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Old Oct 8th, 15, 10:47 PM
nova 1974 nova 1974 is offline
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Default Tri Flow Radiator


I am going to be putting a BBC in my 74 and am going to need to upgrade the cooling system. I was on the Eastwood website looking at tools and saw that they have radiators. They are advertising a three level cross flow radiator. Have any of you used them? I did a few searches and didn't find anything on the forum. But I am new and may be looking in the wrong places.

I have read all kinds of arguments about cross flow, down flow, single tube, 4 tube. But is there any good research done on what works best?

To me it seems logical that bigger tubes are going to be better. My whole life I have heard that more rows the better cooling. But I look at the champion 4 row for my nova and it has .63" tubes. Granted there's 4 of them, but dang they're small.

So what's better?

1. Bigger tubes but less of them?
2. Smaller but more?
3. Single cross flow?
4. Triple cross flow?
5. Just get the biggest darn radiator you can fit under the hood?

The Eastwood site makes some good points, and you can't really argue with the prices if the results are legit.

I'm just another nova guy wanting to have fun and learn some along the way.

Thanks for your input.
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Old Oct 9th, 15, 08:04 AM
Big Dave Big Dave is offline
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Default Re: Eastwood Tri Flow Radiator

I wrote this three days ago on Team Camaro but it applies to your Nova. 1967-'69 Camaro and 1968-'79 Nova use same radiator, fan and shrouds. A Cross flow does not cool any better than an upright. The factory went to a cross flow because of lower hood lines. I could put a tunnel ram on top of my big block and close the stock hood on my '55 2dr sdn. Can't do that with a Nova.

Look to what the factory did with their high horse motors that shipped with A/C (in other words the 350 horse 396). Radiators are sized by horsepower because a third of the power you make is wasted to the radiator. This is a fact of Thermodynamics. So a bigger higher horse engine gets a bigger (in size) and number of rows of copper tubes in the core.

The factory went to aluminum core radiators (except on the 'vette) only because the price of copper went through the roof. Copper actually transfers more heat through the metal than aluminum does. The 'vette has had an aluminum radiator since 1963 because an aluminum radiator is lighter than a copper one by quite a bit.

A welded aluminum radiator with it's bigger tubes allowed by aluminum's extra strength reduces the number of tubes to two that are one inch to 1-1/4 inch in diameter. That larger size tube allows for more surface area to shed heat to the passing air, even though the aluminum isn't as good as copper at transferring heat. The reduced number of tubes also allows more air through the radiator to cool the engine better as there is less air resistance. Finally aluminum is a stronger metal than copper is so IF and only if you have a welded heater core as well you can run a higher pressure radiator cap to raise the boiling point of the coolant even higher than is possible in a copper/brass radiator that is soldered together because of the dissimilar metals.

It isn't the cast iron block that is in danger of failing from over heating at 284 degrees F (the boiling point of water with a 24 pound radiator cap: add some antifreeze and it increases the boiling point higher still). No the limit is the motor oil in the block. It begins to oxidize (turn from that new golden honey to black) at 240 F degrees. Above 260 F and it actually starts to break down into simpler molecules. So if you are worried about over heating, install an external engine oil cooler in front of the radiator off of an old Chevy Caprice cop car. That is what comes factory standard on all high horse 'vetts and pick-ups with a towing package.

A stock copper brass construction base V8 SBC radiator has only two cores. A BBC radiator uses three cores. Add to that A/C to either motor and you hit the lotto with four cores on a BBC A/C radiator as A/C adds a core. So you want a radiator sized for a BBC with A/C. That means trimming the radiator core support and adding a longer top plate and welding in a new aftermarket bottom radiator support to do it right. This is because a BBC radiator is two inches wider than a SBC radiator and it needs the support.

By the way you want that internal transmission cooler in your radiator (I know they cost more than without) this is because in addition to paying for that tranny oil cooler (that is insufficient to cool a tranny with a higher stall speed than stock) you get a higher fin count. Simply put there are more of those little brass combs between the copper tubes per inch with an automatic radiator than there are for a manual transmission radiator. They do that to shed the extra heat the transmission is dumping into the radiator. I also recommend adding an external transmission oil cooler in front of your radiator, even if you do not have a high stall torque converter top get any extra heat out of your coolant.

Finally I can address the 800 pound gorilla in the room. Electric fans. They don't work for Sith spit. The factory went to electric fans because the motors in modern cars sit side saddle. They are all wrong wheel drive so they can not use the motor to power the fan. Electric fans do not work better at moving air. They are just a stop gap until your car starts to move again. Few cars have an accurate heat gauge because if you had an accurate mechanical gauge monitoring head temperatures you will notice the temp rising while you idle.

The BEST fan is a factory BBC fan and fan clutch. The only thing you can do to improve upon this is to add a thermal control unit to the fan clutch that will disengage the fan when the car temp is in the normal range while driving. This saves energy. Do not buy a HD thermally controlled fan clutch, they hardly ever slip. (they are designed for 20 inch diesel truck fan, not an 18 inch fan in a car).

An electric fan doesn't save horsepower. It costs you more per horsepower (which is pulled out of the system by the alternator) because you are converting mechanical energy to electrical energy and then going back and converting electrical energy back into mechanical energy. Any engineer will tell you every time you convert energy you loose some. Same applies to a flex fan. It takes energy to straighten out those blades so that they can slip through the air. There is no free lunch!

Luckily there isn't that much to loose. A 30 AMP electric fan is at best making a quarter of a horsepower to turn the fan blades. If you attempted to have the electric motor drive the seven blade 18 inch in diameter mechanical fan it would burn up as it takes several horsepower to get a fan to move that much air. (you can look at warehouse fans that are sold by the air flow to see the correspondence between cfm and horsepower needed to drive the fan).

The only problem you will have with a BBC radiator is the fan shroud. A BBC is offset in a Camaro and Nova so the hole in the BBC shroud is offset as well. To compensate you will need a BBC Chevelle fan shroud to work with your SBC powered Camaro./Nova This will cover the radiator properly. But your fan clutch might have to be spaced out for length as there are two inches less room between the water pump on a BBC and the radiator than on a SBC.

Big Dave
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Old Oct 9th, 15, 03:00 PM
onovakind67 onovakind67 is offline
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Default Re: Eastwood Tri Flow Radiator

Originally Posted by nova 1974 View Post
The Eastwood site makes some good points, and you can't really argue with the prices if the results are legit.

Here's the Eastwood video on youtube. Read the comments, including all the replies.

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.

I won't get into the electric fan argument except to say that I've never had any cooling problems with an electric fan. They work really well at idle, and once you're going 20-30 mph you will have enough natural flow that you don't need a fan. They only consume current when you have them on.
I want my empty vee...
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Old Oct 10th, 15, 08:18 PM
nova 1974 nova 1974 is offline
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Default Re: Eastwood Tri Flow Radiator

Thank you Dave for the explanation. It gave good insight as to how a radiator works.

Maybe I'm slow...
But can you or someone else give me a two or three bullet point outline on what I want to look for when finding the right radiator?
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