Surge well on the throttle

Has anyone noticed the surge in power/ acceleration at 3500-4000 rpm?

lifted 2016 tacoma trd sport auto

 

yes, "normal operating characteristic of the vehicle"

 

That is pretty typical of this engine. It makes it's power in those RPM ranges, that is where the torque seems to have a sweet spot. That is one of the big complaints is that it is not in the lower RPM range.

 

I think that's when it transforms from an anemic hybrid Atkinson pos to a real engine .

 

Yea that too!

 

I have occasionally, when going up a hill or something, gotten a very slight boost of power without pressing any further on the throttle pedal, without switching gears, and without an increase in RPM. It's very slight and almost imperceptible. I would bet money that this is the Atkinson valve timing turning off. Usually its not enough extra power for the hill so it'll downshift seconds later. But it is definitely something I've noticed a few times.

 

Yup. I noticed it when I had to get on the gas after pulling out of an Arby's.
Had an OH CRAP! moment when I saw the speedo creeping up on 50 in a 35 zone.
I just slowed down, made sure no cops saw that and smiled.

 

I don't think it's Atkinson so much as it is VVTi (I know one is dependent on the other) and hitting the sweet spot in the power band.

 

If you mat it just as you are hitting the 3500 power band, it almost feels like a small 500 cfm four barrel with the secondaries cutting in.

 

one of my only complaints about this truck is the dead spot. its a lot more noticeable with a manual transmission. hopefully some one will come out with a tune or a supercharger kit...

 

Yeah I'm talking about something else that happens at variable rpm. What OP is talking about is clearly just hitting the power band at 3500-4000+ RPM.

I suspect what I'm talking about though is the Atkinson valve timing switching off. Theres really not anothet explanation. As I mentioned it's very slight and kind of hard to notice.

 

It doesn't do it with ect on, so I'm pretty sure it's the Atkinson cycle garbage.

 

its definitely the VVTi
https://www.tacomaworld.com/threads/vvt-i.49392/

 

i blame the d4s port and direct injection. dyno chart looks identical to the one in the frz/brz/86 especially the dip in the torque curve around 3500rpm and it also features d4s injection

 

Many things are switching on and off...

VVTiW (which IS the Atkinson cycle)
Port to Direct Injection (D4S)
Intake plenum door (variable intake runner)
Plus there is a drive by wire throttle curve that modifies pedal inputs vs throttle position.

All that stuff changing and certain points makes for a "discontinuous" feel to the torque curve. I would agree that they could have done better in the ECU algorithms in order to make the transitions less noticeable.

 

but there are as many threads on the 86 forum about this as there are transmission threads on TW. if it were poorly programmed algorithms, you dont think they would have addressed it? thinking its a hardware issue that software cannot make up for.http://www.ft86club.com/forums/showthread.php?t=7438

 

Apparently not, we all still feel the "bumps" in the torque curve! Perhaps you are correct in that they are trying to control too many items (hardware) with the software and they will only be able to mitigate the feeling of those changes rather than eliminate them.

FWIW, mine appears to have learned since the very initial test drive. The "bumps" in the power curve are hardly noticeable in my MT equipped truck anymore. I normally shift around 2500 RPM or lower though, only getting to 3,000 when merging on the freeway. Every once in a while I do a 3rd gear pull to redline, but even then, it isn't as rough as it was initially.

 

There is a lot going on, but I believe it is Atkinson to Otto. I too feel it around 3500 rpm. As previously stated, like secondaries on a four barrel.

 

Coming from the FRS, this is exactly it. Everyone here is speculating when the FRS/BRZ community has nailed down the exact same problems and characteristics as this engine. Both engines share many of the same technologies. I was very surprised when I first started driving the Tacoma at the similarities. The crickets, the ticking, the power band, the torque dip (a wellllll known issue with the FRS), etc.