Hi all,
Today I test fitted my new aluminum Cold Case direct fit radiator. I had to take the fans and shroud off to get it installed which it did rather well. Especially where the petcock and lower rad hose are located. However, the factory lower shroud tabs cause an interference issue with the electric fan shroud as they are in the way. Also, if I don't use the factory shroud then there's an open area below the trans engine bay side which I'm guessing I would need to get something fabricated up to enclose that area. I had originally planned on using the mechanical fan/shroud, etc. but I talked myself into going the electric fan route (maybe it was the March Performance tech who said, "why would you do that!?"). So now I either have to cut off the tabs to use the electric fans and fab up an enclosure or use the factory shroud? Is there any alternative that I'm not currently thinking about that I could do otherwise?

I also have to fit up the new parallel flow condenser and trans rad but the space looks really good. There's 2" of space between the aluminum rad and the normal location of the condenser but if I put it on the inside of the brackets I gain that space where I can put the trans rad, if that makes sense to anyone. I loose about an inch but then I should not have a hood clearance issue. Pics!


Fitment Issue Electric Fan Shroud & Factory Shroud Attachment Point

Fitmet Issue Electric Fan Shroud & Factory Shroud Attachment Point #2

Crossflow Condenser & B&M Trans Rad

Checking Potential Fitment of Condenser & Trans Rad

Condenser & Trans Rad Potential Location #2

New Rad Petcock & Its Trans Rad Fitment that's too close to sway bar bracket. So not going to use rad's trans rad.

Aluminum Cold Case Rad Installed

 

I could not fully open my hood with the larger tranny cooler up against the radiator a/c condenser. I got an additional tranny cooler that was "shorter" and that way I could place it against the a/c condenser for forced air to be drawn through it. I then placed the larger tranny Heat Exhanger (HX) on the rails below on a padded surface.
If I was you I'd make sure that the hood will open before deciding ont the placement of the tranny cooler.
My tranny coolers cool are hooked up in series.
Per the specs on the coolers the small one is supposed to "sufficient" but I find that iffy so I'm using both.

 

You guys with automatics. Bloody trans coolers.
Why not just learn to shift gears.
Ya I know. Your auto can shift faster than any man.
Still. No fun!

 

Position 2 would be better if it fits or rotate it 90*.

 

Thanks carriljc,
Yeah, my parallel flow plate and fin condenser and trans cooler are about 1/2 the size of your coolers so I'm pretty sure hood fitment won't be an issue, but I do plan on confirming that with test fitting the hood. I think my biggest issue to determine is which shroud setup to use. Cut off tabs and use electric fan and figure out how to fab a piece to close up the open area at the bottom or use the factory shroud which test fits well but then I need to use mechanical fan which would give it that old school look?
I missed posting the pic of the factory shroud, but I'll edit and add it.

Test fitting with factory shroud that closes up the area around rad vs. electric fan shroud that leaves the area below open.

Electric Fan Shroud Test Fit

 

4-vettes,
Yeah, I wish it was a manual. All my last 3 Vettes were manual. Maybe someday I'll change it out. Just need more $'s!

 

Thanks, resdoggie,
I think I'm leaning that way as well. Probably easier to mount there, the thing hardly weighs anything.

 

I would go with an electric fan in the factory shroud if you must use an electric fan, even though I'm pro factory mech'l clutch fan.

 

Hmm, didn't think of using electric with factory shroud. I'm guessing there are e-fan setups that would mount in between the two. I had a local radiator shop (American Radiator) across the river in Pasco that fabed up my shroud and e-fans. But I think I may just go factory/mechanical for now anyway and I can always change it out later.
Thanks for the feedback.

 

I have the factory 7-blade fan and a Hayden 2741 clutch. You'll stay cool with that and the Cold Case. I do.

 

Not sure why you are concerned with the open area below/beneath the radiator? Mine has been open since I installed the Lincoln Mark VIII ages ago....

 

Why though? You lose sooooo much space that way. And the factory shroud is just a shroud, it isn't a structural element designed to hold anything.

The #2 advantage of electric fans is the space savings. (The number #1 advantage remains the HP savings, but we aren't here to argue that today, I hope).

 

It would be interesting to know what affect that open space created by the missing shroud does to the underhood aerodynamics. Does this create MORE airflow under the hood?

The factory shroud blows air directly at the engine, including above the engine, where the electric fans are pointing down, and do NOT create airflow over the engine. Does any of this have any affect on underhood temperatures,.....and by default, temperatures inside the car? For those of you who have done electric conversions, have you noticed any changes in cabin heat? And just to be clear, I am not talking about engine temperatures, I am talking underhood heat.

 

I've actually done this experiment, but not precisely. I measured temperatures a few times using my 4-port Arduino thermocouple shield. I did not try to test the shroud vs. the fan directly, but I have data from my 79 L48 with the stock clutch fan and shroud, and from my 80 L48 with dual-Spal electric fans. Both have the Lars(TM) tune, so they are not overheating.

But first, let me point out that the stock shroud's purpose is to funnel the air through the radiator to the stock clutch fan. The shape of the car required the radiator to be at an angle, so the shroud is fairly long to meet the fan. Allowing air to pass under the engine was not a consideration, just getting the air past the radiator, where the heat is removed. In nearly every C3, cold air (sometimes mixed to meet a minimum temperature) is pulled into the engine independent of the ambient engine compartment air. Both of my cars have L82-style dual-snorkel cold air intakes, with all mixing valves and flappers removed.

Anyway, here are two graphs that may show something interesting. Similar drive profiles, a mix of country road and highway. Different days, different cars, and different, but similar, engines. Note that the electric fans in my 80 did NOT come on at any time during the graphed test, they ONLY come on when stopped at idle. It was 20 degrees colder when I drove my electric fan 80 (70 deg vs 90 deg F), but the lowest engine compartment temperature was 50 degrees lower than in my stock-shroud 79. A lot of this, I'm sure, is due to the better design of the 80's nose.

 

This info may or may not be helpful to you.
I have twin 11" fans also. I have installed a dual temp sensor gauge in my car with one sensor placed under the hood on the firewall were the AC relay is mounted and the other inside of my air cleaner. This was done to determine if there was benefit to be had from a cold air intake in my car with the high rise vented greenwood hood. in my case both temp sensors climb while the car sits idling at stop lights but temps drop almost immediately after the car gets moving and in some cases the temps recorded in my air cleaner have been a degree or 2 below ambient. the temp sensor at my firewall near my sidepipe headers does typically read a few degrees higher than the one in my air cleaner but also drops close to ambient once moving.

 

Not sure why space is a concern. I guess for some folks it is. Weight would be a bigger concern for me.

Seeing you brought it up , the myth continues that there is some great HP savings vs the clutch fan. Even if it was 10 hp, what is the benefit? You wouldn't even notice it at 6000 rpm and at 60 mph when it only takes 50 HP to move the car along, the HP difference would be less than 1, i.e. negligible! But with a fan mounted vertically, electric or mechanical, it will blow air over the top of the engine thus removing some heat. But with electric fans pointing downwards when mounted to the rad, no air is blown across the top of the engine - disadvantage.

 

You should take a look at what I just posted. I did not run an experiment sitting in my driveway, because when I drive, I'm driving. But it seems that when I'm driving, the engine compartment is significantly cooler with the electric fans.

I did not expect that result, and I was not looking for it, but there it is.

 

The gains are through the whole rpm range not just 6000rpms... Like everything, theres are plenty of variables... just look at the differences in the types of mechanical fans alone. .

Being my engine compartments temps equalize with ambient air temps when the cars moving, the direction my fans blow and the "Myth" they cause hotter engine compartment temps is unfounded and dis proven in my particular actual application. In reality I believe the direction the fans are blowing allows cooler air to be more easily pulled through the cowl area with less turbulence from those fans blowing that hot rad air down.

I ran the stock shroud, fan and new replacement clutch for over 8 years before going to the electric setup last year and it had a huge positive impact on my temps. I would never go back to the mechanical setup on this car.

 

What most folks don't understand is that it takes say 10 hp at 6000 rpm to run a clutch fan but it doesn't take 10 hp sitting at idle. HP required to propel a car is exponential. So at 60 mph, it takes about 50 hp and not the max rated engine HP. But the fan at 60 mph doesn't take 10 hp to drive it. If it did, that would mean 20% of the developed hp of the engine is driving the fan. Using that same incorrect logic of 20%, a 500 hp engine would use 100 hp to drive the clutch fan. Utter nonsense. So, no advantage in electric fans because they use power too and sotp performance is zero.

It's nice to see members posting underhood temperatures. But others have posted their underhood temperatures being near ambient with clutch fans. I would never put in electric fans because their is no benefit for my setup. My car cools just fine with the stock shroud that was designed to pull copious amounts of air from idle on up across 100% of the rads surface area all the time. If there are overheating issues, its usually corrected only by replacing the rad with a nice big aluminium one. If it ain't broke.................

 

I don't care how much HP my fan takes at idle (although at 15 Amps per fan, it's about 400 W, so perhaps 1 HP by the time my alternator is done). My electric fans use ZERO HP at all other speeds. Whatever number you want to accept for the power loss of the clutch fan, it will still be greater than zero. You keep saying there is no advantage to electric fans, but that clearly isn't the case.

The engine doesn't care about the engine compartment temperature. We aren't driving Corvairs. As I'm sure you'll agree, the radiator (stock, or a nice big aluminum one), cools the engine, not the air blowing around in the engine compartment. With a CAI, the engine will be fed ambient air, or a regulated mix.

Perhaps I'll repeat the experiment with fewer variables when I convert my 79 to electric fans. But to @CorvettePassion's question, the only data I have shows that my car with electric fans has a significantly lower engine compartment temperature than my car with the stock fan and shroud. There is no noticeable heat coming from the firewall or floor, but I always run with the T-Tops off.