Turbo Saver
Junior User
Joined: Apr 2007
Posts: 59
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Originally Posted by duffman77
I think this is something that many overlook when they shut down thier truck based on exhaust temps. The exhaust temp is largely based on engine load which can change rapidly, but the point of the cool down period is to cool down the turbo. The turbo housing has high mass and will not cool in 30 seconds like the time it would take to cool the sensor (pre-turbo).
Mountain Pass
Joined: Sep 2003
Posts: 143
Likes: 0
From: So Cal
Originally Posted by duffman77
I think this is something that many overlook when they shut down thier truck based on exhaust temps. The exhaust temp is largely based on engine load which can change rapidly, but the point of the cool down period is to cool down the turbo. The turbo housing has high mass and will not cool in 30 seconds like the time it would take to cool the sensor (pre-turbo).
Elder User
Joined: Apr 2006
Posts: 804
Likes: 0
From: Edmonton, AB
No what I am saying is that if you have the probe located before the turbo, the exhaust tempurate in the gas stream is not the same temperature as the turbo housing until right away. The turbo housing will still be at an elevated temperature until its heat can be transfered into the cooler exhaust stream or into the oil.
Basically a pre-turbo probe tells you whats going on in the engine and a post-turbo probe is giving you an idea of whats going on in the turbo. There are pros & cons of each.
Basically a pre-turbo probe tells you whats going on in the engine and a post-turbo probe is giving you an idea of whats going on in the turbo. There are pros & cons of each.
Hotshot
Joined: Dec 2003
Posts: 15,369
Likes: 121
From: Stuttgart, Ar
Here's another school of thought yall might not have considered. Preturbo EGT's are actually a good way to monitor PISTON temps which is where you really have a problem. The pistons will melt long before the turbo impeller melts. Also, with todays oil formulations you don't have coking in the bearings like you did with older formulations which is why there was a need for a cool down/flush of the bearing/bushing. Again, just not needed with todays engineering. I'm not saying you DON"T need a cooldown period after towing long and hard, but for the average trip, IMHO--No. It's just a waste of fuel.
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CharlieLed
1948 - 1956 F1, F100 & Larger F-Series Trucks
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