Automotive Engineering - November/December 2021 - 8

TECHNOLOGY
REPORT
PROPULSION
No-batteries-included Corvette Z06: More sting for
the 2023 Stingray
SAE INTERNATIONAL
BOARD OF DIRECTORS
Jeff Hemphill
President
Todd Zarfos
2020 President
Srinivasa (Sri) Srinath, Ph.D
2022 President Elect
Susan Ying, Ph.D
Vice President - Aerospace
Ken Washington, Ph.D
Vice President - Automotive
Michael Weinert
Vice President -
Commercial Vehicle
The 2023 Z06's increased power required the heat exchanger inlets on the car's flanks to be
redesigned for increased air flow.
Topping the eighth-generation (C8) 2020-22
Chevrolet Corvette is no mean feat. Customers
still pay premiums and patiently wait in line to
own one. Yet the new Z06 edition, due next
summer as a 2023 model, suggests that the
Corvette design and engineering team is just
hitting its stride. The Z06 is an ambitious blend
of Corvette heritage, state-of-the-art technology
- including a new 670-hp DOHC V8 - and
lessons learned in racing. This latest member of
the C8 family, soon to include two hybrids, is a
championship-winning racer tamed just
enough for street driving.
Sixty years ago, Corvette patron saint Zora
Arkus-Duntov attached the first letter of his
name to a sub-rosa component set engineered
for racing. Only 199 customers selected the
Z06 option ($1,818), making a 1963 Corvette so
equipped worth millions today. In 2001, the
badge was reprised for the hottest model in
the lineup, and Z06s have thrived through
three subsequent generations.
'Flat-plane' 5.5-L DOHC V8
Sharing only its 90-degree V-angle, 4.40-in
(111.8-mm) bore-center spacing and a few fasteners
with the immortal ohv small-block, GM's
new " flat-plane " LT6 V8 is a totally fresh design.
A horizontally split block secures each main
bearing with four bolts. The block and heads
are cast aluminum reinforced with cast-iron
cylinder liners and valve-seat inserts. A drysump
lubrication system provides six stages of
scavenging and an 8-quart oil capacity.
8 November/December 2021
The star of the LT6 show is a crankshaft
with all four throws lying in a single plane
(versus the standard approach of four throws
spaced at 90-degree intervals). Flat-plane
cranks provide 180° of spacing between the
exhaust pulses of adjoining cylinders to augment
power at the expense of NVH. This approach
is standard racing practice, and the
reason why exotic Italian sports cars shriek at
their red lines rather than emit an American
V8 engine's motorboat rumble.
The LT6 V8's steel crankshaft, titanium connecting
rods and aluminum pistons are all forgings.
The four chain-driven overhead camshafts
are equipped with phasers to facilitate variable
valve timing. Finger followers lie between each
cam lobe and its adjoining valve stem. A pair of
coil springs closes each valve and lash is set
with shims which require no attention throughout
the life of the engine. Intake valves are titanium
to minimize mass and exhaust valves are
sodium-filled for heat resistance.
Combustion chambers yielding a 12.5:1 compression
ratio and the engine's intake ports are
all fully machined. A molded-plastic intake plenum
with valve-connected runners and an
electronically controlled throttle body feeds
each bank of cylinders. Unlike the C8's LT2
overhead-valve V8, the LT6 does not deactivate
cylinders to reduce fuel consumption.
Using a 4.104-in (104.25-mm) bore inhibited
coolant flow between the cylinders. The solution
- drilling passages through the block's deck -
does provide some lateral flow to cool the very
Andrew Jeffers
Treasurer
David L. Schutt, Ph.D
Chief Executive Officer
Gregory L. Bradley, Esq.
Secretary
Pascal Joly
Jeff Varick
Rhonda Walthall
Joan Wills
SAE International Sections
SAE International Sections are local
units comprised of 100 or more SAE
International Members in a defined
technical or geographic area. The purpose
of local Sections is to meet the technical,
developmental, and personal needs of the
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.
SAE International
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
CHEVROLET

https://www.sae.org/participate/membership/sections https://www.sae.org/participate/membership/collegiate-chapters

Automotive Engineering - November/December 2021

Table of Contents for the Digital Edition of Automotive Engineering - November/December 2021