Yup, usually around 200-300 degrees cooler.....
Not necessarily.
If the probe is in the exhaust INPUT side of the snail then the temp drop is only about 100 degrees - according to Banks. That is where the probe is on my Banks setup and they say up to 1150 degrees is safe - and the material the pistons are made of has a known melting point of 1250. That's only a 100 degree difference.
Now, if the probe is in the exhaust EXIT side of the snail, then yes, 300 degrees temp drop is the accepted number.
As for the lag, Agnem mentions, that is a very good point. There is a bit of a lag in the guage response to start with, and the farther you locate the probe from the exhaust ports the worse it is going to get.
The good news is that it isn't a major issue. You can actually exceed the 1250 melting point of the pistons for VERY short periods of time on occaision and not do any damage. Metal doesn't instantly liquefy when it reaches its melting point - it takes a little time at that temp to get it to actually melt. PLUS although the temp in the cylinder reaches 1250 degrees, that is only the temp at the surface of the top of the piston. Just below the surface the metal is slightly cooler due to the fact that aluminum is such a fantastic conductor of heat and it is dissapating it rapidly into the cylinder walls. There is also the fact that our engines have the nozzles that squirt oil onto the bottom side of the pistons for cooling to help keep the whole piston from reaching that critical 1250 degree melting point.
Don't get me wrong, I'm not advocating pushing it on the EGTs, and I still agree that the closer you can mount the probe to the actual exhaust ports of the cylinders the better. I'm just saying that the slight temp drop and lag of the more remote mounting isn't that big of a deal in my mind - as long as you compensate for it by lowering the max temp you allow the EGTs to reach.
Just my 2 cents....
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on a N/A engine with two cyl heads, I would use a dual setup where each bank is represented with its own scale and needle within one single gauge.
and can afford it(READ I CANNOT)
one can never have enough info when it comes to knowing whats going on within ones vehicle.
