Has anyone tried installing backup knock sensors?
Howdy folks,
Having my 2002 4.0L XKR supercharger out, it looks to me like I could make (2) cantilever bars fastened on one end to the existing knock sensor mount on each bank and to the middle and front end of the bars (nearer front of vehicle for sensor wires) fasten both my new knock sensor along with my "good" old sensor. That way, to my thinking, the "listening source" would remain the same, but in the future, if one "old" sensor goes bad, I could just disconnect the old sensor and plug in the new one without having to remove the supercharger.
Has anyone done similar, or does anyone see the error of my ways?
Any thoughts appreciated!
EDIT: SEE SKETCH BELOW IN POST #3
Having my 2002 4.0L XKR supercharger out, it looks to me like I could make (2) cantilever bars fastened on one end to the existing knock sensor mount on each bank and to the middle and front end of the bars (nearer front of vehicle for sensor wires) fasten both my new knock sensor along with my "good" old sensor. That way, to my thinking, the "listening source" would remain the same, but in the future, if one "old" sensor goes bad, I could just disconnect the old sensor and plug in the new one without having to remove the supercharger.
Has anyone done similar, or does anyone see the error of my ways?
Any thoughts appreciated!
EDIT: SEE SKETCH BELOW IN POST #3
Last edited by Dr. D; Feb 14, 2026 at 02:34 PM. Reason: clarity
Surely the knock sensors screw into a threaded collar, or similar, which is part of the cylinder head casting? I don't understand how one could mount additional sensors as there are only two collars?
Richard
Richard
Nothing will substitute for the stock system.
To be clear, once again I do NOT recommend anyone make any substitutions to the stock knock sensor system. I’m just documenting what I did, for better or worse.
Just look at the comments made in response to the knock sensor HACK that I made in October 2020 to get me by until I found time to remove the supercharger on my 2002 XKR and replace the one bad knock sensor
https://www.jaguarforums.com/forum/x...r-hack-238806/
it’s been 6 years and 45,000 miles since then. I’ve been so busy driving the car (my daily driver) that years and tens of thousands of miles you have gone by without me even thinking about the imminent danger being done to the engine. I can’t even count the trips to the tachometer redline.
Numerous weeklong cross country trips of 1,500 to 3,000 miles too.
After a couple of years I got a boroscope and started looked at the combustion chambers and piston tops. All eight looked identical and no visible signs of damage.
I could never tell any performance / acceleration differences from before the hack and afterwards. The gas mileage stayed the same too, FWIW.
the car now sits at 204,500 miles, about 90,000 miles under my ownership, and 45,000 miles since the passenger side knock sensor hack. The original driver side knock sensor is still in place and working normally.
I fully intend on pulling the supercharger and replacing the bad knock sensor before the 2030’s (are over).

Z
To be clear, once again I do NOT recommend anyone make any substitutions to the stock knock sensor system. I’m just documenting what I did, for better or worse.
Just look at the comments made in response to the knock sensor HACK that I made in October 2020 to get me by until I found time to remove the supercharger on my 2002 XKR and replace the one bad knock sensor
https://www.jaguarforums.com/forum/x...r-hack-238806/
it’s been 6 years and 45,000 miles since then. I’ve been so busy driving the car (my daily driver) that years and tens of thousands of miles you have gone by without me even thinking about the imminent danger being done to the engine. I can’t even count the trips to the tachometer redline.
Numerous weeklong cross country trips of 1,500 to 3,000 miles too.
After a couple of years I got a boroscope and started looked at the combustion chambers and piston tops. All eight looked identical and no visible signs of damage.
I could never tell any performance / acceleration differences from before the hack and afterwards. The gas mileage stayed the same too, FWIW.
the car now sits at 204,500 miles, about 90,000 miles under my ownership, and 45,000 miles since the passenger side knock sensor hack. The original driver side knock sensor is still in place and working normally.
I fully intend on pulling the supercharger and replacing the bad knock sensor before the 2030’s (are over).

Z
Last edited by zray; Feb 15, 2026 at 06:35 AM.
Nothing will substitute for the stock system.
To be clear, once again I do NOT recommend anyone make any substitutions to the stock knock sensor system. I’m just documenting what I did, for better or worse.
Just look at the comments made in response to the knock sensor HACK that I made in October 2020 to get me by until I found time to remove the supercharger on my 2002 XKR and replace the one bad knock sensor
https://www.jaguarforums.com/forum/x...r-hack-238806/

Z
To be clear, once again I do NOT recommend anyone make any substitutions to the stock knock sensor system. I’m just documenting what I did, for better or worse.
Just look at the comments made in response to the knock sensor HACK that I made in October 2020 to get me by until I found time to remove the supercharger on my 2002 XKR and replace the one bad knock sensor
https://www.jaguarforums.com/forum/x...r-hack-238806/

Z
I am thinking that I will take your advice and keep it stock. I have second thoughts that my cantilever bar may produce harmonic distortion similar to a prong of a tuning fork that would not be revealed before the SC is reinstalled.
Again thanks
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