Mr.Lopar
Well-Known Member
so what are you doing for a fan?
Terrible mpg 77 Aspen 318
- Thread starter Slanty
- Start date
I have a few flex fans lying around,I want to put and electric fan on it.For now IM just going to use a plastic flex fan but IM going to need a spacer.I also want to ad a GM HEI Module and MSD COIL. also want to add long nosed autolite 985 plugs and gap them at .45.
Mr.Lopar
Well-Known Member
If you plan on doing lots of highway driving get something else, those flex fans are junk,had one on my old 5th and did a road trip,had to keep pulling over so it would cool off cause the flex fan would not keep it cool
80 Lebaron Coupe
Well-Known Member
I know its a long shot, but it happened to me.
I had a 77 Dodge Van with a 318,
and the fuel pump was leaking inside and filling the engine with gas.
Smell your oil and see if there is a gas smell.
Never leaked a drop outside, but filled the engine full.
as far as cooling goes,
I put a 3 core radiator and 7 blade truck fan with a thermo clutch
and have had zero over heating issues.
I had a 77 Dodge Van with a 318,
and the fuel pump was leaking inside and filling the engine with gas.
Smell your oil and see if there is a gas smell.
Never leaked a drop outside, but filled the engine full.
as far as cooling goes,
I put a 3 core radiator and 7 blade truck fan with a thermo clutch
and have had zero over heating issues.
slant6billy
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I strongly recommend an electric fan. I put one in my 95 ram van shorty with a 3.9 and the mpg gain was close to 18 if I'm really easy on acceleration and stay at 55mph, WHICH is incredibly difficult. Get the relay kit with electric thermostat. In regards to acceleration- there is a much easier time acceleration without the drag of the fan. I'm putting an E fan in my Volare. i have a few new in the box electric fans- If anyone wants one for 40 bucks a fan.
Flex fans don't work on the highway because they can't pull air fast enough through the radiator. The air actually cavitates between the radiator and the fan, blocking airflow. Another thing to consider is the blade itself: around here, the only flex fans on the shelf are reverse-rotation, for use with serpentine belts. I had a very-confused customer with an overheating '85 C10 who couldn't understand what was happening, since he'd replaced the flopping fan clutch & blade with a solid-mount flex unit the fine folks at Advance "You want fries with that?" Auto Parts sold him. Yep. The fan was blowing air forward through the radiator. Fine in a parking lot, but not so good once you're moving!
The only way you should see an MPG improvement on the highway with an electric fan is if you replaced a fixed-blade fan, or your fan clutch was shot (locked, or sloppy enough to lock in place while the shaft is spinning). Thermal fan clutches disengage at highway speeds as the airflow through the radiator is enough on its own; the only thing turning the fan at that point is the airflow past it. A constantly-running electric drags more by loading the alternator than a de-clutched fan mounted to the water pump nose. You could see an increase in town, but because the fan de-clutches at even moderate speeds, I wouldn't expect more than maybe a mile per gallon or so unless you live in a super heavy traffic area. Think about this for a second: on big trucks (tractor-trailer rigs) that might travel 200,000 miles in a year, every tenth of a mile per gallon makes a difference. They don't use electric fans. They're clutch fans. Simple, reliable, and efficient.
I have nothing against electric fans, really. I just always consider worst-case scenarios. Stuck in rush-hour traffic in Chicago on a hot summer day, I'd rather have a shot clutch that's at least somewhat turning the fan than a totally-dead windmill up there, and I'm not the kind of guy to travel with a trunkload of spare parts like an extra electric fan, or even a backup fan clutch. Still, I may have no choice but to run electric fans on my project. There will be two if I must, and no way will I use the cheesy thermostat setup that is available from most electric fan sources. The worst are those probes that push into the radiator. No, I'll use a proper fan-control switch from a production application (FWD car application, like an Omni) to actuate an automotive-grade relay, and never worry about it. I might consider an override switch to avoid heat soak after turning off the car; then again if it's that hot the relay can still kick in and cool it down without my help.
One thing to remember about cooling, it's just like everything else: there is the condition of "too much of a good thing" to consider. Running the engine at lower temps adversely affects both performance and economy. It's a simple fact that your car will not be as fast, nor will the fuel economy be as good, at 160° as it is at 195°. It's all about thermal efficiency. Put God's own cooling system in it to be safe if you want, but keep the 195° thermostat!
The only way you should see an MPG improvement on the highway with an electric fan is if you replaced a fixed-blade fan, or your fan clutch was shot (locked, or sloppy enough to lock in place while the shaft is spinning). Thermal fan clutches disengage at highway speeds as the airflow through the radiator is enough on its own; the only thing turning the fan at that point is the airflow past it. A constantly-running electric drags more by loading the alternator than a de-clutched fan mounted to the water pump nose. You could see an increase in town, but because the fan de-clutches at even moderate speeds, I wouldn't expect more than maybe a mile per gallon or so unless you live in a super heavy traffic area. Think about this for a second: on big trucks (tractor-trailer rigs) that might travel 200,000 miles in a year, every tenth of a mile per gallon makes a difference. They don't use electric fans. They're clutch fans. Simple, reliable, and efficient.
I have nothing against electric fans, really. I just always consider worst-case scenarios. Stuck in rush-hour traffic in Chicago on a hot summer day, I'd rather have a shot clutch that's at least somewhat turning the fan than a totally-dead windmill up there, and I'm not the kind of guy to travel with a trunkload of spare parts like an extra electric fan, or even a backup fan clutch. Still, I may have no choice but to run electric fans on my project. There will be two if I must, and no way will I use the cheesy thermostat setup that is available from most electric fan sources. The worst are those probes that push into the radiator. No, I'll use a proper fan-control switch from a production application (FWD car application, like an Omni) to actuate an automotive-grade relay, and never worry about it. I might consider an override switch to avoid heat soak after turning off the car; then again if it's that hot the relay can still kick in and cool it down without my help.
One thing to remember about cooling, it's just like everything else: there is the condition of "too much of a good thing" to consider. Running the engine at lower temps adversely affects both performance and economy. It's a simple fact that your car will not be as fast, nor will the fuel economy be as good, at 160° as it is at 195°. It's all about thermal efficiency. Put God's own cooling system in it to be safe if you want, but keep the 195° thermostat!
What if I bypass the smog pump and ac
I'm not sure what you're asking. Yes, the smog pump is a drag on the engine, but the AC is not unless it's running. Neither one has much to do with the post you quoted, if anything. Either way, unless the smog pump is dragging badly, it wouldn't result in the kind of economy you're describing. We used to pull off smog pumps, gut them, and reinstall to keep everything as-built under the hood.
