6 ms·

> cooling system Didn't watch the video yet, but under normal conditions the car is flying down the freeway so (I'm assuming) gets some cooling effect from tha

> cooling system Didn't watch the video yet, but under normal conditions the car is flying down the freeway so (I'm assuming) gets some cooling effect from that flow of air. But that's not happening in this case. Might be a problem.

bombcar 3y ago
Most cars are cooled by a fan these days, and many use an electric fan that can vary speed to keep the engine cool. Best efficiency would be to use the fact you’re not moving to have more radiator surface area available but it’s probably not worth it.
- yetihehe 3y ago
  The fan in cars is typically not enough to keep it cool while stationary under load, but in typical home applications you won't have that big load anyway. Big load for a car is >10kW. You can also pretty cheaply get a bigger external fan, like those used on dynamometers. One nice side effect of using car as generator - free heat in winter if you extend cooling loop to your home.
  - dylan604 3y ago
    How is a stationary car engine under load? Oh right, like my asshat neighbor that likes to sit in the driveway a 6AM revving his engine every. single. morning.
    - sp332 3y ago
      When you put a generator on it, which is what the thread is about.
      - dylan604 3y ago
        it wasn't a serious question looking for an answer.
    - IE6 3y ago
      fwiw revving the engine while stationary wouldn't really put much (if any) load on the engine
  - philsnow 3y ago
    > Big load for a car is >10kW I don't have any idea if it's relevant at all (or how much the number can be trusted), but when I floor the accelerator in my Bolt, the dash indicator says it's using about 120kW.
- rqtwteye 3y ago
  The fans cars have are not sufficient to cool the engine at high load.
bluGill 3y ago
Your car engine can typically deliver 150 horse power to the wheels, but after 6 seconds of that you are at freeway speeds and then your engine is only delivering about 25 horsepower. A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes (6 horsepower to run the AC) for the next red light where you wait for 10 seconds (again 6 horse power for the AC). Cooling from running down the freeway is easy to replace with a bigger fan. However the radiator itself is not large enough to get all the power the engine is capable of. (I also didn't watch the video, but I'm guessing the donor generator had a 12 horsepower engine so the radiator should be more than good enough). Of course there are other trade offs - many mechanics have a sign "speed costs money, how fast do you want to go", this sign isn't referring to the initial cost to tune the engine for max power, it is referring to max power means your engine needs a full rebuild every 20 hours of operation.
- yetihehe 3y ago
  > A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes My old 2004 Opel 1.6, 105hp could deliver almost full load (car fully packed with passengers and baggage, with roof trunk also packed, going 140km/h uphill with fully open throttle, fuel usage was reported as 16L/100km, typical road usage was 8L/100km) for about half an hour without any problems.
  - ilyt 3y ago
    with 140km/h wind to cool it in addition to radiator fan
    - yetihehe 3y ago
      I don't think fan was engaged anyway, never noticed it working when moving, only when stationary. I don't think it would help anyway. What I mean - cars can do fine for long periods under load as long as they are cooled appropriately, not only for 10s of full power.
asciimov 3y ago
You could do few things to mitigate this issue. 1. install larger fans on to the radiator. 2. use a big shop fan to blow air over the radiator. 3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature.
- yetihehe 3y ago
  > 3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature. Modern engines are designed to work at preferred temperature. They have two cooling loops, one small which is constantly cooling cylinders and one big (with radiator) which cools the small one to keep engine at proper temperature, not too high and not too low, by mixing some of small loop coolant with large loop coolant. Point 2 is the best solution.
- bluGill 3y ago
  Install a larger radiator is the correct fix if this is a concern. While the stock fan is not the most airflow, if it isn't enough you want the bigger radiator.
rqtwteye 3y ago
It gets most of its cooling from the air flow. Cover up all openings if your car and you will overheat the engine very quickly. If you put a car on a dyno you usually put a big fan in front of the car to provide cooling.
dghlsakjg 3y ago
In this case the generator is drawing off 5.5kw of power, if it is maxed out. This engine is capable of around 150kw of power, and the cooling system is capable of keeping up with that at highway speeds. My guess is that if they are using the standard cooling system, it isn't even close to being taxed with a 5.5kw load even at 3600 RPM. That's less power output than you would expect while running the ac in stop and go traffic.
adrianmonk 3y ago
I'd bet this car engine will be lightly loaded since it's many times bigger than the engine in a generator. From what I was able to dig up[1][2], the generator (that the alternator came out of) has a 1-cylinder, 4-stroke, air-cooled, 305cc engine. A Toyota Sienna minivan's[3] engine is around 3L, so it's basically 10 times as big. --- [1] generator product listing: https://www.lowes.com/pd/Troy-Bilt-5-500-Running-Watts-Portable-Generator-with-Briggs-Stratton-Engine/4764073 https://www.lowes.com/pd/Troy-Bilt-5-500-Running-Watts-Porta... [2] similar engine: https://www.briggsandstratton.com/na/en_us/product-catalog/engines/snow-blower-engines/1450-professional-series-snow.html https://www.briggsandstratton.com/na/en_us/product-catalog/e... [3] https://en.wikipedia.org/wiki/Toyota_Sienna https://en.wikipedia.org/wiki/Toyota_Sienna
pdonis 3y ago
As another poster has pointed out, the power output is very small compared to the engine's capacity. So cooling is not really a problem. From the engine's point of view it's pretty close to idle, and the car's fan should have no problem pulling enough airflow.

bombcar 3y ago

Most cars are cooled by a fan these days, and many use an electric fan that can vary speed to keep the engine cool. Best efficiency would be to use the fact you’re not moving to have more radiator surface area available but it’s probably not worth it.

yetihehe 3y ago
The fan in cars is typically not enough to keep it cool while stationary under load, but in typical home applications you won't have that big load anyway. Big load for a car is >10kW. You can also pretty cheaply get a bigger external fan, like those used on dynamometers. One nice side effect of using car as generator - free heat in winter if you extend cooling loop to your home.
- dylan604 3y ago
  How is a stationary car engine under load? Oh right, like my asshat neighbor that likes to sit in the driveway a 6AM revving his engine every. single. morning.
  - sp332 3y ago
    When you put a generator on it, which is what the thread is about.
    - dylan604 3y ago
      it wasn't a serious question looking for an answer.
  - IE6 3y ago
    fwiw revving the engine while stationary wouldn't really put much (if any) load on the engine
- philsnow 3y ago
  > Big load for a car is >10kW I don't have any idea if it's relevant at all (or how much the number can be trusted), but when I floor the accelerator in my Bolt, the dash indicator says it's using about 120kW.
rqtwteye 3y ago
The fans cars have are not sufficient to cool the engine at high load.

bluGill 3y ago

Your car engine can typically deliver 150 horse power to the wheels, but after 6 seconds of that you are at freeway speeds and then your engine is only delivering about 25 horsepower. A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes (6 horsepower to run the AC) for the next red light where you wait for 10 seconds (again 6 horse power for the AC). Cooling from running down the freeway is easy to replace with a bigger fan. However the radiator itself is not large enough to get all the power the engine is capable of. (I also didn't watch the video, but I'm guessing the donor generator had a 12 horsepower engine so the radiator should be more than good enough). Of course there are other trade offs - many mechanics have a sign "speed costs money, how fast do you want to go", this sign isn't referring to the initial cost to tune the engine for max power, it is referring to max power means your engine needs a full rebuild every 20 hours of operation.

yetihehe 3y ago
> A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes My old 2004 Opel 1.6, 105hp could deliver almost full load (car fully packed with passengers and baggage, with roof trunk also packed, going 140km/h uphill with fully open throttle, fuel usage was reported as 16L/100km, typical road usage was 8L/100km) for about half an hour without any problems.
- ilyt 3y ago
  with 140km/h wind to cool it in addition to radiator fan
  - yetihehe 3y ago
    I don't think fan was engaged anyway, never noticed it working when moving, only when stationary. I don't think it would help anyway. What I mean - cars can do fine for long periods under load as long as they are cooled appropriately, not only for 10s of full power.

asciimov 3y ago

You could do few things to mitigate this issue. 1. install larger fans on to the radiator. 2. use a big shop fan to blow air over the radiator. 3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature.

yetihehe 3y ago
> 3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature. Modern engines are designed to work at preferred temperature. They have two cooling loops, one small which is constantly cooling cylinders and one big (with radiator) which cools the small one to keep engine at proper temperature, not too high and not too low, by mixing some of small loop coolant with large loop coolant. Point 2 is the best solution.
bluGill 3y ago
Install a larger radiator is the correct fix if this is a concern. While the stock fan is not the most airflow, if it isn't enough you want the bigger radiator.

rqtwteye 3y ago

It gets most of its cooling from the air flow. Cover up all openings if your car and you will overheat the engine very quickly. If you put a car on a dyno you usually put a big fan in front of the car to provide cooling.

dghlsakjg 3y ago

In this case the generator is drawing off 5.5kw of power, if it is maxed out. This engine is capable of around 150kw of power, and the cooling system is capable of keeping up with that at highway speeds. My guess is that if they are using the standard cooling system, it isn't even close to being taxed with a 5.5kw load even at 3600 RPM. That's less power output than you would expect while running the ac in stop and go traffic.

adrianmonk 3y ago

I'd bet this car engine will be lightly loaded since it's many times bigger than the engine in a generator. From what I was able to dig up[1][2], the generator (that the alternator came out of) has a 1-cylinder, 4-stroke, air-cooled, 305cc engine. A Toyota Sienna minivan's[3] engine is around 3L, so it's basically 10 times as big. --- [1] generator product listing: https://www.lowes.com/pd/Troy-Bilt-5-500-Running-Watts-Portable-Generator-with-Briggs-Stratton-Engine/4764073 https://www.lowes.com/pd/Troy-Bilt-5-500-Running-Watts-Porta... [2] similar engine: https://www.briggsandstratton.com/na/en_us/product-catalog/engines/snow-blower-engines/1450-professional-series-snow.html https://www.briggsandstratton.com/na/en_us/product-catalog/e... [3] https://en.wikipedia.org/wiki/Toyota_Sienna https://en.wikipedia.org/wiki/Toyota_Sienna

pdonis 3y ago

As another poster has pointed out, the power output is very small compared to the engine's capacity. So cooling is not really a problem. From the engine's point of view it's pretty close to idle, and the car's fan should have no problem pulling enough airflow.