Hesitation

[Last Lemming]

Well now I’m concerned again, because in sport mode, with my VDC on, and I give it half throttle the peddle goes kinda mush then a second or so latter it revs up and scoots, feel like lag Or something. It’s when I take the VDC off do the wheels spin up instantly. So IDK.

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[Paolo]

Well now I’m concerned again, because in sport mode, with my VDC on, and I give it half throttle the peddle goes kinda mush then a second or so latter it revs up and scoots, feel like lag Or something. It’s when I take the VDC off do the wheels spin up instantly. So IDK.

Yeah that's not normal. Power should be on tap.

 

[Guff]

Well now I’m concerned again, because in sport mode, with my VDC on, and I give it half throttle the peddle goes kinda mush then a second or so latter it revs up and scoots, feel like lag Or something. It’s when I take the VDC off do the wheels spin up instantly. So IDK.

VDC On meaning Traction Control is still active? If it's cutting throttle with traction control active and then letting the tires spin with traction off, then you've described exactly what traction control is supposed to do. When you mash the pedal, the wheel speed sensors will detect an initial small amount of wheel slip, so the computer will trim throttle, then ramp it back up linearly, while also altering how much the diff is locking, etc.

If you mean the other way around (aka, it's hesitating with traction fully off [5 sec hold]), then I suppose that could be an issue? Perhaps a video of it doing this would help to see if there was an actual misfire or something but from what you've described it just sounds like traction control keeping your 400lb-ft from leaving elevens on the pavement.

 

[freeform911]

Maybe a throttle positioning sensor?

 

[Last Lemming]

Guff,

VDC is on when I get the mush pedal. Thing is I don’t fell any wheel spin initially before it tries to stop the spin. It’s as if it’s stopping it before it has a chance to spin the tires. That or it catching it very very quickly.

turning off VDC the wheels spin up instantly. So that makes me think it’s not a throttle thing or VANOS thing.

it 35 degrees outside, and I know these summer tires are good down to 45, I also know the car’s computer recognizes summer tires. Could the cars computer be putting 2 and 2 together here and working it’s magic?

 

[H2O_Doc]

Guff,

VDC is on when I get the mush pedal. Thing is I don’t fell any wheel spin initially before it tries to stop the spin. It’s as if it’s stopping it before it has a chance to spin the tires. That or it catching it very very quickly.

turning off VDC the wheels spin up instantly. So that makes me think it’s not a throttle thing or VANOS thing.

it 35 degrees outside, and I know these summer tires are good down to 45, I also know the car’s computer recognizes summer tires. Could the cars computer be putting 2 and 2 together here and working it’s magic?

It’s not just the ambient temperature, but the temperature of the tire itself. If it’s 35°F out, but the overnight low had been in the teens, your tires might be much colder than ambient until you have driven a bit.

These tires are unpleasant below freezing. They are passable for modest use in the high 30s to 40s (for me). My 370 (manual) spun constantly below 40°F. I suspect you and others have this diagnosed and it’s tires x traction control.

edit: I should note that I suspect the temperature:hardness (and therefore grip) relationship is nonlinear. So, I think there is a temperature range where grip drops off sharply (maybe around freezing). I could be completely full of crap here, however.

 

[bonomo53]

sounds similar to what everyone in this thread is experiencing.
https://www.supramkv.com/threads/wouldnt-rev-after-starting.6460/page-29#post-115053

 

[Last Lemming]

Saw that, not really the same thing, mine revs just fine.

regardless it appears it was indeed traction control or some other process kicking in. Today on dry roads all was fine, but I’ll keep an eye, or should I say right foot on it.

 

[nibble]

VDC On meaning Traction Control is still active? If it's cutting throttle with traction control active and then letting the tires spin with traction off, then you've described exactly what traction control is supposed to do. When you mash the pedal, the wheel speed sensors will detect an initial small amount of wheel slip, so the computer will trim throttle, then ramp it back up linearly, while also altering how much the diff is locking, etc.

If you mean the other way around (aka, it's hesitating with traction fully off [5 sec hold]), then I suppose that could be an issue? Perhaps a video of it doing this would help to see if there was an actual misfire or something but from what you've described it just sounds like traction control keeping your 400lb-ft from leaving elevens on the pavement.

As you know, supra automatically engages all safety control system as default. pressing the TCS (Traction Control System) once will disable Traction Control. holding it for 5 sec. and releasing it disables VSC (Vehicle Stability Control) also. As I understand, you cannot enable TCS /w VSC disabled.

The difference between these 2 system is, TCS as we all know that it senses wheel slipping and reduces engine power to match the grip wheel can have. Hence it may feel like bogging down time to time. Turning TCS off simply means vehicle will not sense wheel slipping. VSC also senses wheel slip as well as other telemetry in the car to know if the car is "out of control". once it senses it, it is not just controlling engine, but also controls individual brake system to have car "under the control". whether this system also controls steering wheel is unknown to me.

I'm assuming VDC mentioned is VSC and turning it off means basically A90 Supra is a go-kart.

 

[Guff]

Guff,

VDC is on when I get the mush pedal. Thing is I don’t fell any wheel spin initially before it tries to stop the spin. It’s as if it’s stopping it before it has a chance to spin the tires. That or it catching it very very quickly.

turning off VDC the wheels spin up instantly. So that makes me think it’s not a throttle thing or VANOS thing.

it 35 degrees outside, and I know these summer tires are good down to 45, I also know the car’s computer recognizes summer tires. Could the cars computer be putting 2 and 2 together here and working it’s magic?

Yeah, these cars are fairly aggressive with their traction management. It's just the car not wanting to spin in cold weather, so I wouldn't worry about it too much.

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