Cooling ideas...

[POS Dakota]

hey guys,

I have a mopar 408 stroker I am trying to come up with ideas for cooling.
Primarily a streeter. 2000 dakota.

Engine is 4 inch stroke, 10.3:1 compression, 252 #.050 cam, Iron Indy/rhs heads, carbed.
not filled and jackets are very clean.

I have a champion 3 core radiator that they use typically for smallblock chevy s-10 swaps. Fits nicely into the core support.
It's a three row and the core is about 15ish inches tall by 23ish inches wide and probably 2.5 inch thick. Seems like a good rad.

What would be a good fan to use on this? Electric? Flex? what shroud can I most easily use? Sources?
Also, what would be a good target temperature range to maintain this at? I am gonna use pump gas and I dont want things to get too hot.
Oh, my alternator is 100 amp and I am likely using very little of it for just basic stuff. Noting extravagant.

Just looking for a reality check and any suggestions I might be overlooking.
I want the cooling system to be stout and reliable.
I appreciate it.

[Alan Roehrich]

Look at Northern, they have complete kits, aluminum big tube radiators, with electric fans, custom shrouds, and all the wiring.

[Greenlight]

I would use an electric fan rather than a flex fan, etc.

The electric fan turns at full speed whenever it's on and usually come with a matching shroud. This is a big benefit at idle compared to engine operated fans, and its often hard to get the right combination of shroud/fan blade on a modified vehicle that will give a sufficient pressure difference through the radiator to cause adequate air movement. At idle the water pump may not move enough water through the engine, so you are counting on the radiator to produce a high water temperature differential. A high velocity air flow through the radiator will make this happen and an electric fan is the only way to go.

If needed, you can overdrive the water pump by changing the pulley size on the water pump or crankshaft. This will allow more water to flow thru the engine at high rpm (all rpms for that matter) when you really need to dissapate the heat in the block.

Don't remove the thermostat. Use a high flow low temperature thermostat (~160 F or so). Thermostats are sized to allow an adequate amount of time for the water to stay in contact with the 1) engine cylinder walls to take away the heat, 2) walls of the radiator tubes to take away the heat. Water flowing to fast or too slow in the engine/radiator can cause a problem.

A reasonable temperature differential between the radiator inlet and radiator exit is about 10-15 degrees. This is a good indicator as to the proper coolant flow rate and proper radiator sizing.

Also, pure water is much better at transfering heat than a 50/50 antifreeze mixture (or pure antifreeze). Antifreeze will reduce the freeze temperature and increase the boiling point, but is not as good at transferring heat from the engine as water. Therefore, use the minimum amount of antifreeze that meets the freeze requirements for your area of the country. There is a product called "water wetter" that is an even better heat conductor that really works, if needed.

With a 14 lb. radiator cap pure water will boil at ~ 250 degrees, which is higher than you want your engine to ever see.

Shoot for a water temperature of about 180-190 during normal driving. This will evaporate any water condensation that accumulates in the oil as the engine cools when you turn the engine off. This is another good reason to run a thermostat (evaporating the water quicker to reduce wear). Shoot for a maximum water temperature of ~210-215 at extended periods of wide open throttle. I would not allow more than ~ 220 F at WOT. At this water temperature you can bet that the oil temperature in the bearing (not in the oil pan) is getting hot enough to significantly reduce the shear strength of the oil (and we all know how painful that can be on the engine).

[POS Dakota]

Thanks guys. Good info.

I'm using a march rib belt system that turns the water pump faster, and I do have water wetter sitting here as well. I'll use SOME antifreeze to make sure I dont freeze but I agree 50/50 isnt too good for a warmed over engine.

Good points on the full speed e-fan at idle. Around here, I'll be idling in traffic, that's a given.
I'll put a stat in it. I currently dont have one in there. I didnt think about burning off condensation...good thought.
I'm definitely going to need to use a single large e-fan as 2 smaller ones will be hard if not impossible to make work.
I can fit a 16 incher, but I have to make sure I have a good shroud to pull through the whole core. I'll have to find one that works for me. I have a few ideas and a few laying around as well to try.

Basically nothing in this truck is factory. All of it is custom and because of my odd choices....NOTHING has been easy.
I appreciate the great info. It helps.

[Bubstr]

A little tip. Usually the cooling systems weak spot is the transfer of heat to the air.Having ducted cool air going threw the radiator is worth it's weight in gold. The only time a fan really does anything is at idle or lower speeds. This is good because your not pushing air threw the radiator with speed and gives you a head start on temp control for when you really make the heat.

Most times if you have a overheating problem, it comes from air not having to go threw the radiator or a radiator with fins too close together or too thick, restricting flow, or shrouds and fan restricting flow of air. I have seen that flat plastic panel that goes from the core support to the bumper cause all kinds of heating problems, when missing. Big holes in the core support can let air around too. It will take the path of least resistance and make a good cooling system second rate. The little air dam on Pontiacs and Cameros can even hurt them if missing. It let air out under and with smaller grille opening, it's enough to over heat one that makes any kind of power.

The bottom line is, you make heat when in the gas and at that time a fan is useless because air should be going faster than the fan, if not, you have trouble.

[ZIGGY]

There is a product called "water wetter" that is an even better heat conductor that really works, if needed.

Redline's water wetter is a surfactant which reduces surface tension, inhibiting droplet formation. IME it may or may not help, depending on your particular system.
For some good cooling system info, try www.stewartcomponents.com.

[POS Dakota]

A little tip. Usually the cooling systems weak spot is the transfer of heat to the air.Having ducted cool air going threw the radiator is worth it's weight in gold. The only time a fan really does anything is at idle or lower speeds. This is good because your not pushing air threw the radiator with speed and gives you a head start on temp control for when you really make the heat.

Most times if you have a overheating problem, it comes from air not having to go threw the radiator or a radiator with fins too close together or too thick, restricting flow, or shrouds and fan restricting flow of air. I have seen that flat plastic panel that goes from the core support to the bumper cause all kinds of heating problems, when missing. Big holes in the core support can let air around too. It will take the path of least resistance and make a good cooling system second rate. The little air dam on Pontiacs and Cameros can even hurt them if missing. It let air out under and with smaller grille opening, it's enough to over heat one that makes any kind of power.

The bottom line is, you make heat when in the gas and at that time a fan is useless because air should be going faster than the fan, if not, you have trouble.

I dont have an overheating problem. This is a completely rebuilt truck from the ground up. It's a 2000 dodge dakota of all things.
I converted it from EFI to carb. The stock 2 row radiator was junk so I bought a champion 3 row radiator they use in s-10 v8 conversions. It should be able to handle my 408.
Fits very nicely right inside the core support vs the way the old one mounted, so it gives me more clearance for fans and pullies.
And there is no A/C anymore in the way so the rad is open to a direct airpath through the grille.

I understand fully that once I'm moving I'm golden, but here in Detroit during rush hour, or the big woodward cruise we have every year, I may be sometimes sitting in the same spot for minutes at a time and that thought scares the hell out of me.

While the rad is a nice rad, it's odd size of about 23 3/8 core width by about 15 and change inches high leaves me a little screwed as far as what fans I can use.
And also my oldschool 100 amp alternator may likely not put out half that at idle to power smaller dual fans.

I've been working on suspension recently, but I like to think ahead on everything and have a plan. Kinda like how I had a plan when I bought this radiator.
I know the radiator will do the job, but I'm still unsure what to do for a fan. It's likely gonna just be trial and error and I might have to get something stout, or I may be shocked to find a single 16 inch fan will do it just fine.

[POS Dakota]

Holy Crap Ziggy...that's an expensive fan!

http://www.stewartcomponents.net/Mercha ... =ElectFans

2 of those would likely kick ass, but at almost 900 bucks for a pair.....
2 11 inch fans would fit nicely though.

[Barbapapa]

You need a Viper fan. They are OEM quality (Siemens), move big air and have 2 speeds that you can use or not.
I even use one in a non-Mopar car but it would be right at home with you!

[ZIGGY]

Holy Crap Ziggy...that's an expensive fan!

I didn't say buy their stuff, just read their spiel.

[Skeezix]

Look @ DERALE fans,

& the DAKOTA DIGITAL
adjustable thermostats
for the fan(s).


DERALE usually has
the most cfm
for the fewest amps.

ESPECIALLY because your aluminum rad is new,
I cannot recommend any product more highly than RMI-25.

[Supershafts]

You had an 8 originally ? if so the factory rad will be fine and as for the fan you can use a flexalite , never had any issues with there fans

[Skeezix]

Simply adding a simple surge tank rectifies many "mystery" cooling probs.

Always a "must-have" good idea with any cooling system.