Run electric fans all the time?

Heating / Cooling / AC

  1. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    The B/RB ratio was .95:1 or 1.4:1 with AC. The .95:1 was with a high flow 4.38 " diameter 8 blade pump the 1.4:1 was with a 3.5" diameter 6 blade pump. That reflects what the factory did as far as managing the overdriven fan and pump with the water pump output, all of the V8's got an 8 bladed pump with the non-AC set up. With a 1:1 ratio you need the 8 bladed pump for best cooling, the 6 blade pumps were for the overdriven pulleys.

    water-pump-info-all-mopars-jpg-jpg-jpg.jpg

    My engine is a 340, but it's .060" over with iron heads. HP is probably in the 420-430 hp range, I've never dyno'd it though so who knows.

    Yeah between the almost complete lack of a grille opening and the ridiculously tight engine bay I don't know how they kept those things cool. That picture doesn't even really do justice to how little room there is, when I went to pull the fans from a car at the yard I was amazed how tight it was. I pulled a lot of stuff just to get that fan shroud out, radiator included. It was dumb.

    It also doesn't convey the hp per cube, that was a 2.5L V6 that made 200 hp. That's 1.3 hp per cube, and that's an important factor too. My 340 is less than that per cube, although I think goldduster318's is higher.
     
  2. famous bob

    famous bob mopar misfit

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    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    BINGO !
    I`ve been wondering about the engine sizes in these posts , 318 / warmed over ? 340/ warmed over , warmed over 440 ?
    Or an all in street 500 plus inch engine in a tiny engine bay . Makes a hell of a bunch of diff. !
     
  3. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    Big blocks also cool differently though. The HP to cubic inch ratio is important as well, because it gives you a better idea of how hard the engine is working. A 500 hp big block would be easier to cool than a 500 hp small block. That Contour V6 is harder to cool than most of the engines that guys run here, 1.3 hp per cube and pretty much packed in solid. Even a big block in an A-body has TONS of room compared to that v6.
     
  4. DrCharles

    DrCharles Well-Known Member

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    Maybe I should start a poll... what radiator is everyone using to keep their big-blocks cool! :)

    Any thoughts on this one? 26" Big Block Mopar Radiator
    It obviously does not weigh 45 lbs, that'd be a LOT of aluminum!

    I should have just left well enough alone (and the temps are quite reasonable) - but as usual I felt compelled to improve things that are working :rolleyes:
     
  5. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    I think your current radiator is fine. The biggest shortfall in your current system is the controller, buy a Dakota Digital controller and run the fans when they need to be run.
     
  6. DrCharles

    DrCharles Well-Known Member

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    Well... let's back up a bit ;) I started this flog because the temp will not drop below 194 on the highway, so the fans run all the time (both on high speed). That is indeed a factor of my temp switch.

    But I can shut them off manually and the temp stays about the same.
    To me that says either inadequate coolant flow or not enough radiator since there's plenty of air at 60 mph...

    I don't have a problem with the idle temps, since I know that can be fixed with a better sensor and controller.

    I only wanted to run mid 180's on the highway. Am I asking the impossible?
     
  7. 5.7 hemi

    5.7 hemi FABO Gold Member FABO Gold Member

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    It’s airflow if it doesn’t cool at 60, not enough radiator if it won’t cool below 35. If you were to put a scoop on, that air coming over the top of the engine would help some, to what degree, I have no idea.
     
  8. DrCharles

    DrCharles Well-Known Member

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    I need to update my avatar - there has been a glass six-pack hood on for some months now :)

    I can sit in the driveway with both fans on and get the temp down to just above the 'stat opening. Of course there is much less heat to reject since the engine is only making a few hp and the same 1/3 goes into the water jacket.
     
  9. goldduster318

    goldduster318 Overzealous Car Modifier

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    My opinion is your thinking is correct there. The fans will not be the issue. It's either not enough radiator or coolant flow as you mentioned. So that's either pump output, restriction, or just not enough cooling capacity from the radiator. Pick your poison to try first, its hard to know.
     
  10. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    We're bouncing around here.

    You've identified three issues so far-
    • Underdrive pulley on the water pump
    • Standard water pump mismatched to pulley ratio
    • temp switch instead of a controller

    I would fix those issues before doing anything else. You should either drive the water pump 1:1 with a high flow (8 blade) water pump or 1.4:1 with a standard 6 blade water pump. Matching your pump and pulley ratio alone has the potential to make a huge difference. Then get a better fan controller, if you even still need it.
     
  11. DrCharles

    DrCharles Well-Known Member

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    But 0.95 is the standard non-a/c pulley ratio (i.e. 5% underdrive) for big-blocks with the eight-vane pump. Which is what I had, and also in agreement with the chart you posted earlier.

    There is no 1:1 unless I get some custom pulley setup. Will it be worth it for 5%? I'll be shifting at well over 6000 rpm and don't want the pump to cavitate, either.

    The Flowkooler 16-fin pump just arrived and it's a nice looking piece. It should move a lot more water than the standard pump that came out. I'll pop that in tomorrow and see how my temps do (with the fans back in).
     
  12. famous bob

    famous bob mopar misfit

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    Not entirely so , I`ve seen scoops pack the engine compartment enough to fight air flow thru the radiator , making the engine run hotter .
     
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    • famous bob

      famous bob mopar misfit

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      GREE, ditch the small crank pulley !
       
    • mderoy340

      mderoy340 Well-Known Member

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      Agree. Scoop needs to be sealed.
       
    • DrCharles

      DrCharles Well-Known Member

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      That's an interesting idea, thanks.
      I wanted the six-pack glass hood to save weight, provide clearance to the carb & air cleaner, and let heat out when stationary. But I could rig a seal plate and see what that does.
      Today I'll put the fans back on and go for a test drive.
       
    • yellow rose

      yellow rose Overnight Sensation

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      Don’t get caught up in all the OE ratio/impeller crap.

      Speed the water pump up, use the highest flow volume pump you can get and forget the impeller numbers.

      Of all the industry people I’ve contacted not a single ONE, not ONE gave a crap about how many impellers were on the WP.

      They all said overdrive the pump and use a real high flow water pump and be done.

      You aren't dealing with a bunch government regulations and bullshit fuel economy crap.

      Speed up the highest flowing water pump you can get and find something else to tinker with.
       
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      • DrCharles

        DrCharles Well-Known Member

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        How much do you think I should speed it up? Use the a/c (1.3:1) pulley?
        Will there be problems at high rpm?
         
      • MOPAROFFICIAL

        MOPAROFFICIAL FABO Gold Member FABO Gold Member

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        If the cooling system/rad capacity is enough, 5hen the fans should only run under normal driving around town. Hwy the moving air should be enough to cool it. If not then you have either too little capacity or bad duckling to the radiator and need to seal the front up and get the air going through the rad.
         
      • 5.7 hemi

        5.7 hemi FABO Gold Member FABO Gold Member

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        Apparently you’ve forgotten about the scoops that Mopar used. That is what I was referring to.
         
      • DrCharles

        DrCharles Well-Known Member

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        Apparently, Darts were available with the six-pack hood. So that's what I'm referring to.

        Would you mind providing a little more detail?
         
      • 72bluNblu

        72bluNblu FABO Gold Member FABO Gold Member

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        Ok, so it looks like I missed where you said you have a stock pulley, because you just kept saying underdriven. I don't consider the stock .95:1 pulley underdriven because it's a stock pulley. Yes, I understand that technically it is underdriven. But when you kept saying underdriven I assumed you had an aftermarket underdrive pulley and that's a whole different thing. That's on me.

        You also said you didn't know what your water pump was. The terminology also gets confusing, because the factory used "standard" for the 8 blade pump and "AC" for the 6. Well, if you go to buy one now the 8 blade pumps are "high flow" pumps, not standard.

        So, sorry for the misunderstanding. I do run a 1:1 pulley because I do have an aftermarket pulley. I wouldn't worry about the 5%, but you do need the water pump flow capabilities matched to the pulley drive ratio. If you have a .95:1 pulley and an 8 bladed pump then you do have the correct ratio, but that's not how I understood your posts.

        Well that's terrible advice. Would you like to name name's and list the "industry people" you spoke to so we can clarify that overgeneralization? Because you absolutely have to pay attention to pump performance and pulley ratio's.

        The number of vanes on the impeller isn't a good way to measure the pump performance, I'll give you that. But most of the pumps we are talking about aren't rated in GPM and the OE pumps can be separated by the number of vanes so that's commonly what's used. Now, maybe your industry people have the actual GPM numbers and therefore wouldn't use the number of vanes to categorize pump performance because GPM is the better way to do that, but saying it doesn't matter isn't accurate.

        And just overdriving to the maximum and running the highest flow water pump isn't necessarily the best solution. The OP is talking about running his engine over 6k. Why do you assume efficiency had anything do do with the 1.4:1 ratio pulley being used with a 6 vane OE pump instead of an 8? Because most of those pulley ratio's and water pump specs were pre-'70, and efficiency regulations weren't really a thing then.

        Running a massive overdrive on a high flow pump is not what you want to do, especially at 6k+.
         
      • DrCharles

        DrCharles Well-Known Member

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        I put in the Flowkooler pump, reassembled everything with the fans and went for a drive... no change. So much for all the glowing testimonials - I must have a different problem ;) Anyway, it works the same as before except my wallet is lighter. I can tell that the Contour fans are interfering with the airflow when they're off, because the first leg of the drive did not stay nailed to 183F any more.

        Would a modest overdrive (5-10%) be worth trying? - although I bet there aren't any pulleys for that!

        At some point I will either build my own PWM controller or just invest a couple hundred bucks in an Autocoolguy unit, and let the fans do what they need to do. As I said at the beginning, I don't have a real overheating problem. :)
         
      • 5.7 hemi

        5.7 hemi FABO Gold Member FABO Gold Member

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        Max Wedge, Hemi Scoop (64-67) the Dart Hemi Scoop, Twin Scoops (later Darts etc.
         
      • yellow rose

        yellow rose Overnight Sensation

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        Can’t remember the names of the guys, but I talked to two different guys at Evans coolant and one guy from Stewart Components. They all three said the same things...the biggest two core radiator you can get, either the Flow Kooler (which has more “fins” or whatever they call their impellers) or the Milodon pump and speed it up as fast as you can.

        My junk cools. I don’t run a stupid shroud, because the fan is close enough to the radiator and hottest day I’ve driven it (105 degrees) the engine runs at 170 everywhere, and sitting at stop lights it went to 180 once.

        You can’t get too much coolant flow.

        So my advice was and is sound.

        Speed the pump up, buy a Milodon or Flow Kooler pump and get a Stewart Components thermostat and forget about it.

        If Dr. Charles is worried about blowing the belts off he can use a belt that is narrower and get the belts down further in the groove so it can’t climb out with RPM.

        EDIT: I shift at 7000-7200 and haven’t lost a belt yet. He doesn’t need to go 14% over but he can. Won’t hurt a thing.

        I also see that he swapped pumps and nothing. Of course not. You need to correct the pump SPEED to get the flow up. Obviously, the Flow Kooler flows more at the same speed as anything else, but slow pump speed is killing it.
         
      • DrCharles

        DrCharles Well-Known Member

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        I'm certainly willing to try a faster WP speed since that is relatively easy to do (compared to a new radiator), although I'm a bit wary of 30 or 40% overdrive... Not worried about throwing the belt, but of cavitation in the pump.

        Today I've been searching for a pair of single-groove pulleys with faster than 0.95 ratio, but haven't been able to find anything either aftermarket or "pre-owned". The new ones are all "performance ratio" which is the exact opposite of what I'm looking for...
         
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