Well it'd been three years since I did the 12.46 @ 115mph in my XKR, at the time that was all we were going to get.

Until earlier this year, when our Russian associates announced they had cracked the ZF transmission control module, and could now start tuning.
Of course, the strategy in the ZF 6HP26 fitted to the 4.2L X150 had to be totally different to all the other JLR models, so it took a lot of testing & revisions to get it sorted out.

I'd been to the track a few times as part of the testing & development process, and just as we were ready to give it a proper run, it started raining in Sydney...
Got rained out 4 weeks in a row from end of May, and then at the end of June it was the CV-19 outbreak and Sydney was locked down, so the track was closed.
The situation here has only gotten worse, I doubt i'll be getting back to the track before 2022...

So what's the difference with the transmission tune?

Well the shifts are faster, and more aggressive, but I don't think that's really making much difference to the ET...

The main difference now is how you launch the car.

In the past the best 60ft's came from just sitting on the line idling, side-stepping the brake as you smashed the throttle.
Loading it up on the line would trigger a torque limiter, and it'd actually be slower.
Now you can stall it up a little, and launch harder, but it's a fine line between getting away cleanly, & just spinning em.

The 60ft on my 12.46 run 3 years ago was 1.959, now i've got it down to 1.793

Managed to get a couple of 12.1's out of it during testing, however the weight of the car (with me in it) was ~40kg heavier than when I did the fastest runs back in 2018; half a tank of fuel vs. the 1/4 and i've put on some weight myself...

So the mph is down a little compared to 2018, mostly from the weight I think, although it was also given quite a hard time with the circuit events so it might have lost a few horses...

But 12.142 is a solid 0.3s quicker than the previous best, despite extra weight, &/or lost power...



And here's a video of me being handed my **** by a Holden Commodore...


It'll be a while until I'll get another crack at it, maybe I'll have lost some weight by then and we'll get the 11.99 we were aiming for...

 

You need to get by that commodore next time.
Well done!

 

congrats!! 12.1sec is bloody awesome!!