4-Grand Power-Band

Thanks a bunch for posting this, I had not DL'd it from OV's site before they went radio silence until the 12th.

For me, these are critical traces in going forward with a purchase of this truck. What I am hoping based on this plot is that with my loaded camper in the bed, I can manage a long grade at not more than 10MPH under the speed limit at 4000-4500 RPMS. With my current setup I am never above 3500 at 5-10 over on the same grade I am thinking of.

I'm very much managing my expectations going into this engine at this point, so as long as it is a reliable range for the motor, I'll get by.

 

I chose 4000RPM a little arbitrarily as the title of this thread as generally that is the RPM range where I really feel the surge in power. Interestingly, all of these dyno runs have a change at 4K.

In the blue (stock?) tune, that looks like the point there is maybe a downshift (?) followed by a further increase in torque and Horsepower? It could be that’s is just past 4K where I really notice the power plant come to life. I wish these graphs had a little more info for dyno newbs like me. I don’t know if they allow the transmission to shift during a dyno run or not.

If anyone can shed some light, I appreciate it.

 

Dyno pulls are almost always in 1:1 so no gear change.

 

Ok thanks. I wasn’t sure if they could do that with the auto or not. Someone mentioned one of these runs was with the AT.

So something interesting happens at 4K regardless.

 

That is actually a good point, I would say maybe Matt from OV used his Gear Locker version but that would not explain the dip in the stock trace unless he was able to use a special dyno-only tune that also locked the gear out in the stock map.

Either way it is an interesting dip which he seems to have normalized in the tuned versions.

 

Yeah I noticed it was removed on the other two traces, mostly. I wonder if it is a shift if it would be a downshift or an upshift, if it is a shift? Trying to wrap my brain around that.

 

I highly doubt it is a gear shift, you would have to re-trace from the new RPM to start with.

 

Ok that makes sense. It must be some mode swap going on with the VVTI etc. Thanks for helping me out with this.

 

I too think it is VVTI, it is still there if not subdued with the tune plots. No problem!

 

I guess it is a valve adjustment called ACIS. I found an explanation here at the OVTune site, including a description of that dip I was wondering about:

https://www.ovtuned.com/collections/toyota/products/toyota-tacoma-2grfks-calibration

 

I always thought it was vvti as well. Hitting the new cam profile

 

For those looking for a nerdy read on ACIS and variable length manifold tech.

According to the wiki, ACIS kicks in on some engines at 3900RPM, so there is that approx. 4 grand number again.
https://en.m.wikipedia.org/wiki/Acoustic_Control_Induction_System

https://en.m.wikipedia.org/wiki/Variable-length_intake_manifold

 

And the answer is... it's on-off instead of proportional.

 

It is. So the change is going from a long intake manifold at low RPMs for maximum “swirl” for fuel efficiency and low end torque, to put as much bloody air in there as possible with a short intake manifold at 3900RPM (AKA Launch Mode)

 

Yep, the ACIS control is (it's literally a servo controlled door inside the air tank assy).
That's not the same as Atkinson to Otto "switch" via valve timing, as some have been suggesting this surge is. VVT is adjusted as well, but its continuously variable.

I don't have access to it right now, but there's a PDF about the 2GR-FKS engine "new features" that shows the ACIS control and briefly explains what it does.

Edit: Lol, I actually posted this some time ago:





This is from a Toyota document, so it should clear up a lot of confusion about ACIS in the case of the 2GR-FKS.

 

He wasnt aware it was a race, otherwise you would have come in second place. Guaranteed!

 

Can someone explain all this shit to me like I’m 5 years old?

 

The truck make more power the faster the engine spins.

 

foot push pedal truck go zoom, foot push pedal more truck go zoom zoom zoom!

 

He probably wasnt racing you. The 4.0L VQ is a beast compared to the 3.5L unless you went after an older gen or 4cyl Frontier.