Running hot, need bigger fan and other tricks advice please

[767Jockey]

Here's what I have on board now -
Contemporary Shelby Cobra replica
520" FE engine. 744 HP (I know - tough to cool)
Fluidyne Shelby Cobra radiator
Custom made full radiator shroud
Spal 2082 16" puller fan - 1900 CFM
No thermostat in the system right now
2- Cobra style pusher fans
50/50 Prestone coolant mix

The car is running almost 220 degrees in the Texas heat in traffic, I need to cool it off. I believe the issue may be with the fan, it's not moving enough air. At the time I bought it, this Spal 2082 1900 CFM fan was about the best out there. That was years ago. The problem is, in my Contemporary it's VERY tight back there. This fan barely fits between the shroud and the steering rack right behind the fan. It's not a standard Contemporary (CCX) radiator install. In the stock CCX radiator install the rad sits vertically. In my car it's laid back a bit like a typical Cobra. Going back to vertical would be virtually impossible due to changes made to the car. That's not a choice available to me. There is no possible way to get a Taurus style fan to fit back there.

In short, I do not have the room for something like the usual monster Taurus fan, etc. Whatever I use needs to be the typical style 16" fan. What's the best one out there now, moving the most air? I do a Google search and dozens come up, most look like Chinese junk. Anyone using a good quality 16" that moves significantly more than the 1900 CFM that this Spal moves? A very good trusted friend recommends to me to use a 2 speed Volvo fan. I have to look into that as far as installed dimensions to see if it'll fit in my tight space. He also recommends that I use water wetter. I didn't realize that stuff actually works. I always thought it was a gimmick but he tells me it can lower temps by 10 degrees or so.

I've read that the Cobra auxiliary pusher fans are cosmetic only, that they do virtually nothing. Is that true?

Any and all proven ideas you guys might to get this car to run cooler within the limitations of space that I have outlined above would be greatly appreciated.

[patrickt]

I can only offer a small bit of help, my fan is a SPAL #30102120 with the straight blades and it moves 1918 CFM of air in puller mode. It keeps my engine cool without the need for the dual pusher fans. BUT, the dual pusher fans do drop the heat faster when I do turn them on and they work in conjunction with the puller. And in case anyone is curious, those pushers are Dayton 3LCH7 fan motors. I've also always used Watter Wetter. Does it really work? I don't know -- the boys at ERA told me to use it, so I use it. Now, do you have the extra heat vents in the wheel wells? I think those really do help as you can feel the heat gushing out when the fans come on. That's about all I can offer up on the subject.

[Tommy]

Summit Racing lists a lot of 16" fans that claim to pull more than 2500 CFM. And most list their dimensions.

[NorCalCobra]

I have been told by a few sources that running no thermostat can cause the vehicle to run hot. The theory is that with a thermostat installed, the coolant stays in the radiator longer, therefore getting cooler. Without a thermostat regulating the flow, the water passes through the radiator too quickly and doesn’t have time to cool off enough. Worth a shot. Only a couple minutes and a couple bucks to throw one in.

[Lulworth]

I have a Contemporary 482ci FE with the Fluidyne radiator ‘laid back’ position
I run a 180 degree thermostat with a 1/8” drilled top bleed hole.
I use pre-mixed Prestone coolant
It has an Edelbrock aluminium water pump with a thermo fan switch in the lower hose (as per ERA recommended) 87degree on-77degree off
I have an oil cooler but the engine ran too cool so blanked it off, stayed blanked off all summer and no overheating. You’d remove the blanking plate if going on the track.
I have the dual pusher fans but have never used or needed them
The puller fan is a SPAL #30102049A 16” 2185 cfm . No shroud other than the top infill piece to the hood aperture.
All good in heavy traffic at 90 degree plus weather

The Holley 800 DP has a Edelbrock #12410 5/16” insulator base gasket, no room for anything thicker. It helps

[Lulworth]

Deleted due to duplicate post

[mrmustang]

Originally Posted by 767Jockey

Here's what I have on board now -
Contemporary Shelby Cobra replica
520" FE engine. 744 HP (I know - tough to cool)
Fluidyne Shelby Cobra radiator
Custom made full radiator shroud
Spal 2082 16" puller fan - 1900 CFM
No thermostat in the system right now
2- Cobra style pusher fans
50/50 Prestone coolant mix

The car is running almost 220 degrees in the Texas heat in traffic, I need to cool it off. I believe the issue may be with the fan, it's not moving enough air. At the time I bought it, this Spal 2082 1900 CFM fan was about the best out there. That was years ago. The problem is, in my Contemporary it's VERY tight back there. This fan barely fits between the shroud and the steering rack right behind the fan. It's not a standard Contemporary (CCX) radiator install. In the stock CCX radiator install the rad sits vertically. In my car it's laid back a bit like a typical Cobra. Going back to vertical would be virtually impossible due to changes made to the car. That's not a choice available to me. There is no possible way to get a Taurus style fan to fit back there.

In short, I do not have the room for something like the usual monster Taurus fan, etc. Whatever I use needs to be the typical style 16" fan. What's the best one out there now, moving the most air? I do a Google search and dozens come up, most look like Chinese junk. Anyone using a good quality 16" that moves significantly more than the 1900 CFM that this Spal moves? A very good trusted friend recommends to me to use a 2 speed Volvo fan. I have to look into that as far as installed dimensions to see if it'll fit in my tight space. He also recommends that I use water wetter. I didn't realize that stuff actually works. I always thought it was a gimmick but he tells me it can lower temps by 10 degrees or so.

I've read that the Cobra auxiliary pusher fans are cosmetic only, that they do virtually nothing. Is that true?

Any and all proven ideas you guys might to get this car to run cooler within the limitations of space that I have outlined above would be greatly appreciated.

Have you confirmed your timing is set properly and your carb is properly tuned? Either one can cause a hot run condition.

As for cooling a high compression (you make not mention of compression) engine for the street, Be Cool makes a 16", slimline style fan with a 3,000 cfm capacity. CLICK HERE
I've used this one in the past, but uncertain if it was on a Contemporary.
You also need to install a thermostat, again, high volume, 180 degree, mix of 50/50 coolant with an additive like MOTOR MAX installed.

Like I've seen with plenty of street rods over the years, there will be limitations to how cool your car will eventually run, all based on build specs, and fuel used. I'd start with the above, maybe add some additional details as to your engines specs, and whether it has been tuned properly or not, and we can go from there.

Bill S.

[undy]

The factory 2 speed early Ford 1984 Taurus, 3.8L, 17" cooling fan kicks all aftermarket fans' butts as far as CFM! I'm running it on my 482" S/O. On high speed it'll suck an 8 1/2" x 11" piece of paper into my Cobra's nose and pin it against the radiator. I have two sending units to control it, 196 deg F and a 180 deg F. BTW...the fan setup comes with a shroud which I "carved" to fit.

Speaking of radiators... I'm running a griffin, 2ea 1.5" cores, which at the time was the "thickest" radiator I could find.

I had massive cooling problems prior to this. The combination fixed that, ENTIRELY!

[Tommy]

I'll add this bit of theory to back up Bill's comments about tuning. Imagine two cars moving down the same road at 60 MPH. They are identical except one has a 408 Windsor built to 450 HP max, and the other has a 520 FE built to 744 HP max. As it takes far less than max HP to move at that speed, both engines are producing the same power at whatever RPM, throttle setting and gearing that takes (e.g., 70 HP). If both engines are efficiently tuned to extract the optimum amount of propulsive energy from the fuel they are consuming, they should be burning about the same amount of fuel per minute. Thus the engines should be shedding about the same amount of leftover heat through the coolant system every minute. If the cooling systems in the cars are the same but one engine is running hotter than the other, then it must be because that engine is consuming more fuel to generate its 70 HP and the excess fuel is going to produce heat rather than propulsion. . . . In other words, an engine optimized to produce 744 HP at peak RPM may not be optimized to efficiently burn fuel at 2200 RPM, with the excess fuel going to produce heat rather than propulsion. The solution may be to tune or modify the engine to be more efficient at the power levels commonly used in street driven cars.

Here is one example. To make big HP numbers with big engines, builders typically use really big carburetors capable of providing enough air at peak RPM. Big carbs require more air flow to generate enough signal to properly meter fuel to the engine. Such combos often do not run well or efficiently below 2500-3000 RPM, where most street driving occurs. Having your engine dyno tuned with air/fuel ratio readings under cruising conditions might reveal whether you would benefit from changes to your current fuel system.

[mrmustang]

Originally Posted by Tommy

I'll add this bit of theory to back up Bill's comments about tuning. Imagine two cars moving down the same road at 60 MPH. They are identical except one has a 408 Windsor built to 450 HP max, and the other has a 520 FE built to 744 HP max. As it takes far less than max HP to move at that speed, both engines are producing the same power at whatever RPM, throttle setting and gearing that takes (e.g., 70 HP). If both engines are efficiently tuned to extract the optimum amount of propulsive energy from the fuel they are consuming, they should be burning about the same amount of fuel per minute. Thus the engines should be shedding about the same amount of leftover heat through the coolant system every minute. If the cooling systems in the cars are the same but one engine is running hotter than the other, then it must be because that engine is consuming more fuel to generate its 70 HP and the excess fuel is going to produce heat rather than propulsion. . . . In other words, an engine optimized to produce 744 HP at peak RPM may not be optimized to efficiently burn fuel at 2200 RPM, with the excess fuel going to produce heat rather than propulsion. The solution may be to tune or modify the engine to be more efficient at the power levels commonly used in street driven cars.

Here is one example. To make big HP numbers with big engines, builders typically use really big carburetors capable of providing enough air at peak RPM. Big carbs require more air flow to generate enough signal to properly meter fuel to the engine. Such combos often do not run well or efficiently below 2500-3000 RPM, where most street driving occurs. Having your engine dyno tuned with air/fuel ratio readings under cruising conditions might reveal whether you would benefit from changes to your current fuel system.

In addition to the above, I recommend the car be properly tuned on a chassis dyno, as an engine dyno does not take in to account the forces/losses/stress of the drivetrain. Nor does an engine dyno tune offer you anything but max HP/TQ usually at wide open throttle. I've had almost unlimited access to both in the 90's and early 2000's and learned an awful lot from both.

Bill S.

PS: Does your current engine have a High Performance water pump, and are you certain the correct orientated impeller is installed?

[Blas]

What are you using to trigger your fans?
Water Wetter in conventional antifreeze helps.
Have you considered Evans Coolant?
Is your radiator totally shrouded around fan?
Blas

[bobcowan]

Originally Posted by NorCalCobra

I have been told by a few sources that running no thermostat can cause the vehicle to run hot. The theory is that with a thermostat installed, the coolant stays in the radiator longer, therefore getting cooler. Without a thermostat regulating the flow, the water passes through the radiator too quickly and doesn’t have time to cool off enough. Worth a shot. Only a couple minutes and a couple bucks to throw one in.

This is true. I've tried on a 427W. It might be helpful for you to gut a thermostat, and just use a restrictor plate.

Air flow is critical. Most fans do nothing above about 40mph or so. For slower speeds, you need as much air flow through the radiator as possible. A big fan, proper shrouding, and closing the gaps around the radiator will maximize your efforts.

Also, as mentioned above, pay attention to other factors: Incorrect timing, lean mixture, etc.

[Tommy]

I was thinking more about the effect of timing on engine temp and thought of an issue I had with the engine in my Cheetah. You may find this helpful. My engine was built by an alleged race engine builder who was trying to boost his credentials with big HP dyno numbers in spite of my desire for a more street friendly setup. He pulled 600 dyno HP at 6000 RPM from my 427 c.i. engine. As I was trying to make the finished car more streetable, I discovered that the cam it had produced such low vacuum at idle/cruise that is was not feasible to run vacuum advance on the distributor. That meant the timing at cruise was substantially retarded compared to a distributor with operational vacuum advance. Retarded timing is a recipe for excess engine heat because the combustion process is not completed before the exhaust valves open. This reduces fuel efficiency and the late burning transfers a lot of heat to the exhaust valves and other engine components that have to be cooled by the coolant. . . . I did what I could by adjusting the mechanical advance to put in as much as it would stand as early as possible. My setup is tolerable for the conditions where I drive. I don't know how it would be in100 *F and stop-go traffic.

[cycleguy55]

"almost 220 degrees in the Texas heat in traffic". I'm not sure why you think you need to cool it off. 220°F isn't extreme, and it's not going to damage your engine. My BBF used to get that hot in stop and go traffic, but now I hit the fan override switch and let the fans run continuously in traffic. Rarely does it get much above 200°F.

Regardless, as it seems most comments have properly captured the essence that maximum temperature is a result of cooling capacity. Engine timing and tuning can play a role in getting temperature down but, other than that, you're looking at radiator, coolant flow and airflow.

Taking it from the top - do you have cooling issues when running hard? If not, then it's not a radiator capacity issue.

What kind of water pump are you running? Given the specs I'd guess a high flow pump, but that's not a sure thing.

How about pulleys? Are you running standard pulleys or under-driving your pump in a quest for lower pumping losses and more HP? If under-driven that will be a big problem when idling in traffic.

As others have pointed out, you may wish to look into a higher volume puller fan, or a pair of puller fans that provide greater radiator coverage.

What kind of oil are you running - dino or synthetic? My engine oil runs ~10°F cooler with full synthetic.

What weight oil are you running? Running 10W50 or 20W50 when you don't need it takes more HP to pump as well as rotate - and HP generates heat.

Like others, I'd suggest a thermostat - mostly because it gets the engine up to temperature faster and reduces engine wear. It's unlikely to affect your stop and go temperatures. I'm running a 180°F high flow thermostat and would recommend that to many.

[bkozlow]

Just a thought--how is your electric rigged to the fans, it should be running through a closely mounted relay to the fan and what gauge are you running from the battery and relay to the fan. Fans draw a lot of electric and need bigger wires than most people think, to get 100% out of the fan. Just a thought.

Bill K

[spdbrake]

Flex-a-lite is claiming 3000cfm from the Flex-wave design fan.
Shows to be about 0.60" thinner than the Spal
https://flex-a-lite.com/16-inch-flex...an-puller.html

https://flowkoolerwaterpumps.com/pro...rmance-1876cfm


https://www.summitracing.com/parts/flx-105390

[Bobcat]

As others have said , make sure timing and carb are correct first .

I used to spend a lot of time on circle tracks in SC , NC and GA . We didn`t run a thermostat , but we did run restrictors/orifices in place of the tstat . With nothing in there , the coolant circulates too fast to get good heat transfer from the engine to the coolant ..... you have to slow it down . The only way to do that was to play with various sized holes until you found what worked .
We also ran pure distilled water and water wetter .... antifreeze and water mixture wasn`t as efficient on heat transfer as was just water . Plain water also didn`t make the track slick if/when you blew a hose either .

Now for the street , on my ERA with a 482 here in GA and the Carolinas , I run a 180 degree tstat with 3/16" holes ( 3 ) drilled in it at the top to allow some circulation when cold and to help get rid of air .
Summers here are in the upper 90`s to sometimes low 100`s and I run 200 degrees in traffic and that temp is not a problem . Personally , I feel if your traffic temps are in the 200 to 205 range , there`s not a problem .

[eschaider]

+1 on the tuning comments Bill made, Doug. At 1900 cfm your fan is a little on the wimpy side for your engine power level. You ought to be somewhere between half again and 2x bigger

A few years ago I ran across a company at PRI that had some stunning fan and water pump products. Their water pump was a 60 GPH unit and the demo was impressive in the extreme.

They also had fans that were every bit as stunning as their water pumps. Their 16" fan flows 3200 cfm. They also have 12 inch fans that flow 2200 cfm each and an 18 inch that flows 4100 cfm. The fan controller they use will ramp the fan speed up and down with changes in engine temp and provide you with a 1 or 2 minute run on after shutting the car off. The two 12 inch fans are a pretty small package with impressively high air flow.

If you want to do the mounting you can, or they offer custom made aluminum fan shrouds specific to the radiator you have for the fan(s) you choose. You do need to provide radiator specs and dims to them for the fabrication.

The company is called Delta-Pag and they are located in NY. The forum s/w will not allow attachments as big as the catalog so I am sending it to you by email.

[CHANMADD]

How on Earth can you expect to control the temperature without a Thermostat???? I mean you have the coolant going through the radiator so fast it's still just as hot when it goes back in the engine. The fan you have should be sufficient. Also, make sure with that size engine that you have enough coolant in the system. But get a Thermostat first....Then come back.

[767Jockey]

Wow, thanks guys - lots of questions to address, and lots of things to try. First to address some of the questions -
-Compression ratio is 11:1
-Carbs are set us properly and timing is spot on within builders recommendations
-Distributor is Duraspark, custom curved with vacuum advance - all set up properly
-Fan is running well, doesn't sound labored at all, running off a relay with wire size exceeding Spal recommendations
-All the timing, distributor curve and carb setup is as spec'd by Blair Patrick, the builder of the engine. Once installed everything was brought up to the exact spec he outlined. Blair built the carbs (Holley BC/BD) and set the jets, power valves, etc using air fuel equipment on the dyno, then of course everything was further tuned once installed in the car. Plugs look good after install. I'm fairly confident it's not a tuning issue.
-Oil is old school dyno oil for now, as engine isn't fully broken in yet and Blair doesn't want synthetic in it yet. Once broken in it'll get synthetic, for now it's VR1 straight 30W as per Blair's recommendation.
-Waterpump is a standard Edelbrock aluminum FE pump with standard size FE pulleys.
-Shroud is fully fitted and covers the entire back of the radiator

Questions I have -
-Does water wetter really work or is it a scam? How much do I put in? I've never used it.
-Thermostat a must, it'll go in. 160 or 180 degree and why? On or three holes drilled in top for bleed?
-Is there a specific brand/part number thermostat I should be looking for or just a universal one in the right temp range?
-How hot do you begin to start to worry about too hot? Cast iron BBM block and aluminum BBM heads. BBM tunnel wedge intake. Dual Holley carbs. Forged CP pistons, Total Seal rings, forged Crower rods, forged crank - Not sure what other information is needed or relevent here.
-I definitely need a more stout fan. It would be great if I could fit the Taurus or Turbo T'Bird fan back there but there's no room for it. I guess I'll try the Flex a Lite that Bill and Speedbrake mentioned or look into the Delta Pag that Ed mentioned unless someone has a better option. Available space is the limiting factor here.
-Bill, what's the difference between water wetter and Motor Max?

Hopefully I didn't miss anything. Right now I thinkn I'll attack in steps, easiest first. Put in the proper thermostat depending on what yoiu guys recommend, and add the water wetter or Motor Max. See how that goes. If it's still hot, I'll go to a better fan next. Hopefully that'll do the trick.