Jack

iTrader: (2)

Just got back from Watkins Glen, PFC water temps went 129C (264F). Spoke to Evans and was told this is the high "normal side" for their coolant. also found high way temps to run between 100C to 110C. For you track guys, what temps do you see.
My mods include:
Mazda Comp Radiator
Crooked Willow Double Oil Coolers
Under Drive Pulleys
Vented Hood

Should I replace the stock water pump pulley to speed up coolant flow and gut the thermostat?

Should I pull out my AC Condensor?

Any insight would be helpful.

pomanferrari

iTrader: (1)

The CWC Double coolers should help tremendously. However, what you gave you took with the Under Drive Pulley, in my uninformed opinion.

Because of the higher flow requirement of NPG, I would think that drilling a few 1/4" to 1/2" holes on the periphery of the thermostat would help.

I wouldn't gut the t-stat though. Not a good idea as the t-stat operates, in a conventional cooling system, as a restrictor in the system so as to prevent hot spots by coolant not staying in the block long enough. However, I don't know with NPG+. You could always be the first to try.

What's your oil temp reading? Non-synthetic breaks down around 250+ F.

KevinK2

agree with standard water pump speed. also, the mazda comp rad has less frontal area vs stock, and is only about a 25% improvement. for the track, fluidyne is better choice. be sure rad is fully sealed all around, so mouth air must pass thru it (and smic).

t-stat may need more frequent changes, with higher heat. make sure fully open in boiling water test. Best not to gut it, if u can avoid it.

Jack

iTrader: (2)

Thank you for the info gentleman

Jack

BigRed

please tell me that evans doesn't run that high normally.

I was thinking about using it. but right now 87c is my average running temp. with my koyo alumninum radiator.

if I did the swap, would I be looking at temps above 100c on a regular basis?

I've got an R1 with a koyo alumium radiator.

Jedon

I am running a Koyo and NPG+ but still breaking in my engine so I can't boost or go over 4K rpm. I see high temps unless I kick the fans on with the AC at level 2 trick. I'm scared to let it get too hot so when the temps hit about 100c I turn the fans on and it drops temps down to 78c!! I do not have my bottom engine shroud or ducting on so that might be why the fans help so much.
-Jedon

Lunar7

I recently switched to Evans with a Fluidyne.

My temps were high at first, min 195 on the highway and 240+ within 1 lap at Willow Springs. My stock AST also began to leak. So I am glad I had Evans or the leak could have lead to boiling with standard coolant.

Then I replaced the stock thermostat and installed a Petit AST with a 7psi cap. (Evans claims it's better to have slight pressure 5-7psi than 0 pressure.)

Now my min cruising temps are just under 180 and it takes me about 3 laps at Willow Springs in 106 degree weather to hit 250 degrees. I was able to keep running for a few more laps, as that temp is completely safe for Evans.

Evans does require higher flow rates since it absorbs heat faster. Therefore an aging thermostat can cause temps to rise. That is probably what my problem was initially.

Currently, my normal cruising temps are 180 to 200, even now, in the summer. My car typically sees the 180 temps under light cruising as long as I am not boosting/loading the engine too much.

Rob at Pineapple racing said Evans should run at the partial thermostat opening temp (180) and only climb when boosting/loading the engine hard and could climb as high as 260++ (but only on a track). Upon returning to low load, cruising conditions it will recover quickly to normal, thermostat fully open, temperature (200). Then it will slowly drop back to min temp.

That is exactly what I am seeing.
Evans is great stuff.

7-sins

Lunar7, what thermo did you switch too? the Miata one? and can you find the 7 psi cap at any auto parts store?

Jedon, You probably want to get that engine shroud, I ran w/o it and w/ it noticed a 20º drop from w/o.

Thanks for all this great info guys, I am trying to put evans in my car and it's good to know this before.

RX7Elmo

i'm new to this so..

i don't understand why the evans would be good besides it doesnt' boil until very very high temps. I thought the point of coolant is to keep the motor cool, so isn't the lower the temperature the better? so why upgrade to a coolant that runs hotter? wont taht create more stress on motor parts especially the oil?

Just a bit confused. Thanks for any clarificiation.

Danny

93 R1

Is it safe to run it up to 240'-260'

KevinK2

For street use, the no/low pressure evans makes coolant leaks less likely, and offers improved reliability in this regard.

For track use, sustained power, better to have evans at 250F than to have 50/50 with uncontrolled localized boiling in the ports, with gauge rising toward 250F.

Oil will be hotter with evans, so proper cooling and viscosity is important, esp at track.

evans has very high bp vs 50/50, but lower heat transfer props. at track, once t-stat is wide open, u will have higher coolant, metal, and oil temps, vs 50/50, for same moderate power level. but where 50/50 will 'hit the hp wall' at some point and temp will rise quick, the evans will not see that wall, but will continue to get very hot.

50/50 can work at the track with carefully setup system, and metal/oil temps will be lower vs evans, but 50/50 glycol is very dependent on pressure being right, all the time.

Lunar7

I replaced my 50K stock thermostat with a new stock FD thermostat.
My old one may not have been opening as early or as much and could have been reducing flow enough to cause higher temps with Evans.


The Evans actually cools very similarly to standard coolant.
My temps with Evans are comparable to the temps seen when using standard coolant.

If you use the stock guage as a refrence for the temperatures that Mazda considered dangerous:
the top of the normal range on a stock guage is 250 deg and the "RED" is at 260 deg.
These are the temps where the standard coolant will boil and loose it's cooling ability, which will then cause the actual metal temps of the housings to get much hotter than the boiling coolant.
The housings will then warp and expose the coolant seals to combustion heat which destroys them.

If the coolant can keep doing its job (cooling) at elevated temps (260+) then the housings can be kept below the temperature at which they will warp.
I don't know the temp at which the housings will warp but Ron at Pineapple Racing says he has run Rotaries up to 280 with Evans and the engines are fine.

You will probably never see 250+ unless you are at the track on a hot day or you have a serious cooling system failure.
If it's the latter you should use sound judgment and shut your engine down and check things out.
If you are on the track then those temps are expected.
You need to be sure temps are stable and quickly drop when you get off the throttle, in which case you should be ok to 260.

Under extreme conditions either coolant is going to heat up.
Only the Evans will keep working and not boil.
That is the main reason why it is better.
Low pressure and lack of corrosion are also extra benifits.

All this info was relayed to me by:

Rob at Pineapple Racing
http://www.pineappleracing.com/Contact.html

and

Dave at Evans
Tech Support Line: 610 323 3114
Toll Free Sales: 888 990 2665
http://www.evanscooling.com/index2.html

You may want to give these guys a call, they are both very knowledgable and can give you all the info.

RX7Elmo

thanks for the info, it helped out my understanding a lot.

now only if the evans could operate normally at around 200 and still be able to function wel at say 280 as well. best of both worlds

danny

Lunar7

My experience with evans is that it does normally operate at around 200. My coolant temps are usually between 180-200. This is in the summer with the AC on. The only time I see temps rise above this is during or just after hard acceleration or climbing a steep grade. If the engine gets heat soaked due to extend loads then it may run at 210-220 for a while untill it gets a chance to cool down with low load driving.

There are so many other factors that control coolant temps under "normal driving" conditions.
The bigest factor is fan speed due to:
parking/head lights on, blower set on 3 or 4, AC on, fan mod.

Under normal driving conditions coolant temps will be maintained by the fans. The above conditions will turn fans on constant or by 200 degrees. Therefore in this case your Evans will run at 200 degrees and under.

With none of those conditions present the ECU will turn fans on at 220. This rarely happens since in this last case the car only needs to be kept moving with low load to keep temps well below 220 without the fans needing to come on. So aside from the fans, ambient temps, car speed and load determine how cool the Evans stays.

In my case I can clearly see that the electric fans are controling coolant temps very efectively when natural airflow is not adequate. Because of this, I really don't believe there is any real significant difference in coolant temps between regular coolant and Evans under normal driving conditions. If I can see 180-200 in the hot sumer doing 80+ in 5th with the AC on then how can you say Evans runs too hot?

However, under extended load/boost, temps do climb fast (220+). Yet, that is when Evans will offer the most protection compared to standard coolant. Standard coolant will get just as hot, but may take slightly longer. Keep in mind, however, that standard coolant will micro boil at those elevated temps.

I don't think you will find a single Evans user on this board who would switch back to conventional coolant after using Evans.

7-sins,

I forgot to mention that you can get a full size 7psi cap at any auto parts store. You will need an after-market AST that uses a full size cap because the stock AST takes a small cap which is only available in 0, 13 & 16 psi.

turbojeff

iTrader: (30)

So at what point do the rubber o-rings start to experience damage? 260 is OK?

Jeff

Lunar7

It would be very hard to speculate that a particular coolant temperature will cause damage to the water seals.

However, warped housings that allow direct exposure to 1500+ deg exhaust gasses will instantly destroy the water seals. In a car with conventional coolant this will occour at 260 deg when the coolant reaches its boiling point.

It is the warping of the housings caused by boiling coolant and not the temperature of the coolant that destroys the water seals. Therefore raising the boiling point of the coolant reduces the chances of warping the housings and alows the engine to operate safely at higher temps without damage to the water seals.

Please don't take this as an endorsment for running your engine at 260+ deg. It just means you can do it when necessary and still have an engine, if you are running Evans (and synthetic oil as well).

If you get a chance to talk to Rob at Pineapple racing he can shed more light on the subject of running with Evans at 260+. He considers it "no big deal".

Just keep in mind that elevated temps with Evans under light load driving are not normal.
If you can sustain a min highway cruising temp of 180-190 in summer weather with Evans then your cooling system is in good shape.
If not, it may mean that your cooling system requires additional upgrades/repairs.

SPOautos

The reason Evens get so hot is because its doing its job better. It naturally runs hotter than regular coolant cause it absorbs more heat out of the motor. If the Evens wasnt absorbing that heat it would still be in the metal of the motor. That basically hot coolant works, your motor has heat built up in it and the coolant absorbes that heat. The Evens can absorb more heat and also absorb it faster which makes for higher coolant readings but a safer motor.

STEPHEN

RX7Elmo

I understand now that 'normal' use of evans has it around 200 degrees, but under hard/track conditions you can see 250+ easy. Does this mean you must use synthetic oil with the evans? Or are there dino brands that an hold up to the temp? how about a blend?

And yes, the argument makes sense that if the coolant is hotter, the motor isn't.

danny

pomanferrari

iTrader: (1)

As to high oil temp: This is why, when I put my new motor in, I'm installing the dual CWC oil cooler, a separate 2-stroke oil tank, the PCV Technology Oil Metering Pump adapter and Evans NPG+. This way, I can run Mobil 1 synthetic in the engine and not worry about whether synthetic will burn or not burn. I don't care to find out either.

As to high coolant temp reading: yes. hot rodders run pure water to get the greater heat transfer. However, their temp gauge reads higher.