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Enough Already! Your Truck's T, HP and RPM Explained

Discussion in '3rd Gen. Tacomas (2016-2023)' started by hiPSI, Oct 24, 2018.

  1. Oct 20, 2020 at 3:46 PM
    #601
    hiPSI

    hiPSI [OP] Laminar Flow

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    I don't know how mathematical you are but just imagine a 500 rpm amplitude shift. About the same hp and torque.
    I had a few 4Runners with the 4.0 so I have experience with both and they are comparable.
     
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  2. Oct 20, 2020 at 4:05 PM
    #602
    GrundleJuice

    GrundleJuice Well-Known Member

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    Remembered K&N supplies dyno charts for their intake systems. As many would know, K&N is less than ideal source for real HP/TQ numbers but hopefully the tq curve shapes should give an idea of how these engines make power. Also, any dyno testing not done back to back or in a controlled environment (like a lab, not a heated garage) by a competent operator, is not comparable for actual power figures. So basically ignore the peak number, take the curves location on the x-axis with a handful of salt and so on...

    Looks like the 4.0L makes significant amount of peak tq very early in the RPM range, which matches my experience. It takes some right foot to get to that power, but if the pedal is pushed far enough it's easy to break the tires free from a stop and acceleration/passing tq feel linear and flat.

    I just test drove a 2016 last night, 42k miles and looked to be in good shape. I have read various opinions about it feeling gutless and I would have to mostly agree with that unless it's wound up near peak RPM. I felt that power would come on unevenly as RPMs rise and then a surge toward the peak RPMs before a gear shift. The graph shows that power comes on and wavers before a brief surge above 5k rpm. The dyno graph below shows a really ugly tq curve that winds up and down before the final peak tq spike around 5.5k rpm, though it holds pretty steady and flat above 4k, pretty much matching my observation exactly. Not a terrible trade off for the added MPG's, but something that will be noticeable coming from the 4.0L. I suspect that aggressive tuning for fuel efficiency and emissions is a big part of why tq is so unsteady in the lower 2/3's of the RPM band, but that is just a theory. If I am correct, some tuning could (should?) wake this engine up significantly as long as there is no hardware restricting tq production in lower rpm's but not at higher RPMs.

    KN2012.jpg KN2016.jpg
     
  3. Oct 20, 2020 at 4:35 PM
    #603
    GrundleJuice

    GrundleJuice Well-Known Member

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    It looks to be more like 1500+rpm shift and a atrocious tq curve shape to go with it. Ive seen tq delivery like that on other N/A engines. One that comes to mind is the 2.5L subaru EJ253. A tune to eliminate the CL to OL delay and some MAF calibrating made a huge difference on that engine. My somewhat ignorant theory of the 3.5L Tacoma engine, from having driven one and now seeing the tq curve shape, is that a similar tune to nail down MAF, clean up fueling and take out the O2 sensor feedback early may really give this engine some low RPM life. I should start reading the hundreds of pages in the VF tune thread.
     
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  4. Oct 20, 2020 at 5:05 PM
    #604
    MOC221_

    MOC221_ 3 pedal metal

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    :thumbsup:
     
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  5. Oct 20, 2020 at 5:15 PM
    #605
    hiPSI

    hiPSI [OP] Laminar Flow

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    OV Tune will help but it can't fundamentally change the curve that much.
    It's not 1500 rpm difference lol.
     
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  6. Oct 20, 2020 at 5:21 PM
    #606
    MOC221_

    MOC221_ 3 pedal metal

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    You'd be surprised, actually. No, peak torque doesn't change considerably.. but the whole area below that peak does.
    OVT allows access to power that this little V6 can produce down low.
     
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  7. Oct 20, 2020 at 5:22 PM
    #607
    hiPSI

    hiPSI [OP] Laminar Flow

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    Just noticed your curve posted. Thanks for that! Look where the engine lives though between 2500 and 3500.
     
  8. Oct 20, 2020 at 5:23 PM
    #608
    Junkhead

    Junkhead TRDude

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    Will agree, the low end torque is quite strong on the SFOB premium. Its day and night compared to stock tuning. First gear is insanely fast now.
     
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  9. Oct 20, 2020 at 5:27 PM
    #609
    MOC221_

    MOC221_ 3 pedal metal

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    I don't know about insanely fast lol.. how about "immediate".
    There are 2D tables in the stock calibration whose sole purpose is to limit throttle in 1st gear. Nope!
     
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  10. Oct 20, 2020 at 5:32 PM
    #610
    Junkhead

    Junkhead TRDude

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    It feels like its going 2 times faster in first and the wheels wanna spin when im accelerating to around 5k rpm on dry pavement. I felt a huge difference. It does feel insane to me i guess;)
     
    Last edited: Oct 20, 2020
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  11. Oct 20, 2020 at 5:43 PM
    #611
    MOC221_

    MOC221_ 3 pedal metal

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    The change in low end torque delivery is a game changer for me.
    I can putt along at 1100-1200RPM in 6th gear on back roads with light throttle no sweat. It will accelerate with just a bit more pedal. Need a little more if the back road gets a little hilly? 5th all day.
    2nd gear parking lot shenanigans are the norm now.
    Starting in 2nd.. well I don't make a habit of it but it's much easier.
    Most of my shifts happen at 2k or less, unless it's an on ramp launch or I'm feeling sassy lol
     
    Last edited: Oct 21, 2020
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  12. Oct 20, 2020 at 5:57 PM
    #612
    GrundleJuice

    GrundleJuice Well-Known Member

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    I was using the rpm where each curve crossed 200ft/lb as a reference. Looks like about 1600+rpm delta.

    Seems like someone here might have some insight on this so I'll ask, how are the ignition timing tables affected by fuel octane on the stock tune? Any timing advance/ignition advance multiplier/etc gained with 91 octane?
     
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  13. Oct 20, 2020 at 6:02 PM
    #613
    4x4Runner

    4x4Runner Sam’s gone, man. Moderator

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    136HP and 105lbft torques with a 6speed manual FTW!!!
     
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  14. Oct 20, 2020 at 6:16 PM
    #614
    MOC221_

    MOC221_ 3 pedal metal

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    Best person to answer that question WRT stock calibration would be Mat from OVtune. He definitely set up his "premium" files for more advance on 91 and above. In fact, on his latest 2.0 tunes, an octane learning function was coded.
     
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  15. Oct 20, 2020 at 6:18 PM
    #615
    GrundleJuice

    GrundleJuice Well-Known Member

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    Appreciate the reply and insight. Once I have the vehicle I'll start heading down that road.
     
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  16. Oct 21, 2020 at 3:53 AM
    #616
    MOC221_

    MOC221_ 3 pedal metal

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    Having re-read your earlier posts about test driving a 2016, and in all fairness to Toyota engineers, they have updated their calibrations (both auto and manual) several times since the 3rd gen launch in the summer/fall of 2015. I have no personal insight into the auto trans trucks, but you will find both positive and negative opinions on whether or not these Toyota updates improved driveability in addition to solving early quirks (see list of TSBs in the sticky threads).
    Having owned an early 2016 M/T off road and then updating it with a later (TSB) Toyota calibration myself (Techstream), I can tell you it made a difference. I was already OVtuned however, so I didn't stay on the stock calibration for long lol.
    My '19 Sport M/T Sport drove similarly to the updated '16 until I OVtuned it.

    TL;DR - that '16 you drove may or may not have had it's ECM calibration updated. Old versions < new versions.
     
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  17. Oct 21, 2020 at 4:05 AM
    #617
    GrundleJuice

    GrundleJuice Well-Known Member

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    Interesting and thanks for that info. I'll investigate that when I take possession. I assume an ecm update would be something that Toyota would want done and would be free of charge or a minimal cost.
     
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  18. Oct 21, 2020 at 5:04 AM
    #618
    Self Peace

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    Interesting information. I traded my ‘17 for a ‘20 and noticed a nice difference in driveability in the ‘20. Better acceleration and it didn’t have that drop in rpm around 2nd and 3rd gear. .
     
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  19. Oct 21, 2020 at 8:51 AM
    #619
    MOC221_

    MOC221_ 3 pedal metal

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    It depends, as the ECM updates (for driveability) are usually associated with a TSB and not a recall. Technically you'd have to show the specific symptom specified in the TSB to the service dept at your dealer to get them to apply the ECM flash. There are some dealers that will flash without hassle, and some that absolutely will not unless the symptom(s) can be shown or observed. This is why quite a few of us (at least on the M/T side of the house) opted to just flash the ECM ourselves. There are entire threads dedicated to this procedure:

    https://www.tacomaworld.com/threads/ecu-tsb-update.562550/
     
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  20. Oct 21, 2020 at 11:20 AM
    #620
    GrundleJuice

    GrundleJuice Well-Known Member

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    Once again, thank you much. I have a tactrix cable for my Subaru, I believe it is a 2.0. I'll need to find out how to verify that.

    Edit - I went back through my email to 2007 and found the receipt for my cable. It's shown as a 1.2/1.3, so looks like not a 2.0. not sure what the differences are but I don't think I want to try it.
     
    Last edited: Oct 21, 2020

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