When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I just installed an xkr muffler today. I like the new look but I noticed the sport mode downshifts are gone. Any idea why the car is behaving this way? I also noticed a rattle when the car is in idle. It seems to be coming from within the muffler.
Dont mean to be a negative nancy but the carbon fiber wrap on the real plinth is bubbling up in the crease. Some heat and patience will make it flush =]
Looks good though. Where did you get that rear diffuser?
Dont mean to be a negative nancy but the carbon fiber wrap on the real plinth is bubbling up in the crease. Some heat and patience will make it flush =]
Looks good though. Where did you get that rear diffuser?
Yeah, I have been lazy to take care of the carbon fiber. It needs replacement. Way overdue. Too many projects...next I need to install new front spoiler which I have had for month but doing additional upgrades, then fix bubbling dash leather which requires taking off front wind shield, new set of tires,...u know the drill
Anyway, I put that rear diffuser together. Stock xkr diffuser, paint job and the bottom pieces from ebay..some imagination....viola...for less than $80🤪...ooh, and some pin stripes
Probably the valves that rattle. Mine did and I secured them with a hose lamp. 😊
Hmm, will look into first thing in the morning..I am dumbfounded between the rattle and loss of downshift growl. The car is not driving the same. I feel like it lost some power
Hmm, will look into first thing in the morning..I am dumbfounded between the rattle and loss of downshift growl. The car is not driving the same. I feel like it lost some power
I’m surprised at the loss of ‘downshift growl’, as mine was much more pronounced after the change to a XKR backbox. Those throttle blips in sport mode are intoxicating.
It might be related to loss of back pressure in the exhaust system. I noticed the same when I replaced my exhaust to a sport exhaust system from Larini. I had the ECU tuned and gained power.
The noise level of the XKR muffler is controlled by a valve in the muffler that is operated by fuse 19 located in the panel behind the center rear seat cushion. I don't know if the XK is equipped with that circuitry and presume that it is not. If so, then that valve might be flopping around or is stuck in the open or closed position or somewhere in between. Ordinary, the valve is closed at low RPMs to keep the sound down and improve low-end torque (backpressure helps), and it opens as throttle position angle and RPMs increase. Search for the old thread on this Forum that discusses how it works in detail.
Your perceived reduction in power and rattle come from your XKR muffler, particularly if you bought it used. If you bought it because you wanted the XKR sound, then you need to wire that valve so it stays in the open position and live with the slightly lower torque. I suspect that the rattle is from the valve flopping around since it is not controlled by fuse 19. If you wire it closed it's not much different from your XK muffler.
The noise level of the XKR muffler is controlled by a valve in the muffler that is operated by fuse 19 located in the panel behind the center rear seat cushion. I don't know if the XK is equipped with that circuitry and presume that it is not. If so, then that valve might be flopping around or is stuck in the open or closed position or somewhere in between. Ordinary, the valve is closed at low RPMs to keep the sound down and improve low-end torque (backpressure helps), and it opens as throttle position angle and RPMs increase. Search for the old thread on this Forum that discusses how it works in detail.
Your perceived reduction in power and rattle come from your XKR muffler, particularly if you bought it used. If you bought it because you wanted the XKR sound, then you need to wire that valve so it stays in the open position and live with the slightly lower torque. I suspect that the rattle is from the valve flopping around since it is not controlled by fuse 19. If you wire it closed it's not much different from your XK muffler.
Thanks. I welded the valves open this morning. And u are right, loss in torque is noticeable
It might be related to loss of back pressure in the exhaust system. I noticed the same when I replaced my exhaust to a sport exhaust system from Larini. I had the ECU tuned and gained power.
09-20-2019, 02:15 PM
Just installed XKR muffler on my 2008 XK
