My take on this is if it's for a track car go mostly water like 90% or more with coolant and water wetter.

Street cars could benefit from evans or other straight coolants like David is talking about if you don't change coolant often but otherwise no benefit if you change your coolant every two years and run 50 50 or 70 30.

My experience on a road course is evans runs hotter which robs power and also the increased risk of sliding around if a pipe burst isn't ideal for you or others behind you.

great info as usual. this is now in the FAQ thread.

I agree wit Raymond that EVANS is a bandaid instead of fixing the real problem.

Run the Koyo "N" pass radiator which is the best yet made for the RX7.
Run dual oil coolers , block off one for winter.
Use the SARD thermostat that runs around 10 degrees colder than stock instead of the 160 thermostat which runs about 20 degrees colder.
Use the original 1.2 bar or 16 psi radiator cap.
Do everything to increase air flow through the radiator and IC. Be it removing/relocating air filters/battery, and improved ducting.
Using the FAN MOD SWITCH to increase fan speed at will.

Damn this thread is still alive four years later?

Since Evans is just 100% propylene glycol, if you are really convinced that's a good idea (and it sounds like a very bad idea for all the reasons Raymond discusses) then you could save a lot of money and just use another cheaper brand of PG, like Prestone LowTox.



The additives/inhibitors are there to prevent corrosion and stabilize the glycol. PG is typically used in solar systems. Here is a brand of 100% virgin (as opposed to recycled) PG, for that purpose:

Cryo-Tek

I wouldn't be at all surprised if "Evans" was just a re-branded PG designed for use as a working fluid in thermal solar systems.

Reviewing the MSDS sometimes explains what inhibitor is in there. It is worth checking, as the inhibitor can be designed for use with either copper or aluminum.

As PG breaks down, it become acidic (one of the things the inhibitors try to prevent). HVAC guys therefore test glycols with pH strips and replace if the pH drops too low.

http://fire.nist.gov/bfrlpubs/build85/PDF/b85009.pdf

There is some good information on the solar forums too, e.g.:

propylene gylcol - GreenBuildingTalk - GreenBuildingTalk - Green Building Forums on Insulating Concrete Forms (ICF), Structural Insulated Panels (SIP), Radiant Heating, Geothermal Heat Pumps, Solar Power, Green Construction Projects - Green Building

Note the solar guys also never use 100% glycol.

A lot of people have asked me about the Evans stuff over the years. Mostly people who have overheating issues with their cars, whatever the make & model may be.

I tell them that Evans is not going to be a magic bandaid if their cooling system has problems. They need to get in there and find out why they have overheating, not attempt to patch over it with some miracle coolant product.

The other reason I would never run the stuff is (as Dale said) its too proprietary. If I get a leak or cooling system failure, or I perform work that requires a cooling system drain, there's no way I'll find any to top it off unless I order it from overseas and I'm not waiting that long or paying that much.

I've never had any experience using Evans, so I cant say if all my musings about the stuff are correct or way off. But I have no want or reason to use it or recommend it. For corrosion, I run an anode. I check electrolytic levels with a multimeter and I check acidity with Ph strips. I run 50/50 of the GM/Toyota red heavy duty coolant and I am proactive about replacing hoses. I use factory pressure rated new caps, not high pressure caps, because I dont want to gamble by forcing an old system to run high pressures.
I also chemically flush the coolant (using a compressed air gun flusher attachment) once every 12 months.

Maybe I'm backwards as hell, but I've never had a coolant problem with any of my vehicles which are all given the same attention.

Why Not Run Both?
 

Ok this may be the dumbest idea ever, but $h*t its the internet and I can say whatever I want. I am enamored with the idea of keeping my irons rust free but am not willing to put my engine at risk. I live in the DC Metro area and we have 4 seasons. I am considering running Evans in the cold months and a 50/50 or 70/30 in the warm months. You get the best of both worlds; the superior cooling and increasing the longevity of the power plant. I would store the Evans in my garage and use it again. Hell even if I am totally off base and it goes bad after long periods of storage; I wouldnt bat an eye at forking out the cash for a brand new batch. Is it an insane idea to buy an excess supply to keep in your ride if something did go awry on the road?

When it comes to my car I tend to over think before I act. I try tounderstand why I am doing, what I am doing. I TRY to keep perspective and consider the alternatives. I think the counter point to my proposal is cost and I dont run my car as hard as track cars. My suggestion is for the 'spirited' drivers. You know....cars with AC, carpet, airbags, and other crazy things as such. The expense is exponentially higher than the conventional options. But lets put the $135 in perspective. The national average gas price is $3.60 and lets say the FD has 17 usable gallons? Thats $60 a fill up. I see the money spent on seats, LED lights, sub-woofers, leather shift & e-brake boots, I can do this all day, paint jobs, etc and we are talking about the optimizing the cooling in a notoriously hot motor. Sorry for the rant but I really feel like I am missing something here.

Gary

This may sound like an odd interjection, but distilled water will actually corrode metals faster than mineralized water from what I've learned. So my question is, do coolants have additives in them to balance this?

Although distilled water will not conduct electricity. So is that why it is recommended? To prevent premature electrolysis?

I waffled on Evans for a couple years. Almost pulled the trigger on it once. I now just change the coolant EVERY spring when it comes out of storage. Run ~ 60:40 coolant-distilled water mix. Temperatures have been stable and relatively cool. We'll see.

I used it for 10+ years. Anyone that's skeptical is a moron

^ Street car? How many miles?

Ditto for me too. 10 years with a total of 65,000 miles. Never replaced. Voltmeter measured 0.08 volt.

No more dreaded coolant o-ring smoke cloud due to micro-boiling resulting in a damaged housing.

Haven't ruled it out. But anyone who's not skeptical of it is the moron.

I agree.

9 yrs, 35,000 miles, never replaced. Car used for street and track, autox, drag, etc. Puerto Rico ambient temps 75-95F all year with nearly 100% humidity, no problems.

Very Happy with Evans
 

Years ago I converted my car from my daily driver to an occasional weekend but mainly track day car. So I did pretty much everything I could to reduce temps:

'99 front bumper with larger openings
v-mount with koyo radiator
greddy high pressure cap
all coolant hose barbs welded shut except for two to the radiator and two to the turbo (no heater or ast)
all hoses in samco silicone with t-bolt clamps
mazmart remedy water pump and thermostat
FC fan switch
dual parallel flow 25 row oil coolers
pineapple deep oil pan
stripped out engine bay; no a/c or power steering
custom ducting for oil coolers, radiator, intercooler
Evans NPG-R

In the past five years Ive put about 5k miles on the car with lots of track days. A couple of times I even had my friend, a professional race car driver, push the car to its limits for half hour sessions in 115 degree weather at thunderhill. And I have never seen my oil or coolant temps rise above 190F/88C. Except when idling in traffic on a hot day, then my oil temps go a bit higher because I don't have oil cooler fans. So despite pushing the car very hard I have been very happy with Evans. I havn't taken apart that engine, yet, but I expect it to look great.

I called and talked Evans before switching and they advised me to run some pressure in the system to improve water pump efficiency. Also at that time NPG-R was only tested for five years, so it only had a recommended five year life. But they said they expect it to be lifetime as well.