Tacoma - OVTUNE - VFTUNER - Update Info and Original Development

The tune may also take advantage of the ability to adjust the ACIS system, which can help increase torque.

Im excited!

 

Geez dude you are rushing to the rescue of the Atkinson, relax..

In the first half of your response you basically repeated what I was saying

DBW is not the problem, all cars have it.. im not saying anything is "a problem".. what I'm saying is with DBW, vvt-i, and Atkinson design the computer can be more in control of engine operation as a whole.. old school fuel strategy was you control the airflow with the skinny pedal and the fuel system has to keep up with your foot. They have fou nd a way to wrestle more of that control away from the driver and back in the control of the pcm and it's (federally mandated) requirements.. for good, for bad, for better power, emissions, whatever.. it's not about this engine design sucks or emissions are stupid, it is what it is..

I'm curious about what OV has in the works and I like talking shop.

 

You sure about that?

 

Absolutely. I may have been the first person to post that pic. That pic has nothing to do with Atkinson and everything to do with D4-S.

 

So, you're saying VVT-iW is utilized in port/direct and direct only?

 

I didn't mean to single you out as much as you probably think I did. I intentionally started my post with "People..." because so many are like 'turn this Atkinson bs off', etc.

I do think DBW is a problem in this truck. Look at the throttle response curves from the pdf that others have posted (maybe in this thread). People seem to like the pedal commander.

The most significant problem, IMO, with the V6+A/T is the transmission programming. People seems to be happy with the shift sense.

But, you praise the VVT in the 1GR; but, you seem to criticize the VVT in the 2GR (it just works over a wider range). Are people on the Lexus RC-F forum saying turn off this power robbing "Atkinson" BS?

Sounds like OP can change the two issues that I think are the problem and get higher output; but, I doubt they are going to be spending much, if any, time tweaking the low output "Atkinson" area of the ECM mapping.

 

Tharris you need to remember that vvt-i can advance/ retard valve timing but the amount of time the valve is open is unchangeable. It's cut into the camshaft profile.. advancing the valve timing can get good air velocity at high rpms but the valves will still start to close pretty quickly, almost immediately after opening.. Atkinson is special because it can hold the intake valves open (hanging in space, not opening or closing). this is different than just getting the open/close cycle started earlier or later (vvt-i).. th is effectively delays the generation of compression.. The pcm (and yes the Fed gov) gets to decide when the compression gets generated.
That's why OV is talking about a "torque strategy " that the pcm will "go to".. The pcm sees what you are asking from the gas pedal and then selects a "scenario" that it "goes to".. it gets to decide how that power gets delivered and when.. taking into account what it thinks is a good emissions target, etc.

Again.. for good, for bad, whatever.. judging from how many people complain, this engine sounds like it can be kind of a dog some times..

That is why companies like OVtune see an opportunity for their skills. There is enough demand to try to ease the aggressiveness of the factory torque strategy and get something with little more spirit

 

I'm not sure I understand what you are asking. VVT is utilized every moment the engine is running.

 

Throttle response is bad because you hit the throttle and the intake valves are still hanging open..

When you hit the gas pedal you're not telling the car you want to go fast (and the fuel strategy has to hustle to keep up with your foot), you are "asking" the computer " may I go faster?".. pm sees your request, looks at a bunch of options and then picks the best one for (what it thinks) is the best balance of emissions and power. This type of control can be relaxed, tuned down, and given back to th e driver..

 

Vvt-i is not necessarily used all the time.. of no air velocity is needed, then no advance on the valve timi ng..

 

IT IS NOT SPECIAL! IT IS THE SAME!

"Atkinson" is 100% achieved by VVT in this engine! You don't understand.

 

What I am getting at is that after every ECM cycle the truck needs to decide whether or not to change the timing... based on O2 sensor, rpm, intake air temp, etc, etc. Since the timing is not fixed, it has to decide what it should be; so, it is always "on". But, again, I don't know if I understood the ?

 

Whatever.. If it's controlled by the pcm it can be manipulated.. for better driveability and a trade off with higher emissions..

 

Well for most variable valve timing systems the base starting point is considered full retard, and then it advances from there..

Do you know what I mean about the difference between advancing the open/Close event of a valve and actually holding the valve open for a longer period of time? Think about how a cam lobe looks. Open and then close, pretty quickly.. Atkinson design involves not letting the intake valve close and the crankshaft and the rest of the valve train is still moving. That would require a cam lobe that has an up/Open ramp, a huge (fully open) flatspot to hold the valve open and then a down/Close profile.. this is out side of what the traditional vvt-i systems can do. Traditional design is simply creating a device for adjustment of the relation ship between timing chain and camshaft (camshaft where the amount of time the valve spends open is fixed)

 

I know exactly what you mean and I know that is not how this engine works; but, you are not listening. "Atkinson" is achieved by delayed camshaft phasing. It does not change lift duration.

 

Wouldn't blame OVtune at all if they dropped out of this thread. It's getting all junked up. Thanks again for the work OV, looking forward to seeing what you come up with.

 

@OVTune
Been reading some of the development process on the Tundra forums...
Will the process be the same for the Tacoma, as far as locating the most current recalibrations?
We've had 2 transmission TSB thus far. I've heard you mention, on other forums, engine management recalibrations are usually done on the down low; we may or may not have updates there. Possibly '16 vs '17 tune...who knows. I thought this was the reason you begin with benching the ecu; the data logger can accomplish this?
Maybe you could clarify a little bit about how the development process will actually go?

 

Cannot wait for updates, really excited to see something is in the works to help with driveability.

 

Gotcha.. my point was If it's 100 percent controlled by vvti then it can be 100 percent turned off by this program OVtune is talking about..

SORRY GUYS , not trying to muck up the thread! When OV has more I'm sure they will jump back in..