Small Block goes big

maximum engine speed is bumped from

6200 to 6500 rpm.
“More than dynamometer numbers,
the LS2 engine’s range of power and
torque is broad and very usable in every-
day driving,” said Dave Muscaro, GM
Powertrain’s Assistant Chief Engineer of
car Small Blocks. “This engine is smooth-
er, and more refined, but at the same
time retains tire-thrashing output.”
The LS2’s “cam-in-block” Gen IV ar-
chitecture is based on that of the LS1 5.7-
L Gen III engine of the Corvette C5. Like
all Small Blocks, the new engine features
a 90º cylinder bank vee and 4.40-in (112-
mm) bore centers. As with the Gen III, the
latest engine has a lightweight block cast
from aluminum (319-T5) with cast-in-
place iron cylinder bore liners. Structural
rigidity is enhanced by a deep-skirt en-
gine block, which extends below the
The 2005 LS2, the most crankshaft centerline, and by two hori-
powerful standard engine zontal cross bolts for each main bearing
in Corvette history,
gets a 0.3-L increase in
cap, which complement the four tradi-
displacement, a higher tional vertical main cap bolts.
10.9:1 compression ratio, Crankcase breathing and ventilation
and a redline bumped to are improved using techniques employed
6500 rpm.
on the C5 Z06’s LS6 engine, including
moving the crankcase ventilation system’s
PCV valve away from the rocker covers
and into the block valley. A die-cast alumi-
num valley cover and upper deck rails link
the cylinder banks for increased torsional
and bending stiffness. Performance and
efficiency benefit from a “balanced cylin-
der head design” with identical airflow
and energy direction for each cylinder.
The new 2005 Chevrolet C6 Corvette The LS2 incorporates several signifi-
features the most powerful standard en- cant changes compared to the Gen III-
gine in Corvette history. The 6.0-L LS2 based LS1 that help improve perfor-
V8, part of the fourth generation of mance, reliability, and serviceability.
General Motors’ Small Block engines, Its new aluminum block casting incor-
delivers 400 hp (298 kW) at 6000 rpm porates provisions for external knock sen-
and 400 lb·ft (542 N·m) at 4400 rpm— sors, which improve serviceability, and
increases of 50 hp (37 kW) and 40 lb·ft revised oil galleries. The LS2’s new “wing-
(54 N·m) over the previous Corvette’s less” oil pan with cast baffling reduces
5.7-L LS1. (The first Small Block in 1955 mass and provides better oil control un-
displaced 265 in3 [4.3 L] and put out 195 der the extreme demands of high-rpm,
gross hp.) The 0.3-L increase in displace- high g-force driving maneuvers. The
ment is the result of an increase in cylin- switch from a “gull-wing” oil pan also
der bore diameter to 101.6 mm (4.00 in); reduces engine oil capacity from 6.5 to
stroke is 92 mm (3.62 in). Compression 5.5 qt (6.1 to 5.2 L) with a dry filter. The
ratio is raised from 10.1:1 to 10.9:1 and camshaft sensor is relocated from the rear

20 JANUARY 2005 aei

 N·m lb·ft hp kW
and mass reduced by 33%, one of the
500 500
350 major sources of the latter being a wall
thickness reduction from 4 to 3 mm
600 (0.16 to 0.12 in).
400 300
400 Advances in substrates allowed engi-
500 neers to maintain the size of the catalytic
250 converters while making them more ef-
300 300 fective and less restrictive. The new con-

Power
400
Torque

verters are mounted closer to the exhaust

200 manifold for quicker lightoff and reduced
300
200 200 cold-start emissions. So the more restric-
tive quad catalyst design of the LS1, with
150
200 its small, auxiliary “pup” converters, was
100 100
not necessary to meet emissions require-
100 100 ments. An additional benefit of exhaust
system development was elimination of
the LS1’s air-injection-reaction system.
0 0 0 0
0 1 2 3 4 5 6 7 Other adjustments made to improve
Engine speed, rpm x 1000 exhaust system performance included
replacing sharp tubing angles with more
The Corvette’s new 6.0-L LS2 V8 delivers 400 hp (298 kW) at 6000 rpm and 400 lb·ft (542 N·m) at gradual bends. A larger muffler volume
4400 rpm—increases of 50 hp (37 kW) and 40 lb·ft (54 N·m) over the previous Corvette’s 5.7-L LS1. and tri-flow technology eliminated un-
wanted noise, particularly between 1500
and 2400 rpm. The inline (vs. the LS1’s
to the front of the block to provide room the air/fuel mixture. This efficiency en- transverse) muffler flows more efficiently.
for the new oil galleries. Camshaft lift ables a higher (10.9:1) compression ratio, The LS2’s new engine controller incor-
and throttle body size are increased—the which increases efficiency and power. A porates electronic throttle control (ETC)
latter to 90 mm (3.54 in) for the single- flat-top piston with lower ring tension commands, so the separate ETC module
blade design—to take advantage of in- reduces friction, and floating piston wrist of the LS1 is eliminated. This allows faster
creased cylinder head flow. pins reduce NVH. The 2-in (51-mm) in- communication between controller and
The cylinder heads are derived from take and 1.55-in (39-mm) exhaust valves throttle and reduces system mass and
those used on the LS6, including raised get springs upgraded to withstand the complexity. And emissions are slightly
intake ports and an unshrouded valve engine’s increased power and rpm range. improved with the damping of unneces-
combustion chamber design that, when Engineers also increased the efficiency sary throttle movement.
combined with the engine’s flat-top pis- and reduced the mass of the exhaust Joining the LS2 in the Corvette lineup
tons, produces a more efficient swirl of manifolds. Airflow is enhanced by 4% will be the new 2006 Z06’s LS7, the larg-
est, most powerful Small Block ever. The
7.0-L powerhouse puts out 500-hp (373
kW) at 6200 rpm and 475 lb·ft (644 N·m)
at 4800 rpm with the help of racing tech-
nology transfer. GM Powertrain engineers
applied experience gained from the
Corvette C5R racing program to develop

The 7.0-L LS7 for the 2006 Z06 produces 500 hp (373 kW) at 6200 rpm and 475 lb·ft (644 N·m) at 4800 rpm with the help of racing technology transfer.

22 JANUARY 2005 aei

GM Powertrain engineers applied experience
gained from the Corvette C5R racing program
Unique hydraulic rollers for the LS7 help to actuate the larger valves and provide more valve lift.
to develop the LS7.

front cover, oil pan, exhaust manifolds, nected to a forged-steel crankshaft with a
and cylinder heads. The unique block ac- 101.6-mm (4.00-in) stroke via titanium
commodates large-displacement cylin- connecting rods of just 480 g (16.9 oz)
ders, while other components make use each—almost 30% less than those in the
of racing-derived lightweight components LS2. Their light weight enhances high-
to help boost power and ultimate engine rpm performance and range.
speed to 7000 rpm. The engine’s dry-sump oil system, with
The LS7’s block has larger—104.8-mm a high-capacity 8-qt (7.6-L) reservoir and
(4.125-in)—cylinder bores, the latter en- high-efficiency air-to-oil cooler, is de-
abled by pressed-in cylinder sleeves. Six- signed to ensure proper lubrication dur-
bolt, doweled-in-place, CNC-machined, ing high cornering loads. Oil circulates
forged-steel main bearing caps offer the through the engine, to the oil pan, then
strength required for the LS7’s output. back to the reservoir via a scavenge
(The smaller-displacement LS2 engine has pump.
cast-in cylinder sleeves and powder-metal Like other Gen IV engines, the LS7
main caps.) uses a composite, three-piece, friction-
Aluminum flat-top pistons deliver an welded intake manifold, although its pas-
11.0:1 compression ratio and are con- sages are tuned for greater airflow re-

LS7 Specifications
Engine type “Cam-in-block” 90º V8
Block configuration Cast aluminum with pressed-in cylinder sleeves and
six-bolt, forged-steel main bearing caps
Bore x stroke 104.8 x 101.6 mm (4.125 x 4.00 in)
Displacement 7.0 L
Power 500 hp (373 kW) @ 6200 rpm
Torque 475 lb·ft (644 N·m) @ 4800 rpm
Redline 7000 rpm
Crankshaft Forged steel
The LS7 cylinder heads are CNC-ported Connecting rods Forged titanium
and have very large (by production-vehicle
standards) intake and exhaust ports to speed Pistons Cast aluminum
airflow.
Compression ratio 11.0:1
many LS7 components. “In many ways, Cylinder heads CNC-ported aluminum; 70-cm3 chamber volume
the LS7 is a racing engine in a street car,” Valves:
said Muscaro. Intake 56 mm (2.20 in), titanium
The LS7 is identified by red engine
covers and is based on the new Gen IV Exhaust 41 mm (1.61 in), sodium-filled
Small Block architecture. But unlike the Camshaft Hydraulic roller, 15-mm (0.591-in) lift (intake
relationship between the LS1 and the and exhaust)
previous Z06 engine, the LS7 has a dis- Rocker arms 1.8:1, offset (intake only)
tinct engine block casting and reciprocat- Air intake Composite manifold with 90-mm (3.54-in) throttle body
ing assembly than the base engine.
Fuel 91 octane (minimum)
Compared to the LS2, it has a different

24 JANUARY 2005 aei

 Corvette Engine Comparison
Corvette model Base ZO6 The LS7’s
Engine 2004 LS1 2005 LS2 2004 LS6 2005 LS7 aluminum flat-
top pistons are
Displacement 5.7 L 6.0 L 5.7 L 7.0 L connected to
a forged-steel
Power 350 hp (261 kW) 400 hp (298 kW) 405 hp (302 kW) 500 hp (373 kW) crankshaft
at 5200 rpm at 6000 rpm at 6000 rpm at 6200 rpm with titanium
Torque 375 lb·ft (508 N·m) 400 lb·ft (542 N·m) 400 lb·ft (542 N·m) 475 lb·ft (644 N·m) connecting
at 4000 rpm at 4400 rpm at 4800 rpm at 4800 rpm rods.

quirements. Housed in the manifold are and experience with the C5R results in
90-mm (3.54-in), single-bore throttle valve angles of 12º vs. 15º (for the LS2)
bodies and higher-capacity, 5-g/s for enhanced airflow.
(0.18-oz/s) fuel injectors. Unique hydraulic rollers actuate the
lar sections of the flange smooth the ex-
The aluminum cylinder heads are larger valves, and based on C5R racing
haust flow out of the engine.
CNC-ported on state-of-the-art five-axis experience, the LS7’s cam has a new profile
LS7s will be hand-assembled at GM’s
milling machines to meet airflow de- to provide 0.066 in (1.7 mm) more lift—
new Performance Build Center in Wixom,
mands that are 25% greater than LS2’s. 0.591 vs. 0.525 in (15.0 vs. 13.3 mm)—on
MI, using procedures—such as deck-plate
The engine has straight intake runners both the intake and exhaust valve. Higher-
boring and honing of the cylinders and
and very large (by production-vehicle performance (1.8:1 vs 1.7:1) roller rocker
crank line-boring of the block with the
standards) ports to speed airflow. The arms, which are offset on the intake side,
deck plates and side bolts installed—nor-
combustion chambers are fed by large— and raised valve spring seats accommodate
mally associated with race-engine build-
56-mm (2.2-in)—titanium intake valves the high valve lift and large ports.
ing. The engines are pushed through
that each have a mass 21 g (0.7 oz) less On the exhaust side, hydroformed
about 15 subassembly stations. Team
than the stainless-steel valves used in the steel exhaust headers are unique to the
members are engine-build specialists se-
LS2 despite having 22% more area. The LS7. Individual header tubes meet at a
lected from GM’s experimental engine
sodium-filled exhaust valves are 41.0 vs. special quad-outlet collector flange at the
lab, and they complete about 30 LS7 en-
39.4 mm (1.61 vs. 1.55 in) in the LS2. header outlet where they smoothly attach
gines per day.
The valve seats are Siamesed to accom- to the “wide-mouth” catalytic converter
Kevin Jost
modate the large valve face diameters, for reduced back pressure. Four rectangu-

BMW builds better inline six

“Efficient dynamics” is the declared goal timing that eliminates the throttle butter- down by 12%—and the lowest specific
of the BMW Group’s drivetrain develop- flies, and a number of other innovations fuel consumption in its class.
ment division. “This resolves the apparent such as the world premiere of the electric For the first time in modern engine
conflict between reducing consumption water pump. The R6 is said to distinctly construction, BMW uses magnesium for
and emissions on the one hand and en- surpass the final version of its predecessor the engine’s crankcase, with the material
hancing performance and agility on the in every aspect. BMW’s medium-term cor- also employed for the new bedplate and
other,” commented Professor Burkhard porate plans reveal that around half of all cylinder-head cover. The 7%, or 10-kg
Göschel. new BMW cars will be powered by the (22-lb), reduction in engine mass result-
With that goal in mind, BMW under- engine. ing from use of magnesium and from
took development of a new 3.0-L inline- Peak output of the R6 surpasses its other lightweight engine components
six gasoline engine, the R6, that is said to predecessor by 20 kW (27 bhp) with 190 such as exhaust manifolds and camshafts
be the most comprehensive engine proj- kW (258 bhp) at 6650 rpm. Maximum is said to contribute substantially to in-
ect since the introduction of its first auto- torque of 300 N·m (221 lb·ft) is available creased agility and dynamics of future
mobile. Rather than upgrade its existing between 2500 and 4000 rpm. The com- BMW automobiles.
I6 to state-of-the-art technical specifica- pany says the basic unit has the highest The composite magnesium/aluminum
tions, which would have resulted in an specific power output per liter and the crankcase weighs just 57% of a compa-
engine 14 kg (31 lb) heavier, BMW engi- highest power/mass ratio in its class at 63 rable grey-cast iron block, and has a 24%
neers decided to develop an entirely new kW/L (84 hp/L) and 1.18 kW/kg (0.717 advantage compared to aluminum. Being
engine, leaving only the inline arrange- hp/lb), respectively. At just 161 kg (355 the largest single engine component, it
ment of six cylinders unchanged. lb), the R6 is 7% lighter than its prede- makes a significant contribution to reduc-
The high-tech power unit has a com- cessor, making it the world’s lightest six- ing total mass.
posite magnesium/aluminum crankcase, cylinder engine, says BMW. Power output However, use of magnesium does
BMW’s Valvetronic infinitely variable valve is up by 12%, with fuel consumption pose some interesting technical challeng-

26 JANUARY 2005 aei

es. A crankcase made exclusively of mag-
nesium or a conventional magnesium
alloy is inadequate for high-performance
production engines; it has insufficient
stability and the surface structure of mag-
nesium is unsuitable for the cylinder lin-
ers. So the inner part of the R6 crankcase
features an aluminum insert that incorpo-
rates the cylinder liners and coolant
ducts. The insert provides the required
stability under the high thermal and me-
chanical strains of the engine. The cylin-
der head is mounted directly onto the
insert, the lower section of the latter serv-
ing as the upper section of the crankshaft
mounting. BMW overcame the problem
of the chemical incompatibility of magne-
sium and water by not allowing the cool-
ant to come in contact with the magne-
sium crankcase shell because it flows ex-
clusively inside the aluminum insert.
The magnesium jacket accommodates
BMW calls its new R6
the oil ducts, gear casing, as well as most 3.0-L inline six the
mounts and brackets for ancillary compo- most comprehensive
nents. The integration of supports and engine project since the
introduction of its first
brackets increases stiffness of the ancil- automobile.
lary component connection, enhancing
the acoustics of the crankcase/ancillary
component package. The R6 engine con- a die and the tube is subjected to internal
tinues BMW’s tradition of chain drive of water pressure of 4000 bar (58 ksi) to
the valves. The company prefers the achieve the desired wave shape and
method because they say it contributes pressed against the cams from the inside.
greatly to accurate and durable function- crankcase, the new lightweight camshafts Finally, the cams are polished down to a
ing of the engine and reduced mainte- are the largest single contributors to the 39-µin finish.
nance—and cost—for the vehicle owner. R6’s low mass. Hydroforming reduces the New connecting rods also contribute
During engine assembly, the chain drive is mass of each of the two finished cam- to mass savings. When viewed from the
placed into a chamber at the front of the shafts by 25%, or 600 g (21.1 oz). The side, their upper eye is tapered to save a
engine and fixed into place without gear primary camshaft component, a steel few grams each, which might not seem
casing bolts and time-consuming sealing tube, is pulled through the high-strength like a lot but is significant considering the
of the cylinder head and crankcase. steel cam rings. The assembly is placed in high speed at which the connecting rods
Since the magnesium bedplate func-
tions as a load-bearing engine compo-
nent of the R6’s central frame structure, it
also employs composite construction. The
crankcase is mounted on the bedplate
from above, together with the upper sec-
tion of the crankshaft bearing. The lower
counterpart of the crankshaft bearing is
integrated into the bedplate. The crank-
shaft runs on sintered steel inserts sur-
rounded by magnesium. After the bed-
plate and crankcase are bolted together,
a sealing compound is injected under
high pressure between the two compo-
nents. Due to similar coefficients of ex-
pansion, aluminum bolts are used for fix- The R6 crankcase features a magnesium shell
ing parts to magnesium components, around an aluminum insert (image) that
adding to the reduction in engine mass. incorporates the cylinder liners and coolant ducts.
After the aluminum-magnesium

aei JANUARY 2005 27

 kW hp

200
260
lb·ft N·m
180 240
250 220
320 160

Torque
225 200
280 140
200 180

175 240 120 160

Power
140
150 200 100
The R6 gets BMW’s 120
second-generation 80
100
Valvetronic for higher
engine speeds. The 60 80
innovation adjusts 60
valve opening times 40
and valve timing 40
infinitely according 20
20
to accelerator pedal
position and eliminates 0 0
the need for throttle 0 1 2 3 4 5 6 7
butterflies Engine speed, rpm x 1000

Peak output of the R6 surpasses its

predecessor by 20 kW (27 bhp), with 190 kW
reciprocate. The lower area of the con- regulates charge-changing processes, (258 bhp) at 6650 rpm. Maximum torque of
necting rod eye is wider so the gudgeon achieving better fuel economy and im- 300 N·m (221 lb·ft) is available between 2500
pin can transfer the high forces of the proved engine response. The hike in rated and 4000 rpm.
crankshaft via the connecting rod. R6 engine speed and maximum engine
Second-generation Valvetronic makes speed to 7000 rpm necessitated the sys-
its first appearance on the R6, following tem’s redesign, specifically for enhanced injection concepts. Employing it on the six-
implementation of the first generation on stiffness. The system now achieves valve cylinder, the most widely sold BMW power
BMW four-, eight-, and twelve-cylinder actuation acceleration ratings equal to unit, means there will be a quantum leap
power units. The innovation adjusts valve those of bucket tappet valvetrains. It also for this technology’s market penetration
opening times and valve timing infinitely incorporates more aluminum compo- and the overall fleets’ reduction in fuel
according to accelerator pedal position. nents, contributing to mass reduction. consumption, regardless of region. In con-
This technology eliminates the need for BMW believes Valvetronic will be dis- trast, the full fuel-consumption potential
throttle butterflies and very accurately tinctly more successful than lean direct- of lean DI systems, for example, can only
by exploited in markets with adequate
R6 Engine Specifications sulfur-free fuel, which is not available in
some countries. On average and under all
Configuration Inline six
operating conditions, Valvetronic achieves
Maximum output 190 kW (258 bhp) at 6650 rpm a drop in fuel consumption of 10% in the
Maximum torque 300 N·m (221 lb·ft) at 2500-4000 rpm composite EU cycle.
Combustion Naturally aspirated, Lambda=1.0, Valvetronic valve control
The cooling system’s electric water
pump, another R6-first innovation, oper-
Capacity 2977 cm3
ates according to the engine’s actual cool-
Compression ratio 10.7:1 ing requirements, regardless of engine
Bore x stroke 85 x 88 mm (3.35 x 3.46 in) speed. Its use results in a significant re-
Crankcase material Magnesium with aluminum insert, Alusil-type liners
duction in consumption. While a conven-
tional water pump consumes up to 2 kW,
Distance between cylinders 91 mm (3.58 in)
the new electric unit needs just 200 W.
Conrods Cracked, trapezoidal For a conventional water pump, cool-
Camshafts Two, chain-driven, hydroformed, in seven bearings ing capacity is designed to cope with a
Camshaft adjustment Infinitely variable phase adjustment of intake and exhaust
maximum engine load at low engine
(bi-VANOS and Valvetronic) speeds and is, therefore, too great for
many operating conditions, especially at
Valve drive Roller rocker arms, hydraulic valve play compensation
high engine speeds. It also operates con-
Valves Four per cylinder tinually via a belt drive, with excessive
Intake system Three-stage resonance losses due to friction. Pump flow rate is
Engine mass (BMW standard) 161 kg (355 lb) dependent on engine speed and not on
the engine’s actual cooling requirements.
Engine management Digital engine control with integrated Valvetronic valve management (MSV70)
During warmup of the engine, its least
Fuel 87-98 RON (rated output with RON 98 fuel) efficient phase, the electric water pump
Cooling Electric pump, map-controlled coolant temperature requires little power. And the residual

28 JANUARY 2005 aei

heat in the coolant can be used to heat The R6’s three-stage air intake system, graphite ring is used on each cylinder to
the car’s interior with the electric pump a development of the previous dual con- achieve significantly improved tightness
even when the engine is not running. figuration, allows for higher torque at to the engine’s header. The thin-walled
The use of the electric water pump, lower engine speeds. The third resonance ceramic catalysts are smaller and lighter,
which operates without a belt, meant pipe, which is actuated via resonance so they reach operating temperature fast-
that all ancillary components of the R6 valves, effectively increases the engine er and eliminate the need for secondary
could be driven by one belt. The result is speed range downward. air intake.
reduced engine length and lighter weight BMW engineers threw all their know- A new oil/water heat exchanger trans-
since accessory parts such as the belt, belt how into the exhaust manifold, with a fers heat to the engine oil so that it
pulley, and tightener are eliminated. resulting mass reduction of 0.8 kg (1.8 reaches operating temperature much ear-
As with the electric water pump, the lb). The differing thermal expansion coef- lier, shortening the uneconomical
engine’s capacity-controlled oil pump ficients of aluminum (cylinder head) and warmup phase. Conversely, heat is ex-
supplies the specific quantity of oil for steel (exhaust manifold) necessitated new tracted from the oil circuit by the heat
given engine operating conditions and solutions in this particular area. So its exchanger and from the engine via the
consumes up to 2 kW less than conven- lightweight, deep-draw flange is reduced coolant circuit during periods of greater
tional oil pumps. from 12 to 2 mm (0.47 to 0.08 in) and a engine output and oil temperatures.
Kevin Jost

Yamaha engineers Volvo V8

Physics and market forces are pushing
most newly developed engines into very
similar configurations as designers seek to
optimize power and efficiency in engines
that appeal to the broadest array of cus-
tomers. In some cases there are overrid-
ing factors that cause manufacturers to
forego the efficiency, balance, or packag-
ing benefits of these popular solutions. In
Porsche’s case, for example, the heritage
of the traditional horizontally opposed
engine configuration outweighs other
considerations.
Volvo’s most prominent core value is
safety, so when market forces dictated
that an eight-cylinder engine should be The compact 4.4-L
Yamaha-built 60°
offered in its XC90 mid-size SUV, the aluminum V8 measures
company faced a challenge packaging a only 29.7 x 25 in
wider transverse-mounted V8 engine in (755 x 635 mm) and
has a mass of 419 lb
the space of the inline six-cylinder with- (190 kg), but produces
out compromising crush space in the en- 315 hp (235 kW).
gine bay.
A normal, balanced 90° V8 simply cylinder.
wouldn’t fit with the required crush “From the very beginning, we knew
space, the company concluded. Volvo that it takes a V8 to go all the way in the
engineers estimated that to use the premium SUV segment,” said Kjell
Jaguar V8 would require the XC90 front Hvarfvén, XC90 V8 Project Director. “We
end to be extended by 200 mm (8 in). looked for many years for a V8 that
The solution would be to develop a new would fit, even before Ford bought us.”
60° V8. The company’s acquisition by Because Yamaha provides the Volvo’s
Ford helped Volvo engineers make the 4.4-L, 315-hp (235 kW), 325 lb·ft (440
necessary connections, and Ford Chief N·m), 60° V8, using the same bore spac-
Technical Officer Richard Parry-Jones ing and stroke as the old 3.4-L Taurus
pointed them to Yamaha, the company SHO V8, it would be easy to assume that
that supplied first a high-performance V6 the XC90’s engine is simply a larger-dis-
placement version of its predecessor. But Volvo determined that only a very narrow 60°
for the Taurus SHO, and later a 60° V8 V8 would fit in the XC90’s engine bay while
that was derived from the original six- that assumption would be wrong. preserving the requisite forward crumple
While some fundamental dimensions zone.

30 JANUARY 2005 aei

 All new cylinder heads feature combustion chambers with a large
squish area, which assists in reducing emissions and maximizing fuel
efficiency with a lean air/fuel mixture. The block carries its left cylinder
bank staggered ahead of the right for packaging reasons in the XC90.

The 60° V8’s

narrow central
valley leaves just
enough space
for the critical
balance shaft
in the location
of an OHV V8’s
camshaft. The
iron cylinder
liners are cast
into the high-
pressure die-cast
aluminum block.

Contributing to the V8’s compact dimensions are direct-mounted

accessories and exhaust cams that are driven off the intake cams,
eliminating the large-diameter exhaust cam gear near the edges
of the engine.

of the architecture are carried over from ing from its inherently unbalanced 60° 40° of variation on each, and shimless
the earlier engine, literally everything else design. Completely new cylinder heads tappets act on the valves for simplified as-
has changed. The very layout of the feature new combustion chambers with sembly. Volvo maintains optimum intake
block, for example, sees the left cylinder large squish areas. “When combustion flow with a crossover valve that opens
bank shifted ahead of the right, contrary starts, it is quite slow burning the first between the left and right halves of the
to conventional fashion which places the 10% of the charge,” he said. “Then it is intake plenum. Above 3200 rpm, the
right bank ahead. The change was made quite fast combustion with very high tur- valve opens, letting cylinders draw air
for packaging reasons under the XC90’s bulence.” This lets the engine run lean, from the entire volume of the plenum
hood. According to Johan Tollmén, and do so quickly after start-up, to mini- chamber during high-speed operation.
Project Manager, Powertrain Controls, the mize emissions, according to Hvarfvén. The engine’s castings feature built-in
new Volvo V8 engine owes as much to The lean-burn combustion also con- mounts for all accessories, eliminating the
Yamaha V6 outboard-motor technology tributes to the engine’s ULEV-II rating, space consumed by bracket-mounted
as it does to the old Yamaha/Ford en- which fulfills Volvo’s other core character- accessories, along with the resulting
gines. istic, environmental responsibility. Close- noise. Both AC and power-steering
The new engine block is made by coupled catalysts mount to each of the pumps use variable-displacement technol-
high-pressure die casting, rather than the low-thermal-mass stamped sheet-metal ogy, which Volvo engineers estimate re-
previous gravity casting, to help maintain exhaust manifolds, and another pair duces the fuel consumption by about 4%
block integrity. Iron cylinder liners are cast mounted downstream in the XC90 V8’s Working with Japanese engineers
in. Volvo claims that the resulting engine dual exhaust system completes the emis- thousands of miles away posed no par-
is the smallest V8 on the market, measur- sions scrubbing. The catalysts light off ticular hardship for the Volvo team, ac-
ing 29.7 in (755 mm) long and a scant 25 within 15-20 s of start-up, according to cording to Hvarfvén. “We are actually
in (635 mm) wide. The Yamaha/Volvo Hvarfvén, helped by a higher idling speed quite used to working with Japanese sup-
collaboration tips the scales at 419 lb of 1250 rpm that drops to 675 rpm when pliers,” he said. “Denso supplies Volvo’s
(190 kg), only 55 lb (25 kg) more than the engine is warmed up. engine management system, and Aisin-
the inline six-cylinder T6 engine. The valvetrain is also all-new, with Warner has provided the company with
A balance shaft spins in the valley of variable cam timing for both the intake transmissions since the 1980s.”
the engine’s vee to offset vibration result- and exhaust cams, allowing as much as Dan Carney and David Alexander
32 JANUARY 2005 aei