Most people say the 160* thermo is too low,also it will not mean the engine will run cooler with the lower temp thermostat.

Heres the scenario, The be-cool big block radiator kit with elec fan module($1000+) comes with a temp switch that turns the fan on at 195* and turns it off at 175*. If you run a 180* thermostat wouldn't the fan run almost constantly on if not always on.

Just thinkin out loud, any ideas?

Ray

For most all street driven cars the 180* thermostat is preferred.

I too did not like the idea of running the fan all the time. I'm installing the switch in the radiator return tank. That way the fan does not come on until the return coolant is at 185* and will turn off during cold weather.

My fan doesn't run all the time with 180* thermistat. I have my sensor installed in the head and a manual override to ground the relay in case the sensor fails.

From what you said in your post, the fan won't kick on until it gets to 195 degrees...then, it shuts off at 175 degrees...and it won't turn on again until it gets to 195 degrees...so, no, it won't be on all the time. (The way you are thinking, the fan would be on any time the temps are over 175, and that's not the case.)
A 180 T-stat would work just fine. Gets the oil warm enough to burn off contaminents and moisture and ensures good circulation.
If your car is in good tune, you will only see over 195 degrees in traffic on a hot day, or idling for longer periods. Get it out on the open road, and the temps should drop right down.

Thanks guys!

Steve w I know what youre saying about the switch having an on and off temp. but say the engine reached 198* in traffic and fans kick on, they will not kick off till 175*. Will the engine reach 175* if the thermostat closes prior to that at 180*?

Ray

I think you'll find the fan will run most any time you are sitting and idling once the engine comes up to temp. Then most hwy driving it will be off unless the outside air temp really gets up there...

A 180 degree thermostat in conjunction with a fan switch that needs 195/175 (on/off) will run all the time once it starts! So, if you warm up and the fan comes on for ANY reason your stuck with the fan on if the thermostat cycles properly.

The 180 thermostat is the preferred range of operation for both power and longivity. Check out this thread for why. http://performanceunlimited.com/illustrations/thermostats.html

There is a device from Centech Wiring http://www.centechwire.com/catalog/accessories/fc2p.shtml that hooks to your temperature gauge and you can control where it comes on. Yeah...I know it's expensive but worth the non-hassle factor.

Why would Be-Cool sell a $1000+ kit that doesn't work or needs additional parts to work properly?

What thermostat you use is determined mostly by the locall climate of where you live. Here in OR we have a moderate climate and I run a 160* stat all year. Those who live in a colder climate areas should run a 180* in winter and a 160* in summer. The engine should always have a thermostat; for max HP & engine life, a 160* stat, keeping the above statements in mind. graemlins/thumbsup.gif

My Be Cool setup has been on my car for 3 years going on 4 and the fan DOES NOT run all the time. The Spal fan pulls massive amounts of air and works with the 180* to cool the engine down even sitting in traffic.

Hey Dennis, if you are questioning me about my statement about the on/off signalling, it explains itself really.

I am NOT saying that BEcool sells stuff that doesn't work at all, but given if you understand how the system works, how can a fan sensor turn off at 175 if the water jacket stays above 180? It can't. If the sensor is in the radiator located downstream of the thermostat then another story where some cooling will take place and coolant temps could dip below the signalling point.

I have corrected at least four or five systems with this very problem, two of which were Becool I might add. The thermostat will not allow the sensor in the head or intake fall under 180 and the switch will not turn the fan off. If it does, then the signal doesn't represent a 175 degree off point or the thermostat is leaking enough to let the water jacket get lower than the switching point.

There are 170 thermostats out there that work well with this system. In fact 170 is perfect if you think about it.

Since I prefer to run 180 thermostats which are perfect for both longivity and power production, I usually turn the fan on at 195 and off between 180 and 185. This works well for most systems.

Thanks guys! The point I was trying to make is what hotrodsrj is saying. Cut off temp is 175* but my 180* thermo will not allow block temp to reach 175*.

Anyway I'm sure it could be fixed by running a 160* thermo or replacing the thermal switch with one with a higher fan off setting, just wanted to know if anyone ran into this.

Dennis, it is the becool cooling module kit from summit racing part# bci-80168 ( 24" core for 67 -69 camaro up to 700 hp manual trans $1,019)Here is the description per summit:

Vendor: Be Cool, Inc.
Product Line: Be Cool Aluminum Radiator Kits
Material: Aluminum
Finish: Satin

Get a whole new cooling system.

Chevrolet/Pontiac: 1967-69 Camaro/Firebird, standard transmission, satin aluminum radiator package (See Product Guide)

"This BeCool Super Street series power cooling module is designed to cool vehicles with up to 700 dyno rated horsepower. It contains: A BeCool aluminum dual 1 in. core crossflow performance radiator with oval tubes; a dual 11 in. high-torque euro black electric puller fan set with a vented shroud for highway cruising; a complete set of aluminum fan mounting brackets with hardware; a diamond cut, vented coolant recovery tank; a primary fan wiring harness with a 40 amp relay; and a billet BeCool radiator cap. A secondary wiring harness is also included to independently control the second fan. The electric fans in this module are designed to engage at 195 degrees and switch off when the coolant temperature reaches 175 degrees. This provides the ultimate in driver convenience and engine safety.Sold as a kit."

I am considering either the becool kit or ron davis ( they quoted me $944 for radiator and fan module, no switches,wiring,recovery bottle etc....)

Any way thanks for the input guys, Ray

Steve Jack - My question is based on how I would react if I shelled out a grand for a cooling system kit designed to tame the heat of 700 ponies and I got advice that ment spending more money... You know I'm a bit old school in respect to high dollar parts like msd boxes, alum radiators, electric water pumps, expensive serpintine belt and pully systems and even roller rockers.

Mind you I know there are good uses for all I have mentioned, but I see guys with cars that won't make it 10 miles because they don't have the money to put gas in the tank let alone finish their projects and these things are some of the first "COOL" items they buy and install. There are low dollar options available that work just as well that would put the project a lot farther down the road...

I would hope a company like Be-Cool would have a grasp on what they do to a good degree. I think on the avg to stout build the system they sell would drop the temp below the point the fan would turn off or there is a flaw in their system. Steve you've offered testomony to some not doing what was advertised, any thought to why?

My 383 with a 180 stat, re-cored orig type radiator, stock replacement water pump and a cheap fan/clutch will set all day at 175 unless the outside temp goes above 80 degs or I'm romping on it hard. Then all it does is go to the other side of 180 for a bit and then it drops down and the cycle begins over. Again I would expect a system costing almost 3 times what mine did would do as designed and the fan wouldn't run all the time... I just can't see throwing more money at it after the system is a grand to begin with...

Side note: I have seen several alum head BBC's around here have trouble getting their temps up to 180 once they installed high dollar cooling systems.

Hey Dennis, yep.....you are sooooooooo right my friend.....lot's of bucks spent on stuff that doesn't work from time to time is common place. I see it all the time. It is one of the reasons that ConceptOne Pulleys got started and is now up to it's eyeballs in orders... competing against the likes of March, Zoops etal. Spend a grand and still have to pry, weld or hunt for spacers to work.......I don't think so?

Anywho, we have had this discusion before on temperature. First, how accurate is your temperature gauge that you are referencing? If you didn't calibrate the gauge to the unit with a known source or calibration, then you really don't know (and just using an IR gun on the top of the exit hose and/or thermostat housing is not accurate either.....ballpark tho). Next, how accurate is your thermostat? (Balanced ones are far more accurate and standard ones which are typically +/- 8 degrees easily). And, if you have holes drilled in the thermostat as in some high flow ones, then all bets are off determining exactly what your outlet temperture really is? My point is everything is relative. This is why I like the adjustable Centech device, you can set your own range and points, albeit pricey!

And another discusion we have had is location of temperature sensor? Actually, the intake point will be the most consistent and the hottest (or at least that's the way its designed to be) but in reality when we mix and match parts, add headers to the fray, the head sensor often gets heat tainted from stray exaust heat and the head reading is no longer accurate perse, but the hottest that's for sure.

Bottom line .......it's all relative. And if those BBs with high efficiency alum systems are having a hard time making it to temperature,then the thermostat is not working or leaking simply put. The ones with the holes in them will never get to full cycling temperatures. I have went back to the non-holy ones...balanced only tho.. graemlins/clonk.gif Did I say that right?

FWIW, I like the quality of the Becool products, I have used and seen them up close and personal and know lot's of satisfied customers. But, being the skeptic that I am about highly design/performance oriented products and because I have been fortunate enough to have a great education, plus put on top of that that I believe that PRC is a better buy for the money (and no I don't get commissions) being hundreds less for the same design,....but I have noticed that they have information on their web page that is just plain wrong and for the life of me I can't understand why? Their marketing responses over there are just that...marketing BS 101? And, they don't need to do that with their high quality products. So, I wonder if the elevator really goes to the top even tho the end result is an excellent product, although we all agree expensive.

The key is getting it right from the get-go. For example, my wife's 69 ragtop, 350/400+hp (sorry I didn't build a 383 at this point...just call me jealous) airconditioned, Hotlanta trafficised, summer cruiser is a classic example of what you can do with a cooling system and get it right. It will never come off the thermostat cycling point under any circumstance or a combo thereof. I have a PRC crossflow, highflow TuffStuff pump (overdriven at 17%), a stock fan shroud and a Derale 17" heavy duty flex fan.......and a 180 degree "unholy" high flowing balanced thermostat.

Dennis, Jack and whoever else this may concern. I just wanna clear some things up. I am not purchasing this high dollar unit just for the "COOL" factor that was pointed out. I know this cooling unit is very high priced but compared to the $$$ I have in my engine (434 sbc)I feel its a good investment ( Dart block siamese bore $2000,forged rotating assy $2000,afr heads $1500,lunati roller cam $360,red zone lifters $560,t&d shaft rockers $1000 etc.....)Engine should make 577hp/509tq on 92 octane. I also have a vintage air a/c unit and may add nos. So as you can see I want a cooling system to match. If you were to go overkill on something the cooling sytstem would be it imho.

I did not flip through hot rod magazines and place my order based on shiny pictures graemlins/clonk.gif . I carefully check and recheck to make sure my parts will work together, with great advice from team camaro, team chevelle, Udharold,AFR,and many phone calls to people who actually use the stuff.

A good example is the t&d shaft rockers. They are very expensive but after speaking extensively to Ted at Air Flow Research thats what I chose.The springs I will be running are very heavy due to the solid roller cam,most people know that the rockers dont always line up perfectly centered on the valve tip with a stud system.On a race car it may last.On a street car with light springs also not a big deal. But according to Ted on a car that will be street driven with solid roller springs it will lead to rapid wear of the guides. My two options were to get the larger 227cc heads because of the 60/40 valves which help to center.The other choice was a shaft rocker system which have offset arms made specifically to fix that. I chose the latter because I wanted to stick with the smaller higher velocity heads.

Dennis I understand where you're coming from. You can get a prc radiator built for way less(I did the research) I just dont think some universal fan/shroud assembly (mark4, junk yard,summit etc...) Will look/fit/bolt up to/seal (I am talking radiator to fan module fit)as well as a unit that was made together in kit form(ron davis, becool kits etc...)

I am not trying to be offensive in this post and if it sounds that way I apologize in advance, It's just that I have been a mechanic all my life. Went to tech school,worked for GM dealerships as a driveability/electrical tech(you know the stuff no one wants cause you can do a brake job quicker and have more flagged time by the end of the day job :D ) ase certifed master tech now working as a heavy equipment electical mechanic for the city bus(anything that has wires going to it(gps,farebox,elec.cont.engines,trans,abs,multipl exing,articulation joints etc.....) AND I just dont want to be known as some ricky racer who buys his parts based on the bling-bling effect :rolleyes:

Ray

LOL!! Ray no sweat, I wasn't insinuating anyone was a ricky racer. That's why I said "I know there are good uses for all I have mentioned". My point was if someone is going to outlay big dollars for a system that is designed to provide certain results and it's going to cost more money for additional or replacement parts in order to make the system do what it's susposed to then I'm going to start questioning what is going on. I don't think throwing more money at it is a good solution if indeed there is an issue with it.

I always have held Be-Cool in high reguard and until Steve spoke up not doubted if their systems did as they state they are designed to and my initial reply supports that I believed they must know what they are doing...

Your car sounds like it's on it's way to awesome status, post pic's when you get a chance! I'd love to have a less restrictive budget hovering over my projects, but it's fun making the most of limited resources too...

:D You make a good point Dennis! For that kind of money you would expect it to come with a color tv LOL!!!I cant even imagine paying a third of that for my work truck.

Actually this is my first camaro project to have this kind of parts in it. I have owned a plain 68 and a 71 camaro,both were built on a very tight budgets but like you said I enjoyed every minute making the most of what I had.I have been saving up for a while for this 67 and would like to do it right the first time. Its a lot cheaper to pay for the right parts once rather then try to save and ending up buying twice.Been there and done that, more then once too graemlins/clonk.gif .(bought some repro glass trim mouldings and figured they were new and would be a perfect fit :mad: ended up buying a restored GM set.Also got some repro windlace for my car and samething lol)A quick search on this website and I would not have gone through either.

Thats what makes this site and team chevelle so valuable Members like yourself(DJD)chicane67,eric68,udharold,davidpozzi, 69 protouring,mjpell,carlc,and countless others have helped myself and I'm sure alot more by either answering questions via e-mail or just posting past experiences good and bad.

Something simple like using gerber baby food bottle for por-15 so it's resealable and doesnt weld shut to hydroboost brake conversions,it's all here graemlins/hurray.gif

By the way Dennis your 69 is beautiful!How did you get the ride height so perfect front and rear?did you get the spring combo right the first time?(I know my aluminum heads,radiator,w-pump are gonna bring my front end higher then I would like.)

Ray

heres a pic of my car,going to paint shop in a month or two: http://home.hawaii.rr.com/rayzors1/rays67a%20copy.jpg

Dennis, I would like to clear something up about Be Cool. As I said before, I think the company produces quality products that work, but the beef I have is that they try to spin customers with selling mumbo jumbo. For example at their web page under Support:

21)Q.Why does't BeCool offer dual core radiators with 1.25" or 1.50" tubes?

A. Because the thicker the radiator, the more difficult it is to pass air all the way thru the radiator. No performance gains were seen at low speeds(where it is needed the most) and some vehicles actually ran warmer when BeCool tested thicker radiators in their R&D department.

Now this is a direct jab at what is an inherently better designed and PERFORMING product....the large tube Griffins, which are their main competiton! But, the statement is patently wrong on an apples to apples basis and I am certain (because I have cornered them on this) that their R&D engineers did not test the same apples to apples at all.......and know it. This is NOT called R&D, it's called biasing the experiment for your wanted outcome.

While thicker radiators do have slightly more airflow resistance than thinner radiators but the difference is minimal and not measureable to any great extent. For example, a 4" radiator has only approximately 8% more airflow resistance than a 2" radiator. A two inch vs a three inch design is even substantially less than that. But, when you caculate the improvement in coolant flow (larger tubes means more flow due to decrease in resistance) the increase in flow far outstrips any loss of airflow across the radiator AND the increase in shear conduction surfaces in larger tubed (conical design) radiators adds a whole another efficiency upgrade. The 1.25"/1.5" tubed raditors can have another 20 to 40% improvement on paper....apples to apples!

So, to put it to BeCool bluntly, you're full of it! Stand on your own product's accolades and be happy rather than trying to fudge your way into a sale on fear and spin.

Another comment on their web site states that crossflows are more efficient than downflows. THIS IS EVEN ON THEIR DOWNFLOW PRODUCT PAGE. I suspect that they do not sell alot of these and moreover other competitors ARE! They also state that you should always convert to crossflows under all circumstances because they claim that crossflows always offer more area. This is false as well. Downflows can be designed with as much area as crossflows. They also make a big deal out of crossflows that have radiator caps on the "suction" side of the radiator and stating that crossflows are "more efficient" because of this? This has NOTHING to do with efficiency? And, with higher pressure caps available and knowing how to fill the downflow radiator, it's not a big deal at all and certainly not an efficiency issue. I am running a high flow TuffStuff pump on an "117% overdriven" pulley system turning 6000+rpms without coolant loss.

Last but not least is what they recommend for coolant? This is unusual at the least because even the coolant companies do NOT recommend this. They recommend a mixture of 60% ethlylene glycol to 40% distilled water mix? What? 50/50% is about the highest I have ever read and that's good for 30 below. But, the major factor is that they are their own worst enemy here with a 60% recommendation of anti-freeze. This lowers the specific heat number that in effect lowers the heat transfer properties of the system. This is as much as 30% as compared to a system with a 30% antifreeze content. What could they be thinking to sell you a high efficiency radiator then degrade the cooling by offering up this recommendation.

I think they need real thermal dynamic engineers over there :eek:

Steve - that's just the way of the world these days, it really makes the consumers job harder... My experience with a thicker core is if designed they flow fine. I had my radiator re-cored with the thickest Modine core that would fit the tanks and my low dollar fan and clutch pull air through it just fine and that's with a trans cooler mounted in front of it!!

Ray - Thanks for the complement, The stance is a combination of 2" hotchkis drop springs up front, Hotchkis 1 1/2" drop leafs in the back and of course wheel and tire sizing. On the rear I did remove the upper urethane pad and have the springs mounted solid to the spring perch. This raised the rear by about 3/16". The spindle or center of the hub to the fender is set by springs and body bushings and tire size will effect the height from the ground to the rocker panel. I've found how the tire fills the wheel opening is all part of the overall look. That's why you can put the same springs on different cars and they don't have exactly the same stance. The weight of the car also comes into play... If I had an alum heads, alum rad, non-RS coupe the weight difference would surely raise the front a bit.

Your car looks awesome, keep us posted on that big inch mouse...

Originally posted by Rayzor:
Something simple like using gerber baby food bottle for por-15 so it's resealable and doesnt weld Here's my latest trick for POR-15.

I got tired of removing and cleaning the can and lid. If they are not perfectly clean the lid will not come off again. I now punch a 3/16" diameter hole in the lid and pour the paint out through the hole. Clean the hole with a bit of solvent and a rag and cover the hole with a dab of silicone. Just peel the silicone off the next time you need some paint. Swirl the can before pouring, don't shake.

Thanks CarlC graemlins/thumbsup.gif I too had to puncture my por-15 can once but that was because it welded shut LOL!! never thought of resealing it that way.

Ray

Interesting discussion on cooling systems going on here....this is good :D I would just like to mention one thing, in addition to the thickness and area of downflow/crossflow radiators. In downflow radiators, the coolant falls through the core, due to gravity, at a faster rate than a crossflow. Fast is not always good. The slower rate crossflow allows more heat to be transfered out to the air per unit of time than the downflow; thus more efficient cooling. :cool:

A. Because the thicker the radiator, the more difficult it is to pass air all the way thru the radiator. No performance gains were seen at low speeds(where it is needed the most) and some vehicles actually ran warmer when BeCool tested thicker radiators in their R&D department. Lets not forget that the 'fins per inch' can also be changed to accomodate a change in rate of flow through any thickness of radiator core.

I totally agree with Steve. I think they need real aero and thermal dynamic engineers over there. I guess you need to have brown eyes to work there.....

Although, I dont know if I'll believe the 'gravity' concept in a down flow radiator...

If you can repeal the law of gravity, give me the formula, I know I can sell it and make millions!
tongue.gif

;) With no air in the cooling system, gravity has zero net effect on a closed loop cooling system. ;)

I'll split it 75/25 with you........

Gravity is not a function of air. You cannot have an atmosphere without gravity, but you can have gravity without an atmospere(the moon is a good example). The force of gravity is a componenent of many, many engineering calculations; especially pump sizing, pressure(head) and flow rate; pressurized or not. Gravity does not go away just because you pressurize a closed loop system. What I'm talking about is why the crossflow radiator was invented. I would suggest reading "Applied Fluid Mechanics" by Robert L. Mott, as a start. :rolleyes:

Why are you rolling your eyes gmranch? It's all about learning here... graemlins/beers.gif

Dennis,.......yes it is. I guess I may have assumed to much. graemlins/clonk.gif

Yes, you have. And yes, we all know what an assumption is and can be...... :rolleyes:

Ok, so your telling me that a closed system with no fluid pressure and/or no air pressure is going to flow....because of gravity pulling the fluid medium in a downward direction, inside a down flow radiator?

I understand that gravity is not a function of air, but you would need a greater force than gravity applied to the fluid, in a loop system to make your theory valid. Without flow in a specific direction, gravity isnt going to have an effect on how the fluid moves. This would also take into consideration of the pressure and flow reversion that is present in an automotive cooling system. Now if the fluid system truly had unrestricted flow, what you are saying would have some weight here, but you seem to be leaving out some real components to this. Afterall without the pump, fluid pressure would be nill without an acting force. And with what you seem to be impressioning, it is that gravity makes the body of fluid move in the first place? This kinda sounds like perpetual motion to me.


Gravity is mearly a force that opposes the movement of mass in any direction, with the exception being in the direction of gravity. And in dealing with an incompressable medium like that of water and glycol, the "Equivalence Principal" has to be applied:

An inertial reference frame in a uniform gravatitional field is physically equivalent to a reference frame, in the absence of a gravitational field, that is experiencing a constant accleration.

What this basically means is that no experiment performed in a closed system can distinguish between the effects of a gravitional field and the effects of an accleration . This includes the vererable downflow radiator.

If you need a little more on the Equivalence Principal, brush up on your General Theory of Realitivity. It was written by some guy named Einstein, published around 1915.

The water pump is part of the equation, gravity is the other. In order to understand how the system works, all the variables have to be included in the equation. Consider a skydiver's rate of decent(due to gravity) without including wind resistance; as an example. Gravity acts in the downward direction, on this planet, not any direction(last time I checked). A discussion of "any direction" would include mass, accelration and inertia. If you want to discuss Einstien's "Unified Field Theory", please start a new topic; it's only remotely related to downflow radiators. Have another beer(I am), and everything will become relative. graemlins/beers.gif

Gravity has an effect on any thing in motion, in any direction (on this planet). Even though an object in this case, isnt falling in direct parallel to the direction of gravity, it is still effected by it even in an angular plane or vector. So yea, gravity works through an angular direction that isnt perpendicular to the plane of the earth.

So yea,

A discussion of "any direction" would include mass, accelration and inertia.

Which you have excluded in your interpritations of explaination.

Unlike you, I am not attempting to prove that electromagnetism and gravity were different manifestations of a single fundamental field, nor am I leaning toward a Quantum approach. Whereas, my direction is toward the theory that explains the nature and behavior of phenomena on the macroscopic level (things that are visible to the naked eye); whereas your latest approach to this is of a quantum value that would explain the nature and behavior of phenomena on the microscopic (atomic and subatomic) level. And then you bring UFT into this as well? I myself think that you are beyond, simple beer......

Maxwell and Planck, as well as the discussion of UFT are pretty much pointless in a macroscopic discussion. A cooling system and the real world do not correlate with a theory that is largely focused on the Super String Theory and in peticular, the M Theory.

Forces have long been explained by a single theory known as the standard model, and gravitation does not fit into the equation. Nor am I trying to put this into a single essence. But you seem to have a flair with the more dramatic interpritation of what you think incompressable flow really is. We are not talking about gaseous flow, or a sky diver and the rate of his decent concerning gravity in a gaseous environment, are we? Nope, were are talking about an incompressable medium with a sub-relation to laminar flow and the relationship of an ideal fluid and its surface tension.

Afterall, we are dealing with things that are relative, are we not? And if I remember correctly, the General Theory of Relativily, is essentially "the" gravitional theory.....whereas the Principal of Equivalence is the primary mode, concerning an incompressable fluid medium within a closed system.

If not, just throw money at two thermostats and findout what works with the given big block scenario, Ray.

Just for the record, air and water are both considered fluids; the characteristics of which are discussed under the general topic of fluid dynamics. I sorry you did'nt understand the relationship between the falling skydiver(an object falling through a fluid) and falling water(a fluid falling through an object called a pipe). I also think the term "closed system" has been used and abused in the discussion here. To put it simlpy, for the purposes of desribing an automotive cooling system, a "closed system" is a pressurized one; one with a pressure cap on it for express purpose of raising the boiling point of the coolant. Yes, gravity does act on this system.

I think most readers here will understand that the water, in a downflow radiator, is pumped up to the top tank, and falls vertically through the radiator, at 32ft/sec/sec, to the bottom tank. Actually faster, if you add in the velocity provided by the water pump. There are some losses in velocity due to friction.

In a crossflow radiator, a horizontal component has been added, so the water flows through the tubes at roughly the velocity provided by the water pump; there some frictional losses, but I'm just covering the basics here. As one can see, the water does less falling, than with the downflow radiator. This results in a slower velocity of the water it the tubes, which provides for better heat transfer to the radiator, resulting in more efficient cooling. :cool:

First I think we all understand to some degree a closed automotive cooling system and what pressure does to raise the boiling point of the fluid contained within that system. Next doesn't water (to keep it simple) seek it's own level? Unless the closed system has air pockets and the water is pumped to a higher level, gravity will not effect it and there will be no flow.

Now keeping all that in mind once the water pump puts the fluid in motion, and if the water were only being pumped through the rad core I can see the down flow core putting up less resistance than a cross flow core. I'm also thinking that the faster the water is pushed through the core the less difference there will be. I think by the time you attach the entire system to either core the water passages in the engine and the thermostat will add enough resistance to even things out.

Maybe someone like Steve Jack has flow numbers on the same system comparing the 2 styles of core...

Well, I have been away for awhile and this in an interesting thread to say the least AND INDEED learning is what it's all about.

But, with all due respect...we are off spliting hairs here on something that has no appreciable effect on any of these systems and gravity having an actual effect on any of these practical cooling systems is inmeasurable in so far as efficiency is concerned when you are talking the flow rates we are utilizing. If one could measure the resting pressure of two radiators with the exact same capacity at the pump inlet, it would be the same for a downflow or a crossflow because the weight of the water above that point would be exactly the same ;)

The downflow vs crossflow in automotive designs is about area only! Some crossflows can be laid out with smaller tanks and a smiggin more area, but on an area vs area basis head to head with a downflow there is no efficiency issue per se. One of the previous posters purdently pointed out how fins can figure into this as well. While that is true, also a biggy is tube design as well. Round tubes are NOT nessarily the best design. Elongated narrow tubes that force coolant to come in contact with more outside tube surface is what it's all about. All in all, it boils (pun intended) down to overall design regardless of "type" of flow sequence. That includes area, tube design, fin dispersement moreover than any other aspect. System resistance will figure in too, but that is a result of other factors such as tube size and design, number of passes, and some other anomolies.

I would like to politely correct gmranch on a couple of points, respectfully tho. There are alot of guys out there at still believe this myth of slow flow is better. I have read about 140 differing thermal-dynamics books in my engineering education, training or experience, participated on teams that design specifically cooling applications for nuclear power plant heat exchangers as well as myself designed automotive and non-automotive cooling systems and therefore let me say this ONE MORE TIME! SLOWING THE FLOW IN ANY RADIATOR OR HEAT TRANSFER DEVICE/SURFACE REDUCES THE TRANSFER OF BTUS. Simply put flow is king! The old myth of slowing the coolant thru the radiator is just that....a myth. If that were the case then why all the high performance water pumps? And, moreover...show me just one equation that demonstrates such fluid physics allowing for a flowing media to at some point completely reverse the heat transfer characteristics of the system. Under this "slow the flow" theory, sitting still is best?

Here is the "textbook" explanation and formula

Q = M x Cp x T1-T2

where:

Q = heat load (BTU/hr)

M = mass flow rate of the fluid (lbs/hr)

Cp = specific heat of the fluid (BTU/lb°F)

T1-T2 = temperature difference between the liquid in and the liquid out (°F)

And........

M can be calculated water using the following:

M(lbs/hr) = V 60min/hr x p(lbs/ft3) x (ft3/7.5gal)

where:

V = volumetric fluid flow rate

p = fluid density

A more convenient restatement is:

Heat Extracted = Btu/hr = 499 x flow rate in gpm (T1 – T2)

So, as you can see, heat extracted has a direct relationship with flow....not visa versa.

Other reasons more flow is better in an automotive cooling system are that need recognition: Coolant cannot absorb heat after it reaches it's pressure corrected vapor point (boiling at atmos press of course). So, as coolant absorbs heat at a progressively slower rate as it approaches this point. What this means in a closed-loop system is that if the coolant sits in the radiator longer, it also sits in the engine longer. This means as the coolant is heated towards it's corrected vapor point, it looses its ability to carry BTU. While this can be an issue, there are bigger issues. Higher flow rates promote turbulence in the system. This is a GOOD thing to promote efficiency of the system. Also, higher volume thru a fixed volume system (block/heads)means higher pressure. This is also good because it promotes "friendly pressure" that raises the boiling point of the coolant. This helps to stop "hot spotting".

Also, for the record, a closed-loop system one that is just "contained" and the same water/coolant flows thru the heat producing source and the cooling source. There does NOT have to be any pressure to relate to a "closed" system per se. An open-loop system is cooling visa via from media from an outside source. An example of this type of system would be a marine application where the water is pulled in from the lake or sea to cool the engine. The cooling media is not used over. :cool:

Now, I didn't offer all this explanation to embarrass anyone or make light of the incorrect assumption or statement. I offer it only to educate everyone in the good spirit I offer it. smile.gif

[ 03-21-2004, 11:28 AM: Message edited by: HOTRODSRJ ]

Ok, gravity is always in effect on this planet and as of this date we have failed to make it go away. Water always weighs something; in or out of a radiator.

The key to thermal efficiency,in any cooling system,is to match the flow rate of the coolant to the heat transfer rates of both the block and the radiator, while cosidering all variables like coolant type, engine rpm, ambient air temp, humidity, core area/thicknes, and material(aluminum/iron/brass). As crossflow radiator design alows for a closer match of these rates.

gmranch........you have it exactly right on with your statement (and my dissertation) with a few insertions:

"The key to thermal efficiency,in any cooling system,is to match the flow rate of the coolant to the heat transfer rates of both the block and the radiator, while cosidering all variables like coolant type (specific heat performane), engine rpm (more over application), ambient air temp (range), humidity, core area/thickness, and material(aluminum/iron/brass)(shear heat conduction)."

Excellent way of stating the bottom line.

I will stand my ground on this one tho... "As crossflow radiator design allows for a closer match of these rates." ...I don't agree. There is not any performance data or design theory to back this up anywhere that I can find? In fact, some of the most efficient industrial coolers are both crossflow and downflow in design.

Automotive crossflow radiators were invented to aid and abet lower hoodline designs primarily.

Well,I happen to have a degree in Mechanical Engineerig and I too have spent many hours studying Thermodynamics. I respectfully disagree because I will not deny the law of gravity!(I'm also a poet and did'nt know it) graemlins/beers.gif

I am not going to go off the beaten path and add something else to the discussion which doesnt stay in topic....considering the gravitational element that is in question, in a closed system. There is no need to bring elements into this until what was first questioned, gets answered. There are a few multidiscipline engineers in here, to include myself, that would rather deal with one element in this equation at a time. I too have spent a great deal in thermo and aerothermal dynamics, power and thermal cycle optimization, advanced combustion systems and development in advanced high temperature materials......to give you guys some of my back ground.

First of all, comparing a sky diver falling through a compressable medium would be better to comparing water and its waterfall. But you can not compare the sky diver falling through a compressable medium to that of water (which is incompressable) through another incompressable medium.

I know that air and water are fluids. But what you are not grasping is that air is compressable and water is not. That is why it is customary to consider the four characteristics of an ideal fluid, in a simple approach to fluid dynamics. In such a fluid, flow is: 1) Steady, 2) irrotational, 3) non viscous, and 4) incompressable. And with this, it has to meet these conditions:

Condition 1): Steady flow means that all the particles of a fluid have the same velocity as they pass a given point.

Condition 2): Irrotational flow means that a fluid element (a volume of fluid) has no net anguler velocity, which means the possibility of whirlpools and eddy currents (the flow is nonturbulent).

Condition 3): Nonviscous flow that velocity is neglected.

Condition 4): Incompressable flow means that the fluid density in constant.

Air does not meat condition 4. Air is compressable and is considered gaseous. From here the Equation of Continuity can be applied for the incompressable fluid and its density constant.

In a closed system (which has only been used and abused by someone other than myself), meaning without air, the water in a downflow radiator is not going to fall at 32ft/sec/sec, because there is fluid present before what you seem to think of as the wave front. THERE IS NO WAVE FRONT BECAUSE OF CONTINUITY IN A CLOSED SYSTEM. Therefore, the fluid medium can not free fall through the radiator (it needs a compressable volume to act against for a pressure head). Nor does the closed system have to be pressurizied, to be considered closed. So no, gravity does not have an effect on this type of model (an incompressable fluid model), because there is no air present. If there is air present, it would not be a closed system and then the possibility of a true wave front and flow of a free fall fluid would then have its place here. Its like comparing the fluid flow in a pipe, to that of a waterfall. One deals with a closed system and the other does not. Gravity only effects one of them and its the waterfall.........

Dennis obviously gets it. Although in Bernoulli's Equation, pressure is now added to our discussion of flow and velocity. Which in an automotive cooling system is common place. Because of the different convergent and divergent volumes in the system, this has an effect on mass, min and mean flow. This is because Bernoulli's Equation indicates that the pressure decreases as the fluid speed increases. But this would be another topic to deal with specifically representing flow and pressure and really has another place outside the gravitational question here because pressure is irrelevant in a closed system.

Steve. I can always count on you to bring out the end results in an emperical form. This all started on the subject of gravity working on the fluid medium, in a down flow radiator. The true, relevant kinematics, however are understood by some and not so much by others and was best re-inforced by your contirbutions:

something that has no appreciable effect on any of these systems and gravity having an actual effect on any of these practical cooling systems is inmeasurable in so far as efficiency is concerned when you are talking the flow rates we are utilizing. If one could measure the resting pressure of two radiators with the exact same capacity at the pump inlet, it would be the same for a downflow or a crossflow because the weight of the water above that point would be exactly the same And to further ends:

A closed-loop system (is) one that is just "contained" and the same water/coolant flows thru the heat producing source and the cooling source. There does NOT have to be any pressure to relate to a "closed" system per se. An open-loop system is cooling visa via from media from an outside source. I also agree with your statement towards the design and inception of the cross flow radiator and why it is here in the first place:

Automotive crossflow radiators were invented to aid and abet lower hoodline designs Good discussion guys. I am just glad we got to get Steve out of the shop to jump in here and throw in a little schooling at the end. Its rare that we can get ole Steve to put the wrenches down and jump in... tongue.gif

Actually, I need to go to the shop and fix my own disasters. I have been in Nashville Tn hangin with my daughter who is on spring break.

It's back to work tomorrow. graemlins/clonk.gif

All things being equal, hot water rises and cold water sinks. Anyone familiar with Naval nuclear reactors understands the principal of XC or emergency core cooling which essentially places a heat exchanger above the reactor compartment outside the hull. The system uses no pumps or any thing else that requires power. The natural circulation that is established by hot water rising up to the exchanger and cold water returning cools the reactor core. I guess gravity has something to do with hows this system this, but it works completly opposite the way it is being described.

Ok, there are no wavefronts provided that 1) the thermostat is completely open, 2) that the system is full, and 3) the pump output flow equals the pump input flow at the radiator connections.

As for the effect of gravity, a proper summation of forces would determine myth or fact. The "standard model" does not include gravity as an element to considered. I like to keep things simple, just like everybody else; but I also understand a "standard model" is just a starting point.

chicane67, to be blunt, gravity does not discriminate, it does'nt care about about your "incompressable fluid model". I'm not being blunt here......., gravity is.

Ok, so...... basically what you are saying is that the theory that defines, a substantial gravitional theory of a closed systems , specifically the Principal of Equivalance which reads:

That no experiment performed in a closed system can be distinguish between the effects of a gravitational field and the effects of an acceleration.

....and not to mention the one who wrote it and the entire scientific community that follows it, is full of crap !?!!

Thats good. Who is it that you work for? tongue.gif Let me know so that I can pass this on. tongue.gif To be blunt, I think gravity has gotten to your 'greater' understanding. ;) So.......

Lets put this is a very simple term. Lets say we have a closed system, it could be that of an automotive cooling system or that of a tire and wheel. Now, for what reason is the fluid not moving inside the tire and wheel's closed system? You say gravity has an effect on it. Afterall, there is fluid above and below a specific point and it has a direction that can follow gravity, so why wouldnt gravity pull it down to the bottom of the tire? This is essentially the same as your 'downflow radiator' theory.....

Or how about taking a length of pipe, that forms a circle. What effect does gravity have on the fluid flow in this closed system if it were verticle or if it were horizontal? Why and how would there be a difference?

Gravity does care about an incompressable fluid medium in a closed system. Einstein proved this with the greater help of Newton, Eular, Lagrange, Maxwell, Hamilton, Clairaut, Lorentz, Grossmann, Riemann, Ricci, Levi-Civita, Hilbert and Klien.

chicane67, the "Principle of Equivalance" is not an exclusionary statement. It's a statement that defines terms, assumtions, and limits; to faciltate the use of a imperfect mathematical model for the purposes of experimentation. It is not a statement that allows the subtraction of gravity. I think most of the scientific community already understands this.

All I have done here is to question an assumption, which is not considered bad form, IMHO. To say that because we can't measure something or it does'nt fit or model and therefore does'nt exist or is a myth, is patently false logic. :eek:

There is nothing wrong with questioning an asumption, nor is it viewed as a bad thing....I agree. But it can be found in higher math with the inclusion or exclusion of gravity, that it basically has no function in a closed system. I didnt say anything about the effects on the model as a whole.

Without a statement and defining terms, what do you have? An egotistical guess? It would be fair to use such an exclusionary statment in the sake of experimentation , afterall, I surely havent seen any emperical data to prove either view point wrong. Nor have I seen any answers to my previous questions.

The original arguement was that gravity is the key player to why downflow radiators did not cool as well because of a simplistic myth that stated, that the coolant went through the exchanger 'too fast', (for a lack of better words). But, I believe that is mearly a gross assumption on your behalf. And to reiterate your comment of, "because we can not measure something or (because) it does not fit or model and therefore doesnt exist or is a myth, is patently false logic"......is a statement of entrophy and is bound by ill logic itself.

But never the less, this has been a good arguement. graemlins/beers.gif

okay, so which radiator module and which thermostat?

i have a 396, manual tranny, and am considering a (be cool, PRC, griffin) module or building my own cooling system module from parts.....

opinions

I am not sure what you mean by "module" but any of the radiators that you have interest in will suffice. I personally recommend the PRC for the service or price, but if you have air and/or tons of HP and/or live in an extremely horrifically warm place....well you might want to consider a larger radiator from Fluidyne that is three row aluminum albeit them $$$$.

The thermostat thing is pretty straight forward. These engines (and all the chemicals that go in them) are designed for coolant temperatures at or above 175 degrees. So, a 180 will be perfect.

Have a fun and safe cruising season all!

module= radiator, fan,fan mounts,temp sensor, relay, cap, coolant reservoir,etc.......

i figure as such on the 180 stat...

i have a 396, with an OE style radiator and shroud with a flex fan...i want to ditch the fan, but want to make sure i run just as cool as i am now, or cooler...summer is coming .....

Well, let me try and save you some money and see if you want to consider it.

I would order a PRC radiator (take your existing radiator dimensions and mouting specs to DickZ (dick@streetrodstuff.com) at www.streetrodstuff.com

He has a combo package with the dual Spal fans that will be overkill for your application. Additional $575! However, you can buy a Mark VIII fan which is huge but cheaper. There are many temperature sensors available for these fans. But, you will have to upgrade your electric system for either. A high output at idle model 140 amp TuffStuff alternator is recommended and wiring bus upgrade as well. This is a must or you will suffer electrical issues.

I would offer an alternative to all this electrical equipment, albeit the electrical solution will outperform any mechanical set-up you can muster.

I have converted several Camaro, Chevelle and full size late 60s cars with air and stock fans and radiators with air to a Derale heavy duty flex fan with great success.
In your application with your stock 19" shroud, you should be able to buy the #17218 or 18" fan (chrome and stainless...looks great too...about $62 delivered to your door from Summit) and cool just fine with the new alum radiator!

Unless you have other problems or issues, this cheaper but good lookng set-up would be adequate for your application according to my experiences and save you another $500 to boot! I run this exact set-up on my 69 ragtop with a 440hp small block with airconditioning and can sit in heavy Atlanta traffic on 100 degree days for hours on end without getting off the 180 cycling point...and my fan is only 17".

Just some information for you to ponder!

thank you for your advice.

i wanted to steer from the flex...... but i am not totally set on it...

i have considered the mark 8 fan..... but do not need 4000cfm..or the 50 amps of current it requires...

i have done the "new system" by madelectrical on my car...i am running a 94 amp 3 wire AC delco alternator...

another fan i had in mind, was the lower amperage taurus fan, but then that requires mounting modifications, setting up a relay on/off control circuit.... etc...not a big deal.... just more time and parts i have to scrounge for..

i dont mind paying a G for a GOOD module setup that i like, and will last for 10 years....i dont like the fan setup on the be cool module............ so i am looking for other companies with a good module..

i am in no hurry.... but i want to do the change this summer sometime.....

So you recommend PRC...does griffin have a module for the rads? who else?

Kristopher,
If you stick with the mech fan, I'm currently setting up a group buy for custom made alluminum shrouds, let me know if you're interested. Personally, I think my derale stainless steel flex fan with alluminum shroud is going to look and cool better than any electric setup, and without the added expense of a 100 amp plus alternator to support it.

Jim, how much for the aluminum shrouds? Are they basically a stock shroud and what's the opening? Can I still get in?

Thanks.....SteveJ

i did the electrical upgrade for my own piece of mind... i added relays for the headlights to take some of the current out of the bulkhead connector at the firewall..along with the switch.... i also did the remote starter solenoid for the BB hot restart probs..... all the issues the new system helps elimenate i did it for...

i dont want to start the issue of mechanical VS electric....i stand my ground on electric being superior....hands down....dyno proven...electric is where its at....PROPERLY set up of course....

not to mention i have a flexfanphobia...not if, but when will i stick my hand in there, or a buddy does it. Also the one in a million chance that the unit self destructs on me.....with my luck those odds shrink expodentially.

i do appreciate all the advice,,..my mind is set on a brand name module unit...now the question is from whom?????????

I understand the mechanical vs electrical thingy......and you are right...the electric big fans win easily. If you want the best.....then do the MarkVII fans. If you can squeeze 32" of fans in...do the twin new 16" Spals (3000cfms each). They will suck down about 50 amps tho. Don't use any cheapo relays either. Do the Bosch or Tyco 70amp automotive rated only.

you need to check these raiators out,can't beat them

http://www.rondavisradiators.com/

RonDavis does have some good products, but do NOT buy their double-pass designs. This requires 8times the pressure to keep the flow up. This is a design from their "racing" roots which doesn't translate to street applications very well.

i have there double pass in my blown 509 pro street car,works great for me and 7 others that have them for street cars.(4 of them blower cars).all of them are double pass.my car went from running 200-205 cruising 225-230 in traffic to 180-185 cruissing 200-205 in traffic

JAW...While I am sure that your experience is true and that's not to say that multi-passes (double pass or triple passes) do not work, they just don't have the high efficiency of the single-passes from a design standpoint. Single-passes are better because the flow required is not cut fractionally. It's just simple physics. The radiators that you are using can overcome the "flow" efficiency problem with shear size I am sure. If you would have utilized a single-pass design I will guaranty you that your temps would be dramatically lower. What I do....is just suggesting the "best" technology for the street. Single-pass designs with the equivalent area are about 33% more efficient than their double-pass brethern.

Multi-pass technology comes from racing circles or wherever you need to keep the rpms up all the time. This higher rpms produces alot of flow and the want and need for keeping the flow constant and reducing huge amounts of power producing pressure for a single pass design. So, it's a racing thing that has evolved for some designs.

ALL the OEMs are using only single-pass designs on all their applications because of the want and need for the most efficient designs that they can squeeze out. These high efficiencies drive smaller footprint designs which means less weight and lower hoodlines.

Also an interesting note and offering of another professional viewpoint.... "Double pass radiators require 16x more pressure to flow the same volume of coolant through them, as compared to a single pass radiator. Triple pass radiators require 64x more pressure to maintain the same volume. Automotive water pumps are a centrifugal design, not positive displacement, so with a double pass radiator, the pressure is doubled and flow is reduced by approximately 33%. Modern radiator designs, using wide/thin cross sections tubes, seldom benefit from multiple pass configurations. The decrease in flow caused by multiple passes offsets any benefits of a high-flow water pump."

From the mouth of the king of cooling.....Howard Stewart himself at http://www.stewartcomponents.com/tech_tips/Tech_Tips_5.htm

And.....I am not saying your choice is bad either....works for you!

I'm looking to switch to a clutch fan. I have a flex-lite flex fan right now and makes to much noise. What's the best mech. fan setup to have.

I'm looking to switch to a clutch fan. I have a flex-lite flex fan right now and makes to much noise. What's the best mech. fan setup to have.

The original stock design fan/clutch/shroud/radiator worked just fine (as most people find out after they try and catalog-out-engineer the guys who designed the stock system). If you have more motor than original, put more radiator in it, leave the rest alone.
:beers: