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BBC eFan - Single 16" or Dual 11"?

5K views 22 replies 12 participants last post by  pittpens24 
#1 ·
I'm inevitably going to go with an aluminum radiator, and since I've gone serpentine, it looks like an eFan setup is going to be part of the package. Just curious about you guys running big blocks, eFans, aluminum radiators... what's working for you? Also might bring serpentine setups into the picture as they _might_ block some air from moving around the motor.

I'm thinking about using a ColdCase or other 2-tube radiator, but until it's mounted on the core support, I'm not sure about whether a single fan system will fit ok, or whether it has the CFM to cool my 461. I will note that with the 4-core COPO-style curved neck radiator and a no-clutch 7-blade fan, I had no cooling issues in normal driving in any hot weather.

Things to consider; Vintage Air, possibly going EFI down the road.

Are most DeRale, Flex-A-Lite, Spal and other name brand fans multi-speed? I did read in another thread that in a dual-fan setup you don't want one fan working and the other possibly freewheeling in reverse, it that true?
 
#2 ·
IF you go with a single fan....Look into a Mark VIII or Taurus fan.

I've been told 4000+cfm ;)

But, as with ANY E-fan, you will need to make sure you have the voltage/Amps needed and get a relay to handle the draw it pulls.
 
#3 ·
What's your clearance from support to pulleys?

It all really depends on what fans you use. For our setups a single 16" will flow much better than dual 11" but there may also be more clearance issues obviously.

With our radiator and the factory shroud and clutch fan, you may be just fine like you said.
 
#4 · (Edited)
Eric... Right now its kind of hard to determine because the 4-core COPO-style radiator is out so I can only show you some pictures and give you approximate measurements from the core support to the cone of the pulleys. And as we know, the core support is slightly curved with a "bow" towards the center. I put a straight edge on the core and measured from the leading edge. When the radiators in place, there's obviously a slight gap at the outer edges.

I haven't finished installing yet, they sent me a chrome alternator, should've been polished aluminum like the compressor. Everything's loose, nothing totally tightened down. There's a cone-shaped billet pulley for the alternator that I'm not installing yet until I straighten out the polished aluminum swap. But other than these dimensions, tell me what else is needed.

Interesting that you say a single fan flows better, have you tested something like the staggered 2-11" Derale fans pictured? Also, what are the specs on your single fan (CFM, diameter, RPM, Current Draw, Speeds)? Also, can you post some pictures of your BBC setup for a 1st Gen Camaro? I can find pix of the radiator, but haven't seen any with your shroud and fan. As Doug pointed out, the Lincoln Mk VIII/Taurus single 16" fan is one adapted by many performance DIY'ers because of that 4000 CFM capacity, but it has at least a 30 Amp draw, and many will rig it with a 50 Amp Fuse and appropriate wiring, relays, etc..
 

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#5 ·
This helps.
So we now the radiator sticks off the rad support maybe half an inch too so you have to take that into consideration.

I can tell you our kit will not work because you need about 6.5" of clearance.
We use a 2500cfm fan. Compared to 2x 11" fans would probably be around 2300 or 2400 depending on which brand fans you are using.

I am not saying one single fan is better necessarily. In our case, it is because of the flow ratings. You really just have to go off the CFM rating.

Looks like you'd only have about 2-2.5" inches for a shroud and fan. And in your setup, it looks like a dual fan won't save you any clearance, so I would just go with the highest rated CFM setup.

I've attached a picture of ours.
 

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#6 ·
This helps.
So we now the radiator sticks off the rad support maybe half an inch too so you have to take that into consideration.

I can tell you our kit will not work because you need about 6.5" of clearance.
We use a 2500cfm fan. Compared to 2x 11" fans would probably be around 2300 or 2400 depending on which brand fans you are using.
So your saying that while ColdCase makes a compatible (size-wise) aluminum radiator for our 1st Gen Camaro's, the combination of the shroud and the fan would preclude using them in a "typical" 6-row serpentine belt system?

I am not saying one single fan is better necessarily. In our case, it is because of the flow ratings. You really just have to go off the CFM rating.

Looks like you'd only have about 2-2.5" inches for a shroud and fan. And in your setup, it looks like a dual fan won't save you any clearance, so I would just go with the highest rated CFM setup.

I've attached a picture of ours.
I'm curious as to the dimensions of your shroud and separately the mounted fan. Also curious if you sell the shroud without the fan?
 
#7 ·
For those cars yes. We made the full combo set up for guys that absolutely need the most cooling and the most airflow. It's a big kit so most either modify or have different setups that get around it.

Our shroud sticks out about .5" from the core. The fan cage adds another 2"-3" at furthest point.

We can sell just the shroud sure. You can then source a more lower profile fan.
 
#8 ·
Eric... Wish you guys made a shroud along these lines (see image below) for the BBC radiator. I photoshopped an existing shroud image to your BBC radiator. The "wings" on the sides would allow two (2) 12" low profile, high CFM fans to pull plenty of air. And there's probably room for 2-4 rubber flaps to allow airflow at highway speed to pass thru.

I'm still researching fans because there are OEM single larger 16"/19" fans like the Volvo 940 (Ford design), Thunderbird, Crown Vic, and MOPAR units that pull over 3000 CFM. And then there's the usual aftermarket smaller 11'/12" fans from Spal, Flex-A-Lite, Derale, and Mishimoto that pull in the high teens.
 

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#11 ·
#12 ·
Good luck.
I bought a champion BB radiator for my SB along with their shroud and fans.
I tried it first without flaps . went about 7 miles and saw 230 on the gauge. come home, removed the shroud and added flaps. went the same route and saw the same numbers
ordered a mechanical seven blade derale fan and solved my problems
 
#13 ·
This is unfortunately a subject that I'm well acquainted with having had my old Brass & Copper leaking. We attempted to repair it a few times but it needed a full recore which was in the $800 range so I went with a cheap aluminum radiator that supposedly cools better than any old school radiators. It took me a couple of conversations to finally get one that fit under my hood. There are essentially 2 types of radiators for the first-gen Camaros, the more square ones just won't fit and then there's a limited amount that have a 45-degree angle on the filler neck - that's the one. I got the whole setup off e-Bay for a couple of hundred bucks including the shroud and the electric fan.

It was put in September and October turned cold immediately so I never knew there were issues. When it got hot again I was up at 230 degrees and sweating it out in the inner city with the heat on high and 95 degrees outside with just 4 blocks to get home or do I turn it off and block traffic until it cools off which would be hours?

I didn't do the job myself because I have back problems but I had what I used to think was a good mechanic until I found out that they didn't even flush out the system other than sticking a hose in the engine, not even a chemical flush. And soon the Stop Leak was blocking up my brand new radiator which I flushed twice and still I get the occasional glop around my filler neck or in the overflow. It was better but not great. Then I realized that the cap was an odd pressure a bit under what is typical which I think is 14 pounds. No one knew where the cap came from, however. I think it's 11 pounds or something an odd one, to say the least, but the seller said they didn't include one in their package and the mechanic said he didn't order one so strange but it was not my old cap either.

It also just happened that I had started a new gauge project as the analogs were getting to hard to see and so I bought some digitals. Some seem to work fine and others didn't seem quite right. Then as luck would have it I was offered an upgrade of my environmental system the latest greatest VA. I was pretty annoyed that the first one had no heat control. Who sells an environmental system that has no heat control especially in these old classics that were always too hot. I had left the old temperature gauge in because I knew it worked and I needed a new hole for the new sending unit of the new gauge. I thought that way we'd know if there were any overheating issues with my car post the new setup. Except they didn't test it in fact they were working on it outside in the cold under a carport. There were so many problems that I had to take it back. It was then that I realized they were installers, not mechanics the had no clue how to fix what wasn't a problem when I dropped off the car but was now. I got the car back it was worse than it was when I took it in the 2nd time. I barely got it home 30 miles but I certainly wasn't leaving it for them to mess up. It was pouring rain and every single stop the car stalled the lights were so dim I could hardly see with the wipers on high which was more like low. I was lucky that most of it was highway driving but now I have to get into what's going on as no one was touching something that someone else messed up especially electrical.

Well I found a large problem was the A/C fan was shorted across the relay and it was intentionally soldered but I have no idea what the hell they were thinking. Anyway, I got most everything gone through and dropped in a new thermostat just for luck. The only thing I didn't know how to do was to check if I was getting the volume through the system or if there was potentially something wrong with the water pump. For now, I leaving it alone. I'm still overheating but I decided to sleep on it over winter and talk to some different people and see what they could offer.

I spent a lot of time thinking about it and what could potentially keep it from cooling. What I finally realized was the 16" fan supposedly running 2600 cfm that came with the system I just assumed would cool the engine but it wasn't even covering 50% of the radiator and the A/C helper fan pushing in from the front would just hit the shroud and bounce around not really doing much of anything. It was now essentially worthless with the new shroud. The shroud was essentially turning my cooling system into a funnel. Imagine air blowing into the radiator and hitting the shroud over the majority of the radiator. I don't know what pattern the air is taking but it would seem that it would be just making the part that was working maybe a bit worse. The air has to go somewhere and yet there's nowhere for it to go. I had to get more coverage or a higher rated fan(s) but also I needed to move the existing fan away from the radiator so it wasn't pulling from directly in front of it. If it sat closer to the engine it would pull from a wider area. If the fan was a bit starved for air moving it back a bit might actually allow it to pull more. If the fan's underpowered it won't make any difference. Then I remember a post I read regarding a Ford Taurus fan outputting about 4000 cfm which is also a 16" fan. However, the Taurus fan doesn't come out of it's shroud from what I've been told so better off going with a 90's Volvo and there's several models that use the exact same fan or a Lincoln Mark IV however the Lincoln Mark IV from what I saw on Rock Auto only ever had a belt-driven fan in the last year of production 1995.
I was also told that the Volvo supposedly uses the same motor as the Taurus yet I can't find any specs on any of these fans that agree with what I'm being told. They are supposedly 2-speed fans but there's no reference to CFM that I could find so far.

What I ultimately came to figure out was that I needed 2 - 14" fans or 1 20" fan to get to the 70% minimum coverage of the radiator. Both setups would need a special shroud that would have to be attached where the radiator was attached to the radiator support and would have to be cut out around the hoses. That's why I thought I would try to get a hold of 16" Taurus or Taurus comparables but I want to see what the spec are before I go spending money. I did put a request out online to the salvage yards but I've not heard anything. If one of these 3 methods doesn't work I'll be going back to my old belt-driven fan and shroud which I hate because of the noise. The electrics are nice because I could actually enjoy the sound of the car and not the fan.
 
#14 ·
A $200 radiator fan shroud combo is not going to cool a BB imho. I would toss it all and start over with a dual row radiator with 1.25” tubes. Then add dual SPAL fans with integrated shroud. And to keep it quiet a DCC PWM fan controller.

Entropy also sells a decent BB radiator fan setup.

Don
 
#18 ·
OK... here's kind of an update. I came across this article, started reading and then googling the Contour Fans.

SuperChevy: Tame Engine Heat with a Budget Electric Fan System

Eventually, I got in touch with the author of the article (Jeff Smith) and the owner (Eric Rosendahl) of the 461 CI El Camino. We've exchanged several emails and I just picked up a couple of Contour/Cougar dual fan setups, one OEM and one aftermarket. Apparently Eric's having no problems with the two 12" fans cooling his mild 461 BBC.



He was lucky in that a minimum of modifications were needed to retrofit the Ford Shroud and fans to his radiator. Here's a picture of the Contour/Cougar dual fan & shroud unit.



So I'm thinking a little outside the box and because I have a tight fit between the radiator core and the Serpentine system, I'm going to scuttle the Ford shroud and isolate the two fans as a connected unit that I can pivot and mount so the motor plates or fan shielding doesn't hit anything. I've talked to folks in the Jeep, AMX, and other forums who have used these fans. The consensus by actual users is that they are probably good for 3500-3800+ CFM at zero static pressure, maybe 3000-3300 under load. And I have one BBC user totally satisfied with his install. Here's what I'm thinking:





I'll trim away most of the shroud, but leave a couple of small sections to act as mounting tabs so I can mount the fan to a DIY custom aluminum shroud. The fan hubs on the opposite side push further forward than the actual fan blades, and they are 1/4" away from the core in a normal installation. The shroud itself winds up around 3/4" deep. Depending on final fan placement, I'm thinking either angled or horizontal shrouds.



Don't really need the Resistor link if you use a decent fan controller, so more flaps could be added.



The OEM unit just arrived yesterday, and I think that's going to be my test mule. Gonna start carving it up this weekend after I do some testing. I will either update this thread or eventually create a new thread with more details.

Just a couple of comments on Ford fans... I had a Lincoln MkVIII eFan in my supercharged SVT Lightning for over 10 years, never, ever had a cooling issue regardless of traffic or heat. Those fans are the kings of the hill AFAIC. Better than Spal or Derale or any aftermarket unit, supposedly in the 5000 CFM range. The 2nd choice and very close is the Taurus/Volvo unit designed and engineered by Ford as well, supposedly in the 4000-4200 CFM range. The Volvo 2-speed unit unbolts from the shroud and I bought one, but it was too deep in the motor section even if I moved it around... about 4" maybe a little more. The Contour/Cougar setup is 3rd on the list, I've chatted with guys running them on street cars pushing 800 HP with turbo engines. The Contour unit is about 3.25" thick with the shroud.

On conventional fans? I've been stuck for 20-30 minutes in non-moving bumper to bumper traffic on the Merritt Parkway as well as on the interstate heading down towards the cape here in Mass. My car ran fine 185 all the time until traffic... then at 850 rpm parked for 20 minutes I was seeing 210 and up sometimes. Electric fans are not affected by 5 mph or dead stop idling. Thats why I'm going electric, and that's probably why every car built in the last 20+ years has electric fans.

Stay tuned...
 
#21 ·
Couple of drawings I created to explain the "Origami" like shroud design ideas, one for the single Volvo/Taurus size fans, the other for a pair of dual 12" ones.



The single could accommodate a 16" fan without much of a problem. But the water pump pulley could be an issue. I have seen big singles offset to the right or left and then a bank of rubber flaps in the normally dead zone. I started making a illustration board 3D model of this for the Volvo fan, but then realized its too thick.



Here again, its a matter of finding the sweet spot for the dual fans. They could be centered, mounted high or mounted low or... diagonally to fit. The plan is to eventually create a dxf file and then cut it on the CNC Plasma table, then use a brake to bend the sides over, tig weld the seams.
 
#22 ·
So pretty soon I'm going to be building an aluminum shroud for my '69 Camaro. I'm curious about the thickness of material others have used for a DIY shroud as well as store bought ones. My build process will be to use a CNC Plasma cutting table to cut it out, then use a brake to bend the corners as needed. I suspect there might be some TIG welding involved for corners or whatever, so is there a specific thickness or type of aluminum that can be bent on a brake and is OK to weld if needed? I guess the other option would be to rivet corners.

I've been kicking this around for a couple of months, finally found a fan setup (Ford Contour) that has the CFM power as well as being slim enough to give me about 1/4" clearance between the corner of one of the fans and the serpentine AC pulley. I've built a crude 3D model to test fit the fans, and the next step is to refine the dimensions, create a CAD file and cut it. Once I actually had the Contour/Mystique fans in my workshop, I realized they are a little bigger than I had guessed... so I might be be limited to six (6) of the SPAL rubber air flaps but I'm going to see if I can squeeze in a couple more. This is what the cut sheet will look like.

 
#23 ·
Mine that C&R made for me was probably 16GA and was fully welded. Looks great what you have there! Good luck
 
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