The operation of a combustion engine is simple: the pistons move up and down, driven by the gases produced by burning fuel and air, and the connecting rods transmit this linear force from the pistons to the rotating movement of the crankshaft.
The connecting rods used to always be the same, with one end attached to a gudgeon pin at the back of the piston (a bearing allows you to change angle as you turn the crank), and the big end was wrapped in a crankpin so it could rotate 360 degrees while the cranks were turned. pistons push. And we say used because Transcend Energy Group claims it can replace those connecting rods with a new two-piece design, with a secondary gasket.
According to its creators, it is a relatively simple and inexpensive way to greatly increase torque in combustion engines. That secondary gasket sits well below the gudgeon pin and outside the piston skirts. With this solution the pistons would fall further and faster when the crankshaft is at a 90 degree angle, giving better leverage to the crankshaft and increasing dynamic compression by 25-30%.
Speaking to Road and Track Transcend says that with this extra pivot on the connecting rods, the piston moves faster when it matters: when drawing in air, when compressing it, and when coming out of top dead center in response to gas expansion. The extra speed and leverage add torque, especially at low revs.
Do you think few benefits? From Transcend they indicate that their two-piece connecting rods eliminate piston rocking (when they lean from side to side in response to lateral forces from the connecting rods), preventing wear and compression losses, since the piston and crankshaft work more efficiently over each other at key moments.
So far they have only created connecting rods for use in Gernal Motors’ huge American V8 engines, specifically the 5.3 and 6.2 liter LS. In them they managed to increase the torque by 30% between 1,500 and 3,500 rpm. Not bad… especially when you find out that that engine is not optimized to take full advantage of the potential of their invention and they want to see how far they would go if they used specifically designed connecting rods, cylinder heads and pistons.
But… aren’t there buts? Searching in forums, the experts are not very convinced, since there are no third parties that have tried it and the brand has not offered many results either. Also, two-piece connecting rods are heavier, which creates additional inertia forces that will increase as engine revs rise…that could cause you to lose torque as the rev counter rises.
Questions are also raised about the lateral forces that are generated on the pistons, as the lower pivot point and shorter main arm make the angle between the connecting rod and cylinder even greater. Also, the distance between the main gudgeon pin and the new lower pivot seems to be able to amplify the forces that cause the piston to lean.
Let’s hope Transcend proves that its connecting rods do what they say and that they can do it without increasing engine wear. It is not something new, since it is a solution similar to the crosshead connecting rods used in diesel and steam engines, but it would be the first time that it has been applied in a gasoline block. And of course, they have made a video so that you can better see how it works (your speaker or headphones have not stopped working, it is because there is no sound: