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If you want cooling system efficiency...you need larger surface area, and swap to a crossflow radiator instead of a downflow...will net you far better results than a narrow 3 core setup. Of course...not many people want to cut open their radiator support...but if you are willing to do that, you can get a lot of airflow:

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I used a 2-core SN-95 model myself, but there are a variety of radiators that can be made to fit fairly easy....a crossflow from a '66 T-bird for instance...or a foxbody version, etc etc etc, all dependent on what inlet/outlet location you need. When it comes to radiators you get a lot more out of surface area than you do out of core thickness.

That being said, it may well have nothing at all to do with the cooling system itself and could be related to tuning(timing) or mechanical(bad head gasket, etc) issues.
 

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Discussion Starter · #22 ·
This may be a bit of a crazy idea, but ... next time you're at the track remove the fan and shroud and see if the car overheats. That will answer you question.
I pulled the shroud off yesterday and will leave it off until the next track day at which point I'll likely try pulling the fan as well in addition to most likely a new radiator just to be safe.

If you want cooling system efficiency...you need larger surface area, and swap to a crossflow radiator instead of a downflow...will net you far better results than a narrow 3 core setup. Of course...not many people want to cut open their radiator support...but if you are willing to do that, you can get a lot of airflow:

I used a 2-core SN-95 model myself, but there are a variety of radiators that can be made to fit fairly easy....a crossflow from a '66 T-bird for instance...or a foxbody version, etc etc etc, all dependent on what inlet/outlet location you need. When it comes to radiators you get a lot more out of surface area than you do out of core thickness.

That being said, it may well have nothing at all to do with the cooling system itself and could be related to tuning(timing) or mechanical(bad head gasket, etc) issues.
I'm not opposed to chopping the radiator support but I'd rather save that for a last result. There are no mechanical issues or tuning issues, I have reviewed all the data logs and she's running fantastic, I could pull more timing out just to check but I'm not running excessive timing at all. It wouldn't creep up to 238 very fast so I'm hopefully that pulling the shroud and fan at the track as well as a cross flow radiator should work, I'm going to give US Radiator a call and see what they recommend. I guess I may get stuck changing the water pump out to a driver side outlet, oh well.
 

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A crossflow radiator does not make a significant difference in cooling.

A larger capacity radiator will make a difference.

Nice looking set up Wicked. Did you fabricate the mounts for the hood pins?
 

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A crossflow radiator does not make a significant difference in cooling.

A larger capacity radiator will make a difference.

Nice looking set up Wicked. Did you fabricate the mounts for the hood pins?
Well, the theory behind cross flow is it gives the coolant more time in the core compared to a downflow setup, but I suspect the truth is similar to intercoolers...there is going to be a trade off between higher efficiency and pressure drop(IE if the coolant in the radiator stays longer and gets cooler that just means the coolant in the block absorbs more heat before it can be cooled in turn) the trick is always finding the correct balance.

Heh, they aren't hood pin mounts actually, they are radiator isolator brackets I fabbed up...but it would be easy enough to modify the design for hood pin brackets instead.
 

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in addition to most likely a new radiator just to be safe.
I'm sure you've seen this - but in case you haven't - many people have stated that a good 2-row radiator with large tubes is better than a 3-row radiator of similar total thickness.
In my educated opinion (engineer) the volume capacity of the radiator (how much fluid it holds) is the crucial factor. Unfortunately, you'll only see that figure in factory manuals. Take a look in yours and see the difference between the radiators for 6s and 8s, and with and w/o a/c.
 

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Regardless of where the return and suction points are on a radiator, the water will spend x-amount of time in the radiator, all else being equal.

On my 65 with a 17" radiator the AC condenser covers most of the radiator. If I had a 20 or 24" radiator there would be more unrestricted airflow and the radiator would be more efficient.

Im putting a 24" radiator in my 67 for that very reason.
 

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Discussion Starter · #28 ·
Regardless of where the return and suction points are on a radiator, the water will spend x-amount of time in the radiator, all else being equal.

On my 65 with a 17" radiator the AC condenser covers most of the radiator. If I had a 20 or 24" radiator there would be more unrestricted airflow and the radiator would be more efficient.

Im putting a 24" radiator in my 67 for that very reason.
That's sort of the same line of thinking I have with the condenser, ever with the belt off the compressor just to be safe I'm not convinced that the giant restriction isn't part of the problem. I talked to US radiator and they swear that the crossflow is a significant increase in cooling and didn't try to sell me a radiator at the same time so I'll consider the advice. I suppose the reality is if I want a race car per se then the AC should come out but I of course I went too many directions with the car and have a stout track capable car in a street cruiser format so I need to make it work.

I think the next track day I'll go ahead and remove the shroud and fan, may consider a different radiator but not sure, and worst case pull a little more timing out. I pulled my tune and data logs and realized that at WOT and MAP the timing drops to 35 degrees so I think taking anymore out may kill quite a bit of power but I'm willing to try it for the track.
 

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The engine is producing more heat than the cooling system can remove.

I would look at the engine first. Eliminate all possible issues on the engine side before you address the cooling side.

What is your CR and what octane fuel are you running.

What is your cylinder overbore?

Double check your timing.

Double check your WP and Crank pulley diameter.

At high rpm could your belt be slipping?
 

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Discussion Starter · #32 ·
I went with Ron Davis, 2 one inch rows, built in 7 plate oil cooler, twin fan

What are you driving? I run a PIR all the time with SVRA, SOVREN, ICSCC?
I was down there with Track Night In America by the SCCA. Love their events, super affordable and you get a good amount of runs in. I was there with my white 65 coupe, I’ll post videos once I edit them.
The engine is producing more heat than the cooling system can remove.

I would look at the engine first. Eliminate all possible issues on the engine side before you address the cooling side.

What is your CR and what octane fuel are you running.

What is your cylinder overbore?

Double check your timing.

Double check your WP and Crank pulley diameter.

At high rpm could your belt be slipping?
I don’t disagree with the engine producing more heat but at constant triple digits and high RPM runs that’s inevitable to some extent. I do have aluminum heads and ceramic headers to keep the under hood temps down as well.

Compression is 10.5:1 and I run 91 octane. No cylinder overbore. I rechecked the timing before I left and it was good to go and matched the ECU throughout the range. Because it’s MAP driven there are times where it’s going up to 38/39 for highway cruising so I’m thinking I’ll adjust my tune for the track so that it never exceeds 35 and see what that nets. My max power is at 35 WOT but driveabilty, mileage, etc. allow me to go up to 38/39 with my setup.

Good idea on pulleys. One is the performance series March pulley and the other the high water flow pulley. Also good idea on the belt, I’ll double check the data tomorrow and see if I ever had a voltage drop but I could also put my go pro in there and see what it does at high RPM.
 

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Regardless of where the return and suction points are on a radiator, the water will spend x-amount of time in the radiator, all else being equal.

On my 65 with a 17" radiator the AC condenser covers most of the radiator. If I had a 20 or 24" radiator there would be more unrestricted airflow and the radiator would be more efficient.

Im putting a 24" radiator in my 67 for that very reason.
This is true enough...the biggest difference is that when it comes to surface area....well, you simply have more horizontal space in virtually any engine bay than you do vertical(unless you are driving a tractor trailer)...there is a reason they don't bother making downflow radiators on any new cars...its because they can fit a larger core in a smaller engine bay a lot easier with a crossflow design. This is probably only relevant to vintage mustangs though if you are cutting your radiator support.
 

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Do you have access to race gas? Upping the octane to 93-ish may help lower engine heat generation.

Water injection used to be a big deal in lowering cylinder temperatures, not so much anymore.
 

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I didn't read the full context of every post, so maybe I missed it, but what temp are you seeing from the oil? Your water temp while it might seem high is not out of bounds. Assuming this is as bad as it gets, even on hot hot hot days. The more modern hotrods of today run near those kind of temps just idling around town, and do so in order for the detergent oils of today to work their best; (the high temps allow the oil to work more efficiently cleaning and protecting). Years ago we thought cool temps and high viscosity oil was the ticket, now we know higher temps and lower viscosity numbers are the key to long life motors. Poke around and you'll find Mobile One (tech docs on their site) and others commenting on this subject.

If you don't already have one, an oil cooler would help with the temps some (not greatly, but some); just be sure to add a oil cooler bypass so that the oil is not over cooled when you are not on the track. Proper oil temp is very important and for lots of reasons.

Also, the three row radiator is actually not the best for cooling, and as already said it should be a cross flow; but a two row of the same width offers more surface area for the water fin, thus it cools better. A two row, cross flow double pass radiator will absolutely cool that motor; I'm using this same style designed to cool +600 HP and it does. I can run anywhere in the south on any temperature day and not have to worry about heat. I'll not confess what my HP number is, but it's a lot more than yours.

If you absolutely want to lower and better control the water temp, add an oil cooler and oil cooler bypass, and go on the Griffin web site and order a two row double pass for the HP number you have, or HP you hope to have in the future perhaps. It will fit the factory core support and comes ready to bolt in, nothing but a change in hoses. I can guarantee the result based on my own results and that of others.

But: As long as you are keeping the water in the radiator, and your oil temp is not raging in 340 numbers (easy to do without a cooler) then you are likely doing ok. Ideally you'll not have oil temps too much above the 280 numbers, or not consistently anyway, that's assuming you run a high quality full-synthetic oil.

What Is The Optimum Engine Oil Temperature? (hotrod.com)

Best of luck,
 

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This may be a bit of a crazy idea, but ... next time you're at the track remove the fan and shroud and see if the car overheats. That will answer you question.
I agree with this. I assume that if you are at the 230 degree range that your electric fan is on. I am willing to bet that its acting like an air dam at speed. You probably don't need to actually remove everything just figure out how to disable the fan while you are driving so that it can freespin. I have done a lot of fan testing over the past couple of years. What I have seen is that if the electric fan is going the speed at which it spins doesn't match the air speed flowing through the radiator while driving. This prevents enough air actually flowing through the radiator at speed to cool effectively.
 

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Discussion Starter · #37 ·
I didn't read the full context of every post, so maybe I missed it, but what temp are you seeing from the oil? Your water temp while it might seem high is not out of bounds.
I'm not sure, I do not have an oil temp sending unit installed. I do have the provisions for one so I may throw one in. The water is coming out of the overflow tank and spitting out the car so it is out of bounds in that regard which is what I'm trying to control.

I'll not confess what my HP number is, but it's a lot more than yours.
Good to see humility hasn't died.

If you absolutely want to lower and better control the water temp, add an oil cooler and oil cooler bypass, and go on the Griffin web site and order a two row double pass for the HP number you have, or HP you hope to have in the future perhaps. It will fit the factory core support and comes ready to bolt in, nothing but a change in hoses. I can guarantee the result based on my own results and that of others.
I went onto their website and I cannot find the crossflow version, I'm totally down with putting one in and giving it a go but can't find it. I know US Radiator makes one, I'm going to see if Be Cool does as well and go from there.

I appreciate the advice, I'll give it a try. I will pay more attention to my data as well and if I need to adjust the timing I will and that should get me where I'm trying to get.
 

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These guys have a great reputation, too Delta PAG Not sure how much you’re looking to spend, they are not on the low side of $$$.

Rusty
 

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sr1032, I think Rusty's first guess was right. Your shroud blocks airflow through the core, AND when you are at speed, that electric fan is actually BLOCKING airflow. The Deltap Pag LOOKS nice, but their shroud repeats the same flaw that you already have, it blocks flow when you're at speed. I'm not familiar with the water pump you mentioned, does it have a cast / machined, not a stamped, impellor ? My guess is that if you removed the shroud and got a 7 blade thermal clutch fan, you could race with the air conditioner on. Electric fans are for commuter cars idling in trafffic, when you need LOTS of air, they just aren't up to the job. You could also consider getting a bigger puke / recovery tank. And if it was mine, 230 wouldn't scare me anyways. LSG
 

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Discussion Starter · #40 ·
sr1032, I think Rusty's first guess was right. Your shroud blocks airflow through the core, AND when you are at speed, that electric fan is actually BLOCKING airflow. The Deltap Pag LOOKS nice, but their shroud repeats the same flaw that you already have, it blocks flow when you're at speed. I'm not familiar with the water pump you mentioned, does it have a cast / machined, not a stamped, impellor ? My guess is that if you removed the shroud and got a 7 blade thermal clutch fan, you could race with the air conditioner on. Electric fans are for commuter cars idling in trafffic, when you need LOTS of air, they just aren't up to the job. You could also consider getting a bigger puke / recovery tank. And if it was mine, 230 wouldn't scare me anyways. LSG
I’m not sure what the impeller is made out of and can’t find the stars. Doubtful that I’ll go back to a clutch fan at this point but I run this Friday so I’ve already got the fan and shroud off so we shall see. From there I’ll adjust timing if necessary but I think I’m good. It got up to 238 which is a little more out of my comfort range to be honest, 230 I was good with but ramping towards 240 got me off kilter. Not a bad idea on the bigger tank; I’ll go ahead and do that as well.
 
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