Coolant vs Evans NPG
 

hey guys just curious about these two options for "coolant" type liquid.. What do you guys run/prefer? I know to run prolonged track events you really need a great cooling system.. So what do u reccomend and why? I'm taking about the Evans that has no water in it and runs under 0 pressure..

Thanks guys!
Tyler

From what I have gathered about Evans cooling is that its an accencial part for a race car being your not going to have any expanding on high temp engines, meaning no blowing up hoses ect. On another note its specifically designed not to corode anything eaither. It has the largest boiling point, and disapates heat very quickly. Its just the best I've found so far due to rotary companys recomend it and havent seen anything else like it. It also is around $25-35 a gallon.

eeeeeyah, and how much is distilled water????

I'm not 100% positive on this one but aren't race cars required to run 100% water in their cooling systems?

you can run this stuff in your cooling system it is safe to use on the track :) thats another benefit..

but do you think its worth it.. i mean running on the track with a good cooling system like 100% distilled water and everything.. Everything ok should be fine or do u feel like you would not head to the track without this stuff in your car? I just dont know if it justifyes spending a lot more money if the proper coolant mix should do just as good!

None. In fact it isn't compatible with water.

-Max

He was comparing 100% NPG to 100% water, price wise.

I thought distilled water was *bad* for use in engines, because water is most reactive when pure? (Deionized would be a better bet)

What about running 100% Sierra? It's also propylene glycol based, so it should have the exact same benefits of the Evans stuff at a fraction of the price.

info on this Sierra stuff?

evans and sierra are not the same.

check this issue of GRM, it got a good coverage on this

check this issue of GRM, it got a good coverage on this

can you give a good run down on the article on here?

A little clarification is necessary here: Evans does not dissipate heat as well as water, thus the note on their website that specifies the need in some applications for a higher-volume water pump. For a track-only car that has a properly functioning cooling system, I'm not so sure it holds that much of an advantage or is worth the extra $$. For a street-driven car, possibly, in some cases.

Go to here:

http://www.grmotorsports.com/promo.php

Link at the bottom, you can order a free sample mag, if you hurry, they will probably send you the current one. Otherwise head to the store and fork out $5 for the one car magazine that is worth it.

No rundown, that would be copyright infringement.

Distilled and deionized are more or less the same thing, they just use different methods to remove contaminents.

Actually it is quite the opposite of what you stated.

I have been running Evans in my car for almost a year and a half. I am extremely satisfied with it and actually just bought 4 more gallons since I am putting a new motor together.

The conversion was a little work but with a car that has drain plugs it isn't that bad... my beater VW doesn't have a drain plug, not fun.... Basically you have to run a few batches of Sierra because the residue of that will not contaminate the Evans. A few fill ups with Sierra will properly let you remove the water residue.

I have heard of people saying the Evans runs at temps a few degrees hotter but safer still because the high boiling point and not to mention less stress from pressure on your cooling system. The Evans also claims it transfers heat better and prevents your motor from running into hot spots.

On my car I haven’t noticed a temp increase but a temp decrease this was probably due to me installing a Koyo radiator at the same time. I also installed a 7 psi cap, this still allows my system to flow properly but without stress of a high pressure system.

-Chris

And that would be because....?

Okay, in a lab under controlled conditions, you are correct. Evans NPG (regular or +) technically has worse heat transfer caracteristics than water alone. If you drive your car in a lab, then that's great! In the real world, EG/W (Ethylene Glycol and Water) or just plain W nucleate boil on hot spots. Care to guess what the thermal transfer caracteristics of water vapor is? Virtually nil. In other words, in the worst hot spots in the engine, typical coolant is doing a pretty crappy job because it's already at its limits and a bit beyond. Evans NPG, on the other hand, bathes the cooling system completely and, thus, controls hot spots far more effectively. This is in practice; not theory. On top of all this, it does it at low or even zero PSI (less stress on hoses and seals) absolutely nowhere near its limits (375 F boiling point at zero PSI). Furthermore, it never freezes and, indeed, contracts in sub-zero temps, so you can't crack a block even if you park somewhere in Siberia. And, your pets and children can drink it without being poisoned. Good stuff! The downsides are (1) local availability, (2) you can't just "top off" with water so you have to keep some NPG on hand, and (3) the initial expense. On the other hand, provided you don't contaminate it, it is a "lifetime" coolant -- when you work on the cooling system, just drain it into a clean pan and pour it back in when you are done. Evans NPG+ (note the "+") is the thinned-down version that does not typically require changing water pumps and such. You do have to make sure your water pump and cooling system seals are top notch, though, because Evans will tend to get past iffy seals more readily than EGW. Mainly this happenes at the water pump weep hole (indicating you need a new water pump) or at the radiator hose ends (time for new radiator hoses and/or clamps); not so much internally, since there is very little or no pressure.

Evans NPG and Sierra are NOT the same thing. Sierra is an aqueous Propylene Glycol formula, so water vapor would still likely be present in your cooling system, reducing the effectiveness similar to EGW. Sierra is marketed purely for the environmentally friendly nature of Propylene Glycol. It is helpful to us, however, because it can aide in the conversion process to Evans. Sierra will absorb residual water in your cooling system but not, itself, contaminate the Evans NPG. So, you run Sierra coolant for a couple cycles and then drain and replace with Evans NPG. Another good way to convert is to first flush your cooling system (including heater core!) a few times with plain water, then drain and put the system in a strong vacuum using air conditioning service tools, or similar (you can get this done locally almost anywhere inexpensively). This turns the residual liquid water to vapor and sucks it all out. Regardless of how you do it, you must avoid water contamination of NPG as it will ruin it.

BTW, Evans is NOT that "orange" long life coolant that is reputed to damage water seals. That stuff is just ordinary EG with a bunch of additives to extend the life of the product. I only bring this up because, in the past, someone always made that bogus connection based on the "lifetime" nature of the coolant. Evans has been used successfully in rotarys for numerous years, both on the street and in racing, with no detectible negative side effects.

I have a street+track car, and I am switching to NPG+ because my car can overheat in extreme conditions on the track. It is always cool on the street, no matter what the conditions (the fans are set to come on low and I have taken care of all the other stuff - rad, ducting, good coolant mix, oil coolers, synth oil, hoses, caps, ...). On the track in the high desert at 110F with two drivers, it overheats. It gets hot (225F or so) and then just won't come down, even with lots of light driving to cool it off. It boils over when I stop if it gets that hot. This seems like it might be due to some localized boiling in spots that just get hotter since they aren't being cooled very well by the coolant anymore. I'm going to try the NPG+ stuff since it seems like it would get rid of this "point of no return" on my car. I don't want to run it much hotter than that (225F), but it would be nice if I could cool it down with some easy laps if it does start to get too hot. We'll see how it turns out, but I'm optimistic that the NPG+ will at least allow me to avoid boil-overs. I am hoping that it will even run cooler under the same conditions.

-Max

I've tried the evans and it runs hotter. Evans to me smells and feels like some type of oil. The only time I had no return problems was an engine with bad seals. Something else could be wrong if the temps don't come back down from 225f after slow driving or short shifting. I've seen temps of 122c and they always came back down. The best cooling device for a track car is a front bumper with big openings (think mazda speed style) and nice duct work. Seriously I've driven atleast 7 different fd's on the track and nothing works better than big openings in the front bumper its really that simple. Evans, IMO is basically like running straight coolant with a higher boiling point, there is no majic bullet and if the temps are going higher you have less power. I've heard people say the evans actually works better at higher temps than traditional water/coolant mix but imo that wasn't the case if your car is running hot its loosing power. Apparently evans absorbs the heat from the metal keeping it cooler than the coolant running through it. This may be true but I felt my car was running hotter with less pull. Anyway its expensive, you have to always have it with you, the car runs hotter, etc...not worth the hassle, and I question the actual benefit. Finally if it was truly that good more people would be using it other than us turbo charged rotary guys who will try anything available to keep the engine cool.

Good luck with the switch and I will be waiting for your feedback because I only used it for 2 track days before my engine blew (bad seals in the rear rotor on a recent rebuild basically everything caved).

You might want to try drilling your thermostat for increased flow. The theory is that the stock thermostat is overly restrictive. I have 2 holes drilled in the perimeter of the thermostat, some have drilled as many as 5. Note that for street driving and in cooler weather your car may actually run too cool and never get up to proper operating temps.

Mark

If the above posts have not answered this there are a few more things.

Evans has much less surface tension of water and that combined with it's very high boiling point make it more efficient at cooling your engine. When water boils it forms a gas pocket due to its greater surface tension. Gas pockets do not cool the engine and actually prevent contact between the coolant (water mix) and the metal surface. This becomes a cycle as the hot spot continues to get hotter and/or grow and further prevents contact between the coolant mixture and surface of the metal. Evans maintains this contact due to its lower surface tension and higher boiling point. Hot spots etc. like that occur under extreme conditions such as racing and not under normal driving conditions like cruising down to the grocery store.

As for hotter overall running temperatures, that is misleading. Whereas in most cases with NPG+ this would be true, think about where you take your coolant temps from. At the water pump housing for example after the coolant has left the engine full of 'hot spots' that ordinary coolant cannot cool. Hot spots lead to power loss, detonation, premature wear on parts, scaling/rust build up. It is typical that it will run hotter at the t-stat but the internal passages within the engine are more uniformly and efficiently cooled, prolonging engine life, less power loss when compared to equal and even lower operating temps of a coolant mixture.

Running around with 220' temps under track conditions with NPG+ is just fine and you should not be experiencing any power losses. Also, as Blake (I think) had mentioned, the whole system runs at much less psi which is beneficial for obvious reasons, especially with rotaries. Even non-rotary engines that see harsh conditions benefit from this and that aling with the other benefits mentioned is why many race teams use it.

I'd go with experience and testing with actual data than a feeling any day.

if this were true why wouldn't all the race teams use it?

A great many do. However, don't think of it as a "better" or "worse" argument. Engine cooling is about keeping temps in control. Racing is not nearly as hard on engines, thermally, as many would suspect. Going fast means there is a lot of airflow through the radiator. Race cars are also typically well engineered, with big radiator duct openings, oversized radiators, and -- most importantly -- a lot of preventive maintenance and testing. If the car was engineered and built to run all-out on the track using water as coolant, then there is no pressing need for Evans. But for cars cursed with hot-running engines, stressing limits of the the coolant, Evans is worth its weight in gold by keeping the hot spots in check and preventing a potentially disasterous runaway condition.

I actually believe Evans is more beneficial on the street than the track, because of all the stop-and-go driving, hot shutdowns, and such.

I can only assume why. Maybe they don't see the need to as they don't have conditions that would warrant it's use. It is much more expensive and the convienence of topping of with water when needed on the spot is a plus. It's use certainly won't give you extra ponies like chrome plating would, but will provide one less thing to worry about because of the higher boiling point and better cooling capabilities. Even a small sense of assurance is invaluable to some. Kind of like safety wiring things....

Hot shut downs...good point...never thought of that one, especially after tearing down to the grocery store ;)