*Split* Engine coolant temperature and optimum working condition on track

Split from the "Winged Sumps" discussion...

Carry on lads

 

Carry on... gulp, pressure to make it worth while

The thermostat may open quicker, but because the radiator transfers its heat faster the saturation point (where temperature cannot be expelled by the system) is not reached so running temp are still lower, but never lower than the thermostat

 

Yeah, my post wasn't actually an endorsement of the stuff, nor a suggestion that it's a good idea to use it on track. I was just pointing out the contradictions in their own publicity.
They do kinda naturally arise from the fact (if it is a fact) that if you take more heat out of the engine, by improved transfer at the alloy/coolant interface or whatever, the result seems to me inevitably that the coolant will end up hotter (edit: if measured on the way out of the head). This might give the impression that the overall engine cooling was worse, maybe falsely.

Tricky to describe without sounding contradictory to be honest.

I don't think it's necessarily useful to just try to 'lower coolant temperature' without due consideration to where in the loop(s) that's being measured. After all, it's heat transfer into the air, from the radiator, that is the ultimate goal, and the hotter the rad, the easier that is, all other things being equal.

 

I was under the impression that`s too cold ?

My 16VT was running between 68 and 72 at a cold Brands last year, I felt that was too cold and after some searching, I couldn`t find any evidence where such a cool water temp was beneficial, most suggested it was TOO cool.

I don`t have a water > oil heat exchanger, so I`m just talking about water temps here.


If we had the option to pick the ideal operating temperature for the water, what would be the target ? 70, 90 ?

 

Probably too cold for economy running
You may have noticed manufactures now get the car straight to 85-90 and hold it there for emissions and all that, the new generation small TFSI motors even have the turbo manifold cast in the head so they can get the temps exactly right really quickly

For race and maximum power that is fine, more important is the oil, should be minimum around 90, max 110

 

Er..

Fast warm up means less friction and better fuel economy (CO2).
Also in very cold climates at sub 0, there is a requirement to get the heater in the car going as fast as possible.
Very little effect on gaseous emissions or exhaust aftertreatment.

The integral exhaust manifold is pretty much a standard feature on many modern direct injection engines. It allows more heat energy to be transferred to the catalyst and turbo if fitted as well remove the requirement to over fuel at high loads and high rpm.
More a cost save and FE action.

Coming back the engine coolant, in some modern engines with the above technology, you can control the coolant temperature with an ECU controlled thermostat instead to the conventional wax stat.

You can increase the enthalpy of coolant, using different chemicals but you still need to control the mass of chilled coolant flowing into the hot engine via the thermostat. The radiator just increases the surface area to reject heat from the mass flow of coolant.

 

F3 and KC engines run at ca 70C ( exit cylinderhead)
on a N.A engine above 70C there is power loss.

 

Toyo, what happens when a car is on warm up... enrichment. CO2 from that, also not getting the Cat up to temp means NOX.[/QUOTE]
I agree that getting out of the cold running ASAP is important, as Emissions and fitting in with the standardised fuel usage cycle is hardly incidental. after all without that need we wouldn't have stop start or 7+ speed transmissions[/QUOTE]
But that is not just about the driver. The customer in the car is only part of that, new cars will stop start then the HVAC goes into slow mode, even if the selected temp hasn't been reached, fans slow and the heat/cold just goes in to maintenance,
Pretty sure the moulded to head was only released by VW last year with the EA211 on
I use a Brown Davis electric water pump on my race car, switched by the ECU, Ill take a photo and post it up. I seem to remember BMW are now beginning to do it on the road cars

Back to the question at hand
For performance, run your water cold and your oil hot!


I would say run your coolant temp at a threshold that does not increase engine friction ( this temperature can vary).
Keep the mass flow of the coolant regulated by the thermostat at an 'optimum' to absorb the engine's excess heat before rejecting to the radiator. (not sure that was the most accurate stab but if they are any cooling systems engineers please put me right)

 

BMW use electric WP since years:

http://www.clubgti.com/showthread.php?267062-Electric-water-pumps&highlight=electic+waterpumps

 

Warm-enrichment is calibratable feature based on coolant and ambient temperature engine load etc. This is a compensation related to the extra drag on the engine when cold started and manifold or cylinder walls helpful in vaporising the fuel injected. This has an effect on fuel economy or CO2 but a small impact on the emissions on a drive cycle. So having a fast warm up reduces CO2 which is directly related to fuel economy as well as reducing friction.
Switching the catalyst on is critical to starting the maximum conversion of tailpipe HCs, NMHCs, CO and NOx. Unfortunately you tend to take a large FE hit for switching on this legal requirement. This usually not dependant on engine warm up but on start temperature. So the faster you get the cat lit off, the better for FE and tailpipe emissions over a drive cycle.

Emissions reduction and fuel economy are two separate features. Engine warm up tends to play a minor part in catalyst TP conversion. FE hit yes. As manufacturers are legislated to have low CO2/FE fleet averages, you get 8 speed gearboxes, start stop, regenerative charging, underbody aero, VVT, Direct injection, spilt cooling systems, electronic thermostats, pwm cooling fans, low CO2 tyres low friction oil, integrated exhaust manifolds, Inlet manifold Water to Air Charge Coolers and so on.
Most of it is FE driven.

Water Pumps driving off the FEAD or cam belt introduce drag and are a paratic loss. This of course for an OE mean an addition FE hit so does not surprise me what you have seen on the BMW.

I would say run your coolant temp at a threshold that does not increase engine friction ( this temperature can vary).
Keep the mass flow of the coolant regulated by the thermostat at an 'optimum' to absorb the engine's excess heat before rejecting to the radiator. (not sure that was the most accurate stab but if they are any cooling systems engineers please put me right)

 

I think you are arguing in agreement


Here it is, works well, set for 68 degC

 

If I did come across as argumentative, I do apologise. Only expanding on your points. Emissions and Fuel economy form part of my day job

The crossmember running from front to under the gearbox and the clutch actuation, look very japanese in this picture. So I must ask what car/engine is the E-water pump fitted to?

 

ideal target temps for sr8 for racing from radical are water 80, oil 60, but 70/70 is also fine.

 

HPR: Would you be kind enough to explain, for the benefit of those of us who lack your knowledge and experience, what mechanisms are responsible for such power loss, please?
And the fact that you mention NA engines, does that mean there's less loss for FI engines at higher temps?
Any guidance would be appreciated.

 

Long ago Mr Siegfried Spiess told me...above 70 C there is power loss ( Spiess Tuning)
This is certainly true for VW engines, altough other engines might tolerate higher temperatures
( This apply for race engines and i would not advice it on normal road car engines )

By keeping water temp down there is less radiant heat from block and cylinderhead, as you want your engine to breath as cool inlet air as possible, certainly in N.A engines where every little extra count.

In general you want / need to keep temperatures down.... also under-bonnet temp.
so you want to make sure hot air from radiator, oilcooler, exhaust, etc can escape or atleast get isolated from the inlet system and fuel system

There is also something as a micro layer that start to exist between the water and the metal of the engine in the cooling system...hence water wetter,Evans, etc



And you want power output that is solid and not drops off under load at the end of a long straight, its there that you need top end power (as everything gets extremely hot)


In a Turbo engine its possibly less critical as your inlet air is cooled anyway by an Intercooler and possible losses are
compensated by a little extra boost....but the basics of good cooling must be there,but that will be different discusion ..
Ive seen powerfull cars that die on power the longer the staight....

 

Didn't mean it as a negative connotation

Yes, Japan it is, current car is a a GE chassis Ford Telstar (Mazda 626) 2.5 litre V6, does alright in class, mainly E30 325i, few E36 M3, (fortunately the E30 was never sold here, they would kill it) Few Audi 80 Quattro 2.8

New build for 2016 will be this:

Fitted with this:


CBZ which I will run in the under 2 litre class
(1197 x 1.7 for turbo) lucky we have a 2% over bore tolerance so 2 litre is actually 2040 cc effective. Turbo is free, so I am looking at something like a GTX2860 with some expensive MoTeC M1 using the FSI and a second set external injectors. Key will be keeping it light and having a torque to weight that should kill the K20 powered Honda guys

Lot of work coming, whole lot of work...

 

Ah. I remember them and the engine was also shared with the MX6. Having worked on quite a few Japanese engines, both JDM and Export for that era and earlier, I recall them running at 70-80 coolant temperature. EU production cars by contrast ran at least ten degrees hotter!

That is different. Very refreshing that you are willing to take up such a challenge!

I did a study on that engine as fitted to a Golf MK6 TSI 'Bluemotion'. All part of aggressively downsizing and fuel economy driven. This EA111 1.2 motor replaced the EA113 1.6 PFI engine. With 105bhp and up to 150lbft it had more go than the NASP 1.6. However the key to it being fitted in a Bluemotion chassis was, low friction and new technologies such as direct injection, integrated water to air charger cooler and electric wastegate activation. The internal parts are quite cost cut in that motor to making it cheap to produce and feasible as a powerplant for the Polo Bluemotion.

I would definitely be interested how you set this up to be competitive. Perhaps you should start a build thread. Also look into the Life Racing F88 ECUs. They are fully capable of running any direct injection engine and are used on Ford Formulas (1.6 direct injection) and the Radical SR3-Street Legal (2.0 direct injection turbo).

We digress from Coolant ...

 

I hope it isn't too much of a challenge...
This older style I believe it is an EA113, should be a bit stronger than the brand new (14) EA211's, (I thought the EA111 was the 3 cyl) But it is all guess work, has steel crank and hyperutechtic (SP) pistons, rods are a question mark
As you say - that is for another thread!

When you think about he euro JDM changes, the conditions in Japan (where it snows and also gets to 34 with 90% humidity) compared to central Spain's 45 dC can't just be about climate. I think the OEM one for my car was 78dC (using the old boiling water in a glass test), my wife has a new Benz and that runs just under 90, (good thing Mercedes still use real gauges not those non linear things)

I chose my running temp on a couple of things, not all scientific, I looked at what was in the motorsport thermostat from a number of manufactures and called on the experience of a couple of racers I know who are the real "Engineering type"
I also based it on being a race car I knew it was going to warm up properly before it was subject to abuse, not just a superficial amount of heat then driving straight away but a good heat soak making the temps constant through the whole system

 

The 'Export' 626, Telstar, 323 and Laser, in fact many Japanese powertrains of that era and older, sold outside of the home market, ran at similar coolant temps as you described.

I can split this off as the beginnings of your own build thread if you wish.

 

Thats pretty interesting Rob, I'd always thought/been told that the oil needs to be above 100 degrees to get rid of moisture etc? - Coming from Radical must be some science being it! Maybe the oil viscosity being super thin? - In keeping with the finer tolerances of the engine maybe!? Anymore infl on that?

Henry