Derestricting the 'R'
#1
Derestricting the 'R'
I understand Jaguar entered into a voluntary agreement with various other manufacturers to restrict the top speed of their vehicles to 155 mph and I am wondering if anyone has managed to derestrict one and if so, what is the true top end potential of an otherwise standard XKR.
This is a purely academic question - at least it is from me, as I know from experience on bikes that that sort of speed is very rarely obtainable with any degree of safety, but I can't help but wonder...........170?......180??
Also, I assume the restriction is carried out by the engine ECU limiting the RPM once the transmission module has registered it is in fifth gear and therefore presumably, one could create a device to interface between the engine and trans modules that would prevent the engine module from ever seeing fifth gear?
I know Suzuki did something similar with the Hyabusa and one could connect a small box of tricks into the main loom under the seat and hey presto....... one very fast motorcycle!
Andy
This is a purely academic question - at least it is from me, as I know from experience on bikes that that sort of speed is very rarely obtainable with any degree of safety, but I can't help but wonder...........170?......180??
Also, I assume the restriction is carried out by the engine ECU limiting the RPM once the transmission module has registered it is in fifth gear and therefore presumably, one could create a device to interface between the engine and trans modules that would prevent the engine module from ever seeing fifth gear?
I know Suzuki did something similar with the Hyabusa and one could connect a small box of tricks into the main loom under the seat and hey presto....... one very fast motorcycle!
Andy
#3
#4
I understand Jaguar entered into a voluntary agreement with various other manufacturers to restrict the top speed of their vehicles to 155 mph and I am wondering if anyone has managed to derestrict one and if so, what is the true top end potential of an otherwise standard XKR.
This is a purely academic question - at least it is from me, as I know from experience on bikes that that sort of speed is very rarely obtainable with any degree of safety, but I can't help but wonder...........170?......180??
Also, I assume the restriction is carried out by the engine ECU limiting the RPM once the transmission module has registered it is in fifth gear and therefore presumably, one could create a device to interface between the engine and trans modules that would prevent the engine module from ever seeing fifth gear?
I know Suzuki did something similar with the Hyabusa and one could connect a small box of tricks into the main loom under the seat and hey presto....... one very fast motorcycle!
Andy
This is a purely academic question - at least it is from me, as I know from experience on bikes that that sort of speed is very rarely obtainable with any degree of safety, but I can't help but wonder...........170?......180??
Also, I assume the restriction is carried out by the engine ECU limiting the RPM once the transmission module has registered it is in fifth gear and therefore presumably, one could create a device to interface between the engine and trans modules that would prevent the engine module from ever seeing fifth gear?
I know Suzuki did something similar with the Hyabusa and one could connect a small box of tricks into the main loom under the seat and hey presto....... one very fast motorcycle!
Andy
#5
I agree it would be nice to know you were driving a 180mph car, even if you never use it. I mean, how many of us actually need/use 400hp+ anyway? It is my ambition to own a 1000hp car before I die, which is even more pointless given the current move towards the dandelion-powered electromagnetic pods they want us all to drive.
#6
I understand Jaguar entered into a voluntary agreement with various other manufacturers to restrict the top speed of their vehicles to 155 mph and I am wondering if anyone has managed to derestrict one and if so, what is the true top end potential of an otherwise standard XKR......................................
I've read Jaguar tested unrestricted XKR's to 178 mph at Nardo but can't turn up the actual reference to this.
Graham
#7
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#9
As I said initially, the question was an academic one, but clearly it is a pertinent one for someone on a track session etc. I am interested at a technical level how the system is restricted and how you would derestrict it. Perhaps XKRacer, you can shed some light on this please?
I seem to remember reading somewhere that a derestricted XK8 probably wouldn't go much quicker than 155, but the XKR might have the potential to reach 180+ mph.
I fully agree that for the majority of owners, myself included, 400 hp and 155 mph is way more than is ever needed, but I'm with Frog........you can never have enough power.
Andy.
I seem to remember reading somewhere that a derestricted XK8 probably wouldn't go much quicker than 155, but the XKR might have the potential to reach 180+ mph.
I fully agree that for the majority of owners, myself included, 400 hp and 155 mph is way more than is ever needed, but I'm with Frog........you can never have enough power.
Andy.
#11
You actually left out drag coefficient, which I suspect is very low (and lower for the coupe), and I would guess is one of the reasons that these cars can attain such high top ends.
#12
#14
#15
Hey I'm still waiting for someone to figure out how to make my windows one touch up in addition to one touch down (apparently a feature that the 2006 models had). I would think derestricting/delimiting the car would be even more difficult.
Doug
#16
The fuse story I believe is one of mine....
It is how I went around the bowl so fast, my driver took a couple of fuses from the left hand side engine bay, the abs did not work neither did the speedo.
Trust me I did ask but he said he was sworn to secrecy by Jaguar and would cost him his job, it took him seconds!!!
It is how I went around the bowl so fast, my driver took a couple of fuses from the left hand side engine bay, the abs did not work neither did the speedo.
Trust me I did ask but he said he was sworn to secrecy by Jaguar and would cost him his job, it took him seconds!!!
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