Nerd’s Eye View: LA Auto Show 2023

To cool the oil enough for serious track duty, there’s a massive coolant/oil heat exchanger in the bottom of the engine. Something relatively unique to the LT6 is the positioning of the direct injection fuel injector; it’s underneath the headers and squirts into the cylinder on the exhaust valve side. Apparently, this comes from their Indycar engine tech. My guess is the exhaust side is a bit warmer so that would help vaporize the fuel better to improve combustion. Part of making the engine spin faster is to reduce the mass of everything that moves. The pistons look to have relatively short skirts and the cams are hollow.

In direct contrast to the very high flowing parts of the LT6 V8 is the Duramax 6.6L diesel V8. It doesn’t need to flow a lot at high rpm, just enough to make 910 lb-ft of torque at 1600 rpm. There is a turbo hiding under that intake manifold log thing. I’m guessing the plastic box with the Duramax label on it is for intake noise resonance tuning. The darker tube with bellows joints connected to the intake manifold should be cooled EGR. Cummins just got fined almost $1.7 billion dollars for cheating on their diesel emissions, but it looks like GM has the necessary hardware in place at least.

The rectangular cross section on the right/inside of the V should be the intake plenum runner thing. And the exhaust log is on the other side. Like I said, neither are exactly designed for very high velocity flows.

I have been out of the turbo game a while, but this looks like a Borg Warner turbo judging by the CHRA and Variable Geometry Turbine component designs. Turbos with VGTs need turbine wheels with full back disks for strength; the vanes impart a lot more stresses on the turbine wheel blades so the full back disk is required to beef everything up.

Diesels in work trucks are designed to last a long time, so this looks like a metal impeller wheel in the water pump. Unlike BMW and Porsche gas engine water pumps with their plastic parts.