How do I drop my highway temp 8°?

[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]

Originally Posted by 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

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.

Originally Posted by 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?

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.

Originally Posted by 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?

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" 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.



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.

[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]

Originally Posted by 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

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

[Musclerodz]

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

[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.