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

My thoughts exactly. Can it do a four hour drive at 80mph on the interstate? Sure. But it feels like you're doing it in a 4 banger. Add some head-wind and it's miserable. My 2nd gen didn't feel that way at all. It wasn't a race car but it was a hell of a lot better than the 3.5. My 2 cents.

 

You're up against the transmission, ECM calibration and gearing more than you are the engine itself. For example, the sweet spot for my M/T is 70mph, or right around 2500rpm in 6th. I'm going to burn a boatload of fuel doing 80, but the truck will happily do it.

 

It’s not a mystery why these trucks perform differently for different users. And it’s not a mystery why Toyota doesn’t “unleash the full potential” of the engine. Toyota’s game has always been modest power, lifelong engine. This new engine is modest power, better gas mileage. It was never meant to impress people at stoplights... people who need that, are confused, and should have bought something else.

 

Lol. Your theory applies to me for sure. I had a really hard time getting used to this at first.... I came from a 300hp sports sedan.

 

While I get what you're saying, you're kinda oversimplifying the power/driveability "issue" by stating that the people who complain have unrealistic expectations and should have bought something else. Some of these trucks DO perform worse than others. We've seen it time and again working with OVtune. BTW, the 87 Octane tunes do not add additional HP/torque. They do however, change the driving dynamic - especially in the case of the A/T trucks. Hell, even Toyota's updated M/T calibration (04B13 in my case) turned out to be far better than what my truck shipped with in the fall of 2015. Does this mean that Toyota just messed with my engine's durability, mpgs etc? They did it for a reason..

 

Makes sense. Yeah, i was getting 12-13mpg at 75-80mph with a slight wind on the interstate. I think because it was constantly running in 4th gear.

 

What were your rpms in 4th at that speed?

 

You could be right about me oversimplifying the case.

 

I think around 3400-3500rpm, if I remember correctly.

 

I don't know how you can expect longevity out of a transmission that shifts as erratically as the stock one. Constantly running to sixth when it can't hold it down, then jumping to 4th to try and keep up. Stuttering along like it's running on 4cyl.

It's crap. There's no excuse. The power is there. The longevity is still there. This tune were left with is what happens when engineers are put up against a solid deadline, and when corporate says changing it would be akin to admitting a mistake was made.

 

Oh my tranny is most definitely going to outlive this truck. Without a doubt, and it shifts AMAZING. To be honest, I think it’s because the shift controller is a genius.

 

Haha... I should have got a manual.

 

But yeah I get what you’re saying. Who knows though? Maybe it will last. So far I personally haven’t heard of any taking a shit. Just that they feel shitty.

 

I heard about one failure, but it was mechanical factory defect not from normal use.

 

I've seen the torque curve with this Otto/Atkinson 3.5l Toyota tried to introduce with the Tacoma, and the problem seems to me is the big torque dips. There's a big dip ~ 2500-3100 RPM, then another big dip ~ 4200-4800 RPM. The Otto/Atkinson cycle was supposed to be a great innovation and the Tacoma was the first implementation.

Do I have that right? The Tacoma was the test mule for the 3.5l Otto/Atkinson engine?

 

Yeah pretty sure, but the Atkinson cycle in this isn't true Atkinson cycle. It's some fancy valve magic.

Your right though, the biggest issue is the lack of down low available torque. If they'd gone with a 4:30 gear ratio for the a/t off the bat, pretty sure this thread wouldn't even exist.

 

The problem, I think, is that if you "correct" that torque dip at 2500-3100, gas mileage is going to suffer. It could be a 1-2mpg decrease, depending on driver and driving conditions. And then the truck will no longer match up with the city/hiway mpg specs. I wouldn't think they could offer a "tune" (tsb) that puts the truck outside of the mpg specs.

I just don't think they'll be able to correct this without "stealing" some mpg (torque) from somewhere else on the curve. And they've already got it upshifting as fast as possible.

 

Wasn't this Atkinson cycle proven in Lexus vehicles prior to it's use in the taco?

 

I think you're right.

 

I honestly thought it was used on the Prius, didn't realize Lexus too.