how hot is too hot?

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Originally Posted By: Jetronic
On another forum, someone was measuring the temp of the turbo oil feed line after a few minutes of WOT, and it was 240°C (464°F).


Unless you're climbing a steep hill or pulling a heavy load, like towing, I'd think more than ~30 seconds of WOT would take you out of the realm of legal street driving.
 
I would think the feed line does not get that hot but maybe the return line. My turbo feed line comes right off the oil filter adapter after the filter. This is the coolest oil when driving. It's a small ID teflon hose with SS mesh outside of it. The return line is ~ 1/2" or so silicone hose that dumps right into the sump.
 
Originally Posted By: circuitsmith
Originally Posted By: Jetronic
On another forum, someone was measuring the temp of the turbo oil feed line after a few minutes of WOT, and it was 240°C (464°F).


Unless you're climbing a steep hill or pulling a heavy load, like towing, I'd think more than ~30 seconds of WOT would take you out of the realm of legal street driving.


not on the autobahn which is only an hour away...
 
Originally Posted By: SHOZ
I would think the feed line does not get that hot but maybe the return line. My turbo feed line comes right off the oil filter adapter after the filter. This is the coolest oil when driving. It's a small ID teflon hose with SS mesh outside of it. The return line is ~ 1/2" or so silicone hose that dumps right into the sump.


No it's definitely the feed line in this case. The surface of the feed line gets soo hot the oil starts coking and carbonizing. The heat is radiating from the turbine side of the compressor. No idea how hot the oil in the return pipe gets, but with the watercooling might be cooler than going in...

http://www.alfaowner.com/Forum/alfa-mito/835833-qv-dead-turbo-3.html

about halfway down the page (post #65) you can see a cutout of the oil feed line.
 
Good forum that Alfaowner, haven't been there in a while. Time to get another Alfa :-) it's been four years now.
 
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Originally Posted By: Jetronic
Originally Posted By: SHOZ
I would think the feed line does not get that hot but maybe the return line. My turbo feed line comes right off the oil filter adapter after the filter. This is the coolest oil when driving. It's a small ID teflon hose with SS mesh outside of it. The return line is ~ 1/2" or so silicone hose that dumps right into the sump.


No it's definitely the feed line in this case. The surface of the feed line gets soo hot the oil starts coking and carbonizing. The heat is radiating from the turbine side of the compressor. No idea how hot the oil in the return pipe gets, but with the watercooling might be cooler than going in...

http://www.alfaowner.com/Forum/alfa-mito/835833-qv-dead-turbo-3.html

about halfway down the page (post #65) you can see a cutout of the oil feed line.


Then the oil going into the turbo is 240C? What is it in the sump?
 
Originally Posted By: SHOZ
Originally Posted By: Jetronic
Originally Posted By: SHOZ
I would think the feed line does not get that hot but maybe the return line. My turbo feed line comes right off the oil filter adapter after the filter. This is the coolest oil when driving. It's a small ID teflon hose with SS mesh outside of it. The return line is ~ 1/2" or so silicone hose that dumps right into the sump.


No it's definitely the feed line in this case. The surface of the feed line gets soo hot the oil starts coking and carbonizing. The heat is radiating from the turbine side of the compressor. No idea how hot the oil in the return pipe gets, but with the watercooling might be cooler than going in...

http://www.alfaowner.com/Forum/alfa-mito/835833-qv-dead-turbo-3.html

about halfway down the page (post #65) you can see a cutout of the oil feed line.


Then the oil going into the turbo is 240C? What is it in the sump?


the oil touching the pipe likely is...

the oil in the sump will be closer to 100°C, there's an oil/coolant interchanger
 
On my old Suzuki Samurai I had an oil temperature sensor installed in the oil pan. During off-roading, the gauge displayed on occasion 250°F. Consider that I was putting a lot of load on a small engine in very hot >100°F weather. I would expect 250°F to be around that critical point when oil begins to thin out to the point of lubrication becoming insufficient.
 
The turbo on the Volvo was great. Otherwise it was high maintenance (averaged $1100 a year for maintenance all in). It was the only car I've ever owned that I couldn't change the oil on - I couldn't get at the filter (the turbo above and a motor mount below - you could change it by feel when it was on a lift).

On the other hand you could have set off on a 500 Km trip on its last day with me. I did say I sold it to a friend!
 
Originally Posted By: Jetronic
we're talking 400+°F here though....


But that is not the sump temperature. I was merely posting an example for a n/a engine with the oil sump temperature measured, which may be a data point against which to compare similar engines with the same setup, not different engines with different setups.
 
The temperature you measured is the outside temp of an oil supply line, its meaningless, whats the oil temp?

The Dart uses a little turbo and I doubt that much boost, if they wanted it to cool down they would have a program that would idle the engine. Don't worry about it, its engineered to run for a typical duty cycle.


The little turbo's the 4 pots use are cute, I saw the Cruz's engine and a Ford at the car show. Little baby things.
 
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