69 Dart cooling questions
Lots of good advice here and I suppose some of your Ultimate decision will depend on what you intend for the car and how mush $$$ you want to invest.
Since you drive the car on the street, a case can be made for the mechanical fan. Since you already have a mechanical (albeit a flex fan) why not try removing the pusher first and see what happens? Its an easy test and doesn't cost anything!
Regarding the t-stat, 160 vs 180 will not change how long the water is in the radiator, it will only change the temp at which the t-stat is wide open. The size of the opening will be the same, which means the restriction to the flow of water will be the same, just 20 degrees hotter. Having no t-stat might cause water to move through too quick, but I doubt it - that problem is just not seen very often with Mopars.
If you do decide to go the electric fan route, just remember that the cfm ratings by the manufacture are... well... impossible to verify. About the only rating that I've ever been able to rely on is the amperage draw. The simple math here is: the higher the amp draw of the motor, the more work it is doing and the more air it is moving. Now that is a very oversimplified gross statement, but it is more reliable than the cfm ratings often stamped on electric fans.
Next up is packaging. As you have no doubt noticed, your mechanical water pump is the closest object to the radiator - just remember that there is no law requiring the electric fan to be in line with the water pump! I like to offset the electric fans towards the bottom of the radiator on the theory that the top portion may sometimes have no water and I want as much airflow over the water filled section as is possible.
BTW - I am in the middle of building a Hemi powered Dart for a customer and we had a 3" thick radiator custom made to fit. We planned to use a pair of high-output SPAL 10" fans and when they came in - they where too thick to fit!! And we had even done a mockup - just shows no one is perfect (chuckle), some of us a little less than others (!!). Now we are going to change to a pair of regular output 11" fans (SPAL does not have a regular output 10" fan - drat!) Oh yeah - in addition to having an automatic transmission (and needing a trans cooler) the Hemi Dart also has A/C !!
And now back to the cooling bit, final component is a shroud. I am a big proponent of getting all the air to move through the radiator first and then to get it to move through the fan only. To the first aim, seal the radiator to the core support and seal the hood to the core support - the factory used a very simple rubber hood seal and they often work the best, even on fiberglass hoods. When you replace the OEM radiator with something non stock, there will often be a gap around the opening. I use some flat rubber garage door seal to fill the gap (hold it in place with the radiator mounting tabs / bolts).
Now that all the air that comes in the grille is only going through the radiator, I build a shroud around the fan. This is really more important with a mechanical fan as the electric ones often have a shroud built in, but I like to block errant airflow except for the fan opening. I do add some additional holes in the shroud for airflow at higher pressures (zipping down the highway at 75 mph etc.) and they can be louvers or dimple die holes. I will get some pictures of the Dart's cooling setup once the new fans arrive (sheepish grin!).
Here is a pic of the radiator sitting in place. We made a lower mount that cradles the lower core support frame rail brace and an upper mount that bolts to the original core support upper bar. You can't see the A/C compressor as it is on the passenger side of the engine mounted below the alternator (sort of where the original fuel pump was).
And here is one of the garage door seal I spoke of. You can just see the Black seal mounted between the core support and the aluminum radiator on this Challenger.
Hope that helps!
Lots of good advice here and I suppose some of your Ultimate decision will depend on what you intend for the car and how mush $$$ you want to invest.
Since you drive the car on the street, a case can be made for the mechanical fan. Since you already have a mechanical (albeit a flex fan) why not try removing the pusher first and see what happens? Its an easy test and doesn't cost anything!
Regarding the t-stat, 160 vs 180 will not change how long the water is in the radiator, it will only change the temp at which the t-stat is wide open. The size of the opening will be the same, which means the restriction to the flow of water will be the same, just 20 degrees hotter. Having no t-stat might cause water to move through too quick, but I doubt it - that problem is just not seen very often with Mopars.
If you do decide to go the electric fan route, just remember that the cfm ratings by the manufacture are... well... impossible to verify. About the only rating that I've ever been able to rely on is the amperage draw. The simple math here is: the higher the amp draw of the motor, the more work it is doing and the more air it is moving. Now that is a very oversimplified gross statement, but it is more reliable than the cfm ratings often stamped on electric fans.
Next up is packaging. As you have no doubt noticed, your mechanical water pump is the closest object to the radiator - just remember that there is no law requiring the electric fan to be in line with the water pump! I like to offset the electric fans towards the bottom of the radiator on the theory that the top portion may sometimes have no water and I want as much airflow over the water filled section as is possible.
BTW - I am in the middle of building a Hemi powered Dart for a customer and we had a 3" thick radiator custom made to fit. We planned to use a pair of high-output SPAL 10" fans and when they came in - they where too thick to fit!! And we had even done a mockup - just shows no one is perfect (chuckle), some of us a little less than others (!!). Now we are going to change to a pair of regular output 11" fans (SPAL does not have a regular output 10" fan - drat!) Oh yeah - in addition to having an automatic transmission (and needing a trans cooler) the Hemi Dart also has A/C !!
And now back to the cooling bit, final component is a shroud. I am a big proponent of getting all the air to move through the radiator first and then to get it to move through the fan only. To the first aim, seal the radiator to the core support and seal the hood to the core support - the factory used a very simple rubber hood seal and they often work the best, even on fiberglass hoods. When you replace the OEM radiator with something non stock, there will often be a gap around the opening. I use some flat rubber garage door seal to fill the gap (hold it in place with the radiator mounting tabs / bolts).
Now that all the air that comes in the grille is only going through the radiator, I build a shroud around the fan. This is really more important with a mechanical fan as the electric ones often have a shroud built in, but I like to block errant airflow except for the fan opening. I do add some additional holes in the shroud for airflow at higher pressures (zipping down the highway at 75 mph etc.) and they can be louvers or dimple die holes. I will get some pictures of the Dart's cooling setup once the new fans arrive (sheepish grin!).
Here is a pic of the radiator sitting in place. We made a lower mount that cradles the lower core support frame rail brace and an upper mount that bolts to the original core support upper bar. You can't see the A/C compressor as it is on the passenger side of the engine mounted below the alternator (sort of where the original fuel pump was).
And here is one of the garage door seal I spoke of. You can just see the Black seal mounted between the core support and the aluminum radiator on this Challenger.
Hope that helps!