Raften wrote:
Cummins West does good work. It would be helpful if folks talking about EGT numbers mentioned pre or post turbo readings.
That's a great point.
In my earlier post, I believe I mentioned that 1250F EGTs (exhaust gas temperature) is normally considered about the maximum one should see on turbocharged diesels. This refers to "pre" turbo temperatures. That is, EGTs measured as they are leaving the exhaust valves and before the turbocharger.
However, if the EGTs are measured "post" turbo, that is, exhaust temperatures measured after passing through the turbocharger, then the values should be cooler. This is because some of the heat energy from the exhaust gas is used to turn the turbo and create pressure for the intake manifold.
How much cooler the "post" turbo readings should be is a matter of debate. Folks have reported this should be between 200F and 600F cooler than the "pre" turbo values. This is the problem with using a "post" turbo EGT gauge. It is hard to know what the maximum numbers should be. But, I would think using 900F or so as the maximum values would be in the ballpark, usually.