Hi Guys

Just wondering if any one knows how to calculate the cooling power (?) of a given radiator? By my calculations the old 1100 rad has a larger capacity than the starlet one? Plus its copper and 3 core versus 1? Does that make if more efficient (if front mounted and fitted with a thermo fan??). Dimensions below.

Starlet core 655mm x 325mm x 15mm = 3,193,125 cubic mm??

1100 core 310mm x 310mm x 45mm = 4,324,500 cubic mm??

Its gonna be a bitch to get a rad in there so I want to know it will work once I've gone to all the effort and expense.

Cheers

Madmorrie

Madmorrie,

Its got a lot more to do with surface area than volume.

The Starlet rad has a lot more surface area facing the airstream than the Morrie.

Frontal surface area of the Starlet is 655mm x 325mm = 212, 875 square mm,
while the Morrie is 310mm x 310mm = 96,100 square mm

In other words, the Starlet has 2.2x more area to 'radiate' heat with directly into the airflow.

It also comes down to the heat transfer ability of the engine as well. With a lot of alloy, the Starlet can shed heat more efficiently.

In saying all this, I dont have a definitive answer, but I used a 3-core aluminium radiator of 300x300 dimensions mounted directly behind the grill, and I think it would work fine.

Hope this helps.

Cheers,
Tricky

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"Not Speeding Officer..........Qualifying"

Keep in mind the starlet is a single core while the morrie is at minimum a double if not triple core.

So a double core would be 2 x 96,000 = 192,000
and a triple would be 3 x 96,000 = 288,000

Dan

Ahh but, the amount of heat dissipation reduces by 50% once you add a core, due to the already heated air passing over the 2nd and 3rd cores, and not being able to 'recieve' as much heat loading.

So, whereas the first core might be 100% efficient, the 2nd core is only 50% as efficient, and the third core is only 25% as efficient (half of 50%, the preceeding core).

That means that the Morrie radiator in effect is 1.75x greater than the surface area of a single core alone.

Which still leaves the Starlet miles ahead as it is 2.2x the Morrie frontal area.

Cheers,
Tricky

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"Not Speeding Officer..........Qualifying"

i have a swift gti radiator in my starlet gt, its much smaller than the standard radiator as the bigger TD04 turbo i have wouldnt fit unless the smaller but thicker core radiator was used. It always stays cool even in 30 degree plus weather its always either just under half or around the 1/3 mark. dono how this would go in a morrie tho, but it would be easier to fit in id imagine?

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1968 Morris Mini Deluxe......sold
1992 Toyota Starlet GT EP82

Thanks all.

Tricky, Good point about the 2nd and 3rd cores being less effective. Still, it sounds like you will have similar cooling to a standard rad only front mounted and with (presumably) an electric fan?

Rude, thanks for your input. I do have a swift radiator here so maybe I need to look more seriously at that. Do you know if the Gti is the same as standard swift? I have no idea what mine is other than its from a swift?

I have been wondering about a 'gordo style' rad that is built to fit in place of the grille. Only problem with that is it leaves no space for an air to air intercooler. I may have to bite the bullet and run a scoop and a top mount

Madmorrie

not 100% sure if they are different but i assume that the gti radiator would be probably a thicker core or something than the normal swift one, all ask around and hopefully get an answer. unless someone here knows for sure.

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1968 Morris Mini Deluxe......sold
1992 Toyota Starlet GT EP82

I think the Morris radiator will be sufficient, assuming of course it has a thermo fan fitted. Have a look at the radiator Brad fitted to his thing and I don't recall hearing any issues of it over-heating. In addition he was only running a top mount intercooler.

JC

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But he's thriving and striving and hugging the turns.

hope that helps a little bit if you wanted to go that route.

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1968 Morris Mini Deluxe......sold
1992 Toyota Starlet GT EP82

yeh i was running a honda city radiator on my 4efte mini. It was fine, never ran hot, only time it went over 1/2 was around the 14th lap at wakefield park raceway on a 32 degree day, even then it just went alittle over 1/2.

It was the smallest radiator i could find at the local pick and pull, may have even been smaller them a mini radiator, also came with a tiny fan that didnt take up much space.

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1974 Moke - 998cc
76 Clubman B16a2 Vtec AWD Turbo 12.9@105mph
https://www.youtube.com/watch?v=V9PW49e1hYs

I would probably have to agree with that JC, as the 300x300 3-core alloy unit I had built is supposed to have enough efficiency to cool hot 6's.

MadMorrie,

Yep, got a slimline electric fan (Kenlowe I think) behind the radiator running of the std Starlet thermostat switch.

Cheers,
Tricky

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"Not Speeding Officer..........Qualifying"

Stricltly speaking the effiiciency isn't necessarily 50% less per core - it will be the difference in temperature the second and consequently the 3rd core see.
It will be 50% if you increase the temp to second core by 50%. i.e. 1st core sees 25 deg and 2nd core sees 50 deg.
Fundamentals of Thermodynamics say that the greater difference in temps the greater overall efficiency of heat cycle (engine)..... So the cooler you can get your "coolant" the greater performance you will get - hence the use of cool air boxes in drags nowadays - dry ice on air intake.

All that being said - go for greater surface area and greater number of cores.

If i were doing the job (which i'm thinking seriously about, i have a '76 clubby that is to be resprayed soon - once i've made engine choice and test fitted it) i'd be making a custom radiator to fit. Cores and header tanks are bloody cheap and the pipework isn't too bad cost wise - then ya just need someone to tig it all together - voila sweet stainless system that fits where ya want it!!!

my $0/02 anyway....

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Answer the Question....
BUT always Question the Answer

Fundamentals of Thermodynamics say that the greater difference in temps the greater overall efficiency of heat cycle (engine)..... [/quote]

That should read greater power not efiiciency - sorry!

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Answer the Question....
BUT always Question the Answer

Amos,
thanks for the input. I'll have to take your word for the fundamentals of thermodynamics but I definitely agree with you on the greater surface area and cores part.

Where do you source these cheap cores and end tanks?
Also did you say stainless?? I thought alloy was better for heat transfer?

If I can get a stainless one I'll have a go at welding it myself.

Madmorrie

In comparison to aluminium and copper, stainless steel is a terrible conductor of heat. It takes ages to get hot, and then stays hot for much longer.. not a good material for a radiator.

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Simon

The adventures of an owner builder in the Tallarook Ranges