Automotive Engineering - April 2022 - 6

TECHNOLOGY
REPORT
POWERTRAIN
GM details Corvette's new and mighty LT6 V8
SAE INTERNATIONAL
BOARD OF DIRECTORS
Srinivasa (Sri) Srinath, Ph.D
President
Jeff Hemphill
2021 President
Todd Zarfos
2023 President Elect
Susan Ying, Ph.D
Vice President - Aerospace
Daniel Nicholson
Vice President - Automotive
Michael Weinert
Vice President -
Commercial Vehicle
Andrew Jeffers
Treasurer
Although developed
by GM's Small Block
engineering team, the LT6
V8 is a clean-sheet design
that shares only its borecenter
spacing with the
small-block V8 family that
GM launched in 1955.
If the end of the internal-combustion epoch
truly is within sight, General Motors intends to
see it out with a bang. It's latest - who's to say
whether it's the " last? " - clean-sheet V8, internally
designated LT6, arguably is its best, considering
GM touts it as the world's most-powerful
normally-aspirated V8 ever fitted in a production
vehicle.
Earmarked for the 2023 Z06 high-performance
variant of the Chevrolet Corvette, the
LT6's most-illustrious design feature is its flatplane
crankshaft, but engineers in mid-February
2021 laid out for media the numerous other
unique engineering elements that led to the
thunderous SAE-certified output of 670 hp and
from a comparatively moderate - in V8 terms
- displacement of 5.5L. Over its eight-year development
that saw the first prototype in 2015,
engineers from GM's Small Block engine team
dubbed the engine " Gemini " due to its many
" twin " architectural elements.
Just don't call the LT6 a " small-block " V8,
even if it was developed by the engineering
team bearing that name. Apart from its 4.4inch
(111.76-mm) bore-center spacing - the single
architectural dimension that connects all
6 April 2022
five generations of GM's legendary V8 introduced
in 1955 - the LT6 has virtually no connection
to small-block V8s, declared chief engineer
Jordan Lee. Not only does the 90-degree
LT6 have the significant difference of a
dual-overhead-cam (DOHC) layout rather than
the overhead-valve (OHV) arrangement that's
a hallmark of the small-block family, Lee confirmed
the LT6 shares not one part with any
previous pushrod small-block. To further drive
home the point, he added, " In today's day and
age, it's hard to define an engine by one dimension
[the 4.4-in. bore centers]. This is a
unique engine on its own. "
Less mass, better throttle response
To fully exploit the flat-plane V8's intrinsic
quick throttle-response and revving ability -
redline is a dervish 8600 rpm - lightweighting
and reciprocating-mass reduction were key
LT6 priorities. At 364 grams each, its forgedtitanium
connecting rods are 21% lighter than
the titanium rods for the LS7 supercharged 7L
V8 in the sixth-generation (2006-13) Z06
Corvette, pointed out design release engineer
Thomas Halka.
David L. Schutt, Ph.D
Chief Executive Officer
Gregory L. Bradley, Esq.
Secretary
Judy Curran
Rhonda Walthall
Joan Wills
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SAE Members in a given area. For more
information, please visit sae.org/sections
or contact SAE Member Relations Specialist
Abby Hartman at abby.hartman@sae.org.
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Collegiate Chapters
Collegiate Chapters are a way for SAE
International Student Members to get
together on their campus and develop
skills in a student-run and -elected
environment. Student Members are vital
to the continued success and future of
SAE. While your course work teaches
you the engineering knowledge you
need, participation in your SAE Collegiate
Chapter can develop or enhance other
important skills, including leadership,
time management, project management,
communications, organization, planning,
delegation, budgeting, and finance. For
more information, please visit students.
sae.org/chapters/collegiate/ or contact
SAE Member Relations Specialist Abby
Hartman at abby.hartman@sae.org.
AUTOMOTIVE ENGINEERING
GM
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Automotive Engineering - April 2022

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