[ta6point6]

One thing people forget about is how much strain the poor original alternator is under just trying to run ac compressor and blower fan motor not to mention stereo bumping out some bass. Then you add on some electric fans to that poor old alternator at idle, that is putting a drag on the motor.

[JLMounce]

While the alternator does impart some load on the engine, it is relatively small. Even when fully loaded against it's capabilities. We're talking a couple HP is all. Much less than you see with a mechanical fan for instance, or even the water pump itself.

That's not a meaningful contributor to heat generation of the engine, but if you're thinking about switching to electric fans, the alternator does need to be up to the task. As you point out, you're going to be hard pressed to have your factory 60amp alternator power your lights, AC compress, blower motor, stereo AND an electric fan. An upgrade will be needed.

[Nobuddy]

Does the AC clutch really draw significant current? Never thought about it, always seemed it would be trivial compared to other loads.

[JLMounce]

I've read anywhere from 5-20 hp to drive the AC compressor. Here's a youtube video of a back to back dyno that showed around 10hp/tq loss with and without AC running.

https://www.youtube.com/watch?v=zkK5Ip0ADRk

That's on a fairly modern car though, if you've got a classic era compressor on the engine, it may drain more power. While that's probably double what a fully loaded Alternator needs to operate, it's still probably not a huge heat driver. The bigger heat driver with AC is the fact that you've got a condenser in front of your radiator that lowers the efficiency of the radiator. This is also why you have the trinary switch that will raise the idle. This increases airflow through the condenser and radiator as well as increasing coolant flow through the radiator.

[Nobuddy]

But the AC compressor is mechanical load driven by a belt from the crankshaft, nothing to do with the alternator. Alternator load would only be the blower fan and the magnetic clutch. Plus the radiator/condenser fans if those are electric . Perhaps I'm not following the discussion well enough.

[JLMounce]

Apologies I think I misunderstood your question. I don’t know if there is any electrical load from the ac compressor.

[Squidward]

Well, all, an update.

Maybe you saw my post on the Lincoln mk8 thread in the street section. I tried a mk8 puller fan, and it didn't fit. Fan is going back.

Gonna clean my radiator while it is out. Gonna cap it, and soak it in vinegar. And I will do a block flush for the other half.

And then I am going to do a compromise. Car doesn't have so much trouble at speed, so I am going to try and 11" pusher fan in front of the condenser. Maybe an extra 1k cfm from a pusher at idle will be enough to keep it under control. I will run this to supplement a mechanical fan/shroud combo.

I like the brutal simplicity of a mechanical fan, IF it took care of business fully. Maybe I can keep the heavy work in the hands of brutally simple mechanical parts.

[Jay S]

Originally Posted by Squidward

I’ll play. Here is one of mine

Platform (year and model): 1977 Trans Am, 4 speed, 3.23s, factory A/C

Engine (mild to wild): Original engine, looking W72 but with headers. 461 CID, 11.3 SCR, 91 octane, fully ported 6X. 550+ HP

Water pump config (8 bolt, 11 bolt): 11 bolt

Water pump style (cast impeller, stamped impeller, special aftermarket): Cast impeller

Water pump pulley size (small/med/large diameter): standard original small pulley

Lower hose spring: yes

Radiator (# rows, material, brand): 2 core Cold case Aluminum

Tstat: 160*

Cooling fan configuration (blades, clutch specs, electric, etc.): standard HD Hayden with 19” 7 blade, factory shroud

Typical use factors, like ambient temp, AC, etc.: Hot and Humid Mid West summers up to 100* F, typically 80* to 90* and very humid.

Any special mods:
Water pump is blueprinted, impeller depth modified, tight plate clearance.

Waterless Evans Coolant.

https://m.youtube.com/watch?v=HfaFWp...1vdG9yc3BvcnRz


.

Even though the 461 CID engine pretty wild compared to stock, it is easier to keep cool than the original stock W72. I started out with the stock radiator in the 461, but replaced it after it started leaking and needed repair. The cold case was a good upgrade. The Evans was the best upgrade.

The 2 core Cold case or Griffin is suppose to be around 10% more efficient than a 4 core Aluminum Champion or 4 core original style, and 20% more than a 3 core.

We used 19” stainless flex fans for dirt track Pontiac’s and a 2 core full size Griffin. The flex fans rob a LOT of power and can be loud. We have used some on the street. Can’t really beat them with anything else mechanical if the engine temp creeps up sitting in traffic.

For additional cooling on the stock car it could spray water over the radiator. Usually used it at the end of the night when the track was muddy and the radiator was partially plugged with mud. Often racing here can be in the 90s and very humid in the evening.

I have Electric fans and electric water pumps on some street and strip cars also.

We have went to all waterless Evans coolant on older cars now. I still have cars with regular antifreeze though. But the Evans has been vastly superior to regular antifreeze. It does not boil and convert to vapor and create hot spots in the combustion chambers of the heads. It helps a lot when sitting in traffic with the A/C on at idle. At temps above 200*, the engine runs quite a bit cooler. IRC the boiling point of Evans waterless coolant is 375*. The antifreeze boiling off the hot spots in the heads is what creates a lot of issues with high temp detonation, waterless Evans seems to solve that.. You can pull the radiator cap off when the engine is hot, it will run very little system pressure.

[Jay S]

On electric driven motors for fans or A/C components you can generally work backward and figure out how much power that it takes by looking at the wire gauge, and then assume a 20% loss on efficiency.

For example, a 12 ga wire is good for about 20 amps. A 10 ga is good for 30 amps

20 amps x 14.4 Volts / 748 watts per HP

= .385 HP

More or less 1/2 of a HP. It doesn’t sound like much but it does add up.

[JLMounce]

Jay, can you expound on your waterless coolant experience?

Are you using this only in cars that have fresh engines and cooling systems, or is it easily converted? From a 50/50 mix that I currently use, what's a possible over/under on it providing just that extra little bit that my system lacks?

[Gator67]

Originally Posted by Squidward

...Car doesn't have so much trouble at speed, so I am going to try and 11" pusher fan in front of the condenser. Maybe an extra 1k cfm from a pusher at idle will be enough to keep it under control. I will run this to supplement a mechanical fan/shroud combo.

About 10 years ago I installed two 9" (I think) puller fans directly on the radiator in my '68 bird and wired them so they turn on with the compressor. The car would got hot with the A/C on in the summer at stop lights and in slow traffic, so I tried the electric fans as an experiment. It worked well, so I just kept everything in place. I have to replace the water pump gasket soon, and when I do, I plan on making some changes in the cooling system so that I can jettison the helper fans. Even though they work, it feels like a band aid solution.

[Jay S]

Originally Posted by JLMounce

Jay, can you expound on your waterless coolant experience?

Are you using this only in cars that have fresh engines and cooling systems, or is it easily converted? From a 50/50 mix that I currently use, what's a possible over/under on it providing just that extra little bit that my system lacks?

It does not need to be a new build. On a project I am doing radiator or water pump work on I will switch to Evans. On something that has Antifreeze in it already to properly use Evan’s coolant you have to drain the antifreeze completely out the best you can. Evans sells a flush to help clear the antifreeze out, you can have up to 3% water left with basically the same results as straight Evans, so I am not sure the flush is necessary. Some engines are harder to flush than others though. As you add water or antifreeze back into the system the advantages diminish until it acts like typical coolant.

Water or antifreeze can be added to the Evans if you find yourself in a position that you do not have access to Evans. But with basically no system pressure, there isn’t much risk of blowing out a hose or having a radiator leak, there is not much expansion from hot and cold cycles, it would take a water pump seal to cause a leak. Evans will even mix with oil, you can blow a head gasket or leak coolant into the oil pan and it does not turn into grime and slime like regular antifreeze. Cavitation and corrosion on internal parts exposed to coolant are also superior with the Evans.

I have a fleet of cars with 50/50 Antifreeze, unless something on it needs serviced and it is working ok I leave the Antifreeze in service. I much prefer Evans though, if I have to work on the Coolant system on one of my older cars, it goes back together with Evans.

A regular antifreeze 50/50 mix transfers heat better than Evans. It is not unusual for the engine temp to run 10* hotter with Evans if your operating temps are below 200*. If that is where you engine operates, you have to realize it may equalize at a higher temp. Once the temps get up much past 200*, the Evans seems to out cool regular Antifreeze by a lot. I think it is because the Antifreeze is converting to steam where it contacts the combustion chambers. Evans may need a step colder spark plug for high temps, but for high temps regular coolant needs the same adjustment.

I know one guy not to far from me that was having preignition issues on pump gas and solved it by just switching to Evans.

[Squidward]

Originally Posted by Gator67

About 10 years ago I installed two 9" (I think) puller fans directly on the radiator in my '68 bird and wired them so they turn on with the compressor. The car would got hot with the A/C on in the summer at stop lights and in slow traffic, so I tried the electric fans as an experiment. It worked well, so I just kept everything in place. I have to replace the water pump gasket soon, and when I do, I plan on making some changes in the cooling system so that I can jettison the helper fans. Even though they work, it feels like a band aid solution.

Nice solution. Yeah, looking at a little helper fan.

So... What do you think about a pair of small pullers in the shroud, or a single 11-12" pusher? Pro/con opinions on either? I will be triggering a relay circuit off the FiTech.

[Jay S]

On HD and SD Hayden’s there is and adjustment on the thermal spring to make the fan activate the clutch at lower temps. It tends to moves more air thru the entire speed range when it kicks in sooner.

[Squidward]

Originally Posted by Jay S

On HD and SD Hayden’s there is and adjustment on the thermal spring to make the fan activate the clutch at lower temps. It tends to moves more air thru the entire speed range when it kicks in sooner.

If my Hayden clutch/fan fits with the pair of smaller pullers I'm thinking about, then I will definitely tighten up the clutch engagement. If they don't fit, then I will use a flex fan of some sort. I still have the plastic mechanical fan Scirrotica recommended. That would give lots of room.

[RocktimusPryme]

Im working on a Mercedes 18.5 inch PWM fan into my first gen. The factory shroud is very close, maybe just a smidge oversized but nothing insurmountable. I don't really need to, but at this point I feel a bit challenged about it so I want to.

Unfortunately Ive wasted a little but of money because I have burnt up a couple of them testing. But Ill figure it out and make it easy on everyone else if it works and they want to try it.

[JLMounce]

These just hit the market for 67-69 F-Body owners as well.

https://fastmontysgarage.com/the-sho...ed-gloss-black

These are designed specifically for cold case direct fit radiators, but I would lay odds they fit quite a number of other direct fit radiators as well.

I'm not certain I'll get around to it this season as we are getting past the point where we are really hot here in Colorado. But I think I'm going to give this shroud a try with a set of the ProForm brushless fans. I'm right on the edge now, so I just need a bit more airflow at idle and slow speeds. I'm also toying with the idea of putting an LS swap Cold Case radiator in the car which gives the advantage of a dual pass design for a bit more efficiency.

[RocktimusPryme]

Thats a nice peice. Speedway sells a house branded shroud that says it will fit 11 or 12 inch fans. I believe it would be end up the same where the 12 inch fans overlap the sides. Its not as nice and Im skeptical it will indeed fit two 12 inch fans.

I still don't like that it seems like its cookie sheet flat. I know people want maximum clearance but I think they would be more efficient if it had some taper to it to create a venturi effect.

[JLMounce]

A conical shroud is absolutely more efficient, that's not debatable. However there are space limitations and I believe Mike's piece has enough bypass slots that it shouldn't be an issue. It may actually pass more air than my setup with the black magic 180 which has a proper conical shroud.

The black magic uses a 3300 cfm rated 15" fan. It doesn't cover the entire width of the core, there's an inch to inch and a half on each side. Some air is passing through that section, but the basic area for air to pass for the core with this fan is 176.71 sq/in. Not accounting for the relief flaps, the flat shroud with dual 12" fans has a passable area of 226.2 sq/in. Let's take 10% out of that for the area the fans protrude onto the end tanks. You end up nominally around 200 sq/in of passable space.

I'm not accounting for motor area here of course, but I think if you actually measured everything on my current setup to one of Mike's shrouds, there's a decent bit more relief area.

The proform fans have a rated CFM of 4200 for the pair against the 3300 CFM rating on my current fan. Let's again take 10% off that for inefficiency of the protrusion onto the end tanks. So a theoretical 3780 CFM or nominally 13% more theoretical airflow. Is that enough to solve my tiny amount of creep at idle and slow speeds? I don't know, but it's worth trying on my end I think.

[Squidward]

Originally Posted by JLMounce

These just hit the market for 67-69 F-Body owners as well.

https://fastmontysgarage.com/the-sho...ed-gloss-black

I saw those. And in the process of watching some Fast Monty last week, I saw him test a Proform brushless fan rated at 3400 cfm.

I liked the soft start, and it has a nice low profile. So I bought a straight blade 16" fan. I'm gonna mount it on my radiator as a puller, and see if I can run it inside my shroud with a mechanical flex fan running off the water pump (if clearances allow). I should be able to make an easy comparison between the two fans stacked in series, or just the electric.

https://www.summitracing.com/parts/pro-67036

This will make my electric circuit easy, with dc circuit breaker/fuse and a relay triggered off the FiTech and the ac clutch. The FiTech triggers a ground signal for the relay coil, and I will have to use another relay to provide a ground when the ac clutch turns on, like an inverter.