Exhaust Temperature... HELP ME

I need to know the benefits to closely monitoring exahust temperature. I am doing a research project on it and the only thing I can come up with is air/fuel mix. Is there anything else?

in a diesel engine it's important because the diesel exhaust is very hot and if it gets too hot it can destroy the turbocharger. i guess that would apply to any turbocharged vehicle, if emperatures exceed something like 1500 degrees it can melt turbine blades.

not to mention melting pistons and stuff...

Dont listen to them, only reason you moniter it is so when your cooking steaks or bbq on your motor you can controle the tempature. Come on now... use some common since.

i actually saw a video where someone made a bbq that actually worked and ran off of the exhaust. he had the cooking part in the cabin right beside the driver.

anyways, it's only so you dont burn or melt anything, you dont really have to worry about it unless you're running a performance oriented machine, like a diesel that's running alot of boost and alot of extra fuel.

Air/fuel ratio is monitored by the lambda sensor.

Usually there is no need to monitor the exhaust gas temperature, usually it's monitored for developement purposes only. To get an acceptable life of parts such as turbocharger, exhaust manifolds and exhaust valves the exhaust temperature must be kept at an acceptable level. For a gasoline turbo engine max turbine inlet temperature is about 970 degC using conventional materials. With austenitic stainless steel turbine housings and DS alloy turbines the turbocharger can withstand an increase to 1050 degC. For short time racing use 1100-1200 degC can be accepted while variable nozzel turbines can't withstand temperatures above 820 degC.

Stainless exhaust valves usually have a maximum working temperature of 700degC, for higher temperatures a different material or improved cooling must be used. For example Nimonic 80A can replace the ordinary stainless steel, this makes it possible to increase the maximum working temperature to about 800 degC.

Modern cars can also create high EGT intentionally, for exampel to improve the efficiency of the catalytic converter.

EGT's are a useful tuning tool, but only if you are fully aware of what its telling you. There are many things that effect EGT, fuel mixture, detonation, ignition timing are the three that are dynamic, and of course, compression ratio, boost, cam timing etc will all have effects also.

I've yet to run into a site that has great info on how to translate all aspects of engine tuning with a EGT, but high reading doesn't mean X, nor does low reading, it can be one thing or a combination of things.