Better AC with different size pulley?

GoToGuy said:

You want the maximum cooling radiator available in a 400 series. Get the 3500 HD series big block radiator. Full width, full depth of tanks, 3 rows cooling tubes and it's 19 1/2 inches tall. It 2 3/16 inches deep. As this Spectra CU1696. Along with the larger radiator shroud. You have seen cop vehicles, but if actually look at the LEO option there's no magic. As for the 160 , that's unrealistic in so many ways. The ecm doesn't work with that condition. The engine oil operating range is 180 to 245 depending on additives/ mineral or synthetic. The btu transfer rate has limitations.
It's the laws of physics.
Add more exits for under hood heat to escape, results in lower temps.
Your going on about how hot your engine is operating, is futile.
If added a new different style radiator fan, is it positioned correctly, what is gap between blades and shroud. The fan is a type of " ducted fan " to be most efficient, position / blade clearance matters.
Unless you install a radiator out of a " Cat D9 " the math doesn't work. *** temp / btu transfer / outside air temp = temperature reduction point.

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offroadtahoe said:

Here are pics of the Spectra CU1696 and stock 1500.

Those E-fans are 40A Spal 30102120 High Performance puller fans straight blade
I run a 160 thermostat and have also run a 180 degree never had a cooling problem with the smaller radiator

I don't run a E-fan shroud Im sure stock gmt800's might be fine.But alot of aftermarket mix small unbranded fans and a huge shroud & even with good fans the shroud limits airflow at speed.I have seen on multiple forums of overheat problems at standstill and up to 35mph (and even higher speeds still doesn't cool right it is a well documented problem.

Most run a relay setup for 2 fan speeds low and high and when the a/c turns on it's always on high.I don't like this (high inrush current) & they stay on at a semi high rpm on the low setting even in winter or cruising on the highway (This ok for summer and a/c) or they run a derale controller or simliar these burn up since they use the 12v+ postive to run the fan's

I run the hf-125 it is 12- ground run from https://www.autocoolguy.com/product-page/hf-125-7-khz-pwm-controller

It uses a temp sensor on the outlet port & soft starts the fan's & they ramp up or down depending on the temp.

1 min cooldown timer after key off

There is a 12v a/c feed that you wire in that overrides the fan temp settings
(If its higher then the fan temp speed).There is a port with a little screw on the back to adjust where you want the speed at.

& there is the failsafe switch that sets fan's to 100% you just run a 18g ground from controller to the dash & splice a switch in between.runs until you turn key off and still uses 1m cooldown timer.


I like the setup L31MaxExpress use's.This is just the other end of the spectrum of the clutch fan vs E-fan both have a list of pro's and con's.

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L31MaxExpress said:

I tried multiple setups on my 97. The GMT900 fans, 16" 3,000 cfm Flexalite flex waves with and without a shrould. Then ultimately went back to a clutch fan and shroud. I never had a cooling issue at low speeds. It was always at higher speeds and higher loads. Electrics fans on or off it would overheat at even 75 mph climbing a long grade towing a trailer.

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offroadtahoe said:

I want to do a rag test on mine from how far away/hard it pulls in air just keeping temp and fan's at 100%,and clutch fan idle/high rpm.Just to see the differences.

when it comes to max a/c i would definitely go back to clutch.Ive seen your post's on the electric clutch fans.what would be the best fan to run on one of those? the 9 or 11 blade?

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offroadtahoe said:

I want to do a rag test on mine from how far away/hard it pulls in air just keeping temp and fan's at 100%,and clutch fan idle/high rpm.Just to see the differences.

when it comes to max a/c i would definitely go back to clutch.Ive seen your post's on the electric clutch fans.what would be the best fan to run on one of those? the 9 or 11 blade?

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