Wow, I'm looking forward to this being ready! The tune itself looks amazing as I was expecting, have you managed to get round being able to flash through OBD yet?

If possible, I'd also like the maximum airflow limit in the MAF increased so I don't hit the torque limiter and preferably a removal of the speed limiter in 6th.

 

The first modified test tune was flashed into an X103 XKR this morning using a VCM to prove the method. It worked. Next step is a more modified file with updated checksums. If that goes well then it's going in my XJR for road testing, 1/4 mile and dyno.

Yeah don't worry, there are no more torque limiters.

As for the speed limiter, yeah that was already gone some time back, one of the easier things to change.

 

Coooool, We made the front page! I believe if Cambo can crack the ECU and provide great tune, a 1.5 pulley, drop in, intake may get us there or at least close...The pressures on Cambo...The whole Jag world is watching now!!!!

 

Congrats Cambo, nice work!
Keep on, your background guy and you are helping this community of enthusiasts a lot.

 

Who knows may get a nice power increase without a pulley!

 

Sounds promising and exciting.

I may have missed this what equipment would be needed to load the software over the ODB II interface?

 

Jackra, You may want to see how Cambo & Companies tune turns out before dumping 1200$ on 200 cell cats!

 

Too late already done.

Correct me if I am wrong but improving overall "breathing" intake and exhaust especially in an SC car is still beneficial and a tune on top will only add to that benefit I think.

If your point is that a tune is a far better bang for the buck than more freely flowing cats maybe you are correct.

I would be interested to hear what Cambo says.

 

Oh well the cats certainly will help for sure...I spent 25K modifying my Viper and when I sold it and got around 3K more for it over a totally stock Viper...Not doing it again...Again all of this extra power we are all trying to get creates more traction problems from a 1/4 mile standpoint...And the transmission torque limiters which I had no idea existed will further squash power to the pavement...Good news these cars are great from a 60 roll...Most of the races seem to be on the highways anyways in my parts!

 

Following this thread has me salivating for an ECU tune, intake pipe and pulley but I can't ignore the elephant in the room, "traction". Right now my almost bone stock XJR (if you ignore the x-pipe), will break traction at any hint of full throttle at take off, kicking on the traction control and cutting power. Very annoying!


So if I add more power, I would be multiplying the traction issue.


Since I am planning on buying new tires, I was thinking of increasing the rear tire width to maybe a 285 to help with traction. I am not sure if the stock 20 inch rims can handle the new width since they are 8.5 inches. All the 285 tires I've looked at specify a minimum rim size of 9.5 inches.


Will 285's fit the stock rims?


Maybe wider tires will help until I make up my mind about getting an LSD.

 

LSD equals 2K...That could be a deposit on a XKR!

 

I had no idea about the transmission torque limiters.

 

Are you saying traction control kicks in even if you have it switched off?

 

If it is switched off all I do is spin tires. OK, spin one tire. Lol

So basically this car is somewhat useless off the line if you want to hypothetically race someone from a standstill.

 

"Stock" 20" rims (Callisto or Sepang) are 9" wide, for 255 wide tyres.
285 wide tyres is on the high end for 9" wide rims but could still be acceptable.
Best would be however to fit 10" wide rims.
There have been threads posted here concerning fitting 285 wide tyres on XJRs, the rims were not stock.

 

Yes as I mentioned before, leave the pulley alone.

IDS/SDD software, and a VCM interface.

Yes improve the intake & exhaust, it's going to help.

If you read through my previous post it's mentioned about making changes to the DSC torque reduction, DSC = Dynamic Stability Control = Traction Control, so you can leave the DSC switched on but it won't kill power, just work the rear brakes, which kind of works out like an electronic LSD. The X150 XKR test mule has been done this way, it still has no LSD, but launches a lot better than it used to.

The problem with the standard configuration of the DSC is that when it's on, it cuts power when there is "too much" wheel spin and you are going nowhere. So everyone turns it off, and you are left spinning wheels, and again you're going nowhere. By reducing the power cut and leaving only the brake intervention, you can still get moving on an open diff because it doesn't stop the power delivery.

 

First, congrats to you and your team, you are making progress where no Jag owner has gone before.

Second, can you elaborate on the bit I quoted above? My impression was that pulling the timing when the intake charge was really hot was a good safety measure. Especially if someone has a pulley and no meth injection (or if they have injection, are tuned for it, and it fails!).
Also, why is it an issue on the early cars, but not the later cars.

Thanks, we are all learning, and this is exciting!

 

In answer to the wider tyre fitment you can fit them on the stock rims without issue, I had been on 285s with the standard 20s since 2013 before part exchanging them for the cambos old Arden's off Alec Escolme ( now running 295s ) this simple upgrade in tyre width made a huge difference to drivability and traction so I would highly recommend it.

Link to cambos original thread discussing it below.

https://www.jaguarforums.com/forum/x...r-77305/page2/

 

Yes this is an important safety measure, and it must remain in place. The problem is that in the 03-05 cars this function is not very smart, it's kind of working with a fixed value and it's been setup in a very conservative way.

It's actually pulling timing before the charge get's "really" hot and it seems to be based on a worst case scenario of running low-grade fuel. For example you can safely have more timing with a hotter intake charge if with 98RON / 93AKI fuel than 91RON / 87AKI because it's less prone to detonation.

The later cars have a much more sophisticated strategy for dealing with this and it's not costing much power, so not really a problem. The earlier cars however...

I will try to get a better explanation of how this is all working. But for sure we do not want to remove this safeguard, only tweak it a little.

 

I found a staggered setup which consists of 20x8.5, 35 offset front and 20x10 42 offset rear. I'm wondering if the offsets work. I will research further.