Since
Capristo sound is apparently an issue with some of you, I have copied below my reply to inquires about my power switch to the
Capristo controller which, if switched off, will keep the valves closed (and stock quiet) all of the time.
I sometimes run with the power switch open (valves always closed), but not a lot since I have my controller set to open the valves at 80 mbar pressure difference and they are mostly closed around town. That said, I cannot imagine any problems with preignition due to back pressure since the
Capristo exhaust with the valves closed is at least as free-flowing as the stock exhaust. I say this because
Capristo uses 100 cell cats, and only one pair, (hence the CELs which can be corrected by Softronics ECU software) and is about as loud or slightly louder with valves closed than stock so it will have less, not more, back pressure with the valves closed than stock. Therefore, I would certainly not expect any pre-ignition running with the valves always closed. However, you might run this by Scott Slauson for confirmation, and/or confer with Nick for
Capristo factory consideration, but I cannot imagine any difficulty here. With a power switch to the
Capristo controller you have 3 options for the bypass valves: always open, always closed and controller regulated.
Best regards,
Charles