VP Cool Down / Stay Frosty coolants
 

Has anyone tried these on a rotary?

https://www.enginelabs.com/engine-te...ed-horsepower/

The even temperatures from their Miata test is somewhat encouraging. It's likely our engines have similar hot-spots.

Not going to call you dumb, but how could our engines possibly have similar hot spots to a Miata? The are ZERO similarities between the piston and rotary engine coolant passages. The only real similarity is the manufacturer.

From what I've seen Evan's NPG was popular at one time, but I haven't seen anyone speak of it lately.

Vince

A comparison of this VP product to Redline's Water Wetter would be interesting.

I use Evans.. It works for me.

Sorry, I may have misunderstood the description of the Miata cooling design flaws. I took their description as saying the rear of the Miata engine runs hotter than the front of the engine due to the coolant path going from front to rear and then looping back around to the water pump. This is pretty clearly the case on the 13B: all coolant that reaches the rear rotor housing has already travelled through the front rotor housing. I think it's safe to say the 90's RX7 and 90's Miata engines were both designed when computer modeling and analysis were not likely to be used for cooling system design, I suspect there is plenty of room for improvement. I'm hoping that a coolant with higher boiling point and better heat transfer will help prevent problems.

Coolant flow-rate effects
 

Slightly off-topic? But, IMO, the only way to make coolant temperature more constant throughout the cooling system is to increase its flow rate. Has anyone experimented with modifications that could result in faster coolant flow?

That product looks similar to Water Wetter from Redline. It decreases the surface tension of water to help it get into the nooks and crannies better. In general a product like WW is good for a few degrees better cooling.

Using a proper radiator and proper fan control can keep temps in check on an FD with traditional coolant.

Evans is a neat product but it's pricey and can't be mixed with any water. So if you are on a road trip and have a hose tear, you are out of luck unless you have a jug of Evans with you.

Mazmart has an upgraded water pump with a better impeller design that's supposed to improve flow of the cooling system. I haven't seen any hard data of what the improvement is with it but it is definitely a better design.

Dale

Yes what Dale said..

If you live in the south or garage your car in winter, go for a solution of more water.

I live in Houston and run a mixture of 75% distilled water, 25% antifreeze, and 1 bottle of water wetter.
This solution did not start to form ice crystals until about -19F when I tested it in my freezer.
Also install a Koyo "N" pass raditor.

I installed a N Flow radiator and my car ran a little hotter than the stock radiator so I took it out and put the stock one back in and the temps went back down.

IMO the stock radiator has more fin density so the heat exchanges better at lower speed like driving around in traffic normal driving.
The N Flow functions at its best at greater speeds ! The biggest problem with the factory radiator is the plastic which degrades and fails eventually.

Related thread...
 

Related thread: https://www.rx7club.com/3rd-generati...=radiatorworld