So I have this '70 Chevelle with factory A/C. previous owner swapped in a Griffin Aluminum radiator...

BUT there are several things I'd like to change:

1) it has an aluminum flex fan
2) The shroud doesn't cover the entire radiator. I think its a 26" wide shroud on a 28" wide radiator???
3) The car is NOT stock, and a "stock" appearance is NOT necessary...

I was considering swapping to a Derale Stainless steel fan (no clutch) and buying a repro 28" shroud...

But now I wonder IF I should step-up to an electric fan (such as the dual Spal 11" setup with the built-in shroud)... I don't have the time to go junkyard hunting for used options...

I get a little worried about low-speed cooling, especially with the A/C on, so I was thinking the electrics might be a better way to go?

And since I am changing the fan and shroud anyway, I feel its probably not too much more money to upgrade to the electrics anyway...
Any opinions or advice


I am planning on a high-flow T-stat, and maybe a future pulley/pump upgrade, but for now, I feel I need to do the fan/shroud swap...

Call Don at Alumitech - he can set you up with a great electric dual fan setup that will keep you cool. Sounds like you may already have a good radiator.

I see Summit carries Derale dual electric fan setups... Supposed to be 4000 cfm in a shroud with the pressure relief flaps... $205!! Wow... I am going to have to measure my core... I need to order some other stuff from Summit anyway...

Spal 11" duals (2780 cfm) are "list price" of $315, and $350 for 12" duals (3170 cfm), on the SpalUSA website.

Really, call Don and read up on the differences between electric fan setups before you spend any money. They are NOT all the same.

Recent post, linked to some of his history:
http://www.chevelles.com/forums/showthread.php?t=183513&highlight=Finally+solved+cooling

Where we live Tony you really need some CFM and most of the electric fans are dubious there. You will also want to watch out for the area of the fans versus the radiator or original large fan. Many of the dual small fan setups have very little actual fan area compared to the single large fan the factory put in there.

You will also find examples on modern designs using non-shoud open fan cages. These should be expected to be better at high way speed as they can breathe.

I have dual 12"/13" Taurus fans on my Elky and it works reasonably well at idle without AC and an old BC 4-core. Down the highway above 85* and it starts to creep up. My current thinking is to convert to a single 18" fan from a 2001 Mustang GT. Gotcha is depth. Fan is 5.5" and open space is 4.5". So I see a short water pump and pulleys in my future to make more open space.

Then there is the electrical load issue... I put in a power distribution box with relays and fuses on my setup. I still get a voltage drop with the fans on, think I need to check the ground paths out. Then there is the 70A surge when they initially turn on. It is enough to blank out the lights at night sometimes.

is there room for an 18" steel flex fan? aftermarket or original will work if you have room in the shroud. the fan blades need to be half in/out of the shroud. should be able to feel the air pulling into the front of the grill with a good fan/shroud.

Really, call Don and read up on the differences between electric fan setups before you spend any money. They are NOT all the same.

I know, which is why I mentioned the Spal 11" dual in my first post (I believe Don uses the Spal). According to Spal, they only market one 11" dual fan setup, so I assume its the same as Don offers...

Spal does offer a new dual 12" setup...

Thie new Derale setup I saw is supposed to have similar features to the Spal dual fans (integral shroud with pressure relief rubber flaps... Its supposed to move MORE air, but I realize thats not always the case.

It is, however, about 50% less cost (probably partially because its sold through Summit)... I realize that sometimes "you get what you pay for"...

Don doesn't list the cost of the Spal unit separately, just the cost of the units with and without the fans ($365 more with the 11" fans, sensor and relays)... I PM'd him to see what kind of prices to purchase the assemblies outright (and if he can get the dual 12" setup)...



I made a few mistakes in my initial post (I just found out this weekend). The radiator is a 26" core (not 28"). The radiator is not centered in the support, The filler neck interferes with the top panel, so the radiator was mounted offset...

The hoses fit (not sure if they are stock or not). So I am not sure how much further I can slide the radiator over (if I knotch the top plate to clear the filler neck)...

The radiator is a "Northern" (Summit), not a "Griffin"

I also found the fan is a "steel" fan (curved steel blades), better IMO than the aluminum flex fans...

FWIW.. I have tested both series of Spal and Derale fans... and they are both high quality companies for sure... and produce the results they claim. I would NOT be afraid to buy either.

Thanks Steve...

I sent you a pm
In my opinion the Spal twin 12 with shroud is too much money for the same cfm rating as the twin 11 ... on our products pages page 7 .. we do list the the fan kit sold seperate ..depending on the channels you have on your rad .. our brackets fit the Harrison rad and ours no problem ... northern may use the same style channels ..so you may be good to go .
Don

I sent you a pm
In my opinion the Spal twin 12 with shroud is too much money for the same cfm rating as the twin 11 ... on our products pages page 7 .. we do list the the fan kit sold seperate ..depending on the channels you have on your rad .. our brackets fit the Harrison rad and ours no problem ... northern may use the same style channels ..so you may be good to go .
Don

Don,
Just curious if we are looking at the same fans...

the dual 11", rated at 2780 cfm (~2800 cfm), #30102052 (I think this is the same you offer), List price (fan/shroud only, no senders, relays, no brackets etc?), $315, dimensions: 23.5" width, 16.25 " tall, 4.25" thick...

the Spal Dual 12", rated at 3168 cfm (~3170 cfm), #30102130 List price (fan only, not senders, relays, etc?), $350 This also has the full shroud with pressure relief flaps... Overall dimensions, 25.83" wide, 17.32" tall, 4.0" thick at motors....

A little larger (~17%), a little more airflow (~14%) and only a little more expensive ($35 list, ~11%)...


I tried to look at the "channels", but I have no idea what factroy GM ones look like (I have only had older Chevelles with down-flow rads before)...

Of course, I noticed the bottom of my radiator is pretty hacked up... Looks like someone did some trimming with a pair of tin snips, seriously (really jagged)...

At this point, I am looking at function versus my budget...

its a personal choice as far as the higher Cfm rating ...yes its a bit more ..and if your budget can swing it ... its a good fan I installed one as a combo but had to redesign brackets ...as most people are budget concious
I desided not to carry the twin 12 in our products line up ..

depending on your top and bottom channels you will have to fab up a way to mount it ... It a full 17.0 in height .
Don

its a personal choice as far as the higher Cfm rating ...yes its a bit more ..and if your budget can swing it ... its a good fan I installed one as a combo but had to redesign brackets ...as most people are budget concious
I desided not to carry the twin 12 in our products line up ..

depending on your top and bottom channels you will have to fab up a way to mount it ... It a full 17.0 in height .
Don

Thanks Don,
Yes, very budget conscious but I also don't want to need/want to buy another larger fan later. My current core is 26X18. I am sure eventually I will want to go to something like your 28.25 X 17 (70 SB with A/C), which should fit the larger fan. I'd rather have the larger fan, even if its overkill, and eventually be able to use it on a larger radiator... If I wasn't having problems with the standard shroud right now, I would wait on everything...

Dual 11" spal fans for $203:
http://www.the-fan-man.com/shop/size-11dual-pull-part-2052-p-189.html?cPath=33

$235:
http://www.slickcar.com/productdetails.asp?ProductID=124

$239:
http://www.jaycorptech.com/showproduct.aspx?productid=14&categoryid=2
http://www.a1electric.com/catalog/cat_spal.htm

HTH

Dual 11" spal fans for $203:
http://www.the-fan-man.com/shop/size-11dual-pull-part-2052-p-189.html?cPath=33

$235:
http://www.slickcar.com/productdetails.asp?ProductID=124

$239:
http://www.jaycorptech.com/showproduct.aspx?productid=14&categoryid=2
http://www.a1electric.com/catalog/cat_spal.htm

HTH

$203.00 is not a bad price .. dont for get you will need the wire harness
Spal retail $95.90 for both .. then fabing up brackets $ ??
spal retail fan and harness no brackets $410.85

complete set up on our products pages .

http://www.chevellecooling.com/44.html?psid=p28Pd4OFW0sEkO2oQlLR&i127051:page=7
page 7 pic #69
$365.00
Don