cooling system upgrade

I've built a 4.7L engine for my '90 Cherokee. Since the stock cooling system is marginal at best, I'm pretty sure I'm going to need more cooling with some 20% more HP. I read in one of the forums that NAPA sells a "tropical" fan clutch or maybe a water pump to deliver more airflow or coolant flow. Do you remember anything like that? I've already installed a 3-core radiator using the newer system with the pressure cap on the radiator, but I want a bulletproof cooling system, as I haul a travel trailer across the Arizona desert and up long, steep grades :flame:. Thanks for any ideas!

Grand cherokee fan clutch and a Hesco hi flow water pump should match up nice with a 3 core raidiator.

If your xj runs an auto trans, bypass the radiator tranny cooler. I am in the process of installing an aux tranny cooler with a fan in the rear of my xj to isolate the tranny heat from the radiator.

zachandandy said:

If your xj runs an auto trans, bypass the radiator tranny cooler.

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/\ This too. I ran a trans cooler in front to the radiator on the mechanical fan side. Plugging the lines that run throught the radiator. Keeps the trans cool and the cooling system doesn't have to work as hard.

I made my own trans cooler out of 1/2" copper tubing. It consists of 3 (approx. 3') tubes along the outside of the right hand frame connected by tees and ells silver soldered together. The oil flows through it first, then through the radiator cooler to make sure it isn't too cold. If I change to synthetic fluid, I'll eliminate the radiator cooler. So far, I haven't seen temps over 240 degrees F, measured by an electronic oven temperature gauge with the probe clamped to the output end of the homemade cooler.

I used the hayden fan clutch 2737 which supposedly runs somewhere between 75 to 90% of engine speed where the stock one is a lot less. It is a little louder, but it does keep it cooler. I don't have a stroker.

gird123 said:

I used the hayden fan clutch 2737 which supposedly runs somewhere between 75 to 90% of engine speed where the stock one is a lot less. It is a little louder, but it does keep it cooler. I don't have a stroker.

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Is this clutch bigger/heavier than stock?

Maybe my line of thinking is wrong, but if it is bigger and heavier, its more work for the engine to turn it, meaning you'd take a hit on power?

http://www.haydenauto.com/Featured Products-Fan Clutches and Fan Blades/Content.aspx

http://www.naxja.org/forum/showthread.php?t=1085763

It is a little bigger, but i couldn't tell any difference in weight. I have read it does drop your mpg a little due to the fact that it is pulling much more air. I have not seen any noticeable drop.