How do I drop my highway temp 8°?

[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

[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

[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?

[Musclerodz]

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