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

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

  1. Nov 17, 2018 at 8:30 PM
    #301
    ritrawler

    ritrawler Member

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    shakerhood likes this.
  2. Nov 17, 2018 at 8:32 PM
    #302
    ritrawler

    ritrawler Member

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    My only point being I don't think Toyota just threw a new tech Atkinson in this truck... At this point they're pretty familiar with it.
     
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  3. Nov 17, 2018 at 10:21 PM
    #303
    monkeyface

    monkeyface Douchebag, or just douche if we're friends

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  4. Nov 17, 2018 at 10:55 PM
    #304
    KkelX4

    KkelX4 Well-Known Member

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    Stock it's outside of the MPG specs. I only ever got the stated City mileage. Hwy was garbage. Probably 6mpg under what was stated at speeds of 65-70mph and I only ever do about 5mph over the limit.

    Besides that, how would you ever "steal" torque from somewhere else? It's only available after 2500rpm on this truck. This truck is designed to attempt to hum along somewhere between 1200-1500rpm, and fails miserably over 50mph, while maybe pushing 135lbs torque(read via my Carista) before it downshifts.

    On top of that, there already is a tune that outperforms stock. OVtune sells it, I average 21mpg now, about 19.5mpg at 65-70mph and 23mpg at 70+mph. And trust me, there's plenty of torque to go around, doesn't feel like it's missing much anymore.
     
  5. Nov 17, 2018 at 11:49 PM
    #305
    NMTrailRider

    NMTrailRider Well-Known Member

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    Stealing torque was poor phrasing. What I meant was doing something like changing the shift mapping so it up shifts even sooner from say 1-2, 2-3, and 5-6, saving some mpg, and then delaying the 3-4 upshift to alleviate the dead pedal feel and give you some more power there. So, "stealing" some gas from some points in the curve and giving it somewhere else-- thereby staying within the spec'd mpg's.

    I got piss poor highway mileage too.
     
  6. Nov 18, 2018 at 8:41 AM
    #306
    ritrawler

    ritrawler Member

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    hiPSI [OP] likes this.
  7. Nov 19, 2018 at 3:11 PM
    #307
    aacocella1

    aacocella1 Member

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    yeah it does help a lot. just makes cars/trucks feel better. a lot of people think its a "performance part" that will make their vehicle be faster and more powerful. if people understand what it's actually doing i'm sure they'll realize its worth trying.
     
  8. Nov 19, 2018 at 3:37 PM
    #308
    hordboy

    hordboy Member

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    I don't think it's really a transmission problem, it's a problem with using (fake) Atkinson cycle tuning. At part throttle the intake cam is retarded, which kills compression and therefore torque. All this BS from Toyota about it helping fuel economy is just that, BS. Compression is your friend for an efficient engine. Why are so many other manufacturers boosting their engines? Because it improves efficiency. My 3.5 gets maaaaaybe 1mpg better in the city than my 4.0 did, but gets about 2-3mpg WORSE on the highway. Why? No compression. No part throttle torque. No torque = gear hunting.
     
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  9. Nov 19, 2018 at 5:26 PM
    #309
    NMTrailRider

    NMTrailRider Well-Known Member

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    I found the same thing to be true regarding mpg. Overall mpg for me was better in my 2nd gen than 3rd because I drive so many hiway miles. And tbh I never saw anything over 18 in town. Blows my mind seeing +20mpg for some here.
     
  10. Nov 20, 2018 at 7:28 AM
    #310
    NahBehGoPa

    NahBehGoPa Active Member

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    Great post, thanks for putting in the time.
     
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  11. Nov 20, 2018 at 8:31 AM
    #311
    hiPSI

    hiPSI [OP] Laminar Flow

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    Simply put, me, and pretty much everyone else (excepting a few) get around 20 mpg on the highway on normal terrain. Unloaded completely excepting a few passengers and a suitcase or two. I pulled a 3500 lb trailer this weekend and I got 13 mpg. I pulled it around 350 miles. I unloaded it back to 1500 lbs and I got 15 mpg coming home. This truck is tuned for efficiency. ANY weight adder (tires, skids, trailer, four passengers, gear) will immediately cause the mpg to drop like a rock. ANY driving over 65-70 mph kills the mpg too.
    This truck weighs a lot and is designed to do many different things. It will get published mpg, it just has to be under certain conditions, like: Unloaded, no mods, 55 mph, no real mountains, etc.
    I had a truck once, a Chevy. It got 13 mpg loaded, unloaded, pulling a trailer, up hills and everywhere. It was just always 13 mpg no matter what. This truck, like it or not, is all over the spectrum mpg - wise depending on the conditions.
     
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  12. Nov 20, 2018 at 9:14 AM
    #312
    NMTrailRider

    NMTrailRider Well-Known Member

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    That makes sense for me. I drive most of my miles at 75-80mph and always have some wind. So gas mileage has not been good at all.
     
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  13. Nov 20, 2018 at 9:20 AM
    #313
    hiPSI

    hiPSI [OP] Laminar Flow

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    I have driven several hundred miles at 75-80 mph. Enough that I know it gets around 15-16 mpg at that speed. I typically drive 70-75 and get around 19-20 mpg.
    Here ya go and this works with adding a load too, although it is not quite as dramatic.
    MPG.jpg
     
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  14. Nov 20, 2018 at 11:18 AM
    #314
    NMTrailRider

    NMTrailRider Well-Known Member

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    Actually, I was probably running 80mph a lot more than 70. I did carry some weight. With wind I think I was around 13. No wind around 15.
     
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  15. Nov 20, 2018 at 11:20 AM
    #315
    NMTrailRider

    NMTrailRider Well-Known Member

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    This was one of my last trips with the truck on the interstate. This is what it looked like for 3 hours.
    754D76C8-1D51-4021-8636-9DDC80A6D6E5.jpg
     
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  16. Nov 20, 2018 at 8:07 PM
    #316
    Hammer40

    Hammer40 Well-Known Member

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    You're missing out then. I have fun with the 4.0s having owned a couple myself. The 4.0 was a blast anywhere over 4500 rpm but the thing to remember is it also has less HP than the 3.5L. It's funny the looks on the faces of those who forget that fact because in stock forms the 3.5 will always walk away from the 4.0 on the freeway. Light to light though that 4.0 will always take it. I'll also take my 22mpg HWY and 20 combined over the 14 my 4.0 gave me.
     
  17. Nov 20, 2018 at 8:44 PM
    #317
    Syncros

    Syncros Well-Known Member

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    I dunno, The Nissan 4.0L is pretty great. 261hp (5600rpm) and 281lbft (4000rpm), redline is 6250rpm. Nice low end torque for towing, hauling and daily driving. Open it up and it pulls hard right to the top. Some model years have a WOT restriction under 40mph that is easily removed with a programmer. Beyond that there's tons of performance parts available if it isn't enough for you including an S/C. If thats still not enough the 5.6L V8 from the Titan is a straight forward swap, it even came stock in the Pathfinder so all the upgraded parts are "bolt on" as the chassis is the same.
     
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  18. Nov 21, 2018 at 7:12 AM
    #318
    Kamille.bidan

    Kamille.bidan Well-Known Member

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    It’s more efficient to have a smaller compression stroke and a larger expansion stroke. I think that is just physics, but I am no expert.

    The problem is that Toyota implemented this new tech in the most conservative and least risky way possible based on what OV time has said. Honestly, that is the Toyota way, and always has been.

    The engine feels a lot better with Toyotas new tune, and I have a manual transmission.

    The auto transmission really seems to have some quirks that aren’t even related to the engine.
     
  19. Nov 21, 2018 at 8:41 AM
    #319
    hordboy

    hordboy Member

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    It is simple physics, and in a variable-geometry engine where the compression ratio is maintained and rod angularity is optimized, I'm sure it makes sense. The way Toyota is doing it by altering cam timing and pushing intake charge out of the (same size) cylinder, it simply lowers the dynamic CR *and* mimicks being a smaller engine at part-throttle. IE, less torque. I've been building engines for a long time. Engineers don't always make the right choices. In trying to meet ever-increasing emissions demands I'm sure they thought they were doing the right thing, but IMO this 3.5 is not well-suited for truck use. It needs to make 90% of peak torque right off idle, not starting at 2k rpm.

     
  20. Nov 21, 2018 at 9:47 AM
    #320
    hiPSI

    hiPSI [OP] Laminar Flow

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    Maybe you should apply for a job as chief engineer designer for Toyota, understand the realities and economics of producing 250K/yr of a complex component all the while maintaining the reliability and durability that your customers demand? Then report back with your findings.
    I started this to explain simple physics of why our trucks do what they do. Even though I am an engineer and a lot of my job is vehicle drive design, I have no clue what the Toyota guys had as far as design parameters and absolutely will defer to their expertise. Second guessing them without a shred of data is just pissing in the wind man.
     
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