We all know the LS engine is really popular for engine swaps. You will find it in Corvette, Firebird, Camaro, GTO, and other vehicles.
But there are several different LS engines in the industry and they may look very similar. Two of the most popular LS engines would be the LS1 and the LS6. But a lot of people don’t know which one is better for their application.
These two engines are from different generations of LS, but they share some similarities and differences. In today’s post, we will compare the LS1 vs LS6 and find out which one is better.
Keep on reading to learn more!
Main Difference Between LS1 Vs LS6
These are the main differences that you can use to compare LS1 vs LS6.
- LS1 has a compression ratio of 10.2:1, whereas LS6 has a compression ratio of 10.5:1.
- The horsepower rating for the LS1 ranges from 305 to 350 hp, whereas the LS6 ranges from 385 to 405 hp.
- The torque rating for the LS1 ranges from 335 to 365 pounds force foot, whereas for the LS6, it ranges from 385 to 400 pounds force foot.
- The LS1 has a combustion chamber volume of 67cc, whereas the LS6 has a combustion chamber volume of 65cc.
- The exhaust runner volume of the LS1 is 70cc, whereas the exhaust runner volume of the LS6 is 75cc.
- The LS1 has an intake runner volume of 200cc, whereas the LS6 has an intake runner volume of 210cc.
What Is the LS1 Engine?
LS is the name that was assigned to the third as well as the fourth generation of the small-block V-8 engine. This gasoline engine was engineered for use in GM vehicles. it was first featured in the 1997 Corvette.
It features an aluminum block and head. The LS1 displaces 5.7 liters and has a firing order of 1-8-7-2-6-5-4-3. The bore and stroke are 3.898 and 3.622 inches, respectively. It has a horsepower rating of 305-350 hp and a torque rating of 335-365 pounds force foot.
One of the first things you will notice about this engine is the coil near the plug ignition system, which uses individual ignition short spark plug wires and coils to provide more spark energy to the spark plugs.
It has a lightweight composite intake manifold which reduces heat transfer to the intake charge. The manifold positions the port fuel injectors to target the intake valves for superior fuel atomization. The tall intake ports in the cylinder heads, on the other hand, improve injector targeting.
The aluminum cylinder heads feature replicated intake and exhaust ports. So, each intake port is the same as the other ones in the engine. The same applies to the exhaust ports. This unique port configuration minimizes combustion variation between cylinders.
The valve angles are strategically set at 15 degrees to create a shallow combustion chamber. The valve springs are beehive or conical in shape, which allows for a lighter spring retainer. The roller rockers are made of die-cast with a 1.7 rocker ratio that is used to actuate the valves.
The lower end of the LS1 engine features the aluminum deep skirt block, which is incorporated with cast iron sleeves that are cast into the block. The block also uses enclosed lifter bores under each cylinder head to provide a quieter operation.
What Is the LS6 Engine?
The LS6 was the second Gen III engine, which was engineered to be a higher power version of the previous design, the LS1.
It’s easy for most people to assume that the successor of the LS5 is LS6. But LS6 is the successor of LS1. This engine was first featured in the 2001 Corvette Z06.
The LS6 has an aluminum block and head, it displaces 5.7 liters and has a 1-8-7-2-6-5-4-3 firing order. The bore and stroke measure 3.898 and 3.622 inches. The block also has a deck height of 9.240 inches and a main housing bore diameter of 2.751 inches.
The horsepower rating is higher compared to the predecessor, ranging from 385 to 405 hp. The torque rating, on the other hand, ranges from 385 to 400 pounds force foot. This engine features an improved combustion chamber with an increased compression ratio of 10.5:1. The exhaust manifolds have been redesigned to thin wall cast-iron manifolds to improve airflow.
One of the things that made this engine obtain higher speed capability was to manage the airflow not only in and out of the engine but also internally.
The piston is actually flowing down to displace air. The manufacturer cast passage slots in the actual bulkhead of the block. As the piston comes down, it just displaces the air to the adjacent cylinder. So, there is no resistance nor the air going back down into the crankcase and aerating the oil.
The engine has a superior cam profile that increased the lift from 0.525 to 0.551 inches. To complement the cam high lift, the manufacturer hollowed out the intake and exhaust valves as well as modified the valve springs, increasing stiffness and efficiency.
Here is our detailed feature comparison between LS1 and LS6:
The major differences between these two engines are in performance specifications.
The first one is the compression ratio, which plays a big role in the efficiency of the engines. The greater the compression ratio, the greater the thermal efficiency and therefore better gas mileage you are going to get. Having said that, the LS1 has a compression ratio of 10.2:1, while the LS6 has a compression ratio of 10.5:1. This means the LS6 has better fuel economy than the LS1.
They also differ in power ratings. Although they both displace 5.7 liters and have the same firing order, the LS6 has higher power ratings. The horsepower rating for the LS1 ranges from 305hp to 350hp and the torque rating ranges from 335 to 365 pounds force foot.
The horsepower rating of the LS6 ranges from 385hp to 405hp and the torque rating ranges from 385 to 400 pounds force foot.
Combustion Chamber Volume
One of the key factors that help create desired power levels is the combustion chamber volume, which is measured in cubic centimeters or cc.
This is a very important attribute because it determines the compression ratio and ensures there is consistency as far as the performance of the cylinders is concerned. The LS1 has a combustion chamber volume of 67cc, while the LS6 has a combustion chamber volume of 65cc.
So, the LS6 lower combustion chamber volume allows for a higher compression ratio for increased efficiency.
Intake Runner Volume
They also have different intake runner volumes. The LS1 has an intake runner volume of 200cc, while the LS6 has an intake runner volume of 210cc.
According to these figures, the LS6 has a higher intake runner volume, but bigger is not always the better option. Just like other aspects of a car engine, runner volume has to be effectively matched to the specific application.
The small runner of the LS1 allows for more torque at a low rpm and would accelerate much better from a stop. But it may limit airflow at high rpm.
The larger intake runner volume of the LS6, on the other hand, would do a better job of feeding the engine at a high rpm, increasing peak horsepower. But, this may lead to poor drivability at low rpm.
Intake and Exhaust Valves
Valves are very important as far as the performance of these two engines is concerned.
The LS1 has steel solid stem intake and exhaust valves with an intake valve diameter of 2000 inches and an exhaust valve diameter of 1550 inches.
The LS6, on the other hand, has steel hollow stem valves and steel sodium-filled stem exhaust valves with an intake valve diameter of 2000 inches and an exhaust valve diameter of 1550 inches.
The large intake valve diameter of 2000 inches makes it heavier compared to the small exhaust valve diameter of 1550 inches. This has a significant impact on the rpm potential.
The LS6 hollow stem intake valves reduce the weight factor to improve rpm potential, volumetric efficiency, as well as horsepower. The lightweight nature of the LS6 valves helps reduce stress on the retainers, valve springs, lifters, pushrods, and rocker arms.
The sodium-filled stem exhaust valves of LS6 also improve performance for higher heat applications. They help reduce the risk of detonation, preignition, and valve burning.
Unlike the LS1 solid stem exhaust valves, the LS6 sodium-filled exhaust valves allow most of the cooling to take place through the stem, making it possible for them to withstand more heat.
LS6 Vs LS1 – The Verdict
We know we covered this debate really fast. But the LS6 is objectively better based on our findings. It flows more air, has a stronger block, and it can ultimately make more power at high rpm. When comparing these two, always remember that the LS6 is the modified version of LS1.