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Username Post: Sizing Electric Fan        (Topic#365455)
DucatiRod 
Poster
Posts: 81

Loc: Maine
Reg: 12-31-20
06-07-21 04:22 AM - Post#2821267    

I read somewhere that 2700CFM would be the right size for a lightly warmed over 327. I don't know for sure that this info is right, and I found it hard to find any fans of this size! So, the questions become, what's the range, size wise for a SBC, what are the safe brands to buy, and what features should I be looking for so that I won't end up with buyers remorse~ Thanks in advance for the help!!!



 


gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25538
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
06-07-21 07:27 AM - Post#2821278    
    In response to DucatiRod

Use dual fans. If one fan fails, the other can keep it cool enough to keep it from over heating. Spal is top notch. Use separate relays for each fan. My ZZ4 runs a dual fan LS Camaro set up. Both fans turn on at 205 F and off at 190 F. The engine stays close its operating temp of 195.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
65_Impala 
Very Senior Member
Posts: 4797

Reg: 12-29-02
06-07-21 09:03 AM - Post#2821280    
    In response to DucatiRod

Yes, dual fans are the way to go, unless you go with a big brushless fan.

A trend these days is to use a PWM fan controller, which will vary the fans speed so they're not so loud all the time. It's also easier on the fans and electrical system by removing the high switching currents.

If you use relays, get good relay bases or screw terminal relays. The terminal clips in a good relay base should look like a Packard 56 terminal, not those cheesy rolled edge ones.



 
DucatiRod 
Poster
Posts: 81

Loc: Maine
Reg: 12-31-20
06-07-21 12:17 PM - Post#2821293    
    In response to 65_Impala

Who ever thought that setting up a fan to cool an engine now-a days, would cost more than my first engine rebuild back in '67 or '68



 
Rick_L 
Member #409
Posts: 27907
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
06-07-21 06:43 PM - Post#2821315    
    In response to DucatiRod

Don't be fooled by cfm ratings. They will lie to you or rate them using misleading conditions. Use current draw instead.

Actually the best approach is to use the most you can fit in the space. The dual fans are usually what fits that description. Use a name brand or adapt an OEM fan.



 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25538
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
06-08-21 03:11 AM - Post#2821324    
    In response to Rick_L

For a single fan, go big. Lincoln Mark VIII fans are great. My '00 Ram is getting one installed. I fit it into a stock shroud. The fan is bigger than the metal stock 5 blade fan. To control dual speeds, I'm using a Volvo relay. Low speed for A/C cooling. High speed for temp cooling if 195+ F is reached.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
65_Impala 
Very Senior Member
Posts: 4797

Reg: 12-29-02
06-08-21 05:53 AM - Post#2821335    
    In response to gchemist

Where'd you find a Mark 8 fan with 2-speeds? The stock ones weren't 2-speed. They have 3 terminals and lots of 2-speed assumptions were made, but they didn't have 2 speeds.



 
Mel Foye 
*VIP* Original Founding Member Group
Posts: 5251
Mel Foye
Reg: 09-29-00
06-08-21 12:25 PM - Post#2821356    
    In response to 65_Impala

I don't remember the numbers of speed but I had one and even with 2 really small jump wires when the wife touched them to battery it came really close to twisting out of my hands. Big air mover.



 
1983G20Van 
Super Senior Member
Posts: 3894

Loc: Bedford, Texas, USA
Reg: 11-13-02
06-08-21 03:12 PM - Post#2821365    
    In response to 65_Impala

  • 65_Impala Said:
Where'd you find a Mark 8 fan with 2-speeds? The stock ones weren't 2-speed. They have 3 terminals and lots of 2-speed assumptions were made, but they didn't have 2 speeds.



Probably a Taurus fan, looks similar and 2 speed.

For the old 28x17 core radiator GM used in umpteen million vehicles the Nissan NV200 fans fit like a glove. Dual fans in a shroud and each have a 2 speed motor. Motors are simple to wire as well. One set of coils to power and ground you get low speed. Hook up the 2nd set and power both and you get high speed. Lots of CFM. You can get the set for a little over $100 new aftermarket if you shop around. Chevy City Express is the same van. So its an OEM Chevy part as well.

https://www.partsgeek.com/gbproducts/AC/125095- 042...

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 06-08-21 03:17 PM. Reason for edit: No reason given.

 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25538
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
06-12-21 11:33 AM - Post#2821526    
    In response to 1983G20Van

The fan is two speed. I've tested it with a portable 12V booster. High speed sucked debris out from a truck bed. The fan was leaning on the bed cover with an open tailgate. I have a picture of it somewhere. It's mounted but still not sealed to pull only through the fan shroud.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 


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