Does anyone know the formula for determining the BTU output of an engine for also determining the cooling needed for a given type of radiator, such as aluminum or brass/copper? thanks Fred P
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Fred P.

Hey there Fred........I have several ways of figuring BTUs, but you have to know the overall accurate hp rating of the motor and do alot of SWAGing to get there.

Basically, 35% of the engines heat is produced and removed through the conventional cooling system. The other parts of the heat go out the tailpipe, the oil system, conduction and convection, so on and so forth.

It also depend on the design of the water jackets, water pump, etc. Aluminum heads and intakes remove heat through conduction better than iron.....so that is a variable, for example.

Simply put in my experience, there just are too many variables to get it close without exactly measuring the power output. You can even determing the hp of the engine by measuring the heat output at the radiator vs the input temperature at the pump. So, you can work the formula in reverse, but the power has to be known!

Just my 2 cents!
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SOUTHEASTERN GOODGUYS REP

Guess I was kinda thinking the same thing but hoping there was something that sez if you have a certain size motor then a certain size radiator would be required. Seems a bit arbitrary to just grab a radiator and hope it works. Problem is, I don't have any room for overkill here due to the limits of the chassis width and height but I can go to a thichness of at least 4 inches. my limits are 19" high by
13" wide. Not enough for a 2 row Vega size 4 banger radiator and a nicely built Chevy 90º V6.
I think I'll ask Jason about the PRC radiator and maybe he can put me in touch with them so I can ask all of the necessary questions. Now, how do I get in touch with Jason.....?
Thanks for the input. Come to think of it, a BTU formula would have to be for a given static system such as an industrial setup with constant speed etc.
Bet if I come up with an answer it will be posted very quickly for others! lol Fred P
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Fred P.

Fred, have been there before guessing the fit thing!!

But, I would stick to a aluminum 1.25 inch double row radiator. That would be the best that you could design given todays conventional wisdom.

Call Buddy Griffin......I know some people out there don't like Buddy for whatever reason, but I have always found him accommodating.

Steve Jack
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SOUTHEASTERN GOODGUYS REP

i just had an aluminum rad. built by afco. they did a nice job and it fit like a glove. i used their online form for the design of the rad., they called me to give me a quote and go over the specs. seemed like a nice bunch to work with. www.hotrodafco.com
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project...39 ford pickup

I also have an aluminum AFCO rad in my 32 and I am satisfied with it.
Dave

I also have an aluminum AFCO rad in my 32 and I am satisfied with it.
Dave

Thanks for the tip Rick....I filled out their form in detail so maybe they can help. Fred P
might triumphs over right.
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Fred P.

I Feel that the best radiator for the best price is the PRC Radiator. They use the same core that is used in the racing radiator and I know that several of the guys in the UDTRA racing series run them. Those guys are running 800 H.P. and bigger motors. Alot of the rodders in the midwest Indiana, Illionois, Kentucky... are running the PRC rads and the people I have talked to tell me that they are good people and they have a very good product. Not to mention the web site we are posting on sells them. Do any of you have the PRC radiators and what do you think about them and their product? Dick Z and Jason what is your input?

I have heard and seen alot of "racing" radiators (or other parts) action from all kinds of inputs......and there are great, quality and capable products out there make by some racing outlets.....but a warning before buying a "racing" radiator.

Yes....racing engines do produce more heat because of the hp they are making, but they also are designed to MOVE! Not only MOVE but move fast. The airflow they get at speed creates tremendous cooling capacity alone! They are NOT designed to idle in traffic etc. Some of the racing radiators that I have seen do not employ the best heat transfer technologies just to keep the engines to operating temps. Simply put, they are meant to keep the racing engines cool at 100MPH+. They don't even run thermostats but restrictors for the most part.

I am NOT recommending that you shy away from racing radiators necessarily, however you should do your homework first before buying. The biggest and best technology is 1.25 to 1.5 inch two row aluminum tubed raditors with either "Z fin" or traditional fin design. Some of the street rod radiators come with built in overflow tanks which is a real neat deal. Single row aluminum racing radiators will not usually cool at healthy high performance engine on the street and esp with air added. I am not endorsing any brand name here per se, even though I have my preferences.

Just because it is associated with "racing" don't think that it automatically fits the street in spades! My company, for example, makes a line of pulleys and brackets for circle trackers, but I absolutely would not recommend them for the street. The science of racing is completely different and for the most part not applicable to the street science.

Just my 2 cents.....

Steve Jack
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SOUTHEASTERN GOODGUYS REP

PRC has its roots in building radiators for street rods and builds many more radiators for them than for race cars. We at SRS have handled PRC radiators since we first opened for business and have never had a problem.
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Dick Z

DickZ,

I didn't mean to directly or indirectly infer that the PRC product was not a good one. It sounds like you have done a great job of researching this product.

My soap box speech here is about the "racing" labels that get affixed to differing products and we automatically think that just because it's a "racing" product or company that it makes it better for the street, when in fact it is a poor selection for street driven vehicles. I can think of one great example......under drive pulleys! It is a huge product on the racing scene and actually saves hp at very high rpms, however is a very poor choice for the street in that the underdrive pulleys will slow down the cooling process and charging circuit as well. Another myth is people using "racing fuel" for better performance. Patoooey...I say. If you are running higher octane fuels in your engine you may in fact be taking away power and performance and paying to do it! Summit sells racing radiators as well, but will tell you that they are not good choices for the street. Usually pure "racing" radiators are smaller than street versions and spell trouble for those of us in hot climates. I am sure PRC designs their offerings for the street, even though they associate the name of racing with the product.

Once again I was not picking on your product per se. Sorry if taken that way. I deal with a company that is out of Arizona (AirMobile) that sounds like the same thing.

Steve Jack
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SOUTHEASTERN GOODGUYS REP

JUST TOUCH THE RADIATOR, IF YA GET BURNT......TOO MANY BTU`S