Tacoma - OVTUNE - VFTUNER - Update Info and Original Development

it can be changed. DFCO is just the RPM at which the ecu turns fueling off / on when there is no accelerator pedal applied. So for example at 3000 RPM, no gas pedal, fuel is OFF. But the ECU kicks it back as the RPM starts to dip under 2k to easy back into idle and eliminate chances of stalling.

 

Sorry about the repost....but I think my questions got buried and I cant PM OVT direct yet.....thanks for the understanding.

Long time lurker....first time poster. Our 8th Toyota truck is a Tacoma and we have been less than happy with it....so I have been watching this thread closely and with high hopes.
However, a couple questions have come up that have given me reason to pause (plus the site showing sold out). Hoping the OVT team can cover these for myself and anyone else who may have the same questions. ​

• • Our truck is mostly driven locally where 91 octane is available but if I am 3 states away hauling another basket case motorcycle home and need gas....87 or 89 may be my only option. If I am ever expecting to need to run 87....do I need to wait for a different tune?
  • Similarly...our truck typically runs at a certain elevation. However, there are times where I will be coming through mountain passes and I would sure not want to damage the truck. How do we solve for folks who travel to different parts of the country?

Ideally the tune would be able to adapt...providing full power at lower elevations and higher octane...reducing power/timing/etc when the best ingredients are not available. Sure hoping that is the case.
Thanks in advance for your reply and info!​

 

If you are running our 91 only map, then you you need to put in a minumum of 91 octane. However we can create 87 octane tunes. The ECU also has factors / multipliers and progression controls that will give us some ability to create a tune that will be able to "adapt" in some ways to higher or lower octane. Higher octane adaptation is easy, No knock? increasing K-factor by x.xx. Still no knock? increase more (which results in more ignition overall). The tricky part is adapting for LOWER octane. The ECU only has the ability to reduce the factor on the onset of detonation. SO.. there must be that initial detonation for the ECU to adapt lower. The problem is, at compression ratios this high detonation isn't the only concern. it's 3x that with detonation, pre-ignition, EGT. So the engine must register that potentially damaging effect to lower the tunes ignition. Normally a bit of detonation here, a bit there is no concern. Engines always detonate sometimes. The problem is at compression ratios this high a "little bit" of detonation isn't going to happen. 91 octane timing, 87 octane in the tank, you're going to get a massive spike before the ECU pulls the necessary ignition out and reduces the multipliers so that it doesn't happen again. It could be a big problem if you get that spike in desert heat at low RPM hauling something up hill. Thats a real concern, because of the amount of load paired to that detonation.


we still have more work to do before we can safely release 91 octane tunes that are 87 OK.

hopefully that helps

 

how difficult would it be to swap tunes... say I run a 91 tune, and decide to go on a trip where 91 may not be readily available... so switch to an 87 tune to be safe... then switch back when I got home... would I cause any issues swapping back and forth like that until you can do a 91 tune that's ok with 87 (if it's possible)?

 

Also, a 2wd low range function would be fantastic if possible

 

But first, all traces of this shit must be purged:

 

Thanks for the reply OVT.....that helps. Couple of follow-up questions;

• Is elevation a factor when the tune is set up? If so, will the 'tuned ECM' still be able to adjust as the truck is driven through elevation changes?
• It sounds like the 87 octane tune can take advantage of higher octane. As it takes advantage of higher octane fuel and then encounters lower octane....the 'tuned ECM' will quickly pull back timing and other variables to prevent engine damage, correct?
• Is the 87 tune available? If not, any ideas on eta?

Thanks again for the support and the additional details!

 

SO if I understand this correctly, to get consistent engine braking you'd have to disable DFCO completely (it just won't be very strong engine braking). I wonder if the engine is operating in Atkinson mode (reduced compression) at these low speeds/load. Perhaps a forced OTTO mode in 4low? I mean, was it not stated that full control of intake/exhaust VVT has been realized? Just bouncing ideas around.

 

changing the DFCO controls so fuel doesn't come back on until closer to idle would make a difference.
Yes the engine operates in atkinson at low to moderate load, low RPM.

We have control / understanding of the Valve control, maps / tables / limits, etc. But the valve advance control is not very complex. There is no evidence it is mode dependent. Rather it is static based on 2 maps and advance limits.
We can disable and or modify any and all engine characteristics / atkinson via the camshaft control tables. I've done this quite a bit with some Mazda Race cars that use the same style calibration on the Skyactiv. You lose MPG as a consequence.

Elevation is already factored into a stock tune, our tune only accents the stock controls. Elevation isn't as important as load. Engine load is calculated by airflow. More load = more air = targets different area of XXX table with load as an axis. Less air = less load = lower load section of that axis.

here is a picture to show you what I mean, in a simple way.

This is an ignition map. Lets say as an example, at full throttle at sea level, you hit around 1.05-1.10 load. Your ignition target would be somewhere in the area circled in PURPLE.
Load is calculated by measured air.
Lets say you floor it at high elevation. Less air = less load overall.
Now you're only getting around 0.7 - 0.72 load. Your target ignition is now the area in red.
More ignition automatically, not much, but it's more.




anyways that's all for tonight, thanks everyone

 

@OVTune
This is a massive thread with questions getting answered and news updates sprinkled throughout.

Can you update post #1 with this information? Maybe add a FAQ and News section.

Also, I didn't see a website URL.

 

Sorry for the lack of update here, guys. Had a problem finding a windows machine to run their software, ended up needing to update an old tablet and then ordering a USB otg splitter from Amazon before being able to connect it up.

Anyway, for my tune I'm interested in an 87 tune with increased low end tq and compression braking. High end HP-stuff is great and all, just not for me. Daily driver + family offroad vehicle for trails and stuff. But, increased torque at the low end so I don't have to shift constantly and/or rev up past 4k or so ... plus if I'm in no throttle input and the engine is reved past idle I'm trying to go down a hill, etc.

 

The only shifting issues I ever have are in my left foot, I'm afraid.

 

Didn't install the tune yet due to the lack of a windows machine.

 

If I understand correctly this is exactly what the manual needs. No fuel coming back on at 1400 or so rpms. If you can change this so that compression and engine braking occurs anywhere above idle you will have me and many other manual transmission guys sold on this tune. Fuel coming on in the middle of engine braking is the worst tuning ever for a manual transmission.

 

Do you have a Mac? If so you can use bootcamp and window 10 and it works fine.

 

I wanted to summarize what some of the folks hope you can give them with this ECU tune:

1. Better MPG
2. 30% more HP
3. Adjust speedo for larger tires and smaller balls
4. Increase the girth of the drivers shaft
5. Increase suction where the air is thin
6. Reduce drivers weight
7. Increase pumping pleasure without Ethyl
8. ECT button to raise seat probe
9. Spark Advance IQs to upper 60s
10. Give a low end grunt when power is applied to the rear
11. Increase duration of rod action


A few more requests of the ECU tune just in:

12. Tighten loose nuts
13. Stop premature compression release
14. Gently increase torque to bottom end
15. Always reciprocate a blowby with a blowback
16. Reduce drivers belt overlap
17. Increase bore and stroke
18. Continuous polishing of head
19. Scavenge loose change from the seats
20. Reduce rear end leakage
21. Increase number of coil overs on shaft and add unsprung length

More requested additions from holiday

22. Lengthen Drivers Connecting Rod
23. Lock drivers rear end
24. ECU tuned for free XM Radio tunes
25. Improve taste of Rock Sliders
26. Enhance "seat of the pants" testing pleasure
27. CRAWL in low mode to avoid detection
28. Self lubing of drivers front spindle shaft
29. Warming & lubrication of ignition button canal
30. Disable vehicle if driver is in high mode
31. Decrease drivers urgency in P mode while nearing home

 

I received my tune file, and installed it this evening. Install was very simple. Mat's instructions are great.

 

MT specific question. Does the engine always operate in Atkinson mode when releasing the clutch with what could be considered a "normal" amount of throttle input? If so can just this aspect be eliminated to where Atkinson cycle would only activate when under light load with the clutch fully engaged? I'm ok with the ECU trying to get as many MPGs as possible, but when I'm in control of the transmission and all gear changes I want full control of my throttle and all of the engine's available torque.

 

This should have been done from the factory.

Please do.

X3 here on this!

Lowering the DFCO rpm needs to be standard procedure on MT tunes IMHO.

 

My primary machine is a Chromebook Pixel, with a W10 desktop. I have a (for test purposes mostly) Venue 8 Pro, but that by default only has a single microUSB port. Needed to get off my ass and get a multi USB2Go splitter to support the flasher gear.