JusMX141
Moderator
- 15,152
- 1,268
- Dec 13, 2005
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Greensburg,
Pennsylvania
Yet another possible lead on why some Garrett and Holset turbos just don't hold up on certain cars. I'm hoping to one day get to the bottom of this mystery once and for all.
I've been noticing a strange trend among commonly-used oil drains for our cars. Read through the thread and give me your opinion at the end.
First up, the 1G oil drain. This drain is intended to be used on 1G DSM's using a TD05H turbo, which is fed from the head with a restrictor built into the banjo fitting at the turbo. It measures somewhere around 5/8" O.D. (.572" I.D.), and works great for the turbo in which it's designed.
Next, the 2G oil drain. This drain is all aluminum, VERY lightweight, and designed for use on the 2G DSM's using a T25, which is fed from the filter housing with a piece of 1/4" tubing and a .070" restrictor in the fitting at the filter housing itself. Obviously it will be bigger to support the additional oil flow required of the T25....it measures somewhere around 3/4" O.D. (.663" I.D.), and also works great for the turbo in which it's designed.
Now on to the puzzling part.
Most Garrett T3 / Holset oil drain adapters are set up to allow a piece of 5/8" hose to slide over a barbed end of the fitting and be clamped, or they use a threaded adapter to allow push-lock or Army Navy fittings to connect the drain flange to the oil pan.
It's no secret the Garrett and Holset CHRA's require more oil- hell the oil drain hole in the bottom of the Holset center housing is almost 7/8" I.D., and the Garrett center housing has a very large drain hole as well....so why are the holes in all of the T3 / Holset oil drain adapters TINY?
Obviously for such a tiny hole to be used on a gravity-type drain system there's going to be some obstruction. For a popular turbo that most DSMers will feed from the filter housing in order to gain the most flow and consistent pressure as many manufacturers suggest, that sure is a ridiculously small drain orifice....just over 1/2" I.D.; smaller than both the TD05H and T25 oil drains.
Anyone have any input on this?
I've been noticing a strange trend among commonly-used oil drains for our cars. Read through the thread and give me your opinion at the end.
First up, the 1G oil drain. This drain is intended to be used on 1G DSM's using a TD05H turbo, which is fed from the head with a restrictor built into the banjo fitting at the turbo. It measures somewhere around 5/8" O.D. (.572" I.D.), and works great for the turbo in which it's designed.
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Next, the 2G oil drain. This drain is all aluminum, VERY lightweight, and designed for use on the 2G DSM's using a T25, which is fed from the filter housing with a piece of 1/4" tubing and a .070" restrictor in the fitting at the filter housing itself. Obviously it will be bigger to support the additional oil flow required of the T25....it measures somewhere around 3/4" O.D. (.663" I.D.), and also works great for the turbo in which it's designed.
You must be logged in to view this image or video.
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Now on to the puzzling part.
Most Garrett T3 / Holset oil drain adapters are set up to allow a piece of 5/8" hose to slide over a barbed end of the fitting and be clamped, or they use a threaded adapter to allow push-lock or Army Navy fittings to connect the drain flange to the oil pan.
It's no secret the Garrett and Holset CHRA's require more oil- hell the oil drain hole in the bottom of the Holset center housing is almost 7/8" I.D., and the Garrett center housing has a very large drain hole as well....so why are the holes in all of the T3 / Holset oil drain adapters TINY?
You must be logged in to view this image or video.
You must be logged in to view this image or video.
Obviously for such a tiny hole to be used on a gravity-type drain system there's going to be some obstruction. For a popular turbo that most DSMers will feed from the filter housing in order to gain the most flow and consistent pressure as many manufacturers suggest, that sure is a ridiculously small drain orifice....just over 1/2" I.D.; smaller than both the TD05H and T25 oil drains.
Anyone have any input on this?
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