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Username Post: LS1 fans: stock vs aftermarket        (Topic#347676)
gchemist 
Senior Chevytalk Moderator
Posts: 24158
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
10-15-17 06:51 AM - Post#2710909    

Has anyone noticed a difference? Noise or CFM changes?
My C10 uses a set of LS1 fans for cooling and A/C. A stock set was loud when running. A new aftermarket set is quieter. I've noticed it takes longer to cool from 205 to 190 degrees in Park. The new fans stay on longer to get below 190.
Is the difference huge? Now I'm wondering if I should find another LS1 setup instead of aftermarket.
Each fans has it's own 30 amp fuse and relay power. Alternator is a 165 amp out of a Denali.

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


 




77chevy 
Valued Contributor
Posts: 3598
77chevy
Loc: trusting earth to a boys ...
Reg: 01-26-01
10-19-17 04:09 PM - Post#2711414    
    In response to gchemist

Heres what I know...

my almost new ls1 camaro is cooling fine with stock fans with little to no noise. the 100k mile one has troubles. I cut the front metal crash beam to have holes that line up where the nostrils are on the catfish grill to be a grill feeder and bottom feeder for airflow. Ive tuned both fans to come on at 160. this has solved my overheating in traffic. although the 100k mile fan noise drowns out the rocker noise and lifter noise.

the fans I know are under 2000cfm but cant remember exact. the old taurus fans did more than they did. the stock ls fbody fan shroud doesn’t cover most radiators.

The typical ls1 radiator is inadequate and even the lt1 rad offers more capacity.

what most hp fbodies do is swap to a standup griffin or aluminum radiator and aftermarket spal fan(s) and ditch the ac condenser.

is this in your zz4 truck?
any that help?




 
gchemist 
Senior Chevytalk Moderator
Posts: 24158
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
10-22-17 08:28 AM - Post#2711691    
    In response to 77chevy

Yes, the fans are on my C10 ZZ4 motor.
The LS1 fans cover most of a 454 size radiator. I may consider adding a speed controller. Or maybe even an extra A/C condenser fan. A trinary switch is used for A/C. A 205/190 switch is for engine cooling. I was stuck on Interstate traffic dead stop for 10 min or so. The fans kept it at 190-195. The temps are cooler now. If it was 95+ degrees out side, I would worry a little. The replaced stock was very loud. The exhaust drowns out the new fan noise.

Do LS1 fans use speed or individual on/off features? Both of mine run at full power when activated.

Attachment: fans.jpg (169.8 KB) 29 View(s)


Aftermarket LS1 fans.


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


 
77chevy 
Valued Contributor
Posts: 3598
77chevy
Loc: trusting earth to a boys ...
Reg: 01-26-01
10-22-17 05:59 PM - Post#2711752    
    In response to gchemist

one fan runs when high temp is reached and then the other fan kicks on when even higher temp is reach. when the ac is on it will trigger.

the settings were high 225 and 235.

all was set in ecu. ls1 cars ran hot because of this.

my suggestion is dropping the temp down and maybe even run an aux pusher fan in front manually operated for just in case use.

the aux fan idea Ive seen used on some wild turbo hot running cars.



 
gchemist 
Senior Chevytalk Moderator
Posts: 24158
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
10-23-17 06:30 AM - Post#2711802    
    In response to 77chevy

Lowering or raising the temp will not work. I've tried lowering it. The ZZ4 heads like running at 195. At lower temps, performance drops. Fuel usage goes up a lot. At higher temps, the high rise intake and Edelbrock carb don't like heat.

The R4 compressor is almost toast. It will be replaced by an SD7HD compressor. The 6000 RPM operating range will work well with a ZZ4. I'll get to drive the truck more too.
If the LS1 fans have trouble cooling, I may go a Lincoln Mark VIII fan and a modified stock shroud. A stock shroud and two speed speed fan may work better. The low speed for cooling. High speed for A/C. I'll have to find a way to trigger lower control cooling. Both head temp ports are used now. A small auxiliary fan may be a very good option. The 165 amp alternator should have no problem running all accessories at the same time.

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


 




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