Mazda Racing oil cooler, new $85. Anyone ever try these?

[bpu699]

Several posts on here about folks adapting old mazda oil coolers to use as a front cooler on 911's and 944's. Way cheaper than Setrab, for about the same size...

I see that there are now aftermarket companies selling NEW mazda aluminum coolers with the fittings in the right place, for less than $100!!! About 20 inches, by 4 inches by 2 inches. Should fit most 911's...

That seems way reasonable, cheap even. The setrab is $600...

Anyone try one of these recent aftermarket coolers?

Aluminum Oil Cooler Mazda RX2 RX3 RX4 RX5 RX7 S1 S2 Oilcooler | eBay

[KTL]

Yep a lot of people have used the RX7 cooler with good success. Some argue that the fitting size is a bit small and adds further restriction to the external oil system. But nonetheless people have used them with good results.

The plumbing challenge I see is the placement of the inlet/outlet fittings. I'm curious to see how folks have hooked up hose ends to the cooler and cleared the front bumper on the 911. Usually the fittings are on the side of the end tank to best serve a 911 application.

Totally agree that Setrab, Mocal, B&B coolers are extremely expensive. There's other sources like Fluidyne or Earl's that sell cheaper coolers (but no way as cheap as this eBay cooler) of good quality to fit a 911 just fine.

This cooler has to be made in China to be that cheap? $85 is crazy cheap for a pretty aluminum cooler like that. If it seems too good to be true..........

[chrismorse]

I used a RX7 coolerup front on my 72 2.5 914-4 hotrod, supplied by -12 aeroquip hoses. Temps always under control.

I kept dragging it over the ground and so had to continue replacing the cooler.

I wonder if the cooler still has a thermostat built into the side tank. If you are running the stock fender mounted thermo/pressure relief, no problems.

Price is right.

chris

[Trackrash]

I'm running an RX-7 cooler on the front of my 911. Mine was a used one from ebay.

To make it work right you must replace the fittings with something larger. In my case I used AN-16s. And remove the thermostat that comes in it and plug the bypass hole.

I had to modify my front bumper as well, since the fittings hit.

It does keep my 2,5 cool.

[RSBob]

The 914 crowd with 911 motors have been using them front mounted satisfactorily for years. I have one for my 3.0 and it works almost too well. Go for it.

[Walt Fricke]

I've run several Mazda coolers, with replacement being due to crashes on track.

It is easy to disable the built in thermostat. You take it out, and tap the hole connecting the in and out chambers. Then screw a plug into the hole to close it, and screw the outside cap back in.

I've spent some time getting the fittings, especially as I recall the lower one, pointed right. I'll see if I can take a picture. As I recall, the Mazda fittings are on a front or rear face of the cooler in its normal orientation in the front of a 911. You want to make new holes for the fittings so they stick out the end. Maybe could drill and tap, but best, even if that has been done, is to weld the AN fittings on.

[stownsen914]

I looked at some of those "RX7" coolers on eBay. The ones I saw were like $150 or so. This one is even cheaper. The ones I saw weren't really RX7 coolers like the ones the guys are talking about in the posts above with the thermostats, etc. They were just dimensionally similar to the real RX7 ones. I wound up not trying one though because the fittings were too small for my liking, like AN10. Note though that this is similar to the size of the fittings (or the ports where you screw in the fittings) in a real RX7 cooler. Lots of people have used the RX7 cooler successfully on 911s though ...

[bpu699]

The stock mazda cooler is steel right, not aluminum? Would be easier to weld...

Welding is not an issue, I have the tools and welders ,

In regards to fittings, I thought that most of the Porsche stuff was AN12? Any point in welding in a AN16 (isn't that huge?)

Also, I thought most AN fitting I see for sale are aluminum, no? Do they make them in steel?

I am very tempted to buy this cooler for $80. Trying to figure the downside, and the major concern would be burst pressure. Perhaps they made it of very thin aluminum?

Bo

[Elombard]

The Mazda coolers are aluminum, the stock Porsche oil cooler fittings are metric but ~ AN16 (1 inch).

Its hard to argue that the factory made the oil lines the size they are for a reason and anything smaller would cause too much restriction. But I have seen a logical argument that its Ok to use an AN12 size. I am glad I don't have to decide which size to use. It would be tempting to save the money and go AN12.

The vendors make "weldable" aluminum AN fittings for welding to anything aluminum.

[Trackrash]

Here is a poor shot of mine. AN-16 bungs welded on.

[bpu699]

Originally Posted by Trackrash

Here is a poor shot of mine. AN-16 bungs welded on.

The brass lines running to the front coolers are 3/4 of an inch... isn't that AN 12?

Not sure if an AN16 fitting makes a difference if the supply line is 3/4 inch, no?

I believe the elephant racing stuff is AN12 too...

[Walt Fricke]

The stock hard lines are closer to AN12 than to AN16. A hair larger than the -12s. Not enough to matter.

Where the AN16 is useful is in a full on race 911 with a 4 or 5 gallon oil tank in the smuggler's box area. The cooler side of things has plenty of pressure pushing the oil along. But some gravity and the suction of the oil pump are much lower pressure, so there is something to easing the passage of the oil from tank to pump. I thought I was tip top when I put in a -16 line instead of the -12 one (which had worked just fine) on my modified 911, but immediately saw a car with -20. My car came with -10 up and -12 back.

In terms of oiling, what counts on a stock 911 is having the oil level in the tank always high enough to supply the pump's demands. Larger lines may cut down some on the parasitic power lost in driving the scavenge side of the pump, but that's probably trivial.

I suggest using -12. You can purchase an adapter which will allow you to connect a -12 hose end fitting to the metric fittings Porsche uses.

[Trackrash]

For sure AN-16 is overkill. The argument is the AN-12 fittings are restrictive. I have not seen evidence that it would cause problems. Since I was starting from scratch, I figured -16 could not hurt and is not much more expensive.

Here is a comparison of AN-16 fitting and hose compared to an OE SC hose and fitting.

[Busta Rib]

Originally Posted by Walt Fricke

...I suggest using -12. You can purchase an adapter which will allow you to connect a -12 hose end fitting to the metric fittings Porsche uses.

Walt, what is the proper size for the Porsche side of the fitting to buy for the adapter you are referring to? Thanks.

[Walt Fricke]

Gordon - good point. I know that a restriction raises pressure - think of the thumb over the end of a garden hose. What I don't know is what the effect of a fairly minor restriction at just one point in a longish (relative to the restriction) line is. Is flow reduced at the discharge end by the restriction no matter how far away? If the pump can just build higher pressure before the restriction, does its effect go away? How does the drag from the wall of a tube affect things?

Recalling my Carroll Smith, I remember that for the cooling air ideally you want to have the inlet duct smaller than the cooler area, and the exit tuct slightly larger than the inlet. The idea here is to have the incoming cooling air expand and thus slow down as it passes through the cooler. This makes the heat transfer more efficient as the air lingers longer, so to speak, to take up more heat. Up to some limit, no doubt. I suppose that some similar thermodynamic is at work with the flow of oil? If it zips through too fast, is the heat loss side of things less efficient?

Maybe someone who took thermodynamics in engine school and remembers it can educate the rest of us.

On my first Mazda cooler I had a heck of a time wrenching on the fittings with the spoiler in place and the brake ducting, which as a pro for a 12 over a 16. But if it works, I see a -16 as pretty much an economic decision. Marginal cost and marginal gain may be down in the noise here.

[Walt Fricke]

Busta
Try Pegasus if Pelican doesn't carry AN to Metric adapters.

I'd measure the metric to be sure, but look at male and female 30x1.5mm parts.

[Trackrash]

Originally Posted by Busta Rib

Walt, what is the proper size for the Porsche side of the fitting to buy for the adapter you are referring to? Thanks.

BAT has them. http://97.74.32.155/files/metric.pdf

[bpu699]

Think about how many people are driving with partially crushed oil line... That's probably the primary restriction in the system...

Sounds like AN12 would work fine...

Hope to do this in a couple months...

[Trackrash]

Originally Posted by Walt Fricke

Gordon - good point. I know that a restriction raises pressure - think of the thumb over the end of a garden hose. What I don't know is what the effect of a fairly minor restriction at just one point in a longish (relative to the restriction) line is. Is flow reduced at the discharge end by the restriction no matter how far away? If the pump can just build higher pressure before the restriction, does its effect go away? How does the drag from the wall of a tube affect things?

Recalling my Carroll Smith, I remember that for the cooling air ideally you want to have the inlet duct smaller than the cooler area, and the exit tuct slightly larger than the inlet. The idea here is to have the incoming cooling air expand and thus slow down as it passes through the cooler. This makes the heat transfer more efficient as the air lingers longer, so to speak, to take up more heat. Up to some limit, no doubt. I suppose that some similar thermodynamic is at work with the flow of oil? If it zips through too fast, is the heat loss side of things less efficient?

Maybe someone who took thermodynamics in engine school and remembers it can educate the rest of us.

On my first Mazda cooler I had a heck of a time wrenching on the fittings with the spoiler in place and the brake ducting, which as a pro for a 12 over a 16. But if it works, I see a -16 as pretty much an economic decision. Marginal cost and marginal gain may be down in the noise here.

The interesting thing is that if you look at the size of the case oil fittings , they appear rather small in comparison. The outlet measures 15mm ID and the inlet from the tank is 18mm! I'm holding the case fitting for the oil outlet.

[Busta Rib]

Originally Posted by Trackrash

BAT has them. http://97.74.32.155/files/metric.pdf

Thanks!!