How do I drop my highway temp 8°?

[57vette]

Happy to note that I'm using Carl's PWM in my '69 Camaro 461 BBC. Its working exactly as advertised, I'm currently using a 195° sensor and a 180° thermostat. My radiator is a new Cold Case unit with two 1.250" tubes and I'm using a modified set of Ford Contour 12" fans on a custom designed and built aluminum shroud that's about 1" deep inside. When I'm out driving just after the temp gauge hits 195° the fans go on (I have a LED indicator on my dash).

https://i.imgur.com/UpNQIWk.jpg

I included a dozen BeCool rubber flaps in the shroud design to help overall airflow at highway speeds. Generally speaking, its working OK but I think I need more CFM because the car runs a bit warmer than I'd like. On a typical 85° summer day on the highway, I can't get it below 200° while driving at 65 mph. And the minute I'm driving on local streets the temp climbs to 210°-220°. The car now has Vintage Air so there's a almost full width Condenser in front of the radiator. I have the sneaky feeling that if I could turn the fans off with a switch of some kind while on the highway, the temp would stay the same or maybe even go down? One of my friends suggested adding a pusher fan in front of the condenser but that seems like overkill.

https://i.imgur.com/nUbyFmd.jpg?1

I used a corvette kit to put a foam seal around the entire 4-sided perimeter of the shroud/radiator so no engine air is pulled in. I also have a full core support cover to keep air flowing thru the grill and towards the condenser/radiator.

https://i.imgur.com/i4EmKl9.jpg?1

Because of the serpentine setup, its pretty tight as far as space between the shroud and the belts so my choices for 12" fans is somewhat limited. I would've liked to use a Lincoln Mk VIII setup but it was just too deep. Plenty of guys have said 200° isn't that bad for a modded BBC in this car but I'd really like to figure out how to knock down the cruising temp to 195° or slightly under so the fans don't run all the time once the car is warmed up. I thought about the coolant mix but doubt that adding more distilled water to the 50/50 premix would really make any difference. I haven't touched the timing since last year and before the car had the AC it had the 4-core copper radiator and a mechanical fan. It had a 160° thermostat and ran at 175°-185° on a hot day on the highway, maybe 190° around town and only if I was in dead stop traffic would it creep up to 210°-220° and that was after 10-15 minutes of barely moving.

So even though the car is drivable, I'm hoping I can improve something. Is the answer more CFM or maybe something else?-Mike

[raustinss]

My only suggestion is ditch the 200 hp engine contour fans and try to find either stock fans from a higher hp car or aftermarket ,where the blade count, width and pitch will be different. Just a different blade pitch can drastically change the cfm air flow . Again keep in mind those fans were designed for what a 200hp at most 4 cylinder, and I know you're pushing way more than that lol , cheers

[dontlifttoshift]

Lots of questions.

Pulley ratios before and after the AC/serpentine belt install? It obviously worked before, did it change?

How far is your condenser from your radiator? Too far away and the air gets turbulent between the two.

Why the dual 1.5" tubes in the new radiator? You added an inch to the core and then another 3/4" with the condenser. Late model radiators are thin on purpose, it is easier to push air through. It takes a lot of fan to draw through all that.

Where is the fan probe at? If on the bottom of the tank like the instructions say, move it to the top and get the fan running earlier.

At warm idle, what is the temperature differential between the top and bottom hoses?

Confirm gauge readings. Seriously, step one, confirm that your gauge is accurate. Everyone think theirs are spot on, but most aren't.

[dhutton]

With a 195 degree sensor the PWM controller is trying to control the temperature of the coolant exiting the radiator to 195 degrees afaik. If it enters the engine at 195 it seems reasonable that it would be 210-ish when it leaves the engine and enters the radiator.

Maybe try the 185 sensor if you want it to run cooler.

Don

[srode1]

I don't think your fans do anything at highway speed, I agree turning them off with a switch wouldn't change the temperature. You can do the math to confirm if you want. Your set up doesn't look bad to me for an electric fan set up, but you are blocking some of the radiator with the shroud. A pusher fan isn't going to help things, it will block more air, don't do it. Around town bigger diameter fans would help probably, maybe some on the highway too. Do you know what your A/F mixture runs in those conditions? Maybe you are running too lean?

[Vegas69]

On the highway that set up should run cooler than 200 in 85 degree weather. Not far from your t stat rating. I agree with looking at your air/fuel mixture and timing. A vaccum leak? Fatten up your idle circuit or throw some bigger jets in the primary side and see if it cools it down a bit. Does it surge under light throttle? Ping?

[Che70velle]

What rpm are you turning at highway speed?

[57vette]

With a 195 degree sensor the PWM controller is trying to control the temperature of the coolant exiting the radiator to 195 degrees afaik. If it enters the engine at 195 it seems reasonable that it would be 210-ish when it leaves the engine and enters the radiator.

Maybe try the 185 sensor if you want it to run cooler.

Don

I've tried 180° sensor and the 195° no real difference. Have also tried 160° and 180° thermostats, again, no difference in highway temp, fans are always on because once its warmed up its seems to stay at 200° which won't shut the fans down, and in traffic it goes to 220° and a little higher if its stopped and no airflow, just the fans.

I don't think your fans do anything at highway speed, I agree turning them off with a switch wouldn't change the temperature. You can do the math to confirm if you want. Your set up doesn't look bad to me for an electric fan set up, but you are blocking some of the radiator with the shroud. A pusher fan isn't going to help things, it will block more air, don't do it. Around town bigger diameter fans would help probably, maybe some on the highway too. Do you know what your A/F mixture runs in those conditions? Maybe you are running too lean?

I kinda agree about the pusher concept. I don't know for sure what the A/F mixture is or the timing... gonna have to check that.

On the highway that set up should run cooler than 200 in 85 degree weather. Not far from your t stat rating. I agree with looking at your air/fuel mixture and timing. A vaccum leak? Fatten up your idle circuit or throw some bigger jets in the primary side and see if it cools it down a bit. Does it surge under light throttle? Ping?

Hadn't thought of the vacuum leak possibility. No surging, no pinging, shuts off without any knocking or anything else.

While I'll admit that the article "Budget Cooling (https://www.motortrend.com/how-to/1907-tame-engine-heat-budget-electric-fan-system/)" drew me to these fans, plus the fact that they are shallow and many have used them for V8 engines including a 461 BBC although the El Camino has a bigger radiator than the Camaro I'm sure. Perhaps I have to look at a couple of more powerful 11'-12" fans that will fit without hitting the serpentine pulleys or belt.

Derale 16925 High Output Radiator Fan is a 12" that is rated at 2000 CFM at Zero static pressure, so maybe in real use it pulls 1500-1700 CFM? While they sell it separately as a Pusher, they offer it as a dual Puller 12" kit with a shroud and in the video demo they state it must be used with a custom shroud as a puller. I emailed them for more info and some better specs.

https://i.imgur.com/BjHKc6F.jpg

SPAL Automotive USA 30101522 is a 12" puller that's rated at 1328 CFM and I don't know if this one in tandem would be enough, although reviews say guys are using them with Big Blocks and they do the job. SPAL is supposedly the company that doesn't over rate their fans. These would probably fit well.

https://i.imgur.com/HxKxaJA.jpg

[dhutton]

Sensor won’t improve highway temperature. I proposed it since it should affect the slow moving and idle temperature which is 10 to 15 degrees higher than the highway temperature if I understood you correctly.

Highway temperature too high implies undersized radiator imho.

Don

[dhutton]

Suggestion to verify timing and AFR is an excellent one imho.

Based on what I know about you I know that you would enjoy logging and analyzing your AFR… :)

Don

[57vette]

Suggestion to verify timing and AFR is an excellent one imho.

Based on what I know about you I know that you would enjoy logging and analyzing your AFR… :)

Don

Don... I'm trying to get an appointment with a local tuner shop and have him take a look at everything (carb, ignition, timing, vacuum, and anything else that might affect cooling). Radiator is Cold Case's CHC11 which is their BBC model. The VA condenser is mounted according to VA's instructions, bolted to the front of the core support. The water pump is a high flow model that was included with the serpentine kit. The EMP/Stewart thermostat should rule out air trapped in the system, but we'll see. Here's a little video clip of a cold start showing coolant slowly moving, and of course it flies thru there when the motor is warmed up.

https://youtu.be/f9zE_8KdXWU

Someone had suggested moving the temp sensor away from the lower radiator hose neck, but I would think that's where the temp would be the coolest (?) once the car is warmed up and riding down the highway?

As far as fans go, with a 23" wide and 16" high core, the two 12" fans are about as big as I can go diameter wise, and because I'm extremely tight depth wise, I can't use a fan that's more than 3" deep from shroud flange to the rear edge of the motor housing. DeRale tech support emailed me last night and said the 16925 comes wired as a puller, is 12" and 3-1/8" deep and pulls 2000 CFM at zero static pressure. After I get some tuner info, I might buy one from Amazon and see if I can squeeze it in there, although the fans should not be a factor at 65mph. I haven't really explored the SPAL brushless 12" fans but I would guess they'd fit being even flatter. Don't know if you can even buy them without a shroud which I shouldn't need.

Mike

[dhutton]

If you move the temp sensor to a hotter location the fans will turn faster to drive that hotter location cooler. The net result should be lower coolant temperature as measured by your temperature gauge. This applies to idle and low speed driving, not highway driving.

Don

[57vette]

If you move the temp sensor to a hotter location the fans will turn faster to drive that hotter location cooler. The net result should be lower coolant temperature as measured by your temperature gauge. This applies to idle and low speed driving, not highway driving.

Don

I'm fine with 200° highway temp but I need to get that down to the mid to low 190's to turn the fans off. It'd be interesting to see if the fans were off on the highway at 65-70 (roughly 2200-2400 rpm) would the temp just stick at 200° or would it increase or decrease? When I had a 4-core radiator straight no clutch mechanical fan, I think... that fan would be pulling more air thru the radiator than dormant eFans right?

I guess I could move the sensor up higher on the side of the tank and see what happens, but am I missing something with regard to fan RPM? Carl's little PWM does a really nice job on the soft start of the two fans, and even when I shut the car down, its a slow ramp down for about a minute or so that the fans are powered but gradually reducing RPM until they stop. Moving the sensor to a hotter section of the radiator (closer to the top) would also probably keep the fans on at highway speed.

Yesterday I pulled off the bumper and grill because the RS grill's getting painted hopefully next week along with the endura bumper and a couple other items. Gonna take it for a ride and see what happens without a grill. I'm also thinking about building a lower close-out panel to help channel air thru the condenser and radiator. And I keep thinking about Mark Donahue's radiator ducting LOL.

https://i.imgur.com/21fKqkN.jpg

https://i.imgur.com/yt1pG3s.jpg

[srode1]

Seems to me while working on air flow might lower your temperatures it's really not the root cause. Your set up doesn't look bad, I think there's something else going on that is getting your temps that high. Cruising down the highway just doesn't take that much horse power to do so you aren't making that much heat regardless of the engine size.

I'd be going after the basics first, it will be much cheaper and better for your engine longevity if mixture or advance is your problem and you address that.

[69hugger]

I'm going to suggest a very easy trial. I know many here will scoff at this... a few years ago I would have too.
But after I did this, my cooling issues vanished. It is simply see what happens if you remove the thermostat (gasp).
I have a '69 Camaro, 534" big block making 700 hp. My cooling system consists of the 1000 hp rated Be Cool rad w/ twin 11" Spals, and a Stewart water pump. The fans are ECM controlled to come on at 190, and shut off at 170.
When I ran a 160 deg. stat, it would run hot (210-220 +) only if stalled in traffic on a hot day, and take forever to cool down when I'd get moving again.
My very old school engine builder kept telling me to ditch the stat. I thought he was crazy. I'd cite every article ever about how doing so would speed up the coolant flow so the coolant was not removing enough heat from the engine, needing pressure in the block, etc. I was chasing all the stuff you are talking about here. Fan CFM, sealing air leakage cracks, water wetter, blah blah blah.
A few years ago, I was beating on the car pretty hard, and the cooling system blew. Coolant exploded everywhere. The engine bay was drenched. Only after detailed inspection did I discover what happened. With that flow restriction, the cooling system had created so much pressure the rear seal on the water pump had blown out.
I finally tried his suggestion. I have not run a stat since. And the car has not seen 200 degrees since. It normally runs almost exactly 100 deg. hotter than ambient. 80 degree days it runs 180. 50 degree day it runs 150. And makes no difference whether I'm on the highway or sitting in traffic with the A/C on.
I know it sounds crazy. I know the experts will scoff at this & cite why it won't work. And it probably won't work in every case. But in 1/2 hour you can try it. What do you have to lose?

[Vegas69]

A high flow t-stat may be a good compromise to none. If the coolant temp is 150, oil temp could be 150-170. Far from ideal. The moisture won’t burn off very efficiently and your oil pump will work harder. That can lead to distributor gear wear and failure. Lubrication is typically superior with reasonable oil temps. No stat will lead to a long warm up cycle too. A reasonably light synthetic would be my choice if you try it.

No stat in the summer is another option. I can see the benefit of the flow assuming the radiator can take advantage of the extra volume.

[Beechy]

Mike.
A few observations from my daily driven 68 Camaro, mild cam 350 auto, p/steer, no air, no oil cooler, stock brass radiator with trans cooler ports, some kind of Ford v8 electric fan with shroud and flaps, Davies Craig electric water pump with no thermostat. Travelled 120,000 miles so far, mild San Francisco type climate.

Maybe dumb luck with radiator sizing/water pump output (EWP80 running ALL THE TIME) but warm up times are normal despite NO thermostat, coolant temps always normal .....180 most days at all speeds, 200+ in stop/start.

Oil temps are mostly ALWAYS a few degrees cooler than coolant.
-Exception to this is starting quickly on cold morning and driving conservatively at freeway speeds, the oil can barely crack 120 = BAD. As soon as you get on the gas the oil temp will catch up.
-Also, getting on the gas at any time will see the oil HOTTER than coolant quite quickly, as much as 250, and take forever to come back down but will stay 5* hotter than coolant.

Oil has to be approx 180 to do its job, eliminate water and warm the crankcase......just like Todd said ^
Oil starts to break down 260+.

Every carb equipped car should have a 4-wire fuel/air meter, $200 will save you the first unnecessary tune up. Check timing at cruise rpm.
Normally a thicker radiator creates issues in traffic because fans struggle with heat soak but ok at speed because airflow, so not always a happy solution.

NEVER use a pusher fan, they're an expensive way to block airflow.

A/C condenser should be 3/4" clear of rad core.

You have done great with flaps and foam seals but fans for 200 h.p. does not compute.
I hope your first post is a typo where u say BBC with 1.25" rad outlets.....stock SBC is 1.5".

FYI.....Covid boredom got the best of me and I moved that stock radiator under the trunk and added an EWP130 under rear floor.
17 years ago I had built the trunk floor higher to accomodate the rad but never had time to do it.
Why? Because race car.....corner weights.
Outcome? NIGHTMARE....don't do it. :confused18:
It runs cooler so far but spikes in cylinder head temps take a few miles to settle down

[Musclerodz]

Make sure your not collapsing your lower hose at higher rpms.

[SuperB70]

Here is my .02, been building custom cooling systems years. I think 8 now.

Core: its not about rows anymore, thats old scool when there only was one type of tube.

Nowdays tubes comes in many width and height. Even with inside tube fins. Most important is fpi (fin per inch), talking about airflow fins between the tubes. That is industrial scale of efficiency.
Ofcourse adding rows can make a difference means of coolant capasity.
But usually I can get by with 66mm core to first 1000hp at street car.
I choose to build horizontal flow cores, dual-pass. Not a big fan of original style vertical single pass cores. With dual pass design, I can control coolant flow better vs fan/-s.


Fan sensor: I go to local partstore and search/buy oem sensor with right turn on and turn off values.
In here (Finland) I use sensor for Volvo, has little lower turn off temp than on temp. There is two kind of sensors, ones that close the circuit and ones that earth it. I use mainly one that earth it. That controls a relay for the fan/-s or a controller. I can also connect a on/off switch to by pass the sensor if I want to run the fans what ever reasom.
LS and other modern cases ECU will control that.
I've come up a wirins system that uses 1 earthing sensor, 1x 4 pin relay, 1 or 2x5pin relays and a on/off switch. Then fan/-s can be contolled by temp sensor ( even when car is parked, ign. off) ECU or switch.

Fan sensor location: near upper hose or at least first 1/3 of the rad core height. If the sensor is lower down the line, the hole core get hot and takes longer to cool it. Can even be at intake manifold. Never in lower radhose, when thats hot, your rad has already soked the heat and you are

Fans: you cant go wrong with SPAL. If you want, you can get motorsport models, huge cfm but not Amps. With brushless motors. Not the cheapest, but there aint never cheap and good in same package. WRC rallycars, rallycross cars, track cars use them. Many high end supercars use them.

Fanshrout: I dont use those airflaps, not sure why anybody would use them. Fan opening is enough, just 3/4 off the core, seal it with rubber seal and fan/-s sucking hole area of the core. If one is running without the other. There need to be a blocking wall inside the shroud. Othervice the running fan suck the air from other fans opening and not through the core. Again first 1/3 of the heigth of the core is most critical, thats where the most heat is. I always try to amount AC and/or supercharger heat exchangers lower portion just because of that.

Thermostat: if you run without one, replace it with nascar-style restriction plate, just stainless steel "washer" with 3/4" opening. I use that even with electric pumps. And for those I use german-made Piersburgs out of BMW, cheap and flow the same as Davies but better pressure. PWM controlled either by ECU or stand alone controller.
Running with out any restriction means that coolant flows too fast and heat tranfer dosent happen. You gauge reads cool but engine can be boiling hot.

Coolant pressure: that is another friend of yours. Rises the boiling point, raise the pressure and boiling point rises with it. Make sure your core can handel that. You dont want that to turn in to football (american style, not soccer)

Expansion tank: if you have just a line from under the cap to ground. WRONG! You need to install a breatable tank with incoming from rad has inner tube going almost to the bottom. 1/2 or 3/4"short is fine. When the cap releases the pressure the coolant goes, like the name says expansion tank. When the coolant system cool after engine been shoot off, vacuum will refill the coolant system from the tank. How clever is that! Dont need to be refilling that 1"- 1 1/2" that is missing from rad.

Coolant: there is "new" style coolant in the market, no water, boiling point .Evans waterless coolant. Boiling point is 375'f

Oilcooler: Engine oil temp goes hand in hand with coolant temp. If oil temp is always up, you dont get coolant temp down. Hot engine is hot engine.
Good, powerful oil cooler with thermostat is good investment.

Airflow: you are in right track. There needs to be high pressure area in front of the radiator. Air needs to be forced through the core. When you need more cooling power, more fpi (fin per inch) you will need and that develops restriction to the air flow. You need to win that restriction. High pressure is you friend on that. If you have holes in radiator support, if air can go past the rad, no high pressure and you need to use fan/-s to make up for that.

Engine rpm: it plays a import role. Even in highway driving when throttle is at minimun if engine is turning rpm lets say above 3000 you will build alot of heat. That just is how gas engine work. Diesel needs fuel to make heat.

I build custom radiators, air to air intercoolers, air to water intercooler, heat exchangers and oil coolers from hand builded build to order european cores witch are all calculated for the orders spesifications..
So almost any size, almost any shape, even in a angle, width, length and thickness (factory determine that)
Anything from motorcycles, 100hp flathead, 3500hp drag and drive car, race cars to 120psi boosted pulling tractors.

As you can see in my project update posts of my 70 Coronet. Or more in my IG page.

But as of now I'm not shipping to US.

[camcojb]

:thumbsup:

[67-ls1]

The fact that it won’t cool on the highway leads me to believe it’s airflow related. Or lack of…
How is the airflow OUT of the engine compartment?
Do you have a front spoiler? A front spoiler can lower the pressure under the car and allow more engine compartment air to escape under the car.

[57vette]

I'm going to suggest a very easy trial. I know many here will scoff at this... a few years ago I would have too.
But after I did this, my cooling issues vanished. It is simply see what happens if you remove the thermostat (gasp).
I have a '69 Camaro, 534" big block making 700 hp. My cooling system consists of the 1000 hp rated Be Cool rad w/ twin 11" Spals, and a Stewart water pump. The fans are ECM controlled to come on at 190, and shut off at 170.
When I ran a 160 deg. stat, it would run hot (210-220 +) only if stalled in traffic on a hot day, and take forever to cool down when I'd get moving again.
My very old school engine builder kept telling me to ditch the stat. I thought he was crazy. I'd cite every article ever about how doing so would speed up the coolant flow so the coolant was not removing enough heat from the engine, needing pressure in the block, etc. I was chasing all the stuff you are talking about here. Fan CFM, sealing air leakage cracks, water wetter, blah blah blah.
A few years ago, I was beating on the car pretty hard, and the cooling system blew. Coolant exploded everywhere. The engine bay was drenched. Only after detailed inspection did I discover what happened. With that flow restriction, the cooling system had created so much pressure the rear seal on the water pump had blown out.
I finally tried his suggestion. I have not run a stat since. And the car has not seen 200 degrees since. It normally runs almost exactly 100 deg. hotter than ambient. 80 degree days it runs 180. 50 degree day it runs 150. And makes no difference whether I'm on the highway or sitting in traffic with the A/C on.
I know it sounds crazy. I know the experts will scoff at this & cite why it won't work. And it probably won't work in every case. But in 1/2 hour you can try it. What do you have to lose?

Mike.
A few observations from my daily driven 68 Camaro, mild cam 350 auto, p/steer, no air, no oil cooler, stock brass radiator with trans cooler ports, some kind of Ford v8 electric fan with shroud and flaps, Davies Craig electric water pump with no thermostat. Travelled 120,000 miles so far, mild San Francisco type climate.

Maybe dumb luck with radiator sizing/water pump output (EWP80 running ALL THE TIME) but warm up times are normal despite NO thermostat, coolant temps always normal .....180 most days at all speeds, 200+ in stop/start.

Oil temps are mostly ALWAYS a few degrees cooler than coolant.
-Exception to this is starting quickly on cold morning and driving conservatively at freeway speeds, the oil can barely crack 120 = BAD. As soon as you get on the gas the oil temp will catch up.
-Also, getting on the gas at any time will see the oil HOTTER than coolant quite quickly, as much as 250, and take forever to come back down but will stay 5* hotter than coolant.

Oil has to be approx 180 to do its job, eliminate water and warm the crankcase......just like Todd said ^
Oil starts to break down 260+.

Every carb equipped car should have a 4-wire fuel/air meter, $200 will save you the first unnecessary tune up. Check timing at cruise rpm.
Normally a thicker radiator creates issues in traffic because fans struggle with heat soak but ok at speed because airflow, so not always a happy solution.

NEVER use a pusher fan, they're an expensive way to block airflow.

A/C condenser should be 3/4" clear of rad core.

You have done great with flaps and foam seals but fans for 200 h.p. does not compute.
I hope your first post is a typo where u say BBC with 1.25" rad outlets.....stock SBC is 1.5".

FYI.....Covid boredom got the best of me and I moved that stock radiator under the trunk and added an EWP130 under rear floor.
17 years ago I had built the trunk floor higher to accomodate the rad but never had time to do it.
Why? Because race car.....corner weights.
Outcome? NIGHTMARE....don't do it. :confused18:
It runs cooler so far but spikes in cylinder head temps take a few miles to settle down

Make sure your not collapsing your lower hose at higher rpms.

Here is my .02, been building custom cooling systems years. I think 8 now.

Core: its not about rows anymore, thats old scool when there only was one type of tube.

Nowdays tubes comes in many width and height. Even with inside tube fins. Most important is fpi (fin per inch), talking about airflow fins between the tubes. That is industrial scale of efficiency.
Ofcourse adding rows can make a difference means of coolant capasity.
But usually I can get by with 66mm core to first 1000hp at street car.
I choose to build horizontal flow cores, dual-pass. Not a big fan of original style vertical single pass cores. With dual pass design, I can control coolant flow better vs fan/-s.


Fan sensor: I go to local partstore and search/buy oem sensor with right turn on and turn off values.
In here (Finland) I use sensor for Volvo, has little lower turn off temp than on temp. There is two kind of sensors, ones that close the circuit and ones that earth it. I use mainly one that earth it. That controls a relay for the fan/-s or a controller. I can also connect a on/off switch to by pass the sensor if I want to run the fans what ever reasom.
LS and other modern cases ECU will control that.
I've come up a wirins system that uses 1 earthing sensor, 1x 4 pin relay, 1 or 2x5pin relays and a on/off switch. Then fan/-s can be contolled by temp sensor ( even when car is parked, ign. off) ECU or switch.

Fan sensor location: near upper hose or at least first 1/3 of the rad core height. If the sensor is lower down the line, the hole core get hot and takes longer to cool it. Can even be at intake manifold. Never in lower radhose, when thats hot, your rad has already soked the heat and you are

Fans: you cant go wrong with SPAL. If you want, you can get motorsport models, huge cfm but not Amps. With brushless motors. Not the cheapest, but there aint never cheap and good in same package. WRC rallycars, rallycross cars, track cars use them. Many high end supercars use them.

Fanshrout: I dont use those airflaps, not sure why anybody would use them. Fan opening is enough, just 3/4 off the core, seal it with rubber seal and fan/-s sucking hole area of the core. If one is running without the other. There need to be a blocking wall inside the shroud. Othervice the running fan suck the air from other fans opening and not through the core. Again first 1/3 of the heigth of the core is most critical, thats where the most heat is. I always try to amount AC and/or supercharger heat exchangers lower portion just because of that.

Thermostat: if you run without one, replace it with nascar-style restriction plate, just stainless steel "washer" with 3/4" opening. I use that even with electric pumps. And for those I use german-made Piersburgs out of BMW, cheap and flow the same as Davies but better pressure. PWM controlled either by ECU or stand alone controller.
Running with out any restriction means that coolant flows too fast and heat tranfer dosent happen. You gauge reads cool but engine can be boiling hot.

Coolant pressure: that is another friend of yours. Rises the boiling point, raise the pressure and boiling point rises with it. Make sure your core can handel that. You dont want that to turn in to football (american style, not soccer)

Expansion tank: if you have just a line from under the cap to ground. WRONG! You need to install a breatable tank with incoming from rad has inner tube going almost to the bottom. 1/2 or 3/4"short is fine. When the cap releases the pressure the coolant goes, like the name says expansion tank. When the coolant system cool after engine been shoot off, vacuum will refill the coolant system from the tank. How clever is that! Dont need to be refilling that 1"- 1 1/2" that is missing from rad.

Coolant: there is "new" style coolant in the market, no water, boiling point .Evans waterless coolant. Boiling point is 375'f

Oilcooler: Engine oil temp goes hand in hand with coolant temp. If oil temp is always up, you dont get coolant temp down. Hot engine is hot engine.
Good, powerful oil cooler with thermostat is good investment.

Airflow: you are in right track. There needs to be high pressure area in front of the radiator. Air needs to be forced through the core. When you need more cooling power, more fpi (fin per inch) you will need and that develops restriction to the air flow. You need to win that restriction. High pressure is you friend on that. If you have holes in radiator support, if air can go past the rad, no high pressure and you need to use fan/-s to make up for that.

Engine rpm: it plays a import role. Even in highway driving when throttle is at minimun if engine is turning rpm lets say above 3000 you will build alot of heat. That just is how gas engine work. Diesel needs fuel to make heat.



The fact that it won’t cool on the highway leads me to believe it’s airflow related. Or lack of…
How is the airflow OUT of the engine compartment?
Do you have a front spoiler? A front spoiler can lower the pressure under the car and allow more engine compartment air to escape under the car.

Thanks for all the great feedback. I'm possibly looking at two possible problem issues; highway driving (with no eFans running), and very slow or stopped driving with eFans running. I've talked to others who have used these exact fans on both BBCs and SBCs with no issues so I'm not giving up on them yet. Absolutely nothing has changed as far as the engine tune goes. With the old 180° ordinary thermostat and a 4 core copper BBC radiator she ran just fine at 175°-180° on any hot day as long as I was moving at more than 30 mph. But now its a new radiator, Vintage Air, Serpentine belt setup with reverse high flow water pump. Couple of comments regarding your punchlist ideas:

· Radiator is a BBC spec Cold Case with a core size of 23" wide, 16" high, and 3" thick. Its a two-tube core and the tubes are 1-1/4", the coolant hose IN/OUT are standard chevy sizes. There's no room for a bigger radiator unless I have a custom core support built... which seems like a waste since so many people run BBCs in 69 Camaros.

· Lower radiator hose has a coil inside to prevent collapsing.

· Running without a thermostat is something I hear every now and then. I feel I have to try a few other things before doing that... as easy as it is to do. I'm currently running a EMP/Stewart high-flow 180° thermostat and this model has three (3) 1/8" holes drilled into it to ensure there's no air bubbles and that regardless of temp some coolant is always flowing so it can't get stuck shut.

· My shroud inside depth is just a tiny bit under 1" between the core and the inside of the shroud.

· The Vintage Air Condenser is mounted correctly with VA components and is about 3/4" forward of the core.

· The two Ford 12" fans are pullers, not pushers. While I realize they were originally used in a roughly 200 HP Ford Contour SVT, this dual fan setup has been used in numerous V8 applications including off road vehicles.

· I'm using Carl Casanova's PWM to control the fans, and per Carl's instructions the 195° sensor is mounted on the lower PS of the radiator tank just ahead of the return hose that goes to the water pump. At Don Hutton's suggestion I have rewired the PWM so that the POS/NEG wires are both 8AWG and connected directly to the battery terminals bc I wasn't getting full voltage to the fans.

· With regard to airflow, I designed and built a sheetmetal lower closeout panel to prevent a large portion of the grill air from spilling out through the lower valance opening. I actually ran this by some gear heads in the Physics Forum who agreed that blocking the main escape route would increase pressure to the condenser core to flow through them. And I do have an upper closeout panel on the car. Here's some pictures.

https://i.imgur.com/4iVDXN5.jpg?1

https://i.imgur.com/c4t3S7i.jpg?1

https://i.imgur.com/GWTPQWM.jpg?1

https://i.imgur.com/xAjETRD.jpg?1

· Unfortunately, my interior is being redone over the winter and because the shop owner got COVID while on vacation, he could not return to the USA until he was re-tested twice so he lost 3 weeks and then he lost an employee so he's scrambling all alone now to try and catch up. Hopefully by the end of next week he might be done and I can get back on the road for more testing.

· As far as a wide-band goes... I might look into that. I had a AEM wide-band on my supercharged Lightning and I thought it was a great gauge. Once I get on the road I can go get a bung welded onto my exhaust system. On the Lightning my bung was welded on the down pipe from the header collector. Here's a picture of my headers, where would the best spot be to mount a bung?

https://i.imgur.com/2C6UxEs.jpg?1

https://i.imgur.com/4bgJQFf.jpg

Again... thanks for the feedback. Hoping to solve this mystery.-Mike

[srode1]

Hey quick question Mike, did your car ever run cool on the highway? If so what did you change? Is this a new to you engine? Maybe I missed it, but I dont' see any background reading back through the thread. Getting the car to run cool on the highway just shouldn't be this challenging and certainly shouldn't need any fancy modifications.