[bmwfan1234]

Power doesn't feel right, not sure the decision to buy a Remus cat back has helped as i get the CEL every 800 miles or so, clear the codes and it just doesn't feel the same. It's like there's literally no boost...
BMW tell me to put the stock exhaust back on otherwise they're not interested, would continuous CEL/Limp cause this?

[chmura]

What other mods you have? An exhaust after the Downpipe will have no effect on throwing a CEL. Are you located in Europe? Those cars have an Gas filter in the exhaust stream.

[bmwfan1234]

Originally Posted by chmura

What other mods you have? An exhaust after the Downpipe will have no effect on throwing a CEL. Are you located in Europe? Those cars have an Gas filter in the exhaust stream.

Stock car just Remus mid pipes (after opf) and back box. Doesn't feel the same as it did...

[Dav3]

Are you sure it's after OPF? Sure sounds like you removed it

Either that or exhaust leak maybe?

[M-Pilot]

Even just the Remus axle-back might cause CEL on OPF equipped cars (e.g. Joe Achilles M2C with Remus Race). Therefore, I strongly think the car might be cutting power/boost due to the altered back pressure. On US spec cars, the secondary cats have no sensors so this is not an issue regardless you install a secondary catback system or remove the secondary cats all together with a true catback. However, the sensors on OPF can be triggered even by a mild change like the aftermarket axleback. In my opinion, this is also the reason why BMW cancelled the EU version of MPE after initially announcing it.

[bmwfan1234]

Originally Posted by Dav3

Are you sure it's after OPF? Sure sounds like you removed it

Either that or exhaust leak maybe?

Yes, Remus mid pipes are OPF back. Had the exhaust checked and it's fine (mid pipes were knocking).

[bmwfan1234]

Originally Posted by cntzl

Even just the Remus axle-back might cause CEL on OPF equipped cars (e.g. Joe Achilles M2C with Remus Race). Therefore, I strongly think the car might be cutting power/boost due to the altered back pressure. On US spec cars, the secondary cats have no sensors so this is not an issue regardless you install a secondary catback system or remove the secondary cats all together with a true catback. However, the sensors on OPF can be triggered even by a mild change like the aftermarket axleback. In my opinion, this is also the reason why BMW cancelled the EU version of MPE after initially announcing it.

I can understand cutting boost with the CEL on, but when cleared with no codes would it still do it even after a few hundred miles of driving?

[bmwfan1234]

It's beyond stupid how changing just the exhaust can do this, might just get rid and get an RS3 at this rate as i can't even enjoy it.

[M-Pilot]

Originally Posted by bmwfan1234

I can understand cutting boost with the CEL on, but when cleared with no codes would it still do it even after a few hundred miles of driving?

Mine is just a theory based on what I have read and watched online. Aside from that, I have minimal knowledge on how OPF sensor works etc with or without a CEL being present. If I were you, I would put the stock exhaust back on and see if it solves the problem. Also, how's RS3 gonna be any different? My buddy recently bought a 2019 RS3 (with OPF) and it's pretty muted/quiet. Even the US spec RS3 has OPF and there is no other way around unless you get an aftermarket exhaust.

[VIERsr]

Remus axle back with OPFs cause CEL, nothing new. It's a problem of back pressure with the OPF sensor, the same would happen with the RS3 with OPF perhaps. Enjoy your Audi then

[bmwfan1234]

I'm not sure anyone actually understands what's happening so i will try and make it as simple as possible.

- After 800-1k ish miles i get a CEL
- I clear codes (opf bank sensor 1) and CEL
- No more CEL
- Car still drives like shit even after a few hundred miles and NO CEL

Remus UK are great when ordering and they told me i would have no issues, then went all quiet when i started having issues.
I'm sure i'm not asking for much when spending £3k on an exhaust, all i want is my car to still perform the same.

[Commanderwiggin]

Originally Posted by bmwfan1234

It's beyond stupid how changing just the exhaust can do this, might just get rid and get an RS3 at this rate as i can't even enjoy it.

You modified a car with opf and expect it to operate with better performance? The way I look at it is very simple...you suck it up and put the oe exhaust back on...or you tune it. One decision leads to you potentially selling the car/enjoying as-is and the other decision leads to you risking loss of warranty, etc... but will be more fun. You have to pay to play good sir.

[bmwfan1234]

Originally Posted by Commanderwiggin

You modified a car with opf and expect it to operate with better performance? The way I look at it is very simple...you suck it up and put the oe exhaust back on...or you tune it. One decision leads to you potentially selling the car/enjoying as-is and the other decision leads to you risking loss of warranty, etc... but will be more fun. You have to pay to play good sir.

Where did i say i wanted it to operate with better performance? I swapped the exhaust for a bit more sound and to get rid of the back box look more then anything.
Remus told me changing the exhaust will not affect warranty and this was appealing to me, i just didn't expect the issues i'm having now. I was even ok with clearing the codes every so often, but limp even after clearing codes? Nope, not acceptable.

[1mm2]

Originally Posted by bmwfan1234

I was even ok with clearing the codes every so often, but limp even after clearing codes? Nope, not acceptable.

I feel for you, going limp all the time would be rough.

[Malakas]

Originally Posted by bmwfan1234

I'm not sure anyone actually understands what's happening so i will try and make it as simple as possible.

- After 800-1k ish miles i get a CEL
- I clear codes (opf bank sensor 1) and CEL
- No more CEL
- Car still drives like shit even after a few hundred miles and NO CEL

Remus UK are great when ordering and they told me i would have no issues, then went all quiet when i started having issues.
I'm sure i'm not asking for much when spending £3k on an exhaust, all i want is my car to still perform the same.

Wonder if you might need to reset the ECU somehow... Seems like an odd problem. Hopefully the people who did your install will help you resolve it

[Ollie RS]

Did you install the remus mid pipes at the same time as the back box?

I have the race box fitted and haven't had any problems yet, i suspect the mid pipes are the cause although it can happen with just the race box as well.

Have a look at the box that Mr. is starting to sell, it tricks the sensors so that they don't throw any errors

[Fahidm2comp]

@bmwfan1234 Get a miltek system mate! Best thing I ever did, absolutely shits on the Remus (compared with a friends) and no CEL! Very loud in sports plus and invisible in comfort mode.. best thing is it was all in for 2400!! I have a slight problem however, I recently won the deutschtech free custom exhaust giveaway and I am due to get this fitted at the end of the month and will have a spare miltek lying around, which has less than 300 miles done on it (won the competition 2 days after my new exhaust, typical.. so I’ll let you know of what I plan to do when I’ve tried to new system early next month

[Megator]

Originally Posted by Fahidm2comp

@bmwfan1234 Get a miltek system mate! Best thing I ever did, absolutely shits on the Remus (compared with a friends) and no CEL! Very loud in sports plus and invisible in comfort mode.. best thing is it was all in for 2400!! I have a slight problem however, I recently won the deutschtech free custom exhaust giveaway and I am due to get this fitted at the end of the month and will have a spare miltek lying around, which has less than 300 miles done on it (won the competition 2 days after my new exhaust, typical.. so I’ll let you know of what I plan to do when I’ve tried to new system early next month

I might be interested for the right price...

[bmwfan1234]

Update, it's getting tuned by Evolve.
They have promised me i won't have anymore issues once tuned so fingers crossed it's sorted as i would rather keep tbh.

[Danielo58]

Originally Posted by bmwfan1234

Update, it's getting tuned by Evolve.
They have promised me i won't have anymore issues once tuned so fingers crossed it's sorted as i would rather keep tbh.

Hi mate,

I have got milltek and removed the OPF for a 200cells catalyst and I'm getting limp mode too, well I deleted turn off and on again and could drive normally but I'm getting the same feeling as you, at the beginning I feel more power that stock but after 6 limps modes I feel like the car is not as powerful as before like I lost 1/5 part of the full power.

Is that your feeling? If I keep having the same feeling I'm thinking to go to a dyno to see how many hp and nm I get as I did one dyno when I bought the car.

[Dav3]

Originally Posted by bmwfan1234

Yes, Remus mid pipes are OPF back. Had the exhaust checked and it's fine (mid pipes were knocking).

Do you have the race version or the sports version?

Is it the slip-on (backbox + link pipes) or both of the previous plus mid-pipes?

afaik, Remus also makes mid pipes for the US market which do delete opf

There's been cases where the race slip-on variant of the Remus exhuast causes limp mode / cel, so that could be that

If you check the S55 Engine forum section, Manhart has a device that disables OPF

If you get your car tuned, your warranty goes with it, just so you know

[bmwfan1234]

Originally Posted by Dav3

Do you have the race version or the sports version?

Is it the slip-on (backbox + link pipes) or both of the previous plus mid-pipes?

afaik, Remus also makes mid pipes for the US market which do delete opf

There's been cases where the race slip-on variant of the Remus exhuast causes limp mode / cel, so that could be that

If you check the S55 Engine forum section, Manhart has a device that disables OPF

If you get your car tuned, your warranty goes with it, just so you know

Remus Race + link pipes, OPF is 100% still currently on.
I understand tuning voids warranty hence i chose the "warranty friendly exhaust" but that didn't work out so doesn't really matter anymore..as long as a Stage 1 tune fixes the problem, i'm happy.