ICE air intake preheated idea, am I smoking crack?

Discussion in 'Gen 2 Prius Technical Discussion' started by Ianmeister, Jul 11, 2019.

  1. Ianmeister

    Ianmeister Junior Member

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    09652AF9-3492-40B6-9FA9-FB6C6D5A6970.jpeg Greetings to all! So I scavenged this part from an ‘86 Tercel years ago. This is an engine air preheater that works in conjunction with the automatic choke on old computer controlled carburetor cars. If I recall correctly it was placed under the carb to heat cold air fuel mixtures on startup until the intake is hot enough to vaporize on its own. I’ve read some other threads that talk about keeping the air intake on our Prii hot for additional efficiency. Anyone think this could be cobbled into the intake somewhere? Where would I get power from? What do y’all think? Go commentariat

    Ian 2006 with 218500 miles
     
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  2. bisco

    bisco cookie crumbler

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    crack :cool:
     
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  3. Ianmeister

    Ianmeister Junior Member

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    Uh. Ok. Could you expand on that perhaps? ;)
     
  4. bisco

    bisco cookie crumbler

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    you asked if you were smoking crack. is there another question?
     
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  5. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I will mention that the intake tract is very long and tightly up against the block.

    [​IMG]

    Also Radiator water heats the throttle body.

    So your idea is not bad, but perhaps already done.

    I watch my intake air temp, it is about 10F over ambient.
     
  6. WilDavis

    WilDavis Senior Member

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    …to be effective, surely it would need to take considerable power from the 12V AuxBattery? …er, um 10+ Amperes? Many moons ago, back when I lived on the other side of ThePond, I used to have a Mini (…no, not one of those BMWexpansions, but an original, a real Mini) , and it had been fitted with a "Minnow" carburretor (…parent company was "Fish Carburettors" (…geddit?) http://minnowfishcarbs.co.uk/full-history )
    …and I remember there was a heating element in the throat of the Minnow carburretor which allowed the user to prevent icing in the carb (…any aviators in the audience?), but from what I remember it used rather a lot of electricity! (…just sayin' ;))
     
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  7. Ianmeister

    Ianmeister Junior Member

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    Ok THAT’S what I was looking for. Considering the wire leading up to it is 12ish gauge it probably does pull a huge draw. Hacking it into the system is probably a bad idea considering the Prius is very specifically engineered in every respect there’s no room for a high draw accessory. Plus it’s the sort of thing that might work out if properly installed but only in sub zero weather. I won’t be seeing that here near San Francisco. Then again, it would be kinda cool to bring along a conventional car battery to power it and do some ABA testing. Nobody got time for that I guess. And yes. I get the fish carburetor thing.
     
  8. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    eh, you can probably get enough electricity to run it. But I think jimbo covered it- there's already a lot of heat available to that intake air.

    Also remember that it's an atkinson- the flow rate is lower than an otto of the same displacement, so the air has even more time to heat up in the manifold.

    It's not really any more efficient with an intake heater. It's just putting an extra limit on your power production which in turn reduces fuel consumption. Put a small wooden block under the accelerator and you can have a very similar effect, no wiring involved.
     
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  9. SFO

    SFO Senior Member

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    Given that many performance minded enthusiasts use an intercooler to lower the air intake temperature, I would say its generally a negative.

    Pinging @edthefox5 for input on whether heating the intake would have a negative or positive on MPG, since he bypassed his circuit.
     
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  10. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Well it's a negative for power, because you're getting less oxygen in. The ECU will reduce fueling to maintain balance. If you do this on a regular car, you can save extra fuel because the idle will use even less than usual. If you do this in a Prius? There is no idle. The hybrid drive is already saving that fuel for you. When the engine runs, it's because the system wants more electricity- and it isn't idling that engine, it's running it up into the efficiency sweet spot. Once you're under that kind of management, all an intake heater can do is serve as an extra restriction on total power- same as blocking the accelerator at ninety-odd percent.
     
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  11. edthefox5

    edthefox5 Senior Member

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    yes your on crack bless your little cracky heart.

    You got it all backwards. There's no vaporization going on in the intake. Its just plain old air.

    The hotter the intake air the less power.

    Colder the intake air the more dense the charge. More power. That's why there's hood scoops. Thats why the make CAI's....cold air intakes.
    Thats why they make ice boxes for air intake for drag cars. They route the intake air through box filled with ice cubes. It works.

    There's a pre heater on the carb because of winter icing to prevent vapor lock in the carb not to improve performance. In fact it hurts performance.
    There's a very old performance mod you can do to your car if you live in the south lots of cars have engine coolant routed through the carb base to keep the carb warm in the winter. The prius G2 does too. If you remove that loop or bypass that coolant loop the carb will stay nice and cool and it will improve performance.

    I bypassed the coolant loop on my 07 shortly after buying it new in 07. Just disconnected the in and out coolant hoses and used a 3/8 inch PEX barrel and barreled the 2 hoses together. Do it to all my cars. been like that for 12 years on my car.

    Its so hot in Florida I dont think i wore more than a sweater once or twice all winter so throttle body vapor lock is not an issue down here but with the coolant removed the carb and intake stay nice and cool about 75 degree difference between them and the engine IIRC.

    Engine runs great and more importantly I removed constant 190 degree heat off the throttle body greatly increasing the life of the throttle body motor. $1500 throttle body.
    Now the carb has a temp of less than ambient. The heat soak is the worst when you turn the car off that's when everything under the hood gets super hot. heat skyrockets after you shut the engine off.


    Not recommended for cars that see winter. Unless you re-connect the coolant loop back up for the winter.
     
    #11 edthefox5, Jul 12, 2019
    Last edited: Jul 12, 2019
  12. Skibob

    Skibob Senior Member

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    I think you are thinking about using it when it cold out to increase gas mileage? Put down the crack pipe son. You live in California the song police would probably impound your car when you went to have it smogged.
     
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  13. sam spade 2

    sam spade 2 Senior Member

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    A lot of people go to great lengths to COOL the intake air, not make it hotter.
    That includes owners, mechanics and designers.
    Exactly the WRONG approach.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    You are conflating different auto enthusiast audiences.

    Cold air intakes are for increased horsepower, for people who don't care about efficiency. Cold air is denser, allowing a greater air mass intake charge during WOT operation, useful for racers.

    Warm air intakes are for people with old Otto-cycle fixed-valve-timing engines who want greater efficiency, and don't care about losing a bit of peak horsepower that they never use anyway. Warmer air is less dense, reducing fuel charge during partial throttle operation. This leads to opening up the throttle valve a bit, reducing air pumping loss for any given level of power production, thus helping efficiency. This was a somewhat common modification in the old eco-modder and hypermiler communities.

    The Prius Atkinson-style engine has already greatly reduced this pumping loss, so has much less to gained from a warm air intake than would an old-fashioned fixed-valve Otto-cycle engine.

    The electric heater shown in the OP is not for efficiency purposes, but rather for cold weather startup or runability or icing issues. Its electric power requirements will defeat the overall efficiency goals of warm air intake mods.
     
    #14 fuzzy1, Jul 12, 2019
    Last edited: Jul 12, 2019
  15. Ianmeister

    Ianmeister Junior Member

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    Bullseye! I had the concepts of vaporizing carbureted air fuel mixture on cold startup mixed up with the idea of heating up the prius engine on cold subzero startups swirling in my head. (And yes i was thinking about sacrificing power for striaght line fuel efficiency) There have been threads regarding ways to make the initial engine heating on startup shorter, (like blocking the grills) and i think that's where I was going with this idea. Either I need to cut back on the crack or find a better connection. Thanks all!
     
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  16. edthefox5

    edthefox5 Senior Member

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    Pius uses a throttle body/fuel injector not a carburetor. The mixture of fuel and air is done in the combustion cylinder like most cars made in the last 40 years.

    (And yes i was thinking about sacrificing power for straight line fuel efficiency)

    The Atkinson cycle already does this.
     
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