TCC what it means
TCC what it means Allow the TCC to lock during upshifts what will that do for performance because in the efi live the have option that like you choose to turn it on or off can someone explain it to me it (D2801)
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Originally Posted by camross998
Allow the TCC to lock during upshifts what will that do for performance because in the efi live the have option that like you choose to turn it on or off can someone explain it to me it (D2801)
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Joined: Mar 2006
Posts: 326
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Originally Posted by camross998
what do that mean can you explain
Torque converters have a natural slip which is pure
inefficiency (as well as the slip that is making fluid
torque multiplication, which is not inefficiency). A
locked converter clutch eliminates the remaining
slip and any torque multiplication. So at some point
you will deliver more rear wheel power with the
clutch locked than unlocked. Where this point is,
depends on the converter (slip), the motor (torque)
and the car (load).
Locking through the shifts will make the shift cycle
faster because converter unlock otherwise has to
precede the actual shift and then lock follows, and
has to lock into the face of a spun-up converter's
slip (tough).
On some vehicles commanding it to stay locked
seems to not do anything. Not sure why and don't
know all of, which. Just don't be surprised if it doesn't
do what you think.
The biggest benefit of locking may come from 3rd
WOT lockup down-track, especially if you're geared
so short that you'd need to upshift with a sloppy
converter but could trap in 3rd if locked. Or just a
way inefficient converter that quits multiplying
torque early. What you need is, a means of logging
acceleration vs MPH both unlocked and locked, plot
your two cases on top of each other and set the
lockup-point for WOT where locked becomes better
than unlocked. Simple, except you need the tools....
Me, I only lock in 4th so the rest of this is pointless.
inefficiency (as well as the slip that is making fluid
torque multiplication, which is not inefficiency). A
locked converter clutch eliminates the remaining
slip and any torque multiplication. So at some point
you will deliver more rear wheel power with the
clutch locked than unlocked. Where this point is,
depends on the converter (slip), the motor (torque)
and the car (load).
Locking through the shifts will make the shift cycle
faster because converter unlock otherwise has to
precede the actual shift and then lock follows, and
has to lock into the face of a spun-up converter's
slip (tough).
On some vehicles commanding it to stay locked
seems to not do anything. Not sure why and don't
know all of, which. Just don't be surprised if it doesn't
do what you think.
The biggest benefit of locking may come from 3rd
WOT lockup down-track, especially if you're geared
so short that you'd need to upshift with a sloppy
converter but could trap in 3rd if locked. Or just a
way inefficient converter that quits multiplying
torque early. What you need is, a means of logging
acceleration vs MPH both unlocked and locked, plot
your two cases on top of each other and set the
lockup-point for WOT where locked becomes better
than unlocked. Simple, except you need the tools....
Me, I only lock in 4th so the rest of this is pointless.
To answer your question simply.... it will hurt performance but increase your mileage around town.
When the TCC is locked the converter is basically eliminated from the driveline. It acts like a manual clutch that is engaged at that point. The main reason the TCC exists is to improve the cars fuel efficency and transmission life especially when in overdrive.
When the TCC is locked the converter is basically eliminated from the driveline. It acts like a manual clutch that is engaged at that point. The main reason the TCC exists is to improve the cars fuel efficency and transmission life especially when in overdrive.
It sounds like he's talking about during upshifts only guys. In that instance, I'd say allowing the TCC clutch to lock during upshifts takes some of the strain off of the clutch packs in the trans. I think for this to work, the TCC lockup for 3rd gear needs to be set in accordance with the 3>4 shift table. It doesn't lock up at all in 2nd and there's no 4>5 upshift table, so I think the only table/shift it does affect is the 3>4 upshift. I never fully looked into this, but it's my theory on why it's there. IIRC, it's set to enable from the factory and the 3rd gear TCC apply table resembles the 3>4 part throttle upshift table.
