1. The LTG engine in the Cadillac ATS & CTS (also in Chevy Malibu & Buick models) is a thoroughly modern and sophisticated engine and was chosen by Ward’s Auto as a 10 Best Engine for 2013. It has one of the highest factory rated outputs of any 2.0 Liter Turbo engine in mass production that I am aware of. However, some individuals in this forum used a chassis dyno and proved that the equivalent BMW engine has a bit more output at the drive wheels – even though it is only rated at 240 HP. The BMW always requires high octane gas, while GM can use regular or high octane - a substantive cost advantage. The GM engine is rated a couple of mpg lower than the equivalent rating of the 3 series; the ATS is a bit lighter, but the 3 series has an 8-speed automatic transmission, Valvetronic variable valve lift & higher compression. All the head to head comparisons I read have given the nod to the BMW powertrain for better responsiveness, smoothness and NVH. Honda just announced a new 2.0L Turbo with perhaps 280 HP and Mercedes has announced the significantly more powerful 2.0L Turbo AMG engine for the CLA.
2. The LTG has the following characteristics / features:
a. 2.0 Liter Turbo 4 cylinder; 5W30 Oil
b. Premium Fuel: 272 HP & 260 Torque (295 Ft-Lbs in the CTS); Regular Fuel: 250 HP
c. Compression ratio = 9.5:1
d. Max engine speed: 7,000 rpm
e. 20 psi (1.4 bar) max turbo boost pressure
f. DI ( direct injection ); high-pressure multi hole injectors
g. Dual-scroll turbocharger
h. Stainless steel dual-scroll (1-4, 2-3) exhaust manifold designed to withstand 980 °C (1,800 °F) turbine temperatures
i. Electronically controlled wastegate/bypass valve
j. Dual CVCP (continuously variable cam phasing)
k. Air to air intercooler
l. Two-stage variable-displacement oil pump
m. Overall 16% less friction than previous equivalent engine
n. Aluminum block with cast in place cast iron liners; modular balance shafts in oil pan
o. 2-stage thermostat (90 and 105 C); thermostat control on radiator is electric
p. Composite intake
q. Sodium-filled Inconel exhaust valves
r. Aluminum pistons with oil jet-spray cooling on piston bottoms
s. Forged Powdered Metal (PM) connecting rods
t. Forged Steel crankshaft
u. Hollow camshafts with pressed on lobes vice cast on
v. Semi-permanent-mold 356 Al cylinder head
w. Variable pressure fuel rail (50-150 bar)
x. Stronger block bulkhead and deeper water jacket
y. Coil-on-plug ignition
z. 58x engine position sensing
aa. Stainless steel fuel system components
bb. Dual cat converter system
cc. Cam driven high pressure fuel pump
dd. Mechanical brake vacuum pump
3. POTENTIAL UPGRADES: GM is probably not as motivated to make some of the following suggested changes because too many car buyers erroneously believe there is still “no substitute for cubic inches” or that 4 cylinder inline engines cannot be smooth & vibration free. Perhaps for the first time in history there are now practical, cost effective technical options available to mitigate the classic disadvantages of the turbo 4 cylinder engine versus a V-6. However, the 3.6L V6 is still the top of the line engine for the ATS, but weighs 88 lbs. more than the turbo 4. Put 88 lbs. on a bar bell and try to curl it; the entire car front structure could also have been made a bit lighter. The 2.0T could easily be developed to equal / exceed the power & torque output of the V-6 and to a large degree the smoothness. The cost of these improvements could have been paid for by not having to integrate the existing 3.6 Liter V-6 engine into the chassis. Many of these proposed changes improve both fuel economy and torque / horsepower; they are under serious consideration at all car companies. The payoff is an engine with all the needed performance, but in a smaller & lighter package and better fuel economy.
4. LOW RISK CHANGES THAT IMPROVE THROTTLE RESPONSE, HIGH RPM POWER &FUEL ECONOMY
a. IVLC (Intake Valve Lift Control, two-stage) for better fuel economy, peak power & smoother response. Already implemented in the 2.5 Liter Normally Aspired (NA) ATS 4 cylinder base engine.
i. First stage is 4 mm intake valve lift; second stage is 10.5 mm intake valve lift
b. Improved exhaust manifold - while the engine already employs a dual scroll arrangement, there are additional improvements that can still be implemented.
i. Integrated head / exhaust manifold with liquid cooling from the head extended to the exhaust manifold. The cooling of the exhaust manifold eliminates the need to enrich the fuel mixture at high output levels to thermally protect the turbocharger and catalyst, which will allow the engine to more consistently meet its EPA highway fuel economy estimates. Has already been implemented in the newest mass produced VW turbo four cylinders and the brand new Ford 3 cylinder engines. Do not believe this has much of a cost impact, but does require careful design. Integration of the exhaust manifold into the head would also smooth airflow to the turbocharger making it more responsive. The heater would also heat up faster during the winter.
ii. Equal length exhaust headers and perhaps longer, more highly tuned 4-2-1 type to remove hot gasses more efficiently during each exhaust stroke (classic scavenging affect). Used successfully recently by Mazda for their Skyactive NA engines with really high compression ratios (13.0 on premium fuel) as well as part of the Pfadt P45 ATS 2.0 L Turbo upgrade kit. It would be larger & cost a small incremental amount more, but there should be plenty of room where a V-6 fits. Might also improve the quality of the acoustic signature.[/INDENT] iii. Improvements from i. & ii. above allow an increase in compression ratio (CR) from the current 9.5 to 10.0 & above; which significantly increases power, fuel efficiency and most importantly for a Turbo engine - throttle response. The 10.0 CR for BMWs 2.0 T equivalent engine in 3 series is one of the reasons the power train is rated higher overall than the ATS in almost all the comparative reviews that I read.
c. Implement engine mounted, water-to- air intercooler. From review of LF3 3.6L Turbo V-6 in the new CTS Vsport ”…Overall, air flow routing volume is reduced by more than 60 percent when compared with a conventional design that features a chassis-mounted intercooler (like the ATS). The water-to-air cooler system achieves more than 80 percent cooling efficiency with only about 1 psi (7 kPa) flow restriction at peak power for fast torque production. By doing so, the engine’s compressor is able to draw air directly from the inlet box and send pressurized air through the intercooler immediately and thus improving throttle response”. This would effectively eliminate the remaining turbo lag / improve throttle response.
d. Substantively lighter weight pistons & connecting rods. Costs more, but reduces rotational inertia, static weight and NVH. This will also somewhat improve acceleration and fuel economy.
e. Gun drill crankshaft to reduce weight. Remove the ‘dead’ material at centerline of the crank and throws. Will reduce engine vibration forces and improve bending and torsional stiffness of crank relative to its weight. Removing weight of components in motion is significantly more important than static weight removal (e.g., crankshaft, pistons, con rods, wheels, tires, brake discs, etc.). Cost increase is modest.
f. Lower weight oil: 0W15 vice 5W30. Lower friction results in higher fuel economy and better power. This change is just a matter of time.
g. 8-speed auto transmission keeps engine in most effective rev range. Improves acceleration, lowers noise & increases fuel economy. Also, a Dual Clutch Auto will eliminate the need for two different transmissions (auto & manual).
h. Stop start system, already rumored for the ATS 2.0T for 2015 Model Year along with an 8-speed transmission.
5. MORE EXPENSIVE CHANGES THAT DISTINGUISH ENGINE FROM ALL THE COMMON ALTERNATIVES
a. Fully variable valve lift control can eliminate throttle and associated pumping losses – minimum 10% improved power & fuel economy; potential for enhanced throttle response.
i. Currently implemented in multiple Fiat / Chrysler & BMW (Valvetronic) engines
ii. Should license from Fiat (Multi-Air) or equivalent. Schaeffler Technologies has full marketing rights to Uni-Air (aka Multi-Air).
b. Dry sump oil control. Allows engine to sit lower in chassis (lower center of gravity) which would improve roll control, transient vehicle dynamics / handling. This would be a significant differentiator for Cadillac (the standard of the world). Might present a packaging challenge & costs more. Perhaps this would be a differentiator for the V series.
c. Advanced, low-friction coating on cylinder walls (Nickasil has been used on many ‘exotic’ engines for years – Ferrari, Porsche, Jag, etc.) but there is probably something better available in 20 d. This premium engine could be a test bed; this is the type of tech that everyone needs to meet fuel economy standards in the near future. Would also presumably improve engine durability.
2. The LTG has the following characteristics / features:
a. 2.0 Liter Turbo 4 cylinder; 5W30 Oil
b. Premium Fuel: 272 HP & 260 Torque (295 Ft-Lbs in the CTS); Regular Fuel: 250 HP
c. Compression ratio = 9.5:1
d. Max engine speed: 7,000 rpm
e. 20 psi (1.4 bar) max turbo boost pressure
f. DI ( direct injection ); high-pressure multi hole injectors
g. Dual-scroll turbocharger
h. Stainless steel dual-scroll (1-4, 2-3) exhaust manifold designed to withstand 980 °C (1,800 °F) turbine temperatures
i. Electronically controlled wastegate/bypass valve
j. Dual CVCP (continuously variable cam phasing)
k. Air to air intercooler
l. Two-stage variable-displacement oil pump
m. Overall 16% less friction than previous equivalent engine
n. Aluminum block with cast in place cast iron liners; modular balance shafts in oil pan
o. 2-stage thermostat (90 and 105 C); thermostat control on radiator is electric
p. Composite intake
q. Sodium-filled Inconel exhaust valves
r. Aluminum pistons with oil jet-spray cooling on piston bottoms
s. Forged Powdered Metal (PM) connecting rods
t. Forged Steel crankshaft
u. Hollow camshafts with pressed on lobes vice cast on
v. Semi-permanent-mold 356 Al cylinder head
w. Variable pressure fuel rail (50-150 bar)
x. Stronger block bulkhead and deeper water jacket
y. Coil-on-plug ignition
z. 58x engine position sensing
aa. Stainless steel fuel system components
bb. Dual cat converter system
cc. Cam driven high pressure fuel pump
dd. Mechanical brake vacuum pump
3. POTENTIAL UPGRADES: GM is probably not as motivated to make some of the following suggested changes because too many car buyers erroneously believe there is still “no substitute for cubic inches” or that 4 cylinder inline engines cannot be smooth & vibration free. Perhaps for the first time in history there are now practical, cost effective technical options available to mitigate the classic disadvantages of the turbo 4 cylinder engine versus a V-6. However, the 3.6L V6 is still the top of the line engine for the ATS, but weighs 88 lbs. more than the turbo 4. Put 88 lbs. on a bar bell and try to curl it; the entire car front structure could also have been made a bit lighter. The 2.0T could easily be developed to equal / exceed the power & torque output of the V-6 and to a large degree the smoothness. The cost of these improvements could have been paid for by not having to integrate the existing 3.6 Liter V-6 engine into the chassis. Many of these proposed changes improve both fuel economy and torque / horsepower; they are under serious consideration at all car companies. The payoff is an engine with all the needed performance, but in a smaller & lighter package and better fuel economy.
4. LOW RISK CHANGES THAT IMPROVE THROTTLE RESPONSE, HIGH RPM POWER &FUEL ECONOMY
a. IVLC (Intake Valve Lift Control, two-stage) for better fuel economy, peak power & smoother response. Already implemented in the 2.5 Liter Normally Aspired (NA) ATS 4 cylinder base engine.
i. First stage is 4 mm intake valve lift; second stage is 10.5 mm intake valve lift
b. Improved exhaust manifold - while the engine already employs a dual scroll arrangement, there are additional improvements that can still be implemented.
i. Integrated head / exhaust manifold with liquid cooling from the head extended to the exhaust manifold. The cooling of the exhaust manifold eliminates the need to enrich the fuel mixture at high output levels to thermally protect the turbocharger and catalyst, which will allow the engine to more consistently meet its EPA highway fuel economy estimates. Has already been implemented in the newest mass produced VW turbo four cylinders and the brand new Ford 3 cylinder engines. Do not believe this has much of a cost impact, but does require careful design. Integration of the exhaust manifold into the head would also smooth airflow to the turbocharger making it more responsive. The heater would also heat up faster during the winter.
ii. Equal length exhaust headers and perhaps longer, more highly tuned 4-2-1 type to remove hot gasses more efficiently during each exhaust stroke (classic scavenging affect). Used successfully recently by Mazda for their Skyactive NA engines with really high compression ratios (13.0 on premium fuel) as well as part of the Pfadt P45 ATS 2.0 L Turbo upgrade kit. It would be larger & cost a small incremental amount more, but there should be plenty of room where a V-6 fits. Might also improve the quality of the acoustic signature.[/INDENT] iii. Improvements from i. & ii. above allow an increase in compression ratio (CR) from the current 9.5 to 10.0 & above; which significantly increases power, fuel efficiency and most importantly for a Turbo engine - throttle response. The 10.0 CR for BMWs 2.0 T equivalent engine in 3 series is one of the reasons the power train is rated higher overall than the ATS in almost all the comparative reviews that I read.
c. Implement engine mounted, water-to- air intercooler. From review of LF3 3.6L Turbo V-6 in the new CTS Vsport ”…Overall, air flow routing volume is reduced by more than 60 percent when compared with a conventional design that features a chassis-mounted intercooler (like the ATS). The water-to-air cooler system achieves more than 80 percent cooling efficiency with only about 1 psi (7 kPa) flow restriction at peak power for fast torque production. By doing so, the engine’s compressor is able to draw air directly from the inlet box and send pressurized air through the intercooler immediately and thus improving throttle response”. This would effectively eliminate the remaining turbo lag / improve throttle response.
d. Substantively lighter weight pistons & connecting rods. Costs more, but reduces rotational inertia, static weight and NVH. This will also somewhat improve acceleration and fuel economy.
e. Gun drill crankshaft to reduce weight. Remove the ‘dead’ material at centerline of the crank and throws. Will reduce engine vibration forces and improve bending and torsional stiffness of crank relative to its weight. Removing weight of components in motion is significantly more important than static weight removal (e.g., crankshaft, pistons, con rods, wheels, tires, brake discs, etc.). Cost increase is modest.
f. Lower weight oil: 0W15 vice 5W30. Lower friction results in higher fuel economy and better power. This change is just a matter of time.
g. 8-speed auto transmission keeps engine in most effective rev range. Improves acceleration, lowers noise & increases fuel economy. Also, a Dual Clutch Auto will eliminate the need for two different transmissions (auto & manual).
h. Stop start system, already rumored for the ATS 2.0T for 2015 Model Year along with an 8-speed transmission.
5. MORE EXPENSIVE CHANGES THAT DISTINGUISH ENGINE FROM ALL THE COMMON ALTERNATIVES
a. Fully variable valve lift control can eliminate throttle and associated pumping losses – minimum 10% improved power & fuel economy; potential for enhanced throttle response.
i. Currently implemented in multiple Fiat / Chrysler & BMW (Valvetronic) engines
ii. Should license from Fiat (Multi-Air) or equivalent. Schaeffler Technologies has full marketing rights to Uni-Air (aka Multi-Air).
b. Dry sump oil control. Allows engine to sit lower in chassis (lower center of gravity) which would improve roll control, transient vehicle dynamics / handling. This would be a significant differentiator for Cadillac (the standard of the world). Might present a packaging challenge & costs more. Perhaps this would be a differentiator for the V series.
c. Advanced, low-friction coating on cylinder walls (Nickasil has been used on many ‘exotic’ engines for years – Ferrari, Porsche, Jag, etc.) but there is probably something better available in 20 d. This premium engine could be a test bed; this is the type of tech that everyone needs to meet fuel economy standards in the near future. Would also presumably improve engine durability.