Brigadir
Active Member
- Thread starter
- #1
The gearbox shifts VERY stupidly (slowly and not consistently in tech. terms). I got some logs via Forscan to illustrate what exactly I mean.
Quick explanation: recorded it in city drive in standard mode. Here are three cases which show how slow and unpredictable is the gearbox.
On the top chart there is commanded (requested) and actual gear ratio. We see constant delay when shifting to higher gear (to lower gear ratio).
On the middle chart purple line is accelerator pedal position, orange/yellow area - car's speed (yellow means braking). The next chart is RPM, and the last one - transmission slip ratio, what should mean how much input and output speed differs in the gearbox's torque converter. We see that the ratio is 0.0 when the car doesn't move, goes to 1.0 on constant speed and drops to 0.5 when changing gears.
So, regarding the good and bad cases:
In the good case as soon as acceleration pedal gets pressed, RPM and speed starts growing (the delay is ~200ms). And worth to notice that slip ratio doesn't drop a lot.
In the bad case there is actually 1 second delay since we press acceleration pedal and the car starts accelerating. How this is possible in 435Hp "sport" car - it's a big question to Ford engineers. At least they should place this info in promo booklet where they mention that 435Hp.
From the chart we see that this delay matches commanded gear ratio change, and probably the reason is that before this moment the car was changing the gear while braking and hasn't finished this job. You see it on top chart with Gear ratio measured line - in the good case it has reached commanded gear ratio, and in the bad one - has not, so there is delay until it actually reaches it.
So, the question is how to resolve this issue? Probably with tuning... Some time ago I asked Lund and AEDHP (Advanced Engine Developement), but they deal with sport mode to make it more aggressive, which is completely other area.
Quick explanation: recorded it in city drive in standard mode. Here are three cases which show how slow and unpredictable is the gearbox.
On the top chart there is commanded (requested) and actual gear ratio. We see constant delay when shifting to higher gear (to lower gear ratio).
On the middle chart purple line is accelerator pedal position, orange/yellow area - car's speed (yellow means braking). The next chart is RPM, and the last one - transmission slip ratio, what should mean how much input and output speed differs in the gearbox's torque converter. We see that the ratio is 0.0 when the car doesn't move, goes to 1.0 on constant speed and drops to 0.5 when changing gears.
So, regarding the good and bad cases:
In the good case as soon as acceleration pedal gets pressed, RPM and speed starts growing (the delay is ~200ms). And worth to notice that slip ratio doesn't drop a lot.
In the bad case there is actually 1 second delay since we press acceleration pedal and the car starts accelerating. How this is possible in 435Hp "sport" car - it's a big question to Ford engineers. At least they should place this info in promo booklet where they mention that 435Hp.
From the chart we see that this delay matches commanded gear ratio change, and probably the reason is that before this moment the car was changing the gear while braking and hasn't finished this job. You see it on top chart with Gear ratio measured line - in the good case it has reached commanded gear ratio, and in the bad one - has not, so there is delay until it actually reaches it.
So, the question is how to resolve this issue? Probably with tuning... Some time ago I asked Lund and AEDHP (Advanced Engine Developement), but they deal with sport mode to make it more aggressive, which is completely other area.
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