This has been a very frequent discussion for the last 10 years. The market for Jaguar is just so tiny compared to Audi, BMW, Ford, Chevrolet and Dodge and nor would a Jag owner be willing to spend thousands to develop a bespoke tune unlike say someone who just paid three hundred plus grand on a McLaren where another five grand or more is pocket change.

I know for a fact Old Jaguar have created their own tunes and like I said the F-Type forums show mostly positive feedback and what Velocity offers for the 5 litre.

Apex, RSR, etc are race engineers and likely used Motec or something similar for engines what are no longer stock in fact little about those cars is stock,

 

I tried and got refunded. Traction control was working weird (car was jerky) and I was not able to get any fix for that issue. But they have a good reputation and they claim many people have used their soft (in XKR).
From the customer service perspective I could not complain. We both invested a lot of time to make it happen, but it didn't...

And figures provided above (50-100mph in 4 sec) are rather unrealistic. I had around 8.5 on their soft for 100-200kmh, so maybe 6-7 sec 50-100 mph.

But definitely you will find car faster after their soft. The only question will be if it works okay on your car or the way it worked on mine...

 

Thanks for the feedback @tmich. Traction control acting weird sounds odd but seems like the ECU using brakes and TC system to adjust unexpected wheel speed. I imagine that might be more evident on the XKR-S and the eDiff. Any Jag techs care to comment?

 

Frankly I think that ECU and maps in my car were slightly different vs other Jags with 5.0s/c which they coped with and maybe they changed something in wrong maps.

My learning was - make it with someone local, who can ride your car after a tune. Their toolkit (isoftloader) is great (2 min and you have tuned soft, another 2 min and you are back to stock with all errors erased). But it is a little tricky when you are communicating over email trying to diagnose a problem. Which btw was not to be captured with a simple obd2 logger, as all parameters were absolutely okay (but car was heavily "braking" to get more "grip" when you are trying to accelerate).

So - you can try, maybe it will be fine for you (see above there are positive opinions), but be aware that it may go other way round.

But to underline - no one made any problems with a refund etc. So you are safe, just a matter of your time.

ps. I don't know if they have any dealers in the US or you need to get it from NL. If so - can image that shipping they staff back and forth can make a huge bill for an entire operation.

 

There are a couple guys at least in this forum that offer tunes that are supposedly quite good.

I shall not name names as to not show preference.

 

It isn't the most accurate of tools but mine does it in under 5.

 

Latest Xfr customer tuned

 

Pretty sure “under 5” was referring to 50-100mph

 

To be precise- he said "about 4 sec" (50-100mph).

@Alex
0-60mph in XFR <4sec - never driven one of them, so don't know their traction, but it is hard to believe that it goes faster than XKR, and I have never seen <4 for XKR. Not due to power, IMO due to traction and RWD.

In general question is about a measuring tool. I use app with an external GPS antenna (10mhz) so it is rather precise (~300usd set), but still it makes error (e.g. have records like 0-100kmh below 3 sec which is b/s). I'm only convinced with repetitive results, not one offs.

 

My quote is in regards to u102768 stating his does 50-100mph in under 5 sec (not 0-60mph as Alex is referring to) you tool

 

Mine will do it in less than 4 seconds, 3.74 is the best I have seen, but that is for a perfect launch. Generally it is low 4s for the reasons you state.

50-100mph or 100-200km/h is a much better indicator of power and the 1/4 mile gives a better indication than the 1/8 mile.

 

How much did your car on a dyno and what is your 100-200kmh time?

Interesting for me, as I have never been close to 3.99 (I think ~4.3 is my best on new, high end 295 rear tires).

 

7.6 100-200, 197.7kph trap speed at 1/4mile, 682hp/850Nm
0-100 is 4.4, MASSIVE traction issues up to 130-140kph.
However i have diffrent rear diff ratio (2.56 vs 3.31 on xkr) and a bit more weight (2160kg)

 

I seem to recall that Jaguar listed a 4.3 sec 0-60 time for the 5.0l XKR in their sales specs.

 

Can imagine 100-200 in 7.6s with almost 700hp. It's 100hp more vs mine.

But still cannot imagine <4s 0-100kmh in XKR, and your figures confirm my scepticism.

 

Yep, the main problem is a traction, it's almost impossible to launch it with a that amount of hp/torque, even with 2.56 rear diff (actually less power to the rear wheels). It's still possible to limit torque on a low end to make things easier, but with that mod the car won't forgive you early upshifs and you'll have to rev it all the way to get a decent acceleration (been there).

 

I lose traction easily at half throttle from 60-70mph 255 and 3.58 final ratio. My tech made simulation fot the next summer setup - we we do all the things tourque should be over 1000Nm from 3500rpm and max 1075Nm. Gentle British saloon

 

I've had a 295 PS4S, they can't withstand a traction. For a next season i've got a set of semi-slicks and will break a 1000Nm too For now a peak torque starts from a 2500 and lasts till 6000, so far no problems to have a 1000 in that area. Yep) Nice and long british sallon with basic bolt-ons and no cheating (nos or watermeth)

 

You're referring to the 5 litre XJ, not the 4.2 XKR, right?

 

Hi
I posted about the RICA tune on my 2013 XKR
I bought the car new and it took them 3 tries to get the software right.
The first download was horrible - the throttle tip in was virtually impossible to control and unusable - the "jerking" problem people are referring to.
The second download solved the throttle tip in problem but basically unmasked a problem with the E-Diff.
I've been running the third download for 7 years with no problems. The whole process took about 6-8 weeks as I recall.

It should go without saying that the Stage 2 version includes a smaller pulley to increase the supercharger boost, and the ECU map requires that.

The whole point of my statement about the 50-100mph time was that, as others have noted, the car doesn't have launch control and obviously isn't AWD, so when you shut the traction control ALL the way off, you just can't use the horsepower from a standing start - you have to be going 40-50 mph for there to be enough grip without any wheelspin to hook up under full throttle. I haven't done a run with an electronic timer, but stopwatch timer showed sub-5 seconds 50-100mph when I posted my comment..

I'm curious now to see what an electronic timer will show and will try it next year (car is already off the road for the winter here in New England) . Frankly though, it scares me to push the car over 100. I find that when accelerating under full throttle through 110 the front end starts feeling very light, and it would be very easy to lose control. Not sure if true, but a UK Jag engineer told me that the hood vents on the XKR are designed to relieve underhood pressure for this reason.

I don't profess to be any kind of expert here, just relating my experience..