<VV> turbocharger

[shortle]

I worked in a new car dealer (Volvo cars) as a service tech. in the eighties and replaced many a turbocharger (made by Garrett) because the cars were smoking out the tailpipe. We also replaced the oil feed pipe as it was a requirement for warranty reasons. Most of these units were not getting oil to the turbo due to not changing the oil enough or by not letting it idle after driving. Then in 1987 they changed to a water cooled turbo and that pretty much ended the turbo jobs unless the owners never changed the oil. Then in 1989 they started using a Mitsubishi turbo that was also water cooled but had a feed pipe almost twice the size of the Garretts. These turbos seemed to last the life of the car so long as the owners were reasonably conscience of oil change intervals. Of course the water cooled turbos got A GOOD AMOUNT OF COOLANT FLOWING through the center section from the water pump. It was not a siphon effect that would keep it cool but a pressurized flow. All these cars used EFI and wastegates, and starting in 1985 they all had intercoolers.
Timothy Shortle in Durango Colorado

-----Original Message-----
>From: Frank F Parker <fparker at umich.edu>
>Sent: May 25, 2009 12:18 PM
>To: jvhroberts at aol.com
>Cc: virtualvairs at corvair.org
>Subject: Re: <VV> turbocharger
>
>>
>> Ball bearing turbos also have oil feed and drain lines. There's no other way to keep them cool enough. And during operation, oil is THE primary coolant. However, should you decide to make yours wet, do consider the thermosiphon option.
>>
>I like the thermo siphon idea but it does not apply in the GT series 
>case. I just measured the restrictor size in the oil feed line in my 
>turbo and compared it to a normal id of a conventional feed line. There
>was 94 times LESS area to feed oil in the GT turbo line. It is pretty
>clear that oil is NOT the major cooling in this case but the continuous
>flow of water. In a normal BB turbo, the oil line is restricted. Maybe
>some older BB turbo used nonrestricted lines. In that case, oil could be
>considered to be siginificant to cooling but to make a blanket statement
>that ALL bb turbos use oil as main cooling is not correct. Explain how
>94 times lees oil cools as well.
>I do like the thermo idea but it does not apply for mw where I need 
>cooling all the time, not just at shutdown
>
>frank
>>
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