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Oil cooler mounting and air management.


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So, Im working on mounting the oil cooler for my Z. The oil cooler is nearly as large as the opening for my radiator! 

 

So I wanted some opinions before I make all the bracketry and plumb the whole thing only to find out its a bad idea. 

 

Most aftermarket oil coolers are mounted in front of the radiator, many race setups are mounted behind (Nascar stuff seen on ebay) 

 

OE applications that I have had the privilege of working on (BMW) are mounted BELOW the radiator. 

 

Obviously based on this, you can see I am limited on space... 

9353050657_543c090469.jpg
Untitled by peej410, on Flickr
 
So here are my questions. Should I seal the cooler to the radiator? Should I put it as close as possible? Should I leave an air space between them? Should I mount it off set to the PS side since the "hot side" of the rad is on the DS ? Does any of this even matter? 
 
Heres a few other angles, 

9355827926_4b098e42a4.jpg
Untitled by peej410, on Flickr
 

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Untitled by peej410, on Flickr
 
This is what I am doing to combat the cooling and aero issues. 

9355819240_c881755fc5.jpg
Untitled by peej410, on Flickr
 

9355825532_c22b005d63.jpg
Untitled by peej410, on Flickr
 

9353045859_a2ae7b52a3.jpg
Untitled by peej410, on Flickr
 
I think that the curve of the duct exiting may be too shallow. Any input?

 

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If you set the cooler in front of the rad, you'll kill the airflow through the rad behind the cooler. If you have them sealed, then air will go through both. If you duct them out to the front, then air can't bypass and go around them and through the radiator only. I seem to recall preith did a nice job on his oil cooler and posted pictures. 

 

Oil should be at least as hot as the water, which probably explains why you are seeing the oil coolers behind the rad. 

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No it won't. A properly setup coolant/oil heat exchanger works better then an air/oil heat exchanger mounted in the airflow to the radiator. I rand a smaller liquid capacity double pass radiator then a stock sized 3 row radiator for a 325hp road racing NA L6.

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John,

 

Respectfully, mine is a 500+hp build with block fill. Though a dual pass radiator will likely end up in the car haha. Maybe its worth a try but i have two events upcoming and this setrab and the parts to plumb it are already here!

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And I worked with the engineers at C&R/Visteon when designing my radiator and we calculated the BTUs for my setup.  Worked great in 110 degree weather at WSIR.  Maybe give them a call with your specs.  You might be surprised and can maybe plan for a later upgrade.

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Pete, My oil cooler is about one third the size of yours and during the event at NCCAR it was very hot. The 8 laps I got in before the fuel issues sidelined me we were seeing (and I logged this) coolant temps at 187 and oil temps at 206. My 383 stroker is only making about 450BHP, but it is something to consider. I also dont have it stacked right up against the radiator. It stands about an inch in front of the leading edge on mine.

 

I kinda agree with Coffey on the heat exchanger idea. As you know Porsche has been doing this for ever. My twin turbo was making over 650BHp and never suffered heat soak at the oil or coolant temps.

 

Mike

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Mike,

 

Thats not really very hot most performance oils are good to 300. My motor makes 240deg driving around on the street at 70deg ambient. Part of it could have been the headers, most of it because of the block fill. At this juncture the block fill was a temporary solution to finish out the season three years ago, but it still runs great. $4k for a new dart short block doesnt sound fun right now. If this doesn't work properly I will try what you guys suggested. I am at budgetary limits for the season at this point and just need to get it out on track!

I will post some info as I test it!

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Pete. I know that isnt hot. Point was that my setup is pretty efficient at keeping the oil cool. On that particular day it was in the 90s and humid, so I would have expected higher oil temps after just a few laps.

 

Good thing about that FAST Dash display is if you set it up properly, it will log any analog channel you turn on. Having the oil and coolant temps, along with oil pressure sure is nice to map out against RPMS when you are in the pits between sessions.

Mike

Edited by Mikelly
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Gotcha! Ill be running a race capture pro by next season it will be easier to watch whats goin on.

 

I am almost done with the cooler install.

 

Note to self. Next time you build a car plan ahead for everything! What a pain in the ass!

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I would mount it maybe an inch or so off the rad. Need some room for the air to move from the oil cooler fins/tubes over to the radiator fins/tubes since the dont line up. Cant comment on the vents but they cant hurt. My splitter hurt cooling a lot - if you are in a pinch remove splitter and see if that helps. Im curious why your shroud is a funnel - seems it would force lots of air into the radiator and without a way to get the air out the backside may be hurting cooling. I ended up with off the shelf Ron Davis dual pass that works great.

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Sorry, but mounting an oil cooler so the hot air from it flows into the engine bay is just plain stupid. So much great aero info on this site yet this sort of thing keeps on happening. Crazy.

 

On my turbo S130 the oil cooler is mounted so that the hot air exits into the right wheel well low pressure area, all protected by mesh and oil temp stays well below 212/100 all the time on the hottest day. And believe me it gets hot here in summer.

 

It's just plain common sense that the engine bay should be kept as cool as possible. Isn't it? Or should I give up?

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Well, the rest of the front of the car is closed off. Only the rad opening feeds air into engine bay.

I would wager that the heat coming through the rad and cooler is largely insignificant in temperature change. What is significant is eight primaries that have an external temp of 500+ at idle. Furthermore the engine will make the same amount of BTU as before. Now the engine oil temp will go down but the overall temp created will be the same. At cruise bay temps were usually within 20 deg of ambient before.

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" At cruise bay temps were usually within 20 deg of ambient before. "

 

That kind of says you could use exit air from the bay to cool your oil, without sacrificing flow to the radiator, and give yourself some underhood air relief at the same time.

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