ausgeflippt951

So, a few friends have asked for details on the recent oil cooler install I did on the 951. So, I figured I'd do a quick writeup for the steps I took to install a second factory cooler in parallel with the stocker.

Little bit of history: my car has become mostly my track toy in the past couple of years, though it's been seeing fairly consistent track duty for as long as I've owned it. We all know how hot these cars can get on the track: back in AZ I've seen 260F, taken at the oil pan. This past season out in Virginia I was measuring consistent temps of 240F.


I've had a spare factory cooler for years, ever since my previous 951 was totaled in a hit-and-run. Well, I finally got around to installing the cooler.

Not including the cost of the cooler (which was free for me), the total cost was less than $140.


NOTE: I do NOT have power steering on my car, so I'd imagine you'll be dealing with a bit more of a headache in trying to route lines around the PS assembly.


The placement:
If you've ever looked up under the front fascia (splitter/batwing removed), you'll notice there is a small blockoff plate on the opposite side of the radiator from the stock oil cooler (basically a mirror image). There is a convenient sense of symmetry when you look at this gap: what a perfect place to put the new cooler.

If you've got A/C in your car, you'll notice the condenser lines run adjacent to the radiator, meaning your new cooler will need to be angled slightly to compensate, and the bracket you make will need to allow the cooler to protrude accordingly.

Another note: you will need to remove the original alternator cooling pipe, which snakes under the frame up to the very front of the driver's side fender. This pipe will interfere with your ability to install the new cooler. I simply replaced this pipe with flexible 2" hose, which enabled me to route it more inconspicuously.

You'll want to remove the front fascia, as it really helps with this whole process.


Oil Cooler Orientation:
You'll need to flip the orientation of the cooler, such that the side-protruding opening is on top, whereas on the original cooler it is on the bottom.


Prep of Cooler and Purchase of Lines:
My goal in this was to keep things as cost effective-yet-efficient as possible with no sacrifices in quality. Before you begin, it's important to note that the cooler itself uses a 22mm x 1.5 male-male adapter that, in turn, screws onto a 26mm x 1.5 fitting used by the cooler hoses. This means the lines require a 26mm x 1.5 fitting.

First thing: remove all fittings from the cooler, including adapters. That adapter will be a real bitch to get out, so be VERY CAREFUL you do not bugger the face of the fittings.


I spoke with the quite helpful experts at British American Transfer and they recommended the following:

- Do not route in parallel; routing in series is sufficient (this one surprised me as well)
- No need for a thermostat, given the car already has one
- It will be most cost effective to convert to AN and use AN fittings for all new lines (I independently crunched the numbers and the difference was ~$50 total).
- If you can, try to get 22mm x 1.5 adapters, rather than 26mm -- the 26mm are virtually impossible to find nowadays.


I also wanted to steer clear of stainless braided hose, given that (a) it's a PITA to work with and (b) the minimum bend radius tends to be too inflexible, in case I needed to keep things tight-ish.

So, I settled on BAT's push-lock hose, which use a socketless hose that presses onto a barbed AN fitting. The guys at BAT confirmed they'll do just the trick, and don't even need Oetiker clamps (the fittings have been taken to 300psi without blowing)! Finally, I knew I wanted to use the currently-existing cooler lines due to simplicity --- this was a big requirement of mine. I didn't want to deal with removing the lines from the oil filter housing.

So to make this work, I needed the following adapters/fittings:

- Three (3) 22mm x 1.5 to 12AN male-male adapters
- One (1) 26mm x 1.5 to 12AN male-male adapter
- Four (4) 12AN socketless barbed fittings
- 8ft of Aeroquip FC332 AQP hose



Installation:

At this point, I'm obliged to inform you that I made the conscious decision to defy the convention for oil cooler flow (bottom-to-top) in an effort to make hose routing easy. Shouldn't be a problem, though I did want to let y'all know in case you decide to do things differently.

See diagram below for routing.


You'll need to make a bracket to mount the cooler to the radiator frame, just like with the original cooler. I happened to have heavy duty galvanized strapping lying around, so a few bends in the bench vice + a bit of grinding + a couple holes and I had myself a bracket that fit. Note that I also chose to create a lower bracket to "enclose" the A/C lines (see pic) -- this lower bracket is out of thinner gauge steel I had lying around. Next, paint it up to make it look nice.

Once you have the cooler installed, you'll need to handle routing of the lines. I chose to repurpose the lower cooler line from the original cooler as the crossover line I was going to run to the new cooler. So, remove the lower cooler hose from the cooler end, leaving it in place on the oil filter housing side. Discard the 22mm male-male metric adapter, as you will not need it.


Install the fittings onto the cooler (if you haven't already done so) and install the new lines. If you're using push-lock fittings, you will need to heat the lines up before installing. I simply brought some water to a boil and submerged the hose for about 30 sec or so. At that point, it helps to secure the fitting in a bench vice between two blocks of wood so as to not bugger the aluminum fitting. Then, push the hose onto the fitting.


Now that your cooler is installed, make sure the lines are secured and out of the way of any moving parts. You can get a decent idea of my routing in the pictures below; note that some clamps were not completely secured yet due to my undertray still needing to be installed.



You're almost there!
Note that during this whole process I had intended to install the small factory oil cooler cowling onto the new cooler. In order to do this, however, you're going to need to do some fairly extensive modification with either a die grinder or dremel, given that (a) you've flipped the orientation of the cooler, and (b) the cowling is actually angled off in the wrong direction -- it was intended to be installed on the right side of the car. This means that unless you modify the cowling, it WILL interfere with the driver's side fog light.

See the last picture for the extent of the modifications required to the cowling. Almost doesn't seem worth it at the end.




So, it ain't pretty per se, but it is functional. I haven't had a chance to get it to the track yet, but I have been able to confirm I have yet to get my oil temps above 190 in traffic, when before they'd hit 210-220 in traffic on the street.

Ski

Track car setup, it's worked well.

ausgeflippt951

That looks so clean, Bret. Clever idea hooking your brake duct straight to the radiator fans... (j/k)

Amazing how much cleaner it is when you don't need to worry about A/C!


What kind of drop did you see in your oil temps at the track? If I can get a delta of 15-20F I'll be happy. Not sure how feasible this is but we'll see! You routed in series?

Ski

yes in series, we did see 290-295 but we also have the temp sensor at the bottom of the oil return from the turbo, other temps with the laser thermometer on the oil lines at the dyno were 260-275; we actually ran the car on the dyno and warmed it up to see what we would have at the track with heat soak. The ducts are just hanging in that one photo, LOL, they mount just to the outside to get that last bit of air

fortysixandtwo

You'll get more cooling by plumbing them in parallel, due to maintaining a higher average temperature difference between the air an oil. Depending how the flow balance, through each cooler, works, the plumbing could get a little more complicated, vs a series configuration.

Either way, nice write up! You should also put this in the DIY area.

ausgeflippt951

Yeah, this one surprised me as well. I had been planning on routing in parallel for the same reasons you mentioned above. In speaking with the guys at BAT, they were very vehement to route in parallel, given that if there is a higher resistance in one cooler than the other, the effects of the additional cooler will be minimized.

Apparently, the probability for this resistance difference between coolers in a parallel loop is greater than the potential for the entire series loop having a high enough resistance to prohibit flow through both coolers.

According to the BAT guys, a parallel loop becomes more attractive for the 911 guys, who have a much greater length of oil cooler flow. For shorter cooler loops, such as for the 951, the series loop is considered to being higher performing, on average.


And thanks for the feedback, BTW.

ausgeflippt951

Wanted to provide a bit of an update, to anyone who is interested in this:

Went for a drive over the weekend through southern MD with Ramius665 and his wife, which was my first test of the car at-length. At no time, during 5+ hours of driving that day, did the oil temp get above 190F. Not bad! Very pleased so far. Unfortunately we'll have to wait until next season to see how she holds up at the track.

Droops83

Very cool, I did this a couple years ago and it has made a huge difference in both oil temps and coolant temps on track, since I still run the stock wet turbo setup. I can run 30+ minute track sessions in 105 degree ambient temps with no issues.

I actually knocked it out the night before a track event and found a couple of early 911 oil hoses on the shelf (working at a Porsche shop his its advantages!) that worked perfectly! I eventually plan to redo it stainless with AN fittings but it has held up well 2+ years later and dozens of track weekends, with all the street driving in between.

Here is the only pic that I can find:

Droops83

I just noticed that you angled the oil cooler to clear the A/C condenser lines so that you could keep the A/C, very cool! I took mine out at the time since my compressor was noisy at the time and I am blessed to not need A/C much here in Santa Barbara. I also managed to do mine without taking the bumper cover off. Doing stuff at the last minute before a track event . . . . not always the smartest idea but it worked out in this case!