olddragger

iTrader: (3)

it is my understanding that in reference to temperature only Evans does run hotter than other engine coolants. It has less heat carring capacity. But, there is more to it than that.
Evans prevents run a way temps. No local vapor will occur. The Evans will always be removing heat no matter what the engines temps are. This is unlike normal type cooling in which at a certain temp the coolant will start to have a localized vapor which will prevent much heat exchange between the metal and coolant.
Evans also doesnt require any pressure in the system to work. This can be advantageous in some cases or of no concern in others. Thats my laymans understanding of it anyway.

Actually increasing the engine normal operating temperture ( and its ability to tolerate) will make the engine more efficent.
Like all other stuff--its a balance and there are limits. I have heard of recip engines at the track that run Evans ( when rules allow) having a coolant temp of 250-260F! Insane! Of course they are also using synthetic oil
I understand that when using Evans in our car a coolant tempt of 210-220F is quite normal.
I am thiking of converting myself.
Fan control ( both on at the same time--slow or fast) + EWP with computer control ( no bypass, no thermostat) is the best system i can think off. Even BMW has a secondary EWP for these type of situations.
My exhaust in slow traffic on a 104F day got the o2 sensor so hot--it wasnt working right. True story.

999miki

So what will happen if the coolant temperature is higher? Internal temperatures will be even higher for same deltaT. Apex seals will be very thankful

Not in well designed pressurized system. So the point is moot.

This has been proved as false. Peak combustion temperature is huge and change in deltaT from higher coolant/surface temperature is minuscule. Actual efficiency gain occurred due to better fuel vaporization as intake manifold was also warmer.

Lets take it even further, there has been research adiabatic rotary engine, no coolant at all, efficiency went up maybe by 1% and most of the heat that would normally go to the coolant went into the exhaust, do you really want even higher EGT's?

HiFlite999

iTrader: (2)

^ do you have a reference for that test?

longpath

iTrader: (1)

I'd been driving at highway speeds for over three hours straight until we reached our motel. As I mentioned, my daughter was asleep, so with the car at a standstill in the parking lot, while my wife checked us in (she'd made the reservations), I was having to run the AC full blast with ambient temperatures of at least 40C (higher if I recall correctly). I'd been watching the temperature climb to about 104C (220F) but figured it would drop back down once we got underway again. Instead, we got stuck in stop and go traffic which made it considerably worse.

To answer your question, I observed that Evans NPG+ generally runs about 3C (5F) warmer than water-based coolant due to it being more viscous than water-based coolants; but nothing like what I saw that day. I do not know, at this point, whether the problem is:
1. inadequate coolant flow at low engine speeds (3K and lower)
2. insufficient air flow at low chassis speeds
3. 1&2 combined

I intend to open the oil cooler vents shortly (got a lovely Dremel for Christmas) and relocate the front plate to low on the left side (quasi-EVO style) to clear airway for the radiator.

As a matter of last resort, I am also considering switching to an AEM intake and relocating the battery out of the engine bay in order free up air flow behind the radiator.

dannobre

iTrader: (3)

As a FYI....I haven't seen ANY elevated temps with the Evans coolant at all. The temp is very stable at the thermostat opening temp...and basically doesn't change at all with load. I found that the temp will vary with different thermostats ...I have one that is 3 degrees cooler than the other...both OEM

The electric water pump works well....I have it hooked to my turbo timer so it will run for a period of time after I shut the car off...

TeamRX8

iTrader: (25)

the extended rpm range of a rotary engine makes this very difficult to achieve i.e proper flow at idle vs max rpm. Simply tying in a mechanical pump to operate based on a linear RPM scalar alone won't and can't address this. The demands of the system are not linear. An electric water pump let's you have your cake and eat it too. A properly designed electric pump is no less prone to failure than any other mechanical device. Pump seals fail, belts break, bearings wear out. It all happens eventually. Who has a mechanical fuel pump any more?

I don't want to get into bashing anyone's merchandise, but IMO there are a lot of products on this forum that are excessively overhyped and overplayed that do little to nothing as compared to the all the advice members here dish out over them.

bse50

You're right saying that an electric water pump can be more efficient overall but I still don't feel the need for one. It's true that my engine bay is fairly empty and there's a nice flow across the radiator so that may play a factor in my case.
Talking about "anyone's merchandise", Mazmart's water pump is not one of the products you mention. I have been running that water pump for years now and the temperatures are more stable, especially when running at high rpms.
To sum my opinion up: An electric water pump is a cool gizmo that is useless on a street car with basic cooling mods and may be interesting for a track setup. May or may not actually, depending on the real cooling needs.

TeamRX8

iTrader: (25)

I didn't specifically mention any merchandise so you are not in the position to state what I am or am not referring to

in general my experience doesn't agree with much of what you post, but feel free to believe whatever you want

bse50

It's the only upgraded water pump sold right now, i thought you were referencing that.
Your experience vs my beliefs? How about your experience vs mine? Running in parking lots doesn't make you the keeper of the absolute truth just like road racing doesn't do that for me.

Spin9k

Which pump is that?

olddragger

iTrader: (3)

I believe dan is running the davis craig pump? I may be wrong?
So Dan--you continued to run a thermostat? I was thinking that one of the benefits of the ewp was the ability to not run a thermostat?
Guys this is just another option, depending on what your particular needs are. I do think it has lots of benefits over the mechanical--mainly increased flow in the lower rpms and its ability to prevent shutdown boilover. Team nailed it in saying we have a huge rpm band and no mechanical pump can be expected to be perfect under those conditions.
A coolant system is dependant on flow. Both the coolant and the air over the radiator. Its not a simple system. Our current system is a combination of mechanical valves, bypass channels, pump and electronic fan controls. They are all interrelated and have overlapping responsibility. The EWP/controller can simplify the system a little in that you would no longer need the by pass or the thermostat. Quicker warm ups, less temperature functuations in traffic ( fans on and off), better cool down on shut off are benefits also that come to mind.
One other thing I have read about is high rpm mechanical pump cavitation due to the lost of coolant viscosity. This is something that Evans coolant research papers speak off. It seems to me that the EWP would be less likely to experience this as it's rpms are not as high as the mechanical when the engine is at high rpm.
Its time for me to explore this a little further--me thinks.

VICEdOUT

iTrader: (1)

A cool gizmo an EWP would be yes but not useless, even if the gain is only like 1 HP more or 1 MPG more, it would benefit itself, on top of other mentioned advantages..

http://www.daviescraig.com.au/Electr...5-details.aspx

And this Davies and Craig water pump seems to be my choice when I do this swap, but really around 21.13333 GPM that pump can push can be beat by a Meziere more expensive pump.. But around $200 for that cool Turbo looking D&C pump and another $200 for the plate is not "Too expensive" of a mod that will eventually pay itself off with gas mileage..

HiFlite999

iTrader: (2)

It would be made more efficient when paired with Mazda's upcoming capacitor storage system which charges on decel. Up to the limit of the charge capacity, the running of the EWP then becomes mostly free in city traffic.

VICEdOUT

iTrader: (1)

Ohh sounds cool very similar technology to the KERS system in F1 cars...

999miki

Yes, somewhere I must find it.

Generally, at sea level and low altitudes, higher water jacket temperature does decrease friction horsepower and of course promotes fuel evaporation which is good for overall efficiency, but it also hurts volumetric efficiency so the net BHP is lower.

Decrease in friction horsepower is dependent on lubricant properties itself and in the end of the day, we are talking about magnitude around 1% with 50°C delta, so friction change can be neglected.

Only what remains is VE and fuel evaporation. Cooler engine will ingest more air mass so this is straightforward. And fuel evaporation can be optimized by higher fuel temperature and injection pressure.

Here are some references discussing same subject http://not2fast.com/NACA/naca-tn-476.pdf

http://www.scribd.com/doc/40610101/T...-Harry-Ricardo Chapter III, DISTRIBUTION OF HEAT IN A HIGH-SPEED FOUR-CYCLE ENGINE

Spin9k

I'd appreciate hearing from Dan about some of his experiences like...

- any pic of how/where you have mounted the pump?
- is your application replacing or adding to the mechanical?
- what temp control to you use, if any, of the suggested choices?
- did you do any before/after HP measurments esp. at high RPM as Craig mentions?
- any subjective comments before/after?
- ease of install/setup/use?

Thanx

longpath

iTrader: (1)

Do you use the OEM coolant gauge or something more precise? The 5F/3C increase I saw was measured with a Scangauge II while the engine was at idle, once it came up to operating temperature; but the OEM gauge wasn't precise enough to show a difference that small. I'm asking, not because I doubt your experience but because I want to make sure I am making an appropriate comparison.

Also, which Evans coolant are you using, NPG, NPG+, or NPGR? I'm using NPG+, at the recommendation of Evans; but I am thinking about switching to NPGR because of its lower viscosity.

dannobre

iTrader: (3)

I will try and get some pictures up later

Also...was using NPG-R...but will be going to NPC+C next week...as they have discontinued the other 2 racing coolants for just this one

olddragger

iTrader: (3)

thanks Dan. Good info. So running with a thermostat and by pass intact +Evans. Sweet---simple and efficient obviously.
Have yall seen the mezerine single intake double output remote mount pump?
http://www.meziere.com/ps-1150-1118-wp337s.aspx

VICEdOUT

iTrader: (1)

Got my EWP Plate in... (Thank you Scott) from http://www.rx8performance.com/produc...ric-water-pump





I'll post more pictures of the EWP on this thread when I get the water pump itself and hoses and finally mount it in the STARX8.

For updates on MY custom build, click on the link below and follow the progress on my Picasa Web Album. =D

200.mph

iTrader: (9)

i was wondering what happened to that build. update

slvrstreak

iTrader: (3)

awaiting updates

VICEdOUT

iTrader: (1)

olddragger

iTrader: (3)

very nice--using the merizne pump? One hint--- use a restrictor in the heater hose.
You will not be running the coolant bypass---right? The thermostat housing can be modified to accept a GM barrel type thermostat which will allow increase flow at a lower head pressure.

slvrstreak

iTrader: (3)

elaborate on the "restrictor" part
how did that work out for you?