Anyone who has driven their race car, street car, truck, or SUV on a cool morning knows that cool means more power. And it’s not limited to the cool air entering the engine. Engine operating temperature is a critical factor as well, as the temperature of the coolant directly effects the temperature inside the cylinders. So the lower the temperature of the coolant, the more power the engine can deliver. In essence, by lowering cylinder temperatures you’ve unlocked horsepower that heat has taken away. Specially-developed racing coolant has been in use for years, and as a result, there have been many me-too products on the shelves of auto parts stores, with varied claims and confusing information.
However, for those reading this article, the quest may well end here for a practical, proven solution to reducing coolant temperatures with two new products from VP Racing Fuels: Stay Frosty and Cool Down.
The Subject Of Coolants
Before diving into the specifics of Stay Frosty and Cool Down, we need to talk a little about what “coolant” does and the state of the market at the moment. Walking into the coolant aisle at the auto parts store will make your head spin with all the different products on display — the array of colors alone will make you want to leave. But we’re going to look at the science and not the claims on the labels.
What you need to know for our discussion here is there are essentially three different types of coolant: water, water-based, and glycol-based. There are two different forms of glycol: Ethylene and Propylene. You’ve probably heard of acronyms like IAT, OAT, and HOAT thrown around. The best way to think of these is as an additive package to address corrosion, but they all essentially do the same thing. Each have their pros and cons, but they are all glycol-based (either Ethylene or Propylene).
We turned to VP Chemist, Duane Minazzi, to tell us how Stay Frosty and Cool Down differ from the norm and help us sort through some of the information (and misinformation) out there today in coolants. With just cooling in mind, Duane says the best coolant, hands-down, is pure water (Reverse Osmosis — not tap, distilled, or spring). Every other liquid is compared against it. So, why don’t we just use water?
“Water is the best, most-efficient fluid conductor of heat,” Duane says. “Admittedly, there are a few strikes against its use as engine coolant: One: it lacks corrosion protection, two: it has a high surface tension (which is why bugs can float on it), three, it freezes at a relatively high temperature, and four: it has a low boiling point.” The two biggest concerns about pure water are corrosion and freezing point. For these two reasons alone, the coolant industry was born and continues to evolve its products to address these shortcomings.
How Coolant Is Compared
There are three key properties that affect the effectiveness of coolant: Specific Heat Capacity (SHC), Thermal Conductivity (TC), and Viscosity. Measurements of these three properties are usually taken at an agreed-upon cold and hot operating temperature such as 77- or 200-degrees Fahrenheit.
“Specific Heat Capacity is defined as the amount of heat required to change a unit mass of a substance by one degree in temperature,” Duane explains. “Think of it as the capacity of a substance to hold or carry heat.” Water has the best SHC of any liquid at 1.00 and is measured in BTU/lb. °F. Add anything to the water and the SHC drops, so this is obviously an essential property to measure.
Thermal Conductivity quantifies the heat transfer by adding a time element. It is the net transfer of heat over a specified period of time, and is measured in BTU (ft)/hr (ft2). You can think of TC as how efficient a substance is at transferring heat. As with SHC, adding anything to the water drops the efficiency of TC. Duane says waterless coolant has roughly half the TC of straight water.
Viscosity is where things really get interesting. Viscosity is the consistency of a fluid due to friction. People don’t really think about viscosity with coolant, but it exists, and can really affect the flow rate. Think about motor oil for an analogy — 0W-30 flows faster out of the bottle than 20W-50. This viscosity can also be affected by heat. Think about the cold oil from the bottle versus changing the oil after you’ve run the car — the oil flows much quicker out of the engine.
This is important because thicker liquid travels slower through the system. It’s all about getting liquid through the radiator to transfer heat. “Waterless engine coolant has a viscosity almost 10 times higher than water, and almost 3-6 times higher than a 50/50 mix (depending on temp),” Duane tells us. “This extra viscosity creates drag (and possibly additional wear) on water pumps, since modern OE pumps are designed for the viscosity of a 50/50 mix.”
In Duane’s research, he has seen a 20- to 25-percent reduction in coolant flow through the radiator tubes with waterless coolant. That drop in flow can be calculated and has been proven to directly correspond to a drop in the ability to transfer heat.
Stay Frosty and Cool Down
Plain and simple, a cooling system is designed to transfer heat — that’s it. The problem is the different materials used in the system and chemical reactions which take place. So, the name of the game is to get as much protection as possible while still achieving maximum heat transfer.
We’ve already established water as the best at transferring heat, but the four strikes against it mentioned earlier must be minimized. Engineers have to design a coolant which addresses corrosion and freeze protection, raises the boiling point, and breaks the surface tension — all at the same time — while also trying to keep the flow high.
Engineers at VP designed Stay Frosty and Cool Down as a 100-percent water-based coolant to address these issues, yet still give you the desirable properties of water. Stay Frosty comes in two different formulas: Hi-Performance and Race-Ready. The difference is Hi-Performance has some freeze protection down to 0-degrees F, so it has a little bit of propylene glycol in it; whereas, Race-Ready has none, making it a true racing coolant that’s approved for use at race tracks.
Stay Frosty is a pre-mixed blend of the full-strength concentrate, Cool Down, with chemically stabilized R.O. water added. Think of them as essentially the same product. Both Stay Frosty formulas and Cool Down meet or exceed the ASTM D-3306 corrosion standard and are non-toxic. With the absence of glycol, Race-Ready and Cool Down are also biodegradable.
But, the most important aspect of Stay Frosty is its ability to reduce engine temperatures by as much as 100-degrees Fahrenheit. Yes, you read that correctly.
Remember how we said water has a lot of surface tension? Well, the wetting agents in Stay Frosty reduce the surface tension, allowing it to make better contact with metal surfaces. “Cool Down and Stay Frosty contain multiple surfactants (which reduce surface tension) that perform across a broader, higher range of temps than do most other additives and engine coolants on the market,” Duane explains. “If maximum engine temperature reduction is important for your application, Stay Frosty Race-Ready Engine Coolant is the product of choice.”
Quantifying Temperature Reduction
We were provided an independent, controlled dyno test conducted on a Chevy LS engine to quantify the temperature reduction by comparing cylinder-head operating temperatures using Stay Frosty Race-Ready, waterless coolant, and the standard 50/50 mix of antifreeze and water. While running the engine at 5,000 rpm for 15 minutes to ensure the same operating temps, testers used a dual-laser infrared thermometer to take measurements on different locations of the heads.
The results were impressive. Stay Frosty reduced cylinder-head temperatures by an average of 111-degrees over waterless coolant, and 77-degrees over the 50/50-mix. Those are significant numbers when you have an engine running at the limit such as a race car, or a car that sits in traffic for an extended period of time. Of course, the results for an average car, or a different style engine, may not be as pronounced, but they should still be in your favor.
|Point on Head||Waterless Coolant||Stay Frosty||Delta T||50/50 Mix||Stay Frosty||Delta T|
|Delta T Max/Min||26||13||—||17||13||—|
Though it was not pointed out in the results, one interesting undocumented benefit I noticed was Stay Frosty seemed to even out the temps across the head. The difference between the maximum and minimum temps was reduced from 26-degrees with waterless coolant and 17-degrees with a 50/50-mix, to just 13-degrees with Stay Frosty.
For engines with an inherent flow problem, you’ll generally see higher temps in specific cylinders (usually the rear of the engine) resulting in greater wear in those cylinders over time. Having the ability to even out the temps across cylinders means more even wear across, so one cylinder won’t weaken before the others.
A Not-So-Scientific Test On A Miata
With this data in mind, I decided to do a test of my own on my 188,000-mile, four-cylinder 1996 Mazda Miata, which is now a dedicated race car. I have a big aftermarket radiator, so I don’t have a heating problem as far as overall water temperature is concerned. But, the Miata engine has an inherent (and well-known) issue of bad flow to the rear cylinder, resulting in graduated temps from front to rear.
The Miata engine was originally designed to sit transversely (sideways) in front-wheel drive cars. But, when engineers fit it into the little two-seat rear-wheel drive car, the engine had to be turned to connect to the driveshaft, which put the thermostat housing against the firewall. To remedy this, engineers moved the outlet to the front, so coolant flows in and out of the front of the engine, instead of in one side and out the other. As a result, cylinder #4 is significantly hotter as the flow is significantly reduced.
I typically see a 30- to 40-degree temperature difference from cylinder #1 to #4. There are many aftermarket options out there to reroute the coolant back to the original position which fixes the issue, but I wanted to see if Cool Down would improve the condition prior to installing the aftermarket tubing fix. I had to recycle the antifreeze out of the car for the track anyway, so I decided to give Cool Down a try.
VP recommends one pint of Cool Down for cooling systems of 12 to 20 quarts, but for heavy-duty use like racing, it recommends 50-percent more. This was perfect seeing the Miata coolant capacity is 6.3 quarts, so I could just add one bottle. I drained and recycled the antifreeze and replaced it with R.O. water then added the pint of Cool Down.
I replaced the radiator cap and started the car, letting the engine warm up completely to open the thermostat. I ran the car for an additional 10 minutes after the fan kicked on to make sure it had time to circulate and disperse fully throughout the engine. I had a road-course event coming up in two days and decided to conduct my test there.
After I ran my second 20-minute session of the day, I returned to the pits, grabbed my Intercomp infrared gun from Summit Racing Equipment, and snapped some photos of the temps. Weather conditions were not ideal — it was cold and windy — and the only place to get a clear shot of the head on a Miata is on the exhaust side, so I’m sure that skews my unscientific test a bit, but I was surprised with the readings nonetheless!
Normally, I would see readings from front-to-back of around 250, 270, 275, and 290, respectively. As you can see in the photos, they were considerably lower across the board: 247, 259, 261, and 253. After my third run, I decided to take another reading and got 253, 284, 281, and 246. In my haste to get to HPDE class, I didn’t notice that I had the laser pointed too close to the header on the middle two, so they were probably closer to the 260-range. That being said, #4 was my concern and the Cool Down did the job I was hoping it would do.
I learned a lot in my discussions with the chemists about coolant and things like “nucleate boiling,” which play a lot into the ability of coolant to transfer heat from the metal surface to the coolant. It is essentially localized vaporization of the coolant which causes bubbles and separates the water molecules from the surface of the metal, not allowing the heat to transfer. Wetting agents in the coolant will reduce the occurrence of this phenomenon.
There is a lot of science that goes into the making of coolants and new technologies are being developed all the time. Stay Frosty won new product awards at SEMA and PRI late in 2018 for its abilities. If you find yourself going cross-eyed from checking your temp gauge all the time, check out VP’s website for Stay Frosty or Cool Down and give it a try. Chances are you will find your eyes looking at the road a lot more instead of the dash this summer.