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I have spent over 600 trying different o2 sensors,extensions, bungs,spacers etc and tried 3 different sets of hi flow cats,200 cell,300 cell and even 400 cell and still pended rear efficiency codes.
after spending months trying to figure it out oetuning said to take out the wire extensions. I had bought 3 different brands and that was the issue.the wires change resistant values and trigger codes.
my final setup was just 15 dollar Ebay o2 extenders welded close enough to not have to use wire extensions and the car passed .
I even had the rear o2 sensors plugged before my hi flow cats because the stock wires dont let you install the bungs past the cats.
does your o2 extenders have any type of filling or are they hollow?
so with mbh catless long tube headers and mid pipes and i wanted to install a set of the angled extenders, where should it be installed? i'm assuming it would go on the 2nd set of o2 sensors. bank 1 sensor 2 and bank 2 sensor 2.
I have spent over 600 trying different o2 sensors,extensions, bungs,spacers etc and tried 3 different sets of hi flow cats,200 cell,300 cell and even 400 cell and still pended rear efficiency codes.
after spending months trying to figure it out oetuning said to take out the wire extensions. I had bought 3 different brands and that was the issue.the wires change resistant values and trigger codes.
my final setup was just 15 dollar Ebay o2 extenders welded close enough to not have to use wire extensions and the car passed .
I even had the rear o2 sensors plugged before my hi flow cats because the stock wires dont let you install the bungs past the cats.
What codes did you throw before you got rid of the wire harness extensions?
With the new welded bung and not having wire harness extensions, were you using stock tune for smog?
What i/m monitors do you need ready/complete in MA?
What codes did you throw before you got rid of the wire harness extensions?
With the new welded bung and not having wire harness extensions, were you using stock tune for smog?
What i/m monitors do you need ready/complete in MA?
I can pass with any tune with 2 spacers on my car. Right now I'm running oe 104 map with all monitors on and everything is good.
Ma needs everything on and passed to get a sticker. If you disable a monitor you get flaged and need to go to a specialist and have your car looked over.
Can't remember the codes but would pend a few different codes with extensions.
I´m at this point having them on my C63, but it has cats.
Earlier i had them on my C55 amg without cats and it worked perfect.
C55 at that point had 2.2 litre kleeman supercharger, longtube headers,homemade exhaust(no cats), homemade intakesystem, underdrive pulleys, larger throttlebody.
reviving this old thread. I need to retune my car to pass emissions here in Oregon. My C63 has MBH Long tube headers with high flow cats and a Renntech Tune. I recently found out that the Renntech Tune turs off the cat efficiency monitor and the O2 sensor and 02 heater so I won't pass emissions. I'm being lead to believe that its maybe 50/50 if I have the dealer return the car to a stock tune or if I purchase a different aftermarket tune that leaves those monitors on that I will get a CEL for Cat efficiency (P0420 and P0430) since the high flow cats aren't always efficient enough for the EUC and thus still not able to pass emissions. It seems these 90 degree bungs with the mini cats in them might be just what the doctor ordered. Looks like there has been some success based on this thread. Looking to see if there has been others with success and which extension worked best and if this was a long term solution or just a short term fix to get you through emissions testing. The Fabspeed ones look quite nice but are $300 compared to the $35 ones out there.
reviving this old thread. I need to retune my car to pass emissions here in Oregon. My C63 has MBH Long tube headers with high flow cats and a Renntech Tune. I recently found out that the Renntech Tune turs off the cat efficiency monitor and the O2 sensor and 02 heater so I won't pass emissions. I'm being lead to believe that its maybe 50/50 if I have the dealer return the car to a stock tune or if I purchase a different aftermarket tune that leaves those monitors on that I will get a CEL for Cat efficiency (P0420 and P0430) since the high flow cats aren't always efficient enough for the EUC and thus still not able to pass emissions. It seems these 90 degree bungs with the mini cats in them might be just what the doctor ordered. Looks like there has been some success based on this thread. Looking to see if there has been others with success and which extension worked best and if this was a long term solution or just a short term fix to get you through emissions testing. The Fabspeed ones look quite nice but are $300 compared to the $35 ones out there.
you have high flow cats, can’t your request rentech to leave the 02 sensors alone? I know EC you can request to leave them alone. You should pass then. If not, 90 degree bungs are the way to go. Also could find someone with star diagnostics to turn off your 02 for a more permanent measure..
reviving this old thread. I need to retune my car to pass emissions here in Oregon. My C63 has MBH Long tube headers with high flow cats and a Renntech Tune. I recently found out that the Renntech Tune turs off the cat efficiency monitor and the O2 sensor and 02 heater so I won't pass emissions. I'm being lead to believe that its maybe 50/50 if I have the dealer return the car to a stock tune or if I purchase a different aftermarket tune that leaves those monitors on that I will get a CEL for Cat efficiency (P0420 and P0430) since the high flow cats aren't always efficient enough for the EUC and thus still not able to pass emissions. It seems these 90 degree bungs with the mini cats in them might be just what the doctor ordered. Looks like there has been some success based on this thread. Looking to see if there has been others with success and which extension worked best and if this was a long term solution or just a short term fix to get you through emissions testing. The Fabspeed ones look quite nice but are $300 compared to the $35 ones out there.
Good to have a fellow Oregonian who still drives a V8 and not a Tesla LOL. Here Skratch77 says:
"after spending months trying to figure it out oetuning said to take out the wire extensions. I had bought 3 different brands and that was the issue.the wires change resistant values and trigger codes.
my final setup was just 15 dollar Ebay o2 extenders welded close enough to not have to use wire extensions and the car passed .
I believe you should be able to pass DEQ with this. Idk about Lake O but I know in Hillsboro all they care about is your OBDII read where it shows ready. Keep me posted with how it goes as I have to do mine over the next few months and I don't wanna switch my license plates every couple years lol.
reviving this old thread. I need to retune my car to pass emissions here in Oregon. My C63 has MBH Long tube headers with high flow cats and a Renntech Tune. I recently found out that the Renntech Tune turs off the cat efficiency monitor and the O2 sensor and 02 heater so I won't pass emissions. I'm being lead to believe that its maybe 50/50 if I have the dealer return the car to a stock tune or if I purchase a different aftermarket tune that leaves those monitors on that I will get a CEL for Cat efficiency (P0420 and P0430) since the high flow cats aren't always efficient enough for the EUC and thus still not able to pass emissions. It seems these 90 degree bungs with the mini cats in them might be just what the doctor ordered. Looks like there has been some success based on this thread. Looking to see if there has been others with success and which extension worked best and if this was a long term solution or just a short term fix to get you through emissions testing. The Fabspeed ones look quite nice but are $300 compared to the $35 ones out there.
you have high flow cats, can’t your request rentech to leave the 02 sensors alone? I know EC you can request to leave them alone. You should pass then. If not, 90 degree bungs are the way to go. Also could find someone with star diagnostics to turn off your 02 for a more permanent measure..
I asked Renntech that question and the guy was not overly helpful. Basically just said what I have is their base tune and this is how their tunes come and I'll never pass emissions with long tube headers. I called Eurocharged and talked to Sean there and he was much more helpful. Their tune can leave all those monitors on. He did say with high flow cats it's likey I will still get get the p0420 and p0430 codes unless the cats are very good. I started looking into bungs after reading this thread and then just now looked under the car and to my surprise the MBH high flow cats have built in bungs extensions welded to their cats. Maybe I'm good to go already and just need to re-tune?
2011 C63 (Summer toy) 2018 C43, 2023 Audi SQ5 ( wifes car but sometimes allowed to drive it)
Originally Posted by Nor Cal Turbo
I asked Renntech that question and the guy was not overly helpful. Basically just said what I have is their base tune and this is how their tunes come and I'll never pass emissions with long tube headers. I called Eurocharged and talked to Sean there and he was much more helpful. Their tune can leave all those monitors on. He did say with high flow cats it's likey I will still get get the p0420 and p0430 codes unless the cats are very good. I started looking into bungs after reading this thread and then just now looked under the car and to my surprise the MBH high flow cats have built in bungs extensions welded to their cats. Maybe I'm good to go already and just need to re-tune?
This will sound dumb, if i was to put in the LTH's I have and also install the cats in the above picture , would I then be able to use the Tune i already have ? Would I not have to get the O2's turned off ?
I am in the same boat kind of, I purchased the REnntech tune, thinking that I can down the road install the LTH's and the would be able to update my tune to work with the Catless LTH's
but i was told that they wont retune unless you use their LTH's or possibly another companies depending on the quailty ( they are tubes that gas flows through how does a tune know the difference in quality , it does not know the type of welds or material of the pipe)
So now I am stuck with Brand new LTH's and want to use them but i already paid for the tune and used it. If i can use the 90 degree or these cats I could use them
Good to have a fellow Oregonian who still drives a V8 and not a Tesla LOL. Here Skratch77 says:
I believe you should be able to pass DEQ with this. Idk about Lake O but I know in Hillsboro all they care about is your OBDII read where it shows ready. Keep me posted with how it goes as I have to do mine over the next few months and I don't wanna switch my license plates every couple years lol.
My other car is a gen 2 Dodge Viper so yeah I prefer the big engines to the silent whir of electric vehicles, lol.
I took the C63 through Sherwood DEQ and they don't bother doing any sort of visual inspection. They just look to see if the readout from the obdii shows active monitors. So maybe all I need is just a new tune.
reading back through my paperwork on the car, it looks like when the shop installed the headers and high flow cats they used wire extenders to reach the O2s. Reading this thread it sounds like I'm going to get codes as soon as I turn those O2s back on. My question now, is what needs to be done in order to get the cables to reach the O2s without having to use wire extenders? Add another extension to the bung? Its already pretty long.
07-31-2018, 11:25 AM
