C7 z06 A8 transmission slipping on 1st gear

[mJolnir]

The car is a c7 z06, it has a dsx aux pump, a 9 injector meth kit pushing around 30gph, a tsp stage 1 cam with the big fuel lobe, and is running on a mix of 94oct and e98, its crossing the line at 138mph but it seems like i caught some slipping at the top of 1st gear, for next pass i tried adding 15% pressure to the [TCM] 15709 - Base Shift Pressure 1st, TCC on and [TCM] 15673 - Base Shift Pressure 1st, TCC off, but the track got closed due to street car that spread coolant on a lane and a car that caught on fire on the other lane.

have you guys found this before?

pass3.hpt
pass3 10.4 134.hpl

[dhoagland]

I'm not a GEN 5 guy

One question I have is your engine delivered TQ is 640 but Trans torque read 575...
The 575 agrees with your virtual torque from my quick glance, possibly issue?

Shift inertia factor have anything to enhancing shift timing?
(I know it says for feel, but to me feel is speed manipulation)

[mJolnir]

I'm not a GEN 5 guy

One question I have is your engine delivered TQ is 640 but Trans torque read 575...
The 575 agrees with your virtual torque from my quick glance, possibly issue?

Shift inertia factor have anything to enhancing shift timing?
(I know it says for feel, but to me feel is speed manipulation)

I tested taking the torque tables up in the dyno but it would close the throttle so i left it back to where it was.

I did add a couple numbers to the inertia factor as i have read it makes the shifts feel crisper but i didnt feel any difference on the shifting

[kevin87turbot]

I tested taking the torque tables up in the dyno but it would close the throttle so i left it back to where it was.

I did add a couple numbers to the inertia factor as i have read it makes the shifts feel crisper but i didnt feel any difference on the shifting

Does it feel like it slips, then grabs? If so, it could simply be fluid slosh. You typically want to overfill it by a qt when you have a car that launches hard. I've dropped 3-4 tenths on a few cars with the same issue.

[dhoagland]

Does it feel like it slips, then grabs? If so, it could simply be fluid slosh. You typically want to overfill it by a qt when you have a car that launches hard. I've dropped 3-4 tenths on a few cars with the same issue.

And it that scenario I imaging the clutch packs don't survive it too many times

[mJolnir]

Does it feel like it slips, then grabs? If so, it could simply be fluid slosh. You typically want to overfill it by a qt when you have a car that launches hard. I've dropped 3-4 tenths on a few cars with the same issue.

its the other way around, it feels like it grabs and then at 5000rpm flares, i thought it was tire slip but as you can see in the datalog speed doesnt go up when that happens.

[TheMechanic]

Similar issue but with a Gen 3 I tuned.
Is the diff gear a 2.41 with a 26 inch tall tire?

[sevinn]

its the other way around, it feels like it grabs and then at 5000rpm flares, i thought it was tire slip but as you can see in the datalog speed doesnt go up when that happens.

This is when your 1-2 shift starts. Likely 2nd gear is the issue not first.