Rather than replace the O2 sensors and cats on my 05 Prius, I was thinking if just running a straight pipe to the muffle and eliminating the O2 sensors altogether using a kit from Magnum Tuning that simulates the sensors to avoid a CEL. does anyone have any experience using these? It seems like a better option than an eBay cat and would require zero maintenance in the long term. But do they actually work? I’ll leave a link below. Toyota Prius O2 Sensor Eliminator MAGNUM EZ CEL FIX Oxygen Sensor Simulator
I do have advice, but you won't like it. Your Prius was designed to be one of the cleanest, most fuel efficient cars in the world when it was made. You wish to undo both of these for some reason. Please don't. 2004-2009 Toyota Prius 1.5L Catalytic Converters Inc Gasket & Hardware 10H643044 | eBay www.amazon.com/AutoShack-EM26339-Compliant-Catalytic-Replacement/dp/B08FBK1BNM
Go ahead and watch the videos of people failing on Youtube when they do this to random cars. If you do it your car will reek of the stench of a 1970's gas guzzler and the lack of back pressure will cause a big drop in MPG that will cost you more in the long run than fixing is correctly. What's more, the throttle response / power curve will be very disappointing too. It seriously boggles the mind that one of the lowest emissions vehicles ever made can get into the hands of people who think that doesn't matter and can do away with much of it thinking there will be no consequence. So annoying!
Thanks for the advice and the links. Seems like this will definitely be the way to go - and it’s actually cheaper than installed an O2 sensor eliminator. I may still add an O2 sensor spacer though, just to make sure things run smoothly for a while. I’ve heard a lot of people saying these aftermarket cats don’t play nice with the ECU.
Well even there site says you can't replace both 02's with this device, it spoofs the ECU, so that the car always thinks it is at 14.7 plus or minus 1 volt (Narrow band) or plus or minus 5 volt's, (wide band) Air Fuel Ratio, stoichiometric. I don't know which one it actually mimics but most likely the narrow band?? But that is how it turns the Check Engine light off, the ECU can't read the real engine condition's so the car always thinks it is at idle or partial throttle. Because after the cat that is the signal the ECU gets back regardless of actual conditions. And as long as the temp is always 70 degrees, the road's are flat and you don't accelerate hard, no big deal. But most likely, the Prius at cruise runs pretty freaking lean, so it would still use more fuel that it needs to. I don't know? The site actually covers this stuff; https://www.magnumtuning.com/product_documents/notes_and_tips_795.pdf But you want rich under load and lean at cruise and idle. The spoofed ECU won't see that, it would say post cat 14.7? At the minimum it would cause you to burn more fuel then you need. It is kinda cool, I will admit because with the front 02 intact it does base fuel/air and timing requirements on Engine need. So with just the one, it most likely won't blow up your motor?? But it won't be as efficient as a stock Prius. But do you need to do this anyway?? The "Prius," owner's that are "Screwed," are mostly in CA and Carb states. The visual inspect, part. If the Cat is not OEM or Labeled as Acceptable? You fail right there. But I don't know if that applies to Mississippi? But if it does not? Then just go with any of the options on Ebay as linked and call it a day.
The aftermarket cats seem to be more problematic if you have a pre-existing PAO420 error code with the old cat. But if you're swapping out one without that error code it usually isn't an issue.
Thanks for the help everybody. I really appreciate it! I did a bit more research on my own and deleting the cats just seems to be a terrible idea, no matter how you look at it. Guess that idea would be better saved for when I LS-swap this thing later on... kidding of course. I've ordered some aftermarket cats on Amazon, so we will see how they workout.
