Dual Oil Cooler Installation

[backformore]

I've got a 2nd gen with one oil cooler installed. As I run in the SE, I would like to put a second cooler in to help control temps.

I'm curious to know how people are intalling multiple coolers. Both the oil plumbing and the installation location/cooling air routing.

Rory

[C. Ludwig]

I'd show ya how I did mine but I haven't really trialed it yet. Give me a week and I can send some pics. Only thing I know is that you'll have to run them in parallel to minimize the pressure loss.

Chris

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Chris Ludwig
08 ITS RX7 CenDiv

[Allen Brown]

I'll try this a second time....1st reply doesn't seem to have worked

Chris' comment about second cooler to be installed in PARALLEL is the way to go. I asked around, and how it was explained to me was....The second cooler if installed in SERIES will have more pressure loss, and will be less efficient in cooling the oil.

Thanks Chris. I WAS planning to install my second cooler in SERIES until I seen your reply.

[C. Ludwig]

Finally got mine buttoned up and running. Even with the coolers in parallel I lost almost 20 psi. Down to about 62 psi @ 7000 rpm. Dropped the pan last night and installed the high pressure regulator and am now up 60 psi at idle, around 90 @ 3000 rpm and nealry 110 @ 7000. Don't know if that means the stock regulator was faulty because the HP numbers seem to be right on target.

Basically what I did was to take two strips of steel stock about 1"x6-7" and bend them at one end in a half curve shape and weld them to the round cross brace in front of the stock cooler location. Drilled two holes in each and mounted the cooler to them.

I've plumbed the coolers with -10AN line. Find two T's with female swivel fitting on the T end and male ends on the runs. Tighten the T end to the AN adapters on your oil cooler and run stainless between them and the motor. Couldn't find the T fittings anywhere but Pegasus. I'm sure others have them but they were in their catalog and online. Part# 3282-10.

Plumbing I have figured out but mounting location and ducting I'm not sure of and won't be until I try the car next weekend at Waterford. Drove it up and down the road today to test pressure and for leaks. It was about 93* and everything stayed very cool but it was FAR from racing conditions.

Chris

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Chris Ludwig
08 ITS RX7 CenDiv

[paulydee]

My biggest question with this setup is airflow. Mounting two coolers one in front of the other, doesn't that reduce airflow to the cooler in the back? Doesn't that defeat the purpose of adding cooling surface area (twice the surface area with two coolers?) I am still running the stock single and my temps are through the roof on track. I was planning on installing Setrabs or Mocals instead (which would seem like a more efficient cooler). The mazda cooler may be 19" wide but it almost 2" thick which to me would seem like it is making it tougher for air to pass through.

Paul

[Allen Brown]

My second oil cooler is approx. 1" longer, and 3" wider than the factory oil cooler. I mounted the second (aftermarket) cooler approx. 2" infront of rad and factory oil cooler. I had to go diagonal to get oil cooler to fit and for the lines to fit through a small opening beside the factory oil cooler.

My oil temps with the single factory cooler was 240 to 250 on some of the hot days. (Probably doesn't count as hot for the folks in the south).

I teed the discharge and return lines at the engine, and where I had to make a sharper I used tube style elbows (less pressure drop). I had installed a high pressure regulator last season. My oil press went up 20 to 30 psi depending on the rpm.

I haven't had a opportunity to check the pressure drop. I just finished installing on the weekend.

[Allen Brown]

This past weekend, the car seen a real test for the cooling system. Air temps in the shade on Saturday was 107 to 110 F.

With the second cooler installed and pushing the engine hard, water temp came up to 225 to 230 F and oil temp was as high as 230 F.

On Sunday, air temp dropped to only 86. Water temp peaked at 215 to 220, and oil temp reached the 215 to 220 F also.

Oil pressure dropped to the 75 to 80 psi at 7000 rpm when hot with the second cooler installed.

I know for sure, I would not have been able to push as hard if the second cooler was installed.

Saturday ws the hotest temps I've raced in...I now know why they sell cool suits.