After I got home, I busted out the digital Thermometer to see the how hot the turbo got.
I didn't over work the engine getting home, just got home as usual.

This was the one with two rivits.


This was the Turbo heat shield itself.

 

On my diesel truck I have a pyrometer in the exhaust just before the turbo. At cruising speed I see exhaust temps anywhere from 600 to 900 depending on the terrain. I can easily get the temps up to 1100 when I floor it. I know with that vehicle you do not want temps to stay over 1250 or you could melt the fins. Now diesel has more BTUs than gas, but I would think that those temps are well within the specs of a gas engine.

 

Many have posted pics of our turbos glowing a dull orange after a hard run. That relates to over 1100 degrees but the alloys used in the turbo wheel and housing are fine at those temps. The "rivet" you measured is part of a heat shield designed to isolate the "oil in" side of the turbo. This should naturally be cooler than the turbo housing two inches to the left. Give it a run and measure the curved surface under the shield!

 

Talking about high temps, how many of you are driving moderately without going into boost for the last 5 or so minutes before shutting off the engine?

I know with the newer synthetic oils on the market, coking is not going to happen too soon. Preventative measures never hurt though.

 

There is no need like other cars to cool down the turbo. The turbo is cooled after shutdown by water being pumped through it.

 

It's not that the turbo is staying hot it's that it's staying hot and the oil isn't circulating anymore so any oil still in the hot turbo will coke. Yes, the water still circulates to cool the turbo but that does nothing for coking.