Exhaust Gas Temperature

Michael 22/05/2015 0 Comment(s) Articles,
Chips, tuning and safe EGT
Words by Andrew Leimroth
Photography by Tim Munro

what is a safe EGT to run my chipped EFI diesel engine at?” is a question that we are often asked. Unfortunately there’s no simple answer.

Some diesel performance chips have EGT monitoring functions that supposedly safeguard your engine if the EGT gets too high. The problem is how to know what temperature is too high. Before fitting this kind of chip, you need to establish a baseline peak EGT that your engine produces. Then you need to decide what the cut off EGT will be and more importantly, how long the engine can safely run at that EGT. A high EGT for a short period of time (probably a few minutes to get up some big hills) could be safe, as could an EGT 100°C above the baseline for extended periods.

When does EGT finally peak? If you were to measure EGT after five minutes under full load you may think the EGT has stabilised, and call that the peak EGT. But, if you were to continue under full load for another 15 minutes, the EGT might climb even further. It’s for this reason that tuning via peak EGT is very hard to do and also quite risky, as peak EGT after sustained high load may be unsafe. Engine oil contamination is another side effect of high tuning based on EGT, so remember that high power has other complications as well. Many years of tuning has shown us that power gains of around 12-16% at the wheels are safe and sustainable on already high powered EFI diesel engines. To believe that there is a safe maximum EGT, or worse still to think a chip tuning via EGT could be safer, would be a very risky proposition without some serious testing and data logging dyno time. The fact is that there is no documented safe EGT, and the higher the engine is tuned the higher the risk.

Confused? Welcome to the world of tuning via EGT. It is confusing and can be unsafe, so always opt for caution and conservation of your engine and insist on a chip already tuned and offering engine and driveline warranty.

Safe Driving


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