Last night went to Fontana Ca 1/4mi
My previous best run 7 month ago with no mods was 13.19

Yesterday with 1.5lb pulley and OE tuning Tune best runs were 13.29 104mph and 13.24 at 106mph
I always suspected that with the tune the top end seemed to be slightly lacking and I was right. After I took the tune off back to stock immediately got best run
13.16 at 107mph , another run 13.19 at 107mph. 60ft times were all similar at 2.0
This confirms my feeling that I was making less hp on top end with the tune.

 

Let's get this right so with the tune added it runs slower hmmm

Personally I've never been a fan of these generic tunes on FI vehicles, however a proper tune on the dyno is worth its weight in gold

 

So, are you implying he does not have a proper tune?

 

Im not one to bad mouth any company but the proof is right there the car runs slower with aftermarket generic tune

With the pulley upgrade and a tune he should be running into the 12s

 

Does your car have that tune for the 12's? If so, does he have a different tune?

We should call out vendors if what one stated is accurate/factual and not meant to demean. Just get the facts out there on one's experience for us all to learn.

 

I'm not into the tune stuff but if I were to get involved I would think you would need to collect the necessary data to make any comparisons. Info like track runs (maybe 5) to determine best/worse times and also a dyno run to set base line. Then do the dyno run after the mod and then the speed runs . Identify what was done and who did it and let the results speak for themselves. Granted the runs would be subjective to the skill of the driver but the dyno results are pretty much fixed.

 

My vehicle is only the n/a version

Unfortunately the price difference in Australia was going to be a further 20k to land my backside into the xkr.

Having said all that i have a custom dyno tune and have recorded an official e.t of 13.9 (at the drags/terrible heat 90f) then an unofficial time of 13.7 with x-pipe on the gtech pro

 

Im comparing back to back runs with same 2.0 60ft times. I always suspected and told the tuner that the car felt slower on top end, but I thought it was just in my head. Lower rpms felt more powerful with the tune.
The results confirm that instead of 30+ hp that the tuner claimed, Im actually making less hp on top end resulting in slower trap and 1/4mi times.

 

Can variables swing the times that much on the same car and driver to think the tune is not doing as well?

I can see the low end bump with the pulley, but I thought most tunes work more on the top end?

 

Regardless of the posted times if your mph is down your hp is down

 

Its the same track, same day, same launch/60ft time, same driver, same lane even.
1/4mi time is faster with tune off vs on.

 

At this Point OE Tuning has not resolved the issue or give me a refund. I think I will be turning to Eurocharged for help with the tuning.

 

Don't waste your time with either go custom dyno tune with before and after power runs

 

the trap speed always tells the story.

 

Maybe your right, the problem for me is finding the tuner who would do it. Originally I chose OE Tuning that got me the current tune, because they were pretty much the only company near me to also offer a dyno tune. After I found out they dont even have their own dyno machine, and I would need to pay extra for custom tuning as well renting a dyno machine...

 

Agree ...

 

Essentially it's the same principle whether dyno tuning a corvette, mustang or jaguar it just depends on whether the fact they have the correct software program

 

Yes Steve, and it appears only a handful of companies have the software and only one nearby which is OE tuning with the current tune.

 

alex,


my cousin restores jag e's at classic showcase up in Oceanside. if you like, I could ask him if they are aware of a good tuner in the area? let me know.


best,


pcb

 

If you can find someone with a dealers IDS or SDD diagnostic system I have a tune for the 4.2L XKR which can be flashed that way, also a special version of the TCM program which was originally devekoped for the XKR GT3 (before the project was dropped by Jag)