I found this picture on mazdatrix's website:


It looks the same as a standard koyo with exception of two extra baffles welded in and some sort of cap on top of the middle chamber. Mazdatrix says it also has a lower fin count for increased air flow.

I would hope any competent radiator shop could convert it without too much expense or difficulty.

I have a feeling my car will start seeing more track time and while my standard koyo behind my blitz FMIC keeps temps in relative check, it would be nice to have a little extra cushion.

Anyhow, just wondering if anyone has done this or got a price.

Or if anyone thinks I'm crazy/dumb/cheap/etc, bring on the flames.

 

Anyone?

 

Well, I did it. I haven't installed it yet, maybe by this weekend I'll have the car back on the road.

I didn't take any construction pictures, but it's pretty self explanatory. Cut a couple slots in the end tanks between the tubes, weld in some baffles and weld in some sort of bleed device in the center pass at the top.

Just running the hose through it to clean it out, it seems to still flow pretty well, although I don't have a reference to compare it to. I don't have flow requirements or capabilities, but cross sectional area is roughly 30% less than stock (assuming equal tube density and size).

Once it warms up, I'll try to give some sort of quantative report.

 

Nice welding work. The end tank on the upper right is pretty restrictive though. Also, the divider should be welded all the way around to ensure coolant doesn't bypass it. I'm assuming you only got 3 of the 4 sides. With a triple pass it is obviously less important than with a double pass where it allows the coolant to flow back into the motor without passing through any part of the core!

 

Tig'ing this type of job up isn't that hard if you got the equipment. But with a shop doing it, it could run up the $$. Curious - how much did they charge ?

tom

 

I had one of my friends weld it up for me.

Yeah, it was olny welded on 3 of the 4 sides, but the baffles were a snug fit.

And I did consider the narrow passage on the top, but at the same time, I wonder how much water makes it down there in the stock configuration?

 

Welding baffles into the endtanks makes it a multi-pass radiator. You can avoid welding all four sides by making the baffles accurately and using an epoxy on the side nearest the core for sealing.

https://www.rx7club.com/showpost.php...5&postcount=17

 

FWIW,
I'm in discusions with a couple radiator fabricators about a custom, and my original design was a 4-pass. All vendors tell me that the extra passes are alot more work on the water pump, with minimul gain, because the fluid has recieved the majority of it's cooling after the first pass... it doesn't need that long in the core.

Just offering it up. I converted mine to a double pass instead.