BMW 135i & 335i – VRSF Catless Downpipes Install (N54)

I bought some used VRSF 3″ catless downpipes for $300 and decided it was time to put them in. Most people on the forums say they would rather pay to have it done if they had to do it all-over again. In other words, I went into this expecting it to take a while…

BMW 135i downpipe install

We were pretty slow throughout the whole process. I was able to loosen most of the nuts, but one in particular was giving me trouble. It was in a really tight spot and we ended up rounding it off. I had a friend heat the stud with a torch and use an air chisel to snap it off.

BMW 135 downpipe install - torch

After we got that out of the way, we still needed to unbolt brackets, v-bands, four O2 sensors, and unhook the whole exhaust from the hangers. We even had to unbolt the steering rack and move it out of the way for more room. I would recommend replacing both v-band clamps when installing downpipes. Maybe we should have started earlier?

BMW 135i downpipe install

About 8 hours after we started, the OEM catted downpipes were finally out. I initially hoped the car would be buttoned up and back on the road by this time, but that wasn’t going to happen.

BMW 135i catted downpipes

I decided I was going to  finish it the next afternoon. I didn’t take any pictures of the actual install process, but I finally got them in today!

bmw-135-downpipes BMW 135i - VRSF 3" downpipes installed

Also, I wet-sanded and polished my exhaust tips since the exhaust was unhooked. The tips were black and caked with crap. I always assumed the exhaust was a custom setup, but I uncovered a “Riss Racing” stamp once I cleaned the tips. Sure enough, this thing has a $1,300 stainless-steel 3″ catback exhaust!

I had a friend take some videos to capture the exhaust sound inside and outside of the car. Excuse my excitement as I grannyshift up the onramp, I’ve never lost traction in 3rd like that before.

I’ll drop in the Walbro 255 fuel pump next weekend. I can’t wait to get her on the dyno again and hit up the drag strip.

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2 Replies to “BMW 135i & 335i – VRSF Catless Downpipes Install (N54)”

  1. Hello Jake,

    I love your car, choice of mods, and I admire your dedication in taking care of it. I have a 2008 Manaco Blue 6spd with 43k on it. The low miles are because I have a company vehicle, so my 135 is my weekend toy.

    I’m in a bit of a bind and I hope you can give some advice. My two year New Jersey car inspection renewal is due. like you I have catless (BMS)DPs. I’m using the “Xkitty DP fix”, but I’m having trouble dialing it in.

    You are suppose to put the car the through a “full Drive cycle”, but I’m not sure what to look for to know if it’s working properly. If the check engine light comes on(which currently it keeps doing), should I stop the car, make an adjustment, then keep driving again until the check engine light finally stops coming on?

    I have my JB4 tune on Map zero and when I check to see what codes it’s throwing I’m getting 2C31 & 2C6A. Are these normal for my set up and isn’t the DP fix supposed to clear these if dialed in properly?

    I apologize for coming out of the blue asking for help. I do appreciate any advice you can give me though.


    1. I wish I had only 43k miles! Sounds like you’ve got a keeper.

      I don’t have a “DP fix” installed on my car. Fortunately my county does not require emission testing. I know JB4 has a built-in “auto-clear” function. Terry removed it from the JB4 steering wheel control guide, but it still works. I believe if you go to speedo=1 and RPM=3, you will activate the auto-clear function. It will constantly clear codes and never show a SES/CEL light. I believe speedo=1 and RPM=4 deactivates it. I don’t know if this will help you pass your emission test, I guess it all depends on how they test your car. If they look for a code, there shouldn’t be any. Just activate the “auto-clear” function and then deactivate it after your test. That way you can still see codes if you need to. When I connect my laptop to the JB4, it reads the codes and says “catless downpipes detected” next to two of the codes.

      Hope that helped. Wish I knew more about the DP fix.

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