My experience with VelocityAP and tuning the XJ.....

I bought the tune, pulley, and 200 cell cats from VelocityAP and have to say they were great to do business with.

Stuart was quick with answers to my questions. I received the VTECH tuner and there was a software issue with the device. I emailed Stuart and he express shipped me new one. I received it the next day and was able to send them my stock file. That same day I received the tune and uploaded it over the weekend.

My thoughts on the tune...

After I tuned it I couldn't wait to drive it and see what it was like. I have to say when I first drove it I was very underwhelmed, kinda of upset. I drove it for about 20 minutes and the car actually felt slower. It seemed sluggish...so my mind was racing with...I wasted my money!! Then I thought what could be causing this, I read too many good reviews about Velocity and Stuart? I decided to turn off traction control...when I did..WOW is all I can say. This car became a B.E.A.S.T!!! The traction control was killing it..I didn't even feel the tires begin to spin so it wasn't noticeable when I was first driving it. Seriously guys, when I first turned it off, it was like a totally different car! The car breaks loose in the first three gears. First and second gear you have to be careful because a little goose of the throttle and shes going sideways on you. I can tell big increase in throttle response, power and torque. I am sure the ECU hasn't even fully adapted yet. I cannot wait to do the pulley swap and throw those Cats on there. This car is going to be even scarier than it already is...hope she is hungry, because she is going to eat!

I would highly recommend anyone to give VelocityAP a try, you won't be disappointed! Just remember to turn off you traction control!

 

Sounds great. But ... if you turned off traction control before the tune are you sure you wouldn't have seen the same thing? Traction control severely restricts it in stock too

 

Absolutely. I drove it hard prior with traction control off because of TC being so effective. That's what threw me after the tune. Prior to the tune when I would drive it hard with traction control on I could feel when it would get loose and it would kick in to correct. Once I got used to the car, when I would take it through the Kentucky hills, I would turn TC off because nothing beats the feel of sliding through turns as you accelerate and feeling the true handle of the car. Two nights ago when I first tuned it, I just took it up the road a bit...pretty much straight lines, so going side ways didn't come into play, so I really couldn't tell TC was kicking in...the car just felt sluggish. The car was strong stock, but now it's a whole other level.

 

Sounds great. Enjoy the new experience!

 

Enjoy the car! It really surprises you how fast the car really is because of the overall size of the car. XJL even more so!

There is a video on Youtube of a stock XJL Supersport pulling on an S65 with a tune. These cars are no joke! I want to see a bolt-on XJL against one of those AMGs.

 

You're not kidding...it's crazy when you start throwing it around and realize it's a 4300lb car. I had a vette that was slightly modded...and this car can put you back in your seat just like the vette did.

My only concern is the transmission. Has anyone heard about how dependable these are with the added HP and torque?

 

The transmission is a ZF 8P70 good for 700hp. This transmission is used by many manufacturers including BMW, Maserati, Rolls Royce to name just a few. IMHO the transmission has proved to be bullet proof.

 

I have the 6 speed ZF and it is very responsive for a conventional auto. Never any slippage at all.

 

My error. Prior to 2013 the XJ used the the ZF 6HP28 that supports up to 650hp.