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View Full Version : Engine cooling. Electric vs. mechanical



chicane67
08-16-2004, 04:41 PM
MStennes
Tech Team


posted 05-17-2003 10:58 AM
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Help, I need to install a fan system on my 69 I have a Be Cool radiator but was thinking a electric fan would be cool, other wise I will have to buy a new fan clutch system since the bonehead I bought this car from had installed a very low budget direct fan set up from the budget section of JC Whitney. Any thought of which way I should go? The car is a 383 stroker pushing about 450 horse power, with a 700R4.

Thanks,

Mike

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KWIK 69
Tech Team


posted 05-17-2003 06:03 PM
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I've got a 383 Stroker and my 700r4 is currently being built... I'm going to go with the electric fan when I order my BeCool radiator. It seems like I read somewhere the electric fan was recommended... it certainly must be more efficient. (get the pull type air flow, not push)

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69 Camaro Under Construction.

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chicane67
Tech Team


posted 05-17-2003 07:04 PM
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quote:
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Originally posted by KWIK 69:
....it certainly must be more efficient.
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Not nessarily so. The fact of the matter is that a clutch system, the correct fan and proper shroud is the most effective at cooling. The main reason that the manufacturers have gone to electric systems are for space considerations. But none the less, either choise has its pro's and con's.

I would consider an electric. You will definately want to look at the Lincon Mark VIII 18" unit. It is affordable and has the highest rated CFM (well higher than anyone else's efforts). --------------------------------------------------------------------------------

MStennes
Tech Team


posted 05-17-2003 08:55 PM
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Kwik,
Are you going with the complete setup from be cool or the radiator and a different fan set up?

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Mike

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KWIK 69
Tech Team


posted 05-18-2003 02:29 AM
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Not sure yet, I'll jump off that bridge when I get to it. My budget will be playing a factor here.

I'de definately look into those recommended by the guys on this board, they've been there & done it. I'de also check out the fan that BeCool recommends for your application and check comparable prices and performances.

Good luck!

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69 Camaro Under Construction.
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HOTRODSRJ
Tech Team


posted 05-18-2003 06:47 AM
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I must take exception respectfully to the poster regarding the clutch fan set up being the most efficient mechanism for cooling when compared to the electric fan. I think he means compared to a fixed bladed system but I cannot tell for sure. No disrespect meant, but here goes my explanation.

Quality, high-flow electric fans will produce MORE airflow at idle and slow cruising speeds (where it's needed most) and take absolutely no hp per se. Couple this with the want of high airflow on all 134 airconditioning systems, light weight, no parasitic drag on the motor, smaller cubic footprint, higher predictability and reliability...well you get the idea....no wonder OEMs use them profusely. We should too.

Even tho the old tried and true clutch fan set up when working correctly will probably get you by, clutched fans will NOT produce the kind of airflow at idle and slow speeds and are complicated to beat the band compared to an electric motor and switch. This is why their MTBF is lower than electric fans. Clutch fans will also produce parasitic drag of over 15 hp (some as high as 22hp at peak rpms) at higher RPMs regardless of when they "shut off" if there is such a thing....you really can't tell can you?

Moreover, clutch systems produced today are NOT the specifications and quality that were produced of yesteryear by all the OEMs. Many of today's manufacturers tried to reverse engineer these things and there were over 25 differing clutch fan/assemblies specified in 1970 that performed to differing levels depending on applications. For example, PU trucks had clutch/fans that would keep coupled up to 50% more rpms (compared to performance ones) assumming towing and heavy duty use. Cars equipped with air had similar specs. Some were even designed to fit the total capacity of the cooling system in the performance arenas. Today, much to our liking, we are making so much more hp per cube than then and the clutch/fans cannot and are not adequate in most cases for cooling our beasts of fun.

The clutch/fan assemblies that are produced today are relatively non-specific in general and you cannot tell if they are working correctly as well as they are probably eating more hp than you want or need for them too. On the positive side, I do like the look of the fan assemblies in original applications tho.

I used to not run flex fans due to their ability to launch themselves thru hoods and radiators and they were not that great of airproducers either. But a new technology fan product came along from Derale (http://www.derale.com/hdflexfans.shtml). There heavy duty flex series part number 17XXX series got rid of all the old problems of flex fans and produce more air at idle than any fixed or clutch fan that I have seen or tested. They will not come apart and are specified to at least 10000rpm according to the original specification engineer. I use the stainless and chrome 17" on my 69 Ragtop (400HP+ with air) here in Hotlanta traffic and weather and it never comes off the 175 thermostat. I fling this thing regularly with shifts in the 7000 range (with a 17% overdrive pulley....making that over 8,000 rpms water pump shaft speed) and have done so for three years. I just took off the fan this year to xray for cracks and such, the prognosis was perfect health! I highly recommend them and use them on several applications. They are relatively quiet, effective, cheap, good looking, and the highest reliability that you can get and will work with stock shrouds! About $60 from Summit.

If it were mine tho.....with your hp generation and the want for the best, a dual Spal or Derale electric fan set up would blow (pun intended) anything else away! Not cheap tho...


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rolling-robert
Tech Team


posted 05-18-2003 08:02 AM
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recently pulled a radiator with 2 electric fans out of an old Renault van, im gonna use this is in my 383 powered maro in the future.

radiator has about same size as original and prefer the electric fans above the belt driven ones.
because the belt driven turns slow everytime cooling is most needed.--------------------

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DjD
Administrator


posted 05-18-2003 10:03 AM
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No doubt you'll gain a few ponies with an electric fan but is it worth the extra expense? Here are some test results I got from an issue of Car Craft (May 2000) All these tests were run on Flex-a-lite brand fans except for the factory 4 blade. To baseline things the first dyno run was no fan at all but did include an alternator.

No fan = 496hp
Electric = 494hp
Thermal clutch = 487hp
Nonthermal clutch = 485hp
HD thermal = 476hp
HP flex fan = 476hp
Stock 4 blade = 473hp
Low-profile flex = 466hp
One piece plastic flex = 460hp
OE replacement 6 blade = 449hp

You can see your fan choice makes a difference. The cost difference is quite a bit though and the electric fan they used cost $170 as opposed to the thermal clutch fan at $66 and the nonthermal clutch fan at $56 (remember these are all Flex-a lite products and the testing and prices are from May 2000) Also note that this test didn't go into cooling ability.

Both types of fans can keep your mill cool just like both std and alum radiators do as well. Alum and electric adds a wow factor under the hood but are costly compared to the alternative. I have no proof for you that one flows more air than the other at idle I do feel that most electric fans may actually restrict flow through the radiator and around the engine at higher speeds though. Electric fans also require your electric system to be up to the task and power relays and proper setup is critical. If power fails, the fans don't work. I know a fan belt can fail and cause a mechanical fan to quit working as well so it's a draw unless you are not very good with trouble shooting wires... I bring this up because you hear guys talk about wiring things so the fans run as soon as the key is turned all the time. This is because they couldn't figure out how to trouble shoot and fix the problem or just don't understand how it's susposed to work.

I am using Flex-a-lite's nonthermal clutch pn 5255 and fan pn 5718 ($56 through summit) I had my stock rad recored with the biggest core that fit between the tanks (under $200), a stock water pump and a Robert Shaw (Mr Gasket) 180deg stat ($10 - $12). I run about a 60/40 water to antifreeze mix with no other additives. I have sat in traffic for over an hr creeping along and my 383 didn't get to 190 degs. Moving it stays between 175 - 185 no matter how hot it gets outside.

My point, (as it so often is) is all about budget. If you are not on one your car ought to look and perform like the Mule. If you are on one you need to pick the most cost effective parts to get the job done so you have money for the rest of the project. Nothing worse than seeing a project take years and years and never getting completed do to lack of funds!!

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...Dennis

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paulm
Tech Team


posted 05-19-2003 07:27 AM
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I ran a stock type clutch fan, shroud and radiator here in AZ. I was always pushing the limit of comfortable temps. The temp would consistantly creep up at stop lights waiting for the green even when it was cool here.

I switched to the lincoln mark viii fan and griffen aluminum radiator and I have 0 issues so far. I don't hardly even turn my fan on. Once in a while when I'm stuck in traffic I turn on the fan and no matter if it's hot or cool here the temp drops and maintains 180....(the griffen radiator/lincoln mark vii fan maintained 180 for 40 minutes once in a traffic jam!!).

I am no expert and all those experts that say the OEM clutch fan, shroud and brass radiator is the most efficient must have good reason to say so. I can only relay my experience which is that in my car with no other changes the aluminum radiator/electric fan absolutely beats the pants off of the stock type setup....no question, no gray area, no ifs ands or buts!!

As far as costs go, a universal type aluminum radiator from Summit is $169.95(I'm sure it's made by one of the big radiator places.) and the lincoln mark viii fan is about $140.00. A stock brass type radiator is at least $100.00 and I think in Ricks they are over $200.00 for a small block 4 core. To buy a clutch fan and a shroud from Ricks would be $82.00 for the fan, $40.00 for the clutch and $62.00 for the shroud.

That's $184.00 for the stock type fan and $140.00 for the electric lincoln mark viii(add a few dollars for a power relay and a switch). The brass radiator would cost around $200.00 and the aluminum would cost $169.00 for the summit brand or around $300.00 for the Griffin universal.

I don't see very much difference in costs.....--------------------


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Spames
Tech Team


posted 05-19-2003 09:07 AM
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I agree, and while I can't share the experince with mine yet, I will say that I paid ~150 for my LS1 setup with all the extra relays etc to hook it up. I am re-doing the whole electrical system, so I already had plans to upgrade to a beefier alternator.

I am going from a flex fan, and if it produces an additional 20 Peak HP, there aren't many mods that can compete with that price.

--------------------
68 Coupe...in storage

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rolling-robert
Tech Team


posted 05-19-2003 10:17 AM
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i paid 25 bucks for my radiatopr with 2 electric fans (second hand)

i will turn them on/off with 1 or 2 switches so if im racing the 1/4 mile ill turn them off after that ill turn them on to cool the engine down.

so ill safe a few volts during race...

dunno if it helps, but hey, u never know--------------------

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chicane67
Tech Team


posted 05-19-2003 02:07 PM
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And to constructivly rebuttle.....

I am not disagreeing with what any one here says, I am mearly offering food for thought.

Firstoff my comparison was not a comparison between a fixed and a clutch type it was between an electric and a clutch type. As for a comparison of available CFM at idle and slow cruzing speeds that depends on the fan itself, I agree. Also, there is no substitute for surface area when it comes to cooling.....radiator OR fan wise.

Most electric fan units will not keep up with the high pitch- multi blade flex units for sure. There are very few exceptions to that statment, one being the Lincon Mark VIII unit and the other being that of two Spal units: VA18-AP6-41MA and the twin fan unit 2VAO6-AP6-37A. You would think that the twin unit has more surface area than either of the single units, but it is actually in the middle......the Lincon unit has a 21.5% increase in surface area over a 16" fan blade.

Lets rough the known factors:

SPAL single fan 16" VA18-AP6-41MA, 2360 CFM @ 21.6 amps
SPAL dual fan 11" 2VAO6-AP6-37A, 2780 CFM @ 25 amps
Ford/Lincon single fan 18" F8LH-8C607-AA 4800 CFM @ 33 amps

One 16 inch fan can cool more than 2 x 11 inchers (measurments, less hub diameter).

Example 16" fan divided by 2 = 8"
8 squared is 64 times 3.1417 = 201.06 inches of fan area.

11" fan divided by 2 =5.5"
5.5 squared is 30.25 times 3.1417 = 95.03 inches of fan area x 2 = 190 inches.

18" fan divided by 2 = 9"
9 squared is 81 times 3.1417 = 254.47 inches of fan area.

Now, in comparison to the clutch and fixed blade fans, there is no real empirical data for comparison. But it's overall approach is proven. It is still the most reliable system used to date and as for the expenses, it is less than an electrical system.

Mechanical; fan, clutch and shroud.

Electrical; fan, thermostat, wiring, relay's and switches, shroud and an electrical system that will handle the increased amperage load (IE 90-100 amp alternator) to include the wiring to handle that load......you get the picture.

Lets address the horse power issues. While it has only been viewed of one, both type fan systems have an impact measured in parasitic loss. Wheather or not you believe it, they are closer in measurment than you think. The clutch system's loss is through the H20 pump pulley, which has a known driven ratio. As for the electric fan system, its loss is through the alternator pulley.......remember it takes a mechanical force to create power (non-fusion related) and it too has a known driven ratio. Ratios can help and hurt this as well.

The long and the short of it......lets just say 15 HP for a number loss when using a clutch fan. Now lets look at the electrical side of things. Since it takes HP to create power to run the stock electrical system of the chassis that equates to roughly 6-8 HP. Now lets drop the new high current fan into the scenario without any other upgrades. The current used to run that fan is quite large at start up, some fans actually pull in excess of 100 amps at start-up. That takes power away from other current related devices.....like the ignition. So it hampers its ability to burn the mixture (more power loss). And then lets add the radio (very little current for a stock system) and then an electric fuel pump.....oh yeah, how about driving at night.....and is it hot or cold enough to require the AC or heater? So now were are past the ability of the stock alternator and wiring so that too increases the load.....SO, now we have to make the total amount of current available to handle all of this before your lights go dim and the ignition starts to cut out. So we now have a 10-12 hp loss to take care of all of this.

So basically its a wash, at some monitary expense towards the electrical side. Dennis summed that up quite nicely.........

HOTRODSRJ has pointed to a fixed type fan that I am a huge fan of. I have run the 18" version of that fan on a few cars to include my own and it moves more CFM than that of all the previous mentioned EXCEPT the Lincon Mark VIII fan......they are really, really close! But none the less work very well. Derale now makes a clutch fan that is very similar to the one being discussed, so now you can go both ways.

One very overlooked part is the shroud. I am sure the left hand guys here can agree to that. Well, its the same on our street cars.....we really just need to optimize what we already have.

stenn5- If you want an electric, just remember the electrical system and what is really required to run some of the cool guy electric parts. I'd run the Lincon fan myself, as nothing can touch it for size, cost and CFM rating. I have used this fan on 700+ HP street cars that live in Arizona and they never see anything over 195*, in traffic on a 107* day.

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paulm
Tech Team


posted 05-19-2003 02:46 PM
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Wow...What a great discussion!!

Just to clarify, to get the electrical/charging system capable of handling an electric fan and AC would involve bolting on a later model alternator that charges better and stronger at lower RPMs?

My original alternator which I had rebuilt and rewound to put out 100 amps works fine so far, but doesn't push a full charge until about 1000 RPM. The only thing that I wired into my system was a 75 amp power relay($15.00) and a switch($3.00).--------------------


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DjD
Administrator


posted 05-19-2003 03:42 PM
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quote:
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Originally posted by paulm:
Wow...What a great discussion!!

Just to clarify, to get the electrical/charging system capable of handling an electric fan and AC would involve bolting on a later model alternator that charges better and stronger at lower RPMs?

My original alternator which I had rebuilt and rewound to put out 100 amps works fine so far, but doesn't push a full charge until about 1000 RPM. The only thing that I wired into my system was a 75 amp power relay($15.00) and a switch($3.00).
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I'm not an electric expert by any means but if you swap in a 100amp alt for the stock 60amp or smaller alt, you may be taking a risk if you haven't upgraded your wiring along with it.

I too agree that electric fans can do the job as can alum radiators. It's the more expensive choice though, as stated my fan and clutch were $56 new, not used and had I replaced the flex fan before having the rad re-cored I bet I'd still be using the stock rad my car had in it.

One personal observation, I have a car that has and electric fan and alum rad and it's operating temps run in about a 20 deg range depending on if the fans are on or not. What I mean is turn on the air to force the fans on and it drops 20 degs. (I know the reason for this has been discussed and bet Steve or Tom can elaborate on why) My car with a nonthermal clutch runs about an 5-10 deg difference depending on if the stat is open or not.

Like almost everything else out there, there is more than one way to skin a cat. The primary reason for design changes in cooling systems came about to keep up with body style designe changes. The old stuff works well if up to snuff. I know lots of cars from the 50's, 60's and 70's that ran fine in Vegas, Plm Spg or AZ heat.

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...Dennis

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chicane67
Tech Team


posted 05-19-2003 03:59 PM
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Paulm- It is not just the alternator itself that has to have that capacity, the wiring of the entire electrical system has to be up to the task.

I dont know how many people know this, but say you were to upgrade to a different- higher wattage bulb larger than the stock 55/60, the headlight section isnt really rated at any more than that. Some of the aftermarket bulbs go as high as 90/140wt. I know, because that is what I use. Do you guys remember the main reason for VW Bugs catching on fire ?? Well there is the answer. Most were of a 6volt system that was upgraded to a 12 volt system and the wire guage just wasnt up to task......put it under load and *POOF* fire in the hole !!

Now just think about when 'we' start adding all of this cool technology, without paying attention to the most important part of the electrical system itself.....the harness. I myself opted for the Painless harness back in '94 to rid myself of any future problems......and I am glad I did.

Man I just saw that Dennis got to the answer before 'Added my reply' so I wont beat it to death and let some of the other guys chime in.....
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paulm
Tech Team


posted 05-19-2003 05:23 PM
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OK, new alternator and make sure the original harness is in good shape.....or are you guys saying that it is required to "upgrade" your harness with beefier wiring?

I went through every wire on the car when I tore it apart and replaced anything that was messed up, so I know my harness is in good shape....although I didn't do anything to "upgrade" the wiring....

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chicane67
Tech Team


posted 05-19-2003 06:12 PM
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It would be someting to consider.

Just keep tabs on the amperage to individual devices. If it requires more, an upgrade may be necessary.

The more you add, the better the system requirements become. If it becomes necessary, you can always add a relay to control main power functions and use the existing wiring for the "switching" of the relay. This will control higher amperage circuits and not overload the current wiring. --------------------------------------------------------------------------------

DjD
Administrator


posted 05-19-2003 06:54 PM
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Think of wiring in the same way you think of a fuse. A certain gauge wire is requires for any given load just like a certain amp rated fuse is required to protect the circuit and accessory at the end of the wire. The reason for a larger output alt is added accessories, sound systems, cooling fans and anything else that requires power. Now each of those accessories have a draw on the system. A starter has a big draw when it cranks, notice the size wires connected to it. your dash lights have a small draw, compare the size of the wire that connects to them.

If a wire is too small for the draw it will heat up and like a fuse melt if allowed to. So high draw accessories require heaver duty wiring. The next thing is electricity takes the path of least resistance so even if you wire in that fan or system with the proper size wire you may notice other accessories slow down and bulbs go dimmer when the fan runs. This is where having the proper wire for the overall car comes in. Larger wire has less resistance won't get hot when taxed with a running accessory and other accessories won't over power bulbs and such...

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...Dennis

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paulm
Tech Team


posted 05-19-2003 08:12 PM
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You guys are great!! Thank you so much for patiently and thoughfully answering my questions!!

I understand how electricity works and the concepts of big wires and small wires. I was mostly wondering if you guys had any specific areas of the wiring harness that needed to be upgraded to support a large current draw from an electric fan, AC, etc. Like I said earlier I went through all of my wiring and made repairs as necessary, but do not have the experience that you guys do so I wouldn't know of any weak areas in the wiring that would need to be addressed.--------------------


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HOTRODSRJ
Tech Team


posted 05-20-2003 11:01 AM
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This is a great discusion here I agree.

There is some empiracle data available on mechanical fans and I know because we tested them unbenowanced to most. Try this link and remember this was a few years ago. Did not have the Derale heavy duty at that time.....wish I did. Check out
http://carnut.com/ramblin/dyno.html for more information.

Keep in mind that the high idle figures for a BB18 is almost exactly what a typical 16" Spal puts out and the engine is using up more fuel producing more waste heat to turn the fan at that high idle speed.

I would be interested on your guys take on this?

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STEVE "Jack'Stands" JACK
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chicane67
Tech Team


posted 05-20-2003 01:12 PM
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May I say Steve, an excellent effort on your part!

I just so happen to be an Instrumentation Engineer and this kinda stuff is what I do for a living, primarily on developmental research models for fluid dynamic interpretations (supporting various engineering facets)...... and for fun on my '67. I have roughly 45 data channels going in the car.

I believe you're error is in the calibration correction and is possibly missing some needed elements. But for you're "Close Proximity" I think you are close enough to support you're findings to within 8%-10%. To obtain proper calibration and reduce the measurement of uncertainity, you need data 'sets' from three 'sets' of measurement.

1)ambient condition (Baro pressure, temperature, rel humidity and altitude)
2)Pre vessal
3)Post vessal

Measurments required from each set:

1)Temperature
2)Vessal surface temperature
3)Static pressure
4)Total pressure
5)Vessal pressure (2 or 4 point radial measurement; average)
6)Volumes of pre and post vessal
7)Fluid velocity pre and post test surface (air)
8)Corrections factors for ambient conditions

Another good measurement would be the pressure between the rad surface and the electric fan.

As for the measurement, the direction of flow would be repersented on the 'X' axis. To create and average factor the static, total pressure and temperature should be incrimentially measured across the test area on the Y - Z axis (like a grid). There will be a need for a flow strightener before the pre vessal measurement. This will flatten out the pressure across the test area (averaging out dead flow behind the fan hub and peak flow from mid-blade).

Then spend a few hours messing around with "Fortran" and it makes life much more simple.

Great research Steve...... and the oil topic would be another good debate.
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HOTRODSRJ
Tech Team


posted 05-22-2003 05:21 AM
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Hey Chicane......thanks for the information and thoughts. You do have some great ideas on taking the test to the next level. Something that I am too busy to do at this point, but maybe an article for the magazine before it's over. FWIW, all the tests where done at relatively the same time and place therefore I dismissed the need for temperature and barometric issues. The obvious best and most accurate test would have been sucking all the air thru a known orfice (albeit big) calibrated to a known level. Next test will be with electric motors tho! As you know, the measurement of amps, volts and the resulting watts (with +/- 0.25% instruments) is far more precise than an engine dyno. I have several friends with huge three phase electric motors (50hp+) and all I would have to do is make the appropriate hardware to mount all of these. Alot less mess than engines stuff!

I too, am a engineer of varying degrees and interests like yourself it sounds. My main interests use to be all electrical, but I have just as much professional experience with mechanical as well. I stick my nose into just about anything that fascinates me which is from electrical power issues, cooling and fluids, aerodynamics, and even have an A&P, a billion years old (airplanes are too expensive and you wait around alot to fly)?

I like to find myths that are taken for gospel and bust them with science and logic. I also like mind boggling questions that have no apparrent scientific answer for. This is somewhat a format for my articles that I write in Northern and Southern Rodder Magazines and other media....just science based stuff, no subjective or paid for BS.

For example for you folks out there, here is my latest example of a mind buster for engineers. Take any penny and wash it thoroughly with soap. Dry. Then take a piece of flatten aluminum foil about the size of a large pin head (could be larger a bit). Now lay the alum foil piece on any non-metal flat surface and take the edge of the coin and lightly touch the foil. The coin should pick the foil right up off the surface. Hmmmmm? what is going on here? Some force is causing the foil to stick to the copper. What is that force and keep in mind these are NOT ferrous metals therefore magnetism is out! Any takers?

Wow.....did I get off topic or what?

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STEVE "Jack'Stands" JACK
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DjD
Administrator


posted 05-22-2003 06:26 AM
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quote:
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Originally posted by HOTRODSRJ:
Take any penny and wash it thoroughly with soap. Dry. Then take a piece of flatten aluminum foil about the size of a large pin head (could be larger a bit). Now lay the alum foil piece on any non-metal flat surface and take the edge of the coin and lightly touch the foil. The coin should pick the foil right up off the surface. Hmmmmm? what is going on here? Some force is causing the foil to stick to the copper. What is that force and keep in mind these are NOT ferrous metals therefore magnetism is out! Any takers?

Wow.....did I get off topic or what?
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Sounds like static electricty Steve, kinda like the baloon making your hair stand on end but that sounds a bit to simple of an answer since the question is coming from you!!

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...Dennis

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Scoop69RS-SS
Tech Team


posted 05-22-2003 08:32 AM
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Yikes, information overload. I love this stuff. Thanks.

I'm in the process of refitting the cooling system. I've been diligently reading all this information and the refit is growing larger by the second.

Dennis, your comment on the path of least resistance through me to the floor. I never thought of the health of the rest of the electrical system.

My plan was to go with a Griffin 23 (big block type) 23 inch aluminum radiator, with dual SPAL Fans, Edelbrock aluminum water pump with 20/30% increase in flow and a high flow 180 degree thermostat. 12 guage wire to a fan control and accomodate a future Vintage Air A/C.

I thought I read that when the A/C comes on, the SPAL fans need to come on also. Is this true? Or can the fans run under the same demand as the water temp? Meaning if the radiator or water temp is asking to engage the fans, due to slower speeds and air movement, that circumstance will also accomodate the A/C needs. Thoughts?

Side bar: Is there a stock, formed lower hose that will go from a big block radiator location to the small block water pump location? I'm assuming they would be different.


Last year I moved the battery to the trunk, ran a fused 2 gauge wire to the front fender windshield washer bracket, (less the plastic bottle.) There I mounted a Ford type relay for the starter, then down to the starter. I mention this because now I have all that power off the battery closely located, available to where the SPALs will be. I had thought this was going to resolve any potential power issues. (Hmmm, what's the big deal Rick, everyone else has a battery in aproximately the same spot.)

Side bar: Stereo fuses seem to be the quick burn type. I once burnt a 150 amp fuse. I now have a 300. I think my circuit would like a slow burn type but I cannot locate one.


So, your opinions would be most welcome. I know the 23 inch aluminum will be a great upgrade. The SPALs are considered to be of good quality. Now I need to design the SPALs in to the electric system. Do you think the engine harness and front light harness needs to be done right now? Or can a 12 gauge wire, relayed, to the fans do the job?

Rick.

With a four week delivery for the radiator, I don't think I'll ever get to drive my car.


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chicane67
Tech Team


posted 05-22-2003 01:15 PM
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Scoop - I dont think the 12 guage will successfully handle the TOTAL amperage load you will see using the the mentioned fan unit and the exisiting circuit load. IMHO, I think that you should either, up-grade that portion of the harness OR run a seperate circuit with a relay and/or a breaker for the fan itself. This provides independant protection and seperates two or more circuits.

HOTRODSRJ - Yeah, I'm right behind you with the Science and Logic approach.

The usual method of determining air density is to measure temperature, pressure and humidity. As air density can change total volume (depending on pressure and temperature) and relitive velocity which are components of Mass flowrate (which refers to flowrate in terms of mass per unit time).

The equation is not a perfect model of air density and introduces an uncertainty of approximately 1 part in 10^4. Typical routine measurement capabilities for the air density parameters are indicated as follows with the best measurement capabilities in brackets:

Temperature to 0.1 C (0.01 C)
Pressure to 0.5 mbar (0.05 mbar)
Relative Humidity to 5% (0.25 Cdew point)

The above parameters give a typical value on the air density (including the uncertainty from the equation) of 1 part in 10^3 (2 parts in 10^4 best capability).

For lower accuracy measurements the NIST (simplified) air density formula can be used.

AD would be equal to:

[(0.348444xP) - h(0.00252t - 0.020582)]
---------------------------------------
(273.15 + t)

Where.....

AD = Air density (kg m-3)
P = Air pressure (mbar)
h = Relative humidity of the air (%rh)
t = Air temperature (C)

There is a typical uncertainty of 4 parts in 10^4 on this equation over the range of air density of 1.2 kg m-3 10%. Air is dense. A cubic metre of air weighs approximately 1.2 kilograms. A 1 kilogram stainless steelweight displaces 150 mg of air The density of air can vary between about 1.1 kg m-3 and 1.3 kg m-3, which is equivalent to a change of 25 mg in the weight of a stainless steel kilogram of volume 125 cm.

Anywho......I'll take a stabb at the penny/foil anomaly......

Just because the materials are 'non' ferrous, does not mean that there can not be characteristics of magnitism. A magnetic charge can be persent in any material where carbon is present, therefore it is possible to have a charge in either of the non ferrous materials relitive in this theory.

The charge would be evident as a 'negative potential'. With the greater in potential being the copper penny, but its overall potential would be determined from the amount of pure copper in said penny (different year, different amount of pure copper present). With the penny having the greater negative potential due to the larger volume of capacitance available from the higher mass density of carbon present, the aluminum will have a stronger attraction to draw itself towards a greater negative potential.

Use an older penny, and pick up a larger piece of aluminum......

At least it sounds cool (probable)......
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HOTRODSRJ
Tech Team


posted 05-22-2003 06:25 PM
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Scoop69.....you have to do as Dennis has suggested or risk meltdown.

Anytime you add features or electrical load (including alternator upgrades) you have to design the whole circuit. This means wire, connectors, fuses or breakers, and relays if needed.

These current hogging fans need an aux relay of at least 150% of the continuous current of the device. This means if you have a 30 amp device, then move up to a 70 amp relay and don't trust a 40. Upgrades to alternators should be watched carefully too. My suggestion is at least a number 10 for your application. But, don't guess...here is a chart to help since distance vs amperage is the real key. Go to http://www.amplepower.com/primer/gauge/ for more help.

Chicane....you da man, but the age of the penny has nothing to do with it and you are getting there with "opposites attract" theory.

The answer is aluminum and copper have different
numbers of electrons and have the highest filled energy levels at different energies. This means that if you put the two metals together the electrons will move from one to the other because electrons can lower their energy by filling lower energy levels on other atoms. This does not continue forever since the electrons leave positive charges on the metal they have left. When the metal is charged up enough the electrons stop moving and then we have two materials with opposite charges and these charges will attract, hence the force of attraction. However if you do this experiment you will see that the attaction force will only support so much mass of the aluminum foil.

Pretty neat trick to ask fellow engineers....it drives them nuts.
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chicane67
Tech Team


posted 05-22-2003 07:53 PM
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You shoulda seen me today......even using insulated pliers to isolate the human capacitance/charge from the penny.......(not kidding). Ya gotta see it to believe it ya know!! --------------------------------------------------------------------------------


MStennes
Tech Team


posted 05-24-2003 08:04 AM
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So what have we come up with?? Somewhre on the information overload I forgot what we came up with? Stock fan or electric?

--------------------
Mike
69 RS/SS convertable pro-tourer
In 2010, M$ Windows will be a quantum processing emulation layer for a
128-bit mod of a 64-bit hack of a 32-bit patch to a 16-bit GUI for an
8-bit operating system written for a 4-bit processor from a 2-bit company
that can't stand 1 bit of competition.

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DjD
Administrator


posted 05-24-2003 09:03 AM
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I think what's been said is both work and get the job done... It's really up to you. If you go with a fan and clutch there are choices and I found the ones I mentioned and used is a good inexpensive option and doesn't use too much hp. You could buy a factory replacement and loose 30 or so HP. The electric fan is a viable option as well but could be spendy and you have an electrical system to think about...

Decision is up to you and the data to make that decision has been laid out in great detail for you... It's your call!!--------------------
...Dennis

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BPOS
Tech Team


posted 05-24-2003 04:37 PM
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Interesting thread, guys. My brain hurts.

A question regarding the non-thermal clutch fan DjD mentioned. I did a bit of looking and found that it runs a constant 60% of water pump speed. What's the point of that? It seems at idle you'd be reducing airflow where you need it most. Am I missing something?

On the thermostatic clutch fan, I couldn't find a temp rating for them, i.e. at what temp does the fan come on? I know I could call Flex a Lite, but I thought I'd ask here first.

Thanks!

--------------------
Al

69 Base Convertible, ZZ430+ (383 Stroker), TH200 4R, 3.73 posi


DjD
Administrator


posted 05-24-2003 09:11 PM
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quote:
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Originally posted by BPOS:
Interesting thread, guys. My brain hurts.

A question regarding the non-thermal clutch fan DjD mentioned. I did a bit of looking and found that it runs a constant 60% of water pump speed. What's the point of that? It seems at idle you'd be reducing airflow where you need it most. Am I missing something?

On the thermostatic clutch fan, I couldn't find a temp rating for them, i.e. at what temp does the fan come on? I know I could call Flex a Lite, but I thought I'd ask here first.

Thanks!
--------------------------------------------------------------------------------

As I understand it a nonthermal (centrifugal) clutch fan is just that. At lower rpms the clutch is more positive so the speed of the fan is closer to the speed of the water pump. As the rpms increase the clutch slips and and the ratio between fan and water pump changes so the fan goes slower than the pump.

Here's what Hayden says about them. http://www.haydenauto.com/thermal.html

Most thermal clutches engage around 170degs and the 60% of pump speed you mention is for standard duty thermals. Reference Hayden's FAQ page. It addresses your questions. http://www.haydenauto.com/faq.html
--------------------
...Dennis
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CFunK
Tech Team


posted 05-24-2003 09:25 PM
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SJ,

You kill me. One day it's nuclear reactors the next it's penny's and aluminum.

Glad I know you.

--------------------
-Funk
My Daily Driven '67 RS - Yes, I drive it daily

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BPOS
Tech Team


posted 05-24-2003 09:34 PM
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Thanks, DjD!--------------------
Al