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Gen 5 IC Engine Info (mostly the 2.0L)

Discussion in 'Gen 5 Prius Main Forum' started by Hammersmith, Nov 25, 2022.

  1. Hammersmith

    Hammersmith Senior Member

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    We now have confirmation of the engines in both the 1.8L and 2.0L models. (I think it was heavily suspected what they were since last week, but the leaked specs give us confirmation and final details.)

    The 1.8L is the good old 2ZR-FXE that's been used since the gen3 debuted in 2009. No surprises there. Change the oil every 6 months/5000 miles and the thing will run forever.

    The newness comes with the 2.0L engine. It's the M20A-FXS Toyota Dynamic Force engine that's a shared design with the A25A family that debuted in the 2017 Camry. The first M20A was introduced a year later in several Toyotas. (The middle two digits now stand for displacement - the M20A is a 2.0L and the A25A is a 2.5L - there is also a 1.5L M15A, a 2.4L T24A, and a 3.4L V35A because you can't have a naming scheme without at least one misnaming. lol)

    The Dynamic Force line has had a few teething problems but hopefully most of those have been sorted. The most serious was inadequate corrosion protection and sturdiness in the EGR system. When coupled with lower quality fuel, this led to clogging of the EGR valve with dust/crystals and the destruction of the EGR cooler heat exchanger which leads to coolant entering the cylinders. Seems like good quality fuel is a must to protect longevity, but hopefully Toyota has also beefed up the protection of the EGR system by now. (the core culprit is chlorine additives/contaminants in the fuel that oxidizes in the EGR system)

    The most annoying of the Dynamic Force problems is that it's a noisy engine. Because it's both a direct and multiport injected engine(8 injectors total), it needs a high pressure fuel pump for the direct injectors. That fuel pump is loud and it sits right at the top of the engine. I think we now know the reason for the new insulation we've been seeing in the gen5 hood.

    VVT on the Dynamic Force is also interesting. After years(decades?) of VVT being powered by oil pressure, Toyota has switched to an electric motor for the intake cam. This motor spins at the speed of the camshaft whenever the engine is running, and speeds up or slows down to adjust the timing. The oil-powered exhaust cam can adjust the timing a standard 41 degrees, but the electric powered intake cam can be adjusted all the way up to 70 degrees. That much adjustment allows for an engine that can go even further to avoid sacrificing power for efficiency or vice versa.

    I'm going to follow this post with a few videos explaining the engine and showing one assembled from scratch for the gearheads on the board.
     
    #1 Hammersmith, Nov 25, 2022
    Last edited: Nov 26, 2022
    PianoBench, model464, drash and 4 others like this.
  2. Hammersmith

    Hammersmith Senior Member

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    I don't know how many here follow The Car Care Nut on YouTube. He's a 10+ year Toyota Master Diagnostic Technician(the highest level of Toyota technician). After working for Toyota dealerships for well over a decade, he just recently opened his own shop that only handles Toyota, Lexus & Scion. I've spent a decent amount of money and time getting my 2010 back to near-perfect condition, and I'm considering making a trip to Chicago next summer to sightsee and let him do a full inspection and finish the last few repairs on my list.

    Anyway, a year or so back he did a few videos on the new A25A engine that is basically the same as the M20A that's going in the gen5. One of the videos is of a complete assembly of an engine for a rental company customer that had a piston grenade in the block. The piston fragments made their way throughout the entire oiling system, so the repair meant anything that had an oil passage had to be replaced. That's a lot of parts. lol

    If you're interested in the nitty gritty of (hopefully) our new engine, here are the videos...





     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    It has throttle body injection, ie a single injector at the throttle body, not port injection, an injector at each port?
     
  4. Hammersmith

    Hammersmith Senior Member

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    Sorry, brain lapse on my part. Of course it's multiport and not throttle body. I'm blaming turkey hangover. lol

    I'm going to now edit away my stupidity. :D
     
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  5. Mendel Leisk

    Mendel Leisk Senior Member

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    I wonder, did throttle body injection reduce the possibility of intake manifolds getting awash in PCV detritus? Completely off-topic, just to get engineers scheming: how about using all three styles:, port, direct and throttle body. Or like you said, just throttle body and direct. Interesting.
     
  6. bisco

    bisco cookie crumbler

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    after reading about the need to lower the engine 2" on the gen 4 to change the coolant pump, i'm going to want to know a lot more about gen 5 engine service before i will buy one.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    That’s eclipses 3rd gen plug change.
     
  8. Michael Wood

    Michael Wood Active Member

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    Yep.....love the look, but not so crazy about the "sport" focus directed at millennials and genZ. It'll probably be 2025 for me.
     
  9. Trollbait

    Trollbait It's a D&D thing

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    I thought throttle body was an intern technology between multi port and carburetor. You got most of the multi port benefits for lower cost. Once multi port reached mass adoption, there wasn't much call for throttle body.

    If build up from the PCV is a concern, a catch can is a simpler, thus cheaper, fix. I think some cars incorporate such into the engine.
     
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