Need some help w/ buying a new Radiator

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Griffin's claim is supported bya geometric analysis

Postby vega_man_larry » Sat Oct 28, 2006 11:10 am

omparing a "round" 1" tube to a "flat" 1.25 inch tube. the round tube only intercects the fin at the mid point. All the rest of the intercections are at some angular vector which doesn't promote heat dissapation as well as a perpendicular intercection. You wind up with a thrermal efficiency that is reduced by the angular vector. The flat tube technology that Griffin employs allows for a more efficient heat transfer because more of the surface of the tube is exposed to the perpindicular vector of the airflow, permitting more efficient heat transfer, and achieving the 50% reduction that they claim. If you forget to factor in the angular vector in the tube comparison the 1/4 inch difference doesn't appear to be that big of a deal, however it is the flat tube that is the secret to the effeciency, which may be overlooked when one is doing a simple comparison.

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Postby djv8ga » Sat Oct 28, 2006 1:30 pm

Is Griffin the only one who uses oval tubes? Be Cool's web site claims that dual 1.25" tubes are worthless. I wonder if they tested round and/or oval tubes. Very interesting. Thanks for setting me straight on this Larry. I still dont think my Griffin has any chance of cooling a 600HP street car though.
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Postby cjbiagi » Sat Oct 28, 2006 10:12 pm

What radiator uses round tubes? I have never seen round tubes in any radaitor, copper or aluminum. The biggest difference between copper and aluminum is that the tubes are wider. Apparantly a copper tube can only be 1/2" wide. It is not strong enough to be made wider. Aluminum can be made in 1" or 1 1/2" widths which means there is more contact area between the tubes and the fins. Since the fins do not contact the curved portion of each oval tube, making the tubes wider increases efficiency. You also don't have as much wasted space as you do between 3 or 4 rows of copper tubes.
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Postby djv8ga » Sat Oct 28, 2006 10:58 pm

Ok..Let me get this straight. 1.25" flat tube rad will cool 50% better then a 1" flat tube unit. I dont know the math but I sure don't believe it.
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More on Griffin thermal efficiency

Postby vega_man_larry » Sat Oct 28, 2006 11:33 pm

As has already been mentioned aluminum has a better heat conductivity coefficient than copper has. I think Griffin's calculations are based on a round copper tube vs a flat oval aluminum tube. Another thing that needs to be considered are the flow rates of the various tubes. I have friends in the fuel and hydraulics groups in Philly that spend their whole life examining flow rates of various shapes of tubes. Its weirds how a fluid will flow in a tube. From my engineering core physics I remember something about the area being a square function when you increase the diameter of a tube. As the radius increases you increase the area by pi X r squared so a quarter inch in diameter can become a big deal. Flattening the tube cuts down on the area but allows more of the surface to be exposed to the cooling air. It probably is some nasty senior project style calculation that includes flow rate - tube size - and the surface area perpindicular to the cooling flow. The sales ad guys just print the results as most people would be hard pressed to follow the math . I'm sure it gets pretty hairy and involves rates of flow which imply calculus and some form of a determinant table as well as the integration of some trig identities. If the claims of Griffin couldn't be backed up by mathmatics, some Lawyer-Engineer would have probably sued the company for false advertising by now. That's how many lawyers make their living - but that's a topic for another day.

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Postby djv8ga » Sat Oct 28, 2006 11:44 pm

It just seems like too static as well as optimistic of a rating to me. The second row will not cool as well as the first one. I maybe just too skeptical.
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Radiator

Postby danfigg » Sun Oct 29, 2006 12:49 am

This is what I used from SUMMIT Part # BCI 65004. Bolts right in if you have manual steering on the V-8 MONZA body Im not sure on the VEGA. If you have power steering that is where its trick. I cut my upper hose and played with the adjuster on the power steering pump to push it to the side where it has slack as far as i will go. You will have to take the bracket off and make for more adjustment for it to move and then once this is done I used the shorted belt that napa had. Or you can use a flex hose and be done with it. The only problem I had was that the rad is about a 1/4 of an inch short and in the rad holder it was a little loose. I remedied this by using the old hose and cutting 2 inch by 2inch square and put them on the corners of the rad. and tightend down the rad holder. That is it As far as Im concerned BOLT IN--Danny
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Postby cjbiagi » Sun Oct 29, 2006 9:33 am

Don't forget that a dual 1 1/4" radiator also holds more coolant than a 1" model. Not exactly sure how much, but there is quite a bit more coolant being exposed to the fins. The point of the matter is that a dual 1" model gives you 2" of tubes, the same as a 4 row copper radiator which uses 1/2" tubes. However, there is significantly more contact area between the 2 tubes vs the 4 tubes because the fins dont contact the entire area of each tube where it curves around. Generally speaking a 4 row radiator was about as much as was ever put into any stock vehicle and a dual 1" aluminum will outperform it. So, not counting for the greater efficiency of a aluminum radaitor, a 2 row = 4 row copper. A dual 1 1/4" would at least be equal to a 5 row copper, if that doesn't cool your engine what will?
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Postby djv8ga » Sun Oct 29, 2006 11:01 am

Yeah...but this Vega griffin is the size of a postage stamp. 1.25" or not...It doesn't hold enough fluid for a 600HP street car engine. If it did, Guys wouldn't be screwing around slowing down the flow through a 600HP rad while running a 400HP engine IMO.
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Postby cjbiagi » Sun Oct 29, 2006 3:40 pm

Yeah, I agree with that. I am not real familiar with the Vega one, but I do realize it's smaller than the Monza unit. That was a point I made that these HP ratings are a bit arbitrary because I think they list all of there 1" as 400hp and all of their 1 1/4" as 600HP with no real regards to the size difference between cars. There is a calcualtion for total surface area that a radiator should be in the Griffin catalog I believe, maybe it's online too.
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griffin is good

Postby geartwister39 » Sun Oct 29, 2006 5:11 pm

ok guys i just got here 2 days ago now this is what it is ive got a 400 hp griffin in my monza wagon .i have a decently built 355/th 350 in my wagon 256 gears out back i drove this thing from north georgia to south indiana towing a 5x8 u haul trailer 425 miles or so . the griffin performed well as one can expect. the only time my car started to get hot was in a 2 hour traffic jam on i75 in kentucky. so i can say it is a quality part.truly tested. :lol:
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Postby djv8ga » Sun Oct 29, 2006 5:26 pm

One thing that makes me think I could be wrong about the radiator being too small is that Griffin says that a larger radiator with surface area that doesn't get air flow will actually make the car run hotter then a smaller rad. Who knows. I'm going to cough up the money for a US Body cowl induction hood to see if that helps. OMG...I hate to pay that much for freight from FL. to AZ. OUCH!!!
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Cooling points from a profesionals point of view,,,

Postby MonzaRacer » Thu Nov 02, 2006 2:06 am

OK guys I am new here but drove my 76 Shyhawk with a 3 row V6 rad(only dif isthe straight neck instead of the curved neck) and a short water pump and a flex fan after I burnt up my electric from running it with no relay. And my car never over heated with a true 420 hp 327 (dyno numbers on a twin of it)on the street.
One most people think a Monza rad wont cool a 400 hp car but my buddy had a 355 street strip engine in his 71 Vega and never had over heating problems either.
Oh and I took a 350 hp 350 in an 86 Ranger and cooled it with a stock 2.0 4 cyl Ranger radiator so why wont your big dollar aluminums keep a car cool?
So here we go into heat management.
One very large and spectacular rule every one forgets is air flow through the core. Without this you can have a rad 3 time the normal size and never cool a car, Pure fact.
Another thing is if you run aluminum you MUST ,MUST ,MUST change your antifreeze religiously every year even if its not driven a lot. Some say you dont but a friend bought one of the custom ones when the hbody group bought(got same price I guess) and after 2 years its leaking from internal corrosion. This is because of 2 dissimilar metals and a 2 component liquid (um this is same chemical mix that makes a battery) and a corroded intake and Edelbroke water pump. After chemical testing his antifreeze (name brand and new)did not last 2 years and he even used distilled water too. Analisys lab stated that if he had changed it every spring he would have been in good shape but due to large amounts of aluminum and cast iron in fluid content it became a battery after inhibitor broke down (he even had extra water pump lube/inhibitor in it too) .
So in the ineterst of cooling, the coolant must move at a rgulated rate (ie thermostat) and it must stay in the core long enough to release the proper amount of heat (ie the actual condition of heat exchange) so as to manage the heat of an engine.
I have found on most street engines that the difference of stock over underdrive pulleys just doesnt free up much power for the most part (despite some peoples actaul quotes) over cooling problems.
So if you have a properly operating radiator, proper air flow and proper regualtion a car can and will function.
Now this said if your car creaps up to say 230 in traffic and stays there it will not hurt even over a long period of time, does this mean its over heating ,no it is a result of low air flow with proper heat exchange to existing air flow.
Most people keep adding stuff to the system without understanding how they work.
I used a 160 thermostat in summer and got crap mileage, went to a 180 and my mileage came back.
First I use a good condition rad (ie flows good) a good fan that moves plenty of air ( and not at 10000 rpm) till core cools and shuts off.
I have been using electric fans from factory cars for years, my favorite is the ones from older Grand Ams with 4 mounting feet and I always mount it on the inlet side of the rad (on upper rad hose side) and I use a thermostatic switch so it will come on till core cools and it drop engine temp ,then shuts off.
Another thing is I see that most people will run thier cars retarded in timing and this causes a lot of over heating too.
My 327 had the .125 pop ups in it and 71 cc heads and steel shim head gaskets and would never top 220.
OK and another great change and it doesnt have to be changed every year is Evans NPG+ coolant, it boils at 369 degrees with no preasure and has very low nucleate boiling threshold (ie it wont boil up next to hot spots so it absorbs heat) and it has no water so it doesnt cause corrosion as bad (if at all) in a multi metal system.
Most people limit their timing for some reason my 327 had 16 initial , HEI with stock weights, light springs and manifold vacuum advance and would give a total of about 55 to 58 degrees at cruise. Unless you have super new tech heads(ie Vortec, aftermarket heads) you can run this much and never have problems. The 2 best street heads available that i have best luck from without major mods are 487's and 441's (both used with bigger valves on Vettes) but thats just what I used till World started making good heads.
I have similar timing set up on my truck I drive right now and after the other engine(built in 97 for my 71 monte) and in my truck and driven from september 02 till last July 4th. now I have 355,SR Torquers with 202/160 and LT4 HOT roller and it works great and in my contiuously loaded 78C10 with no over drive it runs cool and still averages 14-15 mpg and I drive it 90 miles a day.
Here is the combo, your system must cycle the fan at low speed, if it has proper air flow/proper system design, it will not heat creep at cruise speed.
Seems to me if an Hbody system didnt work with AC condenser from factory, strapped with the lean emission carbs and all the garbage tacked on then your cleaned up properly jetted/timed engine should not have major problems.
Just my findings, leasons and observations from over 20 yrs of car building.
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Postby ColinOpseth » Thu Nov 02, 2006 2:16 pm

You can run Dexcool with aluminum but it can gum up if you aren't careful.

Try hanging a piece of nickel in the radiator. It should attract most of the electrolysis. I believe they did that in Cadillacs in the early 1980s.
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Postby geartwister39 » Thu Nov 02, 2006 4:29 pm

just a dumb question.... with the electrolisis,will a chunk of zinc work? like in marine applications ? i have to know because i completly forgot that electrolisis will happen with that high $ rad. also i need to learn what all will i have to do for preventative maintenance. i have already flushed the system with new antifreeze. thanks
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