2JZ VVTI Drive by wire control!

[MC_Bob]

Hi guys,

The recent fix to the MAP sensor has inspired me to attempt to make my car better to drive.
Ive been plagued for the last 3 years with awful throttle control..

It used to stall a lot, drop revs and be extremely jerky. None of which was noticed when racing, but road driving was crap.

Ive got it to the point now where I want to drive the car, but I've noticed the throttle is most jerky if I lift off the throttle completely so the butterfly closes. Reopening seems late and feels as if the throttle motor is trying to play catch up..

So I plugged in SCAL and watched the throttle position error readings. Slowly depressing I get 0-10%. If I rapidly depress I can get around 20% spike. It used to oscillate aswell, but reducing the kick open duty I got this down.

Can anyone pass any top tips for a smooth drive!

Kind Regards
Nathan

[stevieturbo]

Is the issue that the blade is not behaving as it should, or just the tuning for pedal vs blade is not right for you ? Both are configurable

Of course it could be basic tuning too, ie idle settings, closed throttle settings and general tuning

This video covers blade setup fairly well ( although some values can be inverted compared to what is in the video so if they appear so on your config, keep them in the same sort of area )
Not sure if that relates to blade wiring or direction of rotation or something.

https://www.youtube.com/watch?v=gUHThP2A09k

[MC_Bob]

Thanks for that.
I followed the video as I went and found a few things that dont seem right. And ive attatched some of the before and after graphs. Ive stuck up a picture of tpsB which changest size by the largest amount.

tps1bbefore.png (127.81 KiB) Viewed 23047 times

tps1bafter.png (130.85 KiB) Viewed 23043 times

This was the thottle steps after. And as bad as they are, so much better.

throttle error.png (130.17 KiB) Viewed 23045 times

I noticed the A/B validation difference is set to 40%. Clearly because the initial setup is so poor?

Position control output is set to low side and not half bridge, although im not sure what this effects.

Would any body have an example or a CAL with the settings for a VVTI 2JZ throttle body?

Either way. Idle is stable and drive ability is fantastically better. No longer sticks at throttle closed. Datalogs show it can be so much better.

[stevieturbo]

The settings you've shown there relate to blade position on only the second track.. Was this what you were calibrating ?

A/B validation should be a low value. You havent even shown A. Nor indeed what the pedal inputs are set like ( same process though )

The blade should have two tracks, both of these need calibrated, and pretty much at all times both should read identical % values ( this doesnt mean identical voltage values, hence you need to calibrate )
Some tracks may be linear, some may not
The fact the "before" graph was not linear would suggest either it was wrong, or that track on the blade sensor was indeed not linear and each point was calibrated manually.

Either way, do what needs to be done so the % value of both tracks for any given blade position read the same. That way A/B validation can be a low number.

Cant really see much worthwhile from a screenshot. But as long as DBWTarget and TPS are doing what they should be, then it should be fairly good. The video explains it all fairly well.
Ultimately how something feels under foot matters more than every last detail about testing as per video, so little errors here and there usually wont be noticeable. But it is a lot of trial and error.

If it's set to low side, then you're using an S6 with the little external H-Bridge to drive the blade motor.

As for idle and anything else relating to driving, tuning blade control etc. Just wayyyy too many variables that all interact with each other to even attempt to fix remotely without lots of info.

[Ryan.g]

The Supra VVTI is another of the Toyota DBW throttles which should of been recalled. The internal design and also pot B output from the sensors was only useful up to 40%, above that there is no way to validate and hence the A/B Validation is ignored above that in the VVTI Base maps. After 40% tps it doesn't matter what you have in the linearisation.

Regarding idle control grab the latest s6 firmware as lots of updates in the closed loop area with RPMDT (RPM Delta, parameter which shows the rate of which the RPM is accelerating or Decelerating) Useful to help stop any stalling

Plus you can build comp maps for Idle target added and Idle duty adders to be based on Idle Active time and can then ramp the target and position based on time in idle like OEM Ecus do.

See cal attached in idle

[MC_Bob]

I havent been ignoring you guys, Got a wedding coming up and havent touched the car, Really appreciate the help.
Thanks for the example map Ryan, just seen the CM302 and 304 additions, theyre awesome! Will update firmwares and get on that, theyre perfect additions.

I understand what your saying about the throttle sensor, I dont understand the benefit of having it only give stable readings to 40% like you say..

Stevie, I forgot to add in other pictures, there were more for the other settings you describe. But the car is totally different now, Im gutted I left it 3 years before looking myself!!

[MC_Bob]

PS..
I just realised im on 1.79, but my map doesnt have the CM304 Idle duty adder and CM302 Idle target adder function in SCAL. Have I not updated the map correctly?

EDIT - found them in customizeable options.

[MC_Bob]

Ive been working through and the updated map is far superior. The delta changes are a game changer.

Are people replacing the 2JZ VVTI TB with others which have better control by syvecs? If so, what ones?

Thanks guys

[Slowie]

You can use practically any throttle body. The Chevrolet LS2/LS7 90mm and Bosch 80mm (Chrysler hemi?) units are popular.

[MC_Bob]

Thanks. Do they mostly have more linear sensors an motors?