performance tune xkrs
#41
11-20-2020, 09:40 AM
Senior Member
Exactly.
Since the thread is about a 5.0SC engine, i see no point in speaking about 4.2
However, the 5.0 engines are exactly a same between XKR and 2010-2012 XJ (and there are quite a few powertrain software diffrences between these), so i've decided to chime in
Since the thread is about a 5.0SC engine, i see no point in speaking about 4.2
However, the 5.0 engines are exactly a same between XKR and 2010-2012 XJ (and there are quite a few powertrain software diffrences between these), so i've decided to chime in
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jahummer (11-20-2020)
#42
11-20-2020, 09:58 AM
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..
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..
I'm wondering if they used you as a guinea pig for that tune and if they've adjusted the tune for different cars, particularly since I'm running a XKR-S which would be a different baseline for their tune on both the ECU and TCU.
So far the XKR-S deep in to the triple digits is super stable with no front end lightness that you described in the XKR, maybe attributed to the extra aero parts on the front.
#43
11-20-2020, 10:00 AM
#44
11-20-2020, 10:05 AM
Veteran Member
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MoscowLeaper (11-20-2020)
#46
11-20-2020, 11:41 AM
Veteran Member
#47
11-20-2020, 12:39 PM
I'm trying to sort through the keyboard owners vs. actual owners with real world execution of these tunes, so I can make some informed decisions about how to go about pushing the power envelope.
With so many people with the 5.0L SC motor I was hoping more people would be able to provide some real data rather than all the hearsay.
Anyway, back to researching and sorting fact from fiction.
#48
11-20-2020, 12:53 PM
Junior Member
#49
11-20-2020, 01:42 PM
Senior Member
If that's the case, why aren't there more XKRs rolling around with the XKR-S tune if all it takes is some plumbing and software? I'd like to know because the the sample size of XKR-S owners is very small, with little to no knowledge of where the limitations are that those power levels.
I'm trying to sort through the keyboard owners vs. actual owners with real world execution of these tunes, so I can make some informed decisions about how to go about pushing the power envelope.
With so many people with the 5.0L SC motor I was hoping more people would be able to provide some real data rather than all the hearsay.
Anyway, back to researching and sorting fact from fiction.
I'm trying to sort through the keyboard owners vs. actual owners with real world execution of these tunes, so I can make some informed decisions about how to go about pushing the power envelope.
With so many people with the 5.0L SC motor I was hoping more people would be able to provide some real data rather than all the hearsay.
Anyway, back to researching and sorting fact from fiction.
#50
11-20-2020, 01:58 PM
Sponsor
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.
@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.
I'm using 10ghz gps device which is dead on accurate verified by years of track data. Here is his 1/4 mi this is with a slow 60ft time
#52
11-20-2020, 03:24 PM
Sponsor
Can do an ECU tune on yours as well
Last edited by AlexJag; 11-20-2020 at 03:28 PM.
#53
11-20-2020, 04:04 PM
Junior Member
Yes, but if I'm not mistaken the XFR/S has some form of launch control, correct? That is missing from the XKR/S
#54
11-20-2020, 10:44 PM
Sponsor
No launch control and havier car
__________________
2008 XKR Convertible, (mods: AlphaJagTuning ECU Tune , 1.5lb pulley, (200cel cats( are now melted), xpipe, Bosch 001 pump, 180 Thermostat.
Drag strip : 7.9sec 1/8mi 90 MPH . 1/4 mile 12.55 at 111.98mph
432rwh Dyno on Mustang Dynometer , Approx 511 crank HP.
2013 XJ 5.0 Supercharged, (stock with Alpha Jag ECU tune), estimated power: 600+ hp, 7.7sec 1.8th mi/95mph
2008 XKR Convertible, (mods: AlphaJagTuning ECU Tune , 1.5lb pulley, (200cel cats( are now melted), xpipe, Bosch 001 pump, 180 Thermostat.Drag strip : 7.9sec 1/8mi 90 MPH . 1/4 mile 12.55 at 111.98mph
432rwh Dyno on Mustang Dynometer , Approx 511 crank HP.
2013 XJ 5.0 Supercharged, (stock with Alpha Jag ECU tune), estimated power: 600+ hp, 7.7sec 1.8th mi/95mph
#55
11-21-2020, 03:14 PM
Veteran Member
Best launch in my XK is to engage the e-brake at stop so that car is held, of course foot off brake and ready on the throttle, in sport mode and with traction just one click off (or all the way, your option although much more an adventure in a 500hp or more vehicle). Engaging throttle somewhat heavy is an instant jump off the line, with partial TC seems to real grip and rip. Don't know how it would play out in your XKR or with an XKR-S, would think even more fun!!!
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