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2004 Forester XT
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109 Posts
Discussion Starter #1 (Edited)
NEED HELP WITH OIL COOLER

Here's the deal. i have a worked long block, 1000cc rc injectors, turbo sx fuel rails, wbr fmic, turbo xs 3" inlet, dom 4xtr turbo, kstech 73mm cai, cobb tbe, dc headers, and some other odds and ends. I am going to be running high boost on e85 and possibly race gas so im sure the temps are going to get hot. I WAS WONDERING IF AN TOP MOUNT OIL COOLER IS WORTH INSTALLING SINCE I ALREADY HAVE IT. I NEVER SEEM TO SEE ANYONE RUNNING OIL COOLERS ON SUBARU'S SO DIDNT KNOW IF IT WAS BECAUSE ITS NOT NEEDED OR WHAT? IF YOU COULD TELL ME WHAT THE ADVANAGES AND THE DISADVANTAGES ARE OF RUNNING ONE.
THANKS IN ADVANCE
 

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05 FXT
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1,540 Posts
If you're just drag racing w/ it or messing around on the street occassionally I probably won't bother.

If you plan on taking it road racing or time attack, then I'd 100% do it.

There's quite a bit of thermal mass in to the complete engine/coolant system and oil itself has quite a bit. For just drag passes or the occassional hard pull, it won't be enough to heat soak it. If you're on the track (as in road racing) and constantly pounding heat into it, then you will heat soak it, and once it gets above a certain temp, you're certainly asking for a spun rod bearing.

Reasons for not doing it? Well, oil does need to be up to temp, so extra cooling can hurt you if you're not running an oil thermostat as well to control flow through the cooler. Doing an oil cooler can become awfully expensive as well. Sure they're cheap, but by the time you do all the hoses and fittings, it adds up fairly fast. And last and the biggest reason for me, it's a ton more plumbing to develop a leak.

So in summary, really depends on your usage of the vehicle. Other consideration you could have is an aftermarket oil pan. The extra capacity will give you some more oil to heat up before things go bad.
 

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2007 Forester XT Sport
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403 Posts
You rarely see them for several reasons.

1. Its not a part that makes you any faster. Many people have the short sighted mindset that if it doesn't make you faster, its a waste of money.

2. A good one isnt cheap. A decent one can be fairly cheap, like the mishimoto that I did a group buy on, but those have no thermostat, but are cheap enough to buy a thermostat and STILL be cheap :)

3. Its not a cake easy simple install. Its not hard, but for some reason it scares people away.

4. There are only 2 top mount oil cooler kits, they are both $$$$$
 

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2008 GRB 20th anniversary 6 MT
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6,570 Posts
So is noone using an oil cooler here (not necessarily a top mounted one as that would restrict flow to the I/C).
 

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Don, King of the parts diagram
MY11 WRX STi Sedan 6MT
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2015 Highlander AWD XLE 6AT
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4,255 Posts
So is noone using an oil cooler here (not necessarily a top mounted one as that would restrict flow to the I/C).
I'm an n/a guy, but it's my understanding that the stock turbo motor here in the U.S. is factory-fitted with an oil-to-water (OTW) oil cooler. Check out the adapters between the oil filters and the blocks (lower left) in the following pics.

2010 Forester XT



2010 WRX STI



HTH,
Jim / crewzer
 

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2017 VW Golf SportWagen 5MT
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The stock unit isn't really an oil cooler, it's more of an oil heater if you will. It'll allow the oil to get up to operating temperature quicker. Coolant and oil temperatures aren't that different anyway.

A high-powered, tracked Subaru will very much need an external oil cooler. I was in a GT30R'ed STi at the track, you would watch the oil temperature gauge and basically use it as an indicator of when to slow down -- we'd do one hot lap, then have to slow down and let it cool off. I believe that car did have an oil cooler and even then driving style had to be adjusted. It was a hot day, maybe 130F on the track.

Problem with a good oil cooler is it's expensive. LIC sells their custom radiator/oil cooler setup which is very sweet, but it's over $2,000 (which actually isn't that much if you compare the cost to other alternatives). Another thing to consider is a dry sump.

Check out LIC's setup -- these guys know what's up:

http://www.i-club.com/forums/showpost.php?p=2837276&postcount=64
http://www.i-club.com/forums/showpost.php?p=2838104&postcount=67
http://www.i-club.com/forums/showpost.php?p=2845401&postcount=114
http://www.i-club.com/forums/showpost.php?p=2845653&postcount=118



Stan
 

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2015 Highlander AWD XLE 6AT
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The stock unit isn't really an oil cooler, it's more of an oil heater if you will. It'll allow the oil to get up to operating temperature quicker. Coolant and oil temperatures aren't that different anyway.
Interesting!

Because the OEM oil cooler is an OTW type, I assumed -- perhaps mistakenly -- that it would operate somewhat like the engine oil cooler in my pickup truck. It also uses a sandwich adapter between the oil filter and the block, and relatively cool coolant from the lower radiator hose is used to cool the relatively hot oil.

I'm used to I4's, I6's, and miscellaneous V's. I think I've got some work to do in better understanding the (~reverse flow?) cooling architecture for Subaru's H4:



Thanks,
Jim / crewzer
 
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