Early upshifts at full throttle, how to make car shift at redline?
When I try to do 0-60 on the street and step on it, traction brakes loose slightly but instead of going to redline , it upshifts early into second, sometimes as early as 4000 rpm.
I trued with disabled traction control completely and still can't take off properly. Is bad traction casuing this behavior?

 

I think this is correct. Your car's auto shift feature is designed to shift at the peak of the "torque" curve. This is not necessarily the red line for the engine, The red line is established as a safety feature and of course you get a lot of performance out of shifting at the red line but you would get more performance if the RPM dial also showed max torque points to use when performance shifting.

There are lots of stories in the automotive press these days about auto shifting cars at the track posting faster times than manual shifted cars, mainly I suspect because of slow human reaction time and drivers shifting at red line.

I hope I've stated this correctly. Perhaps there are other takes on the subject...

 

Tarheal agreed, I remember when Crysler launched their 'Neon' in the UK back in the 90's, the auto at the time had a faster 0-60 than the manual.

Simply put a computer 'should' be able to change fare more effectively than 90% of drivers and my reaction time (according to the IAM test) is half that of the national average.

With today's technology and precision it's nice to drive a powerful GT that doesn't have launch control and lots of techno gizmo's...although I do appreciate that a small percentage on here track their cars, whereas my track/airfield days are far behind me...and I've got some great memories

 

Does it still do it in sport manual?

 

Sounds to me something is wrong, shouldn't shift 2000rpm before redline!?
It's not a diesel!:-D

 

No, this is not normal, and it doesn't make sense for a car to shift at the "peak of the torque curve". There is still usable torque beyond the peak, and in many cases more torque available compared to upshifting early and ending up at a lower RPM in the next gear...

 

From 1st to 2nd with an open diff in a modded 4.2L XKR traction is likely the acceleration limit rather than torque.

 

The best shifting is actually for the SHIFT RECOVERY POINT to be at the earliest point of Maximum Torque. That is, the instant the tranny shifts from 1 to 2, THAT point needs to be the earliest point of Max Torque.

As stated, redline is meaningless for performance. It's just a point which beyond, parts start flying off other parts.

A VERY quick synopses for best times:

 

Mine pulls easy to 6000rpm so something is wrong!
Have you tried using the paddles to shift manually to see if it will pull to redline?
Maybe a reset of the gearbox is needed by taking pos and neg terminals off the battery and hold them against each other for 20-30 seconds. Reconnect terminals and do a new test drive!:-)

 

Mine is N/A however with mods it shifts at 6400rpm 1-2 then after that it's 6250rpm

 

Maybe the gearbox has "learned" to upshift earlier by previous driving habits so you'll need to give it more practice so it knows to hang on in the gears longer?

 

By taking the negative and positive terminals of the battery and holding them together for 30s will reset the cars ECU's and gearbox will learn your driving habits.

 

I'm thinking it's mostly lack of traction. Whenever I mage to take off without spinning it goes to redline ,if wheels spin a little or a lot that seems to change the shifting patter. Im going to try reducing the torque in the tune to 1st gear see if that helps ..