Guys,
Firstly if you re-read my post I stated that the exhaust loses about 100 to 200 degrees passing through the turbo. This was off the top of my head, if it is actually exactly 100 to 150 degrees I appologise, but anyway it probably varies from car to car and you will probably find examples that lose more than 200 degress through the turbo if you look hard enough.
Anyway, you guys are crazy if you think that a difference of 100 to 150 degrees in exhaust temperature is insignificant. If your engine is running peak EGTs of 800 degrees you are running pretty safely, you can actually afford to lean it out some more or advance timing a bit, however if you are running EGTs of 900 to 950 degrees you have problems. 100 to 150 degrees makes a VERY big difference.
Steve P. said:
........there isn't a great deal of point (apart from to be amazed at how hot the exhaust gets) in installing an EGT unless you are going to modify your car with a programable ECU in which case it becomes a useful tool for the tuner. If you just want more gauges on your dash, thats a different matter.
You don't seem to realise that the exhaust temperature directly relates to the running condition of the engine. It is detonation that drives up exhaust temperatures if you didn't know. The knock sensor senses detonation and retards the timing, leading to increased exhaust temperatures (combustion event happens closer to when the exhaust valve opens). When tuning my car I use the EGT to determine how much boost I can run and how much fuel to add or remove (using a super AFC).
Don't think that i am arguing against the knocklink. A knocklink can certainly be used for the same purpose, but I personally prefer the EGT. I like the fact that instead of dealing with blinky lights you are dealing with numbers, but I espescially like the peak hold feature and the safegaurd that the warning output signal allows is invaluable. I would much prefer to use the EGT gauge to automatically cut boost and therefore cut detonation rather than having to back off the gas when the red light flashes to achieve the same. Detonation is likely to raise its head exactly when you don't have time to be looking for blinking lights, like when your foot is to the floor in third gear and a left hander is quickly approaching.
By the way, I don't know which brand of EGT probes you guys are used to using, but I very highly doubt that the one on my car is going to fall off anytime soon. It not like there is a nut in there that can back-off and suddenly drop the probe into the turbine blades.The only thing that could happen is that the tip breaks off. How is that going to happen? What is going to break it off, the air pressure? Do you guys even know what the probe looks like and how it is attached? Maybe you guys should just stop buying British products. The fact is, Eclipse guys and others in the States have been putting EGT probes in the manifold before most of you guys knew what an Evo was, and I have never heard of one case where an EGT probe decided to jump into the turbine blades.
Anyway, that is my view. Feel free to disagree or correct any errors, spelling or otherwise.