MIAPLAYA

iTrader: (3)

I'm assuming all even the ARC radiator use a tube and fin core? Someone correct me if I'm wrong on that. I'd like to see what could be done with a bar and plate core radiator. Its already been proven superior in both air to air and air to water intercooler cores to use a bar and plate design but aside from the brief run of Spearco radiators I don't see any radiator manufactureres using the same design.

Q45tech

Nissan and most manufacturers utilize the test facilities near Phoenix to prove the suitability of oem designs at 120F ambient idling in a 3 sided closed box.

Unfortunately idling an engine only uses 10HP with AC on..............30 times more heat is not the design point.

Scientifically one graphs the time vs coolant temp creating a rising graph which shows the minutes, seconds of reserve capacity.

If you test a brand new cooling system vs progressively older system you will see the decline as the fins bend , the rubber surround seals change and blockages build up between condenser and radiator...........electric fan speeds decline with age.

Same thing with AC reserve every year it declines some long before you finally notice it.

Really difficult to improve oem MUCH without more radiator area........the best way is to increase coolant capacity thru redesign.......inline surge tanks.

Since a radiator only decrease in/out temp by 20F [at best] a 10% improvement might be 1.5-2F drop in coolant temperature.

http://delphi.com/pdf/techpapers/2000-01-0579.pdf

doug

iTrader: (5)

for the price of the ARC i will have a monkey sit in my engine and with a chinese style fan

Old School

iTrader: (28)

hermphradites FTW!

doug

iTrader: (5)

your imagination scares me

Q45tech

Spent a moment to calculate the BTU equivalent of 300HP [12,000 x 300= 3.6 Million BTU and segment it into exhaust, block to air radiation, and the 33% that the radiator must transfer to/from the 20 pounds of water/coolant.


http://www.arrowheadradiator.com/14_...utomobiles.htm

Wraith

holy crap thats some technicall high tech sh*T i think the ARC will be the best bet but damn thats some expensive sh%*T.

Thanks for the info guys.

Q45tech

some technicall high tech sh*T.
Why it drive engineers crazy reading forums...........my radiator is bigger than your radiator............why does it overheat.

Owning and modifying a high performance vehicle requires a high level of study or lots of money to pay for others to study.

r0mey

iTrader: (35)

i have and love the greddy rad

Sharif@Forged

iTrader: (92)

Q45 tech, can you email me when you have a moment, I have something I would like to discuss with you. sharif@forgedperformance.com

Ruthless18x

iTrader: (59)

I have the Greddy and it's 110+ here almost everyday, never had a problem.

rcdash

iTrader: (18)

But you've said before that the main issue is coolant volume. I can't think of any more efficient way to increase volume than a larger radiator. There's just no space for a surge tank - unless it goes back near the rear of the car. Then I would think you have to worry about a water pump that can transport through the added resistance, etc.

EDIT: Did a search and found some aluminum surge tanks out there to add 1-2 QTS of capacity. I wonder how this compares to stock vs. larger radiators. Anyone know what the increased capacity of the Arc or thick Koyo is?

rcdash

iTrader: (18)

Hey that was a neat link (thanks!) but your calculations for 300 hp are way off if you're talking about BTU over any reasonable amount of time (like, say per minute). 300 HP = roughly 12000 BTU/min. Not 3.6 million. This is using the formula in the link you provided:

"This means that heat load to the cooling system at rated power (Usually expressed in BTUs per minute) is approximately equal to the rated power of the engine expressed in BTUs per minute (HP X 42.4 = BTU/minute). "

(I actually come out with a larger number doing all the calculations, but hey it was your link )

Also keep in mind that peak horsepower is generated for a very short amount of time. The average horsepower is a better measure - so a JWT TT 530BB kit puts out 300 hp average (under the curve) during a WOT run. So that number may apply *if* you maintained that level of output for a full minute! You'd being doing well over 200 mph (barring air resistance, electronic and gear limitations of course).

I also disagree with the following stated in the link:

"Water has a higher specific heat than an ethylene glycol or propylene glycol coolant mix. Therefore, it provides the best heat transfer performance in a cooling system".

I guess it depends on how you define "heat transfer performance", but considering that copper has a low specific heat and rubber has a high one, and water is even higher (whereas coolant is lower), I'd say water provides poor heat transfer performance. It has a high capacity to maintain temperature, yes, but heat transfer, no.

UPTOWN

greatest thread i've read on this board thus far. keep it going guys.

Sharif@Forged

iTrader: (92)

We are learning a lot by having the Scientist/MD (Raj) and the Engineer (Q45) discuss this topic. Thanks guys.

rcdash

iTrader: (18)

Ha ha - debating theory is always fun. With the innovate electronics set up in my car, I plan on doing a lot of data logging to provide empircal data to back up (or disprove) such claims. A quick WOT run with a real time graph of coolant temps should do the trick, eh?

Q45tech

Don't focus on coolant temp as the real problem is cylinder head and valve temperature.

The ecu coolant sensor is just a PROXY for what's happening...........cheaper for manufacturers to install.

rcdash

iTrader: (18)

I agree. Cylinder head temp (K type probe), coolant temp, oil temp, transmission temp will all be logged by the innovate gear.

Hydrazine

iTrader: (53)

Please explain what you mean here. I have to ask because water does indeed have a higher specific heat capasity.

I don't know your background RC, but liquid water has nearly 2X the mass specific heat capacity of glycol...

Liquid water has a huge heat transfer advantage in both gravimetric and volumetric heat capacities. And even a radically higher enthalpy of vaporization if it comes down to it.

Liquid water also has a much lower viscocity... and this means the reynolds number for a given flow velocity will be higher with water. Resulting in a less laminar (or more turbulent) flow while in the radiator tubes.

This same low viscocity means water will have a lower pressure drop (or flow resistance) while flowing through a given system. Water will therefore have a higher volumetric and mass flow rate at a given motive pressure.

OTOH - Glycol antifreez is added to water to reduce the freezing point of the mixture to below the lowest temperature that the system is likely to be exposed to, and to inhibit corrosion in cooling systems which often contain a range of electrochemically incompatible metals (aluminum, cast iron, copper, lead solder, etc.). The term 'colligative agent' is to be preferred as, in warm climates, the benefit of these compounds is to increase the boiling point of the coolant, which should then be more properly referred to as 'anti-boil', and as anti-freeze decreases and increases both properties, respectively, 'colligative agent' more accurately describes the liquid.

Glycol also decreases the solubility of gases like O2 and CO2 and lowers the overall vapor pressure. But glycol does not increase heat transfer capacity. In fact, glycol will only decrease the heat transfer capacity of the system.

I've included a couple of links below for reference. The physical and chemical reference data shows pure water as an unusually effective coolant at or near STP.

The unusual properties of water are due to its strongly polar molecular stucture and nuclear resonance modes.

There are many substances in the universe that can be used as a coolant, but there are very, very few that are as effective as water.

When you comprehensively study and compare the various physical properties of substances it is easy to see why water is some very cool stuff.

http://www.engineeringtoolbox.com/et...col-d_146.html
http://en.wikipedia.org/wiki/Specific_heat_capacity