Richard Miller

There seems to be a polarizing case with Evans.

One side claims higher boiling point and reduction of vapor that would cause hot spots. This could also reduce detonation in boosted applications. No corrosion and lifetime service.

The other side states that water is better at transferring heat. That the engine will run hot. There has been viscosity concerns stated in some conversations as well. One person I had correspondence with claimed Evans caused detonation in their boosted rotary.

I have no idea how two separate laws of physics can exist on the same plain.


Evans does admit that you should expect to run a bit hotter. So what does this mean for us first gen enthusiasts?

This sample is a ‘85 GSLSE. streetport with a rebuild of under 2000 miles or so. HVAC system was restored based on the wonderful write up. So no old coolant was to be found. Radiator was replaced with the KoyoRad. New water pump, hoses and Mazda thermostat. Stock fan.

It reached 108 degrees today. The picture is after about an hour of in town driving:


Observation is the needle is about a tick from where it rests in cooler weather. Normally when warmed up the needle hits just a hair past the second gauge indicator.

In all, I have found that the detractors may be overstating concerns. As mentioned this was in town driving. Not freeway. I feel this was a good stress test. Sure 108* isn’t Death Valley hot, but warm enough for me to illicit this post. In all I’m damn pleased.

neit_jnf

iTrader: (17)

I've been using Evans on my FD since 2004, it's great.
I also converted several other cars in the family and my dd Infiniti FX50 V8, never had one overheat.

gracer7-rx7

iTrader: (16)

I ran Evans in my FD for ~4 years. It was OK. Difficult to distinguish between regular coolant. It did seem to run a few degrees hotter. It did smell funny.
I switched off it when I got a new engine.
Definitely overkill for the under-stressed cooling system of the 1st gen. Don't think it's worth it for the FD either ime.
Some people with strong opinions on both sides. Not many hard facts but plenty of anecdotes regarding performance.

peejay

I would not consider a 1st gen's cooling system to be understressed. The radiator is very small and the water pump is not great.

I rum about 190-200F in the summer with the A/C off and about 230F with it on.

gracer7-rx7

iTrader: (16)

I meant that in a comparative sense. The FB doesn't have a turbo trying to boil all fluids, for example.

Richard Miller

I'm running a turbo in my '80. At least Ill be running it once I get a few things buttoned up. Engine has ran but not on the road. Still need plates and dialing in the engine. The '80 is running almost the same setup as the GSLSE here, minus the turbo. Same street porting, same parts and upgrades. Radiator, and oil coolers are the same. difference is the Haltech and the S4 intake and of course the turbo, PWM controlled electric fan and supported systems. Ill follow up here when I have data to share.

peejay

It also doesn't have aerodynamics for the cooling system beyond a panel to keep air from mostly flowing around it.

And FBs are even worse than 1st gens, most of them had "oil coolers" with coolant taken from the hottest part of the engine, so oil temps soared, which makes the coolant hot too...

BLUE TII

iTrader: (9)

I used Evans in my 400hp FC for a couple of years and the straight 100% PG coolant (Sierra Petsafe) for another decade. Daily and racing.

100% PG coolant was indistinguishable from Evans and cheap/readily available.

Pointing this out because of the "overkill" statement. If you want to try waterless coolant without the prohibitive cost.

neit_jnf

iTrader: (17)

^^^True! I only run Evans on the FD, all other cars run undiluted EG coolant (long life high quality). Original NPG is mostly PG while NPG+ is about 70/30 EG/PG with their proprietary additive package that makes it "unique" and more expensive. But running pure undiluted high quality EG or PG coolant will provide the same results.

GoodfellaFD3S

iTrader: (213)

I love Evans NPG+, I've posted my experience with it many times here over the years. About to convert my low mile MB and 20B FD to it. Just have to have sufficient oil cooling for your planned driving application.

peejay

Okay, THAT is very interesting. I am putting together a Mini Cooper S with a Subaru EJ turbo engine and cooling is one of my largest concerns. I would love to run Evans in it but I think I would have $80 in coolant just in the tubes running from the engine to the radiator




Goal is a 400hp car that can handle two people making back to back 60-90 second runs with no airflow and no cooldown, so the system will definitely be stressed...

BLUE TII

iTrader: (9)

I personally only did waterless coolant because the sparkplug area of the rotary is such a hotspot.

It has nonstop combustion events and I thought the high boiling point would keep the vapor bubbles from forming on the hotspots near the sparkplugs.

I would think a fourstroke with a well designed quench area (factory turbo engine) isnt going to have this extreme hotspot, but rather would benefit from the superior thermal conductivity of water.

Also, run the coldest sparkplugs that will stay lit for you.

peejay

Subarus are bad for running hot around the exhaust ports and plugs, to the point that proper race engines built by machining the valve seats with the heads at operating temperature do not seal when cold.

You are preaching to the choir re: coolant hot spots. Was just having that discussion on another forum about cooling system woes in an endurance racing environment, it sounds like he has localized boiling because of the way the coolant temp does not find an equilibrium but gets hotter and hotter over an hour. Unfortunately he has to run water per their rules.

BLUE TII

iTrader: (9)

Thanks for the Subaru knowledge.

7aull

iTrader: (2)

Been running Evans in my dead-stock 80SA for about 10yrs. Swapped in while living in Alaska, so any 'runs-hotter' issues moot up There!
New: wPump, Brass rad (Spectrum, IIRC), etc. at that time.
Now past 5 yrs (of the 10) in N. AZ. Def see the needle climb on long hills, but never into the Danger Zone.
I think an important 2ndary consideration - at least for a 22yr + RX owner - is long term protection of engine internals, esp mix of iron and aluminum housings, etc. My understanding is stock coolants (tho some better than others! Have run Benz coolant in my V10 RV for yrs. Very well regarded...) can damage - eventually - metals of the block cooling passages, pump internals. Corrosion is prob a better term. Esp so when we tend to leave changes in coolant for some years btw. Stock coolants degrade, and what do they 'take' with it as it does? This was my main concern.
And I state the obvious that the $200-ish dropped on the Evans and its must-use-first Flush fluid pays for itself over the life of the car. Well, if you are hanging on to your Beloved as long as I have/plan too

Stu A
80GS - 110K miles - original 12A
AZ

peejay

At a coolant class, we were advised that the additive packages used by the OEMs are particular to the water quality local to the factory. German water is different from Japanese water is different from Michigan water.
Upon learning this, I no longer felt comfortable diluting "full strength" coolant with local water, instead preferring to just use pre mixed coolants in everything. I also note that most of the OEMs have gone to selling pre mixed coolant nowadays, too. Toyota Pink is premixed, Subaru Blue is premixed, Mercedes is premixed, etc.

Chrysler coolant is weird, it seems to be acidic by design. I guess it works well enough for them...

TeamRX8

iTrader: (2)

it doesn’t boil over after running hard and shutting the engine off.
.

7aull

iTrader: (2)

[QUOTE=peejay;12528106]At a coolant class, we were advised that the additive packages used by the OEMs are particular to the water quality local to the factory. German water is different from Japanese water is different from Michigan water.
Upon learning this, I no longer felt comfortable diluting "full strength" coolant with local water, instead preferring to just use pre mixed coolants in everything. I also note that most of the OEMs have gone to selling pre mixed coolant nowadays, too. Toyota Pink is premixed, Subaru Blue is premixed, Mercedes is premixed, etc.

PJ-
Local water? Surely they don't mean, literally, local TAP water? As opposed to distilled - which stateside, can come from ANYwhere (in US of A presumably...)
I would think the 'premix' reason is strictly convenience for end user, be it shop or personal. No secret sauce to the water used.
Benz still sells a pure version of its coolant, FWIW...

Stu A
80GS (w Evans)
Az

peejay

Yes local tap water. They aren't distilling millions of gallons of water to fill cooling systems.

MTheoryInc

iTrader: (3)

The crap tap water in Flintown, Mi was literally uncovered by the flint GM engine plant engines corroding from the inside out.