California’s new turbo engine has “zero 
turbo lag” and “instantaneous response,” then defines response time as, 
“less than one second.” Really?  In a car that can hit 60 mph in three 
seconds, one second, is anything but instantaneous.

Immediate, predictable response is a requirement in any driver’s car. 
Naturally aspirated engines react without delay to throttle inputs, but 
a turbo engine is vastly more complicated.  It has two torque curves—one 
when it is off boost and one when it is at full puff.

A naturally aspirated engine’s output is determined by the position of 
the pedal and the engine speed, period.  Turbos change that into a 
complicated matrix with far too many variables for a driver to keep 
track of.

Modern Ferraris do what you ask, when you ask, how you ask.  They are 
pretty much perfect.  Although their forth coming turbocharged 
replacements will almost certainly be faster, I fear they will be 
undriveable without assistance from an onboard supercomputer.

It ‘s sad that the marquee feels compelled by government policy to bolt 
turbos on to their lovely engines, when it won’t make a whit of 
difference to air quality.   And it is doubly sad that we all know it 
will change the way Ferraris drive.”


                         Warmest regards,  Chuck Engles