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Discussion Starter · #1 ·
Hi guys,
Would really favor "original" 7 blade fan and fan clutch on my 406, but is that really the way to go, or should i spring for single or dual electric fans behind an aluminum radiator in the 69 coupe. Seems like I'm getting farter and farther from originality with the car. I much prefer the original look under the hood, but before spending the money, since I don't have either setup yet, give me some opinions on cooling ability of both units, and suggestions please.

As always, you guys rock.

RJ
 

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Mechanical fan w/clutch have always worked. Couple reasons OEM's went to elec fans is MPG, another is more power.
If it were me, I would go with elec fan(s) if it were a track car, otherwise, fan & clutch.
 

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Here's a quote of a post I made a long time ago. You didn't ask about how the fans effect power but I think it's good to know how each effects performance. I've bolded the parts that address your cooling questions... You won't here me bad mouth alum radiators or electric fans but I do believe they are a luxury item for the avg street car.

No doubt you'll gain a few ponies with an electric fan but is it worth the extra expense? Here are some test results I got from an issue of Car Craft (May 2000) All these tests were run on Flex-a-lite brand fans except for the factory 4 blade. To baseline things the first dyno run was no fan at all but did include an alternator.

No fan = 496hp
Electric = 494hp
Thermal clutch = 487hp
Nonthermal clutch = 485hp
HD thermal = 476hp
HP flex fan = 476hp
Stock 4 blade = 473hp
Low-profile flex = 466hp
One piece plastic flex = 460hp
OE replacement 6 blade = 449hp

You can see your fan choice makes a difference. The cost difference is quite a bit though and the electric fan they used cost $170 as opposed to the thermal clutch fan at $66 and the nonthermal clutch fan at $56 (remember these are all Flex-a lite products and the testing and prices are from May 2000) Also note that this test didn't go into cooling ability.

Both types of fans can keep your mill cool just like both std and alum radiators do as well. Alum and electric adds a wow factor under the hood but are costly compared to the alternative. I have no proof for you that one flows more air than the other at idle I do feel that most electric fans may actually restrict flow through the radiator and around the engine at higher speeds though. Electric fans also require your electric system to be up to the task and power relays and proper setup is critical. If power fails, the fans don't work. I know a fan belt can fail and cause a mechanical fan to quit working as well so it's a draw unless you are not very good with trouble shooting wires... I bring this up because you hear guys talk about wiring things so the fans run as soon as the key is turned all the time. This is because they couldn't figure out how to trouble shoot and fix the problem or just don't understand how it's susposed to work.

I am using Flex-a-lite's nonthermal clutch pn 5255 and fan pn 5718 ($56 through summit) I had my stock rad recored with the biggest core that fit between the tanks (under $200), a stock water pump and a Robert Shaw (Mr Gasket) 180deg stat ($10 - $12). I run about a 60/40 water to antifreeze mix with no other additives. I have sat in traffic for over an hr creeping along and my 383 didn't get to 190 degs. Moving it stays between 175 - 185 no matter how hot it gets outside.
My point, (as it so often is) is all about budget. If you are not on one your car ought to look and perform like the Mule. If you are on one you need to pick the most cost effective parts to get the job done so you have money for the rest of the project. Nothing worse than seeing a project take years and years and never getting completed do to lack of funds!!
 

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Discussion Starter · #4 ·
I'm assuming that OE 6-blade test was without a clutch on the fan. That's a huge hp drop. Dennis, why did you use the non-thermal clutch? As for my radiator, I have no great attachment to it other than I own it, haha. Don't even think it is original. No ID on it at all that I can see. Very thin too. Given the way the previous owner put it together, I say it's whatever would fit in the opening.

I agree with Everett as well. Car certainly not a dedicated strip car, plus I can take or leave the appearance of the electric fans and their cost with wiring and such. Plus I have a very low amp alternator that wouldn't be good.

I sort of feel that with a "moder" aluminum radiator and more OEM style clutch and fan, I would do fine. Don't drive the car on the street in the summer here in SW Florida because it's like being in hell, and I have no A/C and it rains every afternoon all summer.

Thanks guys.
RJ
 

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I chose the nonthermal because at low rpm it is tight and doesn't slip (more airflow) as much but as the rpm increases it loosens up and slips more (less airflow). The fan needs to be the most efficent when the car is setting still (idling) or moving slowly.

In the article the nonthermal was only 2hp off the std thermal but was 9hp over the HD thermal. Had I gone with the thermal I would have been inclined to get the HD version and I felt the 9hp was a significant drop that I didn't want to give up.

Sorry I don't remember the specific's on the OE replacement fan...
 

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I'm assuming that OE 6-blade test was without a clutch on the fan. That's a huge hp drop. Dennis, why did you use the non-thermal clutch? As for my radiator, I have no great attachment to it other than I own it, haha. Don't even think it is original. No ID on it at all that I can see. Very thin too. Given the way the previous owner put it together, I say it's whatever would fit in the opening.

I agree with Everett as well. Car certainly not a dedicated strip car, plus I can take or leave the appearance of the electric fans and their cost with wiring and such. Plus I have a very low amp alternator that wouldn't be good.

I sort of feel that with a "moder" aluminum radiator and more OEM style clutch and fan, I would do fine. Don't drive the car on the street in the summer here in SW Florida because it's like being in hell, and I have no A/C and it rains every afternoon all summer.

Thanks guys.
RJ
RJ, In my opinion, you're correct about the modern radiator and clutch fan. I had a griffin radiator and clutch fan in my 400+hp small block and the car never ran over 180 degrees, right here with you in Ft. Myers. With my new big block combo, I need to change to electric fans due to a March serpentine system. I hope it cools as good as before.

Also, thank you for your service to this great country!!
 

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street car mechanical

strip car and looking for all HP you can make electric
 

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One thing to be aware of is the speed you're going to turn the engine. Most standard clutch fans are rated for 4000 RPM max and a standard clutch will spin at around 60% of engine speed. So that means you've got a max engine speed of a little over 6500 RPM. With your hydraulic roller (even though it's yuge like Trump says) that may not be an issue. If you go with a clutch fan, don't be lured into getting a heavy duty clutch unless you can find a heavy duty fan. They spin the fan at 80% or more of engine speed.

Here's a data log of my car after a thirty minute drive through town to the dyno shop followed by five runs to 6000+ with a few minutes between each one to make some adjustments. This is during the fifth run and the car was never shut off. Water temp is bottom graph, temperature is over on the left.
Champion three row radiator
Aluminum high flow water pump
180 degree thermostat
Flex-O-Lite standard six blade clutch fan
Hayden standard thermal clutch


 

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I replaced the stock four blade fan in my ’67 with a Hayden thermal clutch and fan. The clutch and fan were only $60 at a local auto parts store. The fan turns 20 to 30 percent of shaft speed when disengaged which frees up horsepower. When extra cooling is needed the fan will turn 70% of the shaft speed. The clutch will also limit fan speed to 4000 RPM by disengaging at high shaft speeds. This is an important safty feature that makes a clutch fan perfect for a high revving small block. Chevrolet used thermal clutch fans on the Z28. This setup not only works great but it also has the 1960’s muscle car look.

Aluminum radiators and foreign made electric fans just don’t look right to me in an early Camaro.

 

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RJ,

Have you seen the aluminum radiator Fred Ficarra got from Summit ?
Just over $200 and it fit perfectly.
 

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Discussion Starter · #12 ·
Yeh Beth, in fact I asked him about that, he didn't recall the part number as I remember, and they have several, but I will check that out again today. Want to order tonight so I get it on Friday. Confusing subject these aluminum radiators. Some of the manufactures rate them up to 400hp, and another at 600hp, etc. I figure any of them is better than what I have, but don't want heating issues here in Sw Florida, and don't want electric fans.

Thanks
RJ

By the way, I'm assuming you live in the music city? I love it there. Lived and worked there in 2002 or so, if I didn't tell you that before.
 

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Ledfoot, You say you are in Ft Myers??
RJ
RJ, yep, been here since 1973. Boy have things changed around here since then. Jim.

Just sent ya a PM.
 

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Yeh Beth, in fact I asked him about that, he didn't recall the part number as I remember, and they have several, but I will check that out again today. Want to order tonight so I get it on Friday. Confusing subject these aluminum radiators. Some of the manufactures rate them up to 400hp, and another at 600hp, etc. I figure any of them is better than what I have, but don't want heating issues here in Sw Florida, and don't want electric fans.

Thanks
RJ

By the way, I'm assuming you live in the music city? I love it there. Lived and worked there in 2002 or so, if I didn't tell you that before.
Yeah, I do love Nashville. I live in the Inglewood area.

Fred's radiator is part#SUM 381328. Here's the link :

http://www.camaros.net/forums/showthread.php?p=1464946&highlight=summit+radiator#post1464946
 

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From one RJ to another....

Gilroy where I'm at hits 100+ most of the summer but we don't have your Florida humidity. I went with a Derale flex fan after reading several of the posts here and skipped the clutch and electric mess. No where near as noisy as the Flex-A-Lite type fans. I can sit at idle all day long, or at least thru a 2.5 hour parade, and never get over 190F. Running 4 core radiator and 160F t-stat. No A/C, no pwr steering, no heater for that matter.

Here's a pic showing the fan from before I dropped the motor in.

 

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There are some quality flex fans that won't throw a blade, I believe the Derale like RJ has above is one but throwing a blade is what the flex fan is known for so choose wisely.

The design of the flex fan was initially for drag strip use, the fan draws lots of air at idle and low rpm but as the rpm goes up the blades go flat and actually block air coming through the core. They really work well for general street driving but if you are inclined to drop it down a gear and hold the rpms up as you wind around the country side you may see your temps creep up some.

Without a clutch the blades also get spun up as your rpm goes up and that's where many of the flex fans fail so if you opt for a flex fan do your homework like RJ did and get one that will stay together...
 

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Over the years, have tried various oem and after market pitch fans and I still came back to a factory delco fan clutch and 7 blade fan.
Only just recently change to a 23" aluminum wide tube radiator.
 

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I live and drive 2 1967 Camaros in the Tampa area. The 350 SB coupe has AC and a lot of options, the 396 BB convertible has fewer (no AC). Both have thermal clutches and 7 blade fans, neither has had any cooling problems.
 
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