[Mattlong640]

Hi All

Has anyone done this to their (or anyone else's) M235?

https://www.facebook.com/Bimmerpost/...58019440930681

I've found a pic of an opened up backbox from a 335i - are they the same on M235i?

If so, anyone got any experience with what you actually do to the box? Weld all the holes, half the holes?

And finally - anyone know a good welder in the southeast of England?

Cheers

Matt

[Mywifes335]

Unless you have a plasma cutter and the proper welding tools, the cost of labor to do this is just not worth it.

If you weld solid pipes in place of the perforated pipes, it's basically the same as running a muffler delete. The only sound proofing is the muffler enclosure itself...

[Mywifes335]

Edit: I already explored this option with a local reputable muffler shop in NJ. www.mufflex-performance.com. They've done dozens of these mods on C5/C6 corvettes. The cheaper solution was to weld a pipe on the outside of the stock muffler bypassing the muffler upon the opening of the 2nd flap. Still very quiet despite not having a cat.

[bluebro]

PM sent to op.

[Jadar]

Originally Posted by Mattlong640

Hi All

Has anyone done this to their (or anyone else's) M235?

https://www.facebook.com/Bimmerpost/...58019440930681

I've found a pic of an opened up backbox from a 335i - are they the same on M235i?

If so, anyone got any experience with what you actually do to the box? Weld all the holes, half the holes?

And finally - anyone know a good welder in the southeast of England?

Cheers

Matt

Thats my muffler that mod was done 3 years ago. In fact it was on my old F30 335i, and It worked so well that when I purchased my new F30 I transferred the muffler to the new car.

What you need is a right angle grinder with a thin cut out wheel. Open up the muffler and weld all the holes shut. You cant just install new solid tubing because chamber 1 the tube is a T shape and its oval. If you have any other questions PM me.
Here are sound clips from the modded muffler. Both my cars the black F30 and the Blue one is with a down pipe now.

Its cheap and sounds good. I had an M performance muffler before and was quite unhappy with how quiet it was.

Originally Posted by Mywifes335

Unless you have a plasma cutter and the proper welding tools, the cost of labor to do this is just not worth it.

If you weld solid pipes in place of the perforated pipes, it's basically the same as running a muffler delete. The only sound proofing is the muffler enclosure itself...

Not true at all. This was so cheap to do. $80 U.S. dollars just for a shop to weld it all back up for me. I did all the cutting.

[Mywifes335]

Originally Posted by dd1981

Thats my muffler that mod was done 3 years ago. In fact it was on my old F30 335i, and It worked so well that when I purchased my new F30 I transferred the muffler to the new car.

What you need is a right angle grinder with a thin cut out wheel. Open up the muffler and weld all the holes shut. You cant just install new solid tubing because chamber 3 the tube is a T shape and its oval. If you have any other questions PM me.
Here are sound clips from the modded muffler. Both my cars the black F30 and the Blue one is with a down pipe now.

Its cheap and sounds good. I had an M performance muffler before and was quite unhappy with how quiet it was.

Not true at all. This was so cheap to do. $80 U.S. dollars just for a shop to weld it all back up for me. I did all the cutting.

Which part isn't true? I've seen the inside, it's 3 chambers with perforated cores. The mod is replacing it with solid tubes, or in your case welding the holes. You can get new pipes put in, a good muffler shop can fab the intricate Y section.

It might be cheap to do if you cut it yourself I suppose. And weld the holes. If it was $80 for welding pipe perforations AND re-welding the box is dirt, dirt cheap.

If you find someone to do that for you, that's great. Mad kudos. Truly.

Other issue with the welds is you'll have to clean up the welds inside or the inner pipe is no longer smooth. Will look like bird droppings inside the tube.

A good amount of work. But if you can weld and fab, then maybe it's not so bad.

[Mywifes335]

Dd1981:

Full disclosure, your F30 mod is what gave me the idea last year to attempt the mod myself. After visiting a place I have been going to for years, it was decided to go another route.

Again, kudos for a lot of the DIY work you did.

[Jadar]

Originally Posted by Mywifes335

Unless you have a plasma cutter and the proper welding tools, the cost of labor to do this is just not worth it.

If you weld solid pipes in place of the perforated pipes, it's basically the same as running a muffler delete. The only sound proofing is the muffler enclosure itself...

Originally Posted by Mywifes335

Which part isn't true? I've seen the inside, it's 3 chambers with perforated cores. The mod is replacing it with solid tubes, or in your case welding the holes. You can get new pipes put in, a good muffler shop can fab the intricate Y section.

It might be cheap to do if you cut it yourself I suppose. And weld the holes. If it was $80 for welding pipe perforations AND re-welding the box is dirt, dirt cheap.

If you find someone to do that for you, that's great. Mad kudos. Truly.

Other issue with the welds is you'll have to clean up the welds inside or the inner pipe is no longer smooth. Will look like bird droppings inside the tube.

A good amount of work. But if you can weld and fab, then maybe it's not so bad.

The highlighted part. Its not expensive to do.

[Jadar]

Originally Posted by Mywifes335

Which part isn't true? I've seen the inside, it's 3 chambers with perforated cores. The mod is replacing it with solid tubes, or in your case welding the holes. You can get new pipes put in, a good muffler shop can fab the intricate Y section.

It might be cheap to do if you cut it yourself I suppose. And weld the holes. If it was $80 for welding pipe perforations AND re-welding the box is dirt, dirt cheap.

If you find someone to do that for you, that's great. Mad kudos. Truly.

Other issue with the welds is you'll have to clean up the welds inside or the inner pipe is no longer smooth. Will look like bird droppings inside the tube.

A good amount of work. But if you can weld and fab, then maybe it's not so bad.

If you have a decent welder the holes can be pretty smooth, but not perfect I suppose. You can definitely go the custom oval T pipe designed by a good exhaust shop, but this is where it will get expensive and probably above the 'worth it' cheap mod factor. If I had to guess that type of fab work would cost a nice $250-$350 dollars. That point is questioning if its worth it anymore. You can get a Megan racing muffler on ebay for under $400 shipped on ebay. I tried it, and the sound was good so I just kept the muffler on, sold the M performance and that was pretty much all.

I cant take the credit for coming up with this mod at all, as this was done long ago by E90-92 M3 guys, and they used the method you mention, replacing the entire perforated tubes. But those are easy and all 4 are round.

[Jadar]

Originally Posted by Mywifes335

Dd1981:

Full disclosure, your F30 mod is what gave me the idea last year to attempt the mod myself. After visiting a place I have been going to for years, it was decided to go another route.

Again, kudos for a lot of the DIY work you did.

Also, knowing what I know now, and having modded my 2nd F30 and with how far JB4 has come with can flap and opening and closing the valve when I want now via JB4 with the added down Pipe as well I probably would leave the muffler alone as is.

With a down pipe and OEM muffler with valve open 100% the car really sounds amazing, I cant stress that enough. If you dont plan a down pipe I would probably do the mod.

[Mywifes335]

Originally Posted by dd1981

The highlighted part. Its not expensive to do.

You're right, but only if you do some of the heavy lifting with the cutting and welding the holes right?

[Mywifes335]

Originally Posted by dd1981

Also, knowing what I know now, and having modded my 2nd F30 and with how far JB4 has come with can flap and opening and closing the valve when I want now via JB4 with the added down Pipe as well I probably would leave the muffler alone as is.

With a down pipe and OEM muffler with valve open 100% the car really sounds amazing, I cant stress that enough. If you dont plan a down pipe I would probably do the mod.

Loudness is subjective sometimes. I run a bypass once the 2nd flap opens as well as a catless downpipe. Otherwise it still retains the stock rear muffler and rest of the exhaust. Although it's a bit louder and the overrun is more exaggerated, I still think around town it's kinda quiet. I think the next step is to just remove the muffler altogether, but I'm afraid of drone.

[Jadar]

Originally Posted by Mywifes335

Loudness is subjective sometimes. I run a bypass once the 2nd flap opens as well as a catless downpipe. Otherwise it still retains the stock rear muffler and rest of the exhaust. Although it's a bit louder and the overrun is more exaggerated, I still think around town it's kinda quiet. I think the next step is to just remove the muffler altogether, but I'm afraid of drone.

It's sounds very good without the muffler, but same reason I avoided it, the drone. I get a bit of drone now with the down pipe but nothing even close to annoying.

I'd stick with your plan, open it up and have them replace the tubes. Maybe it won't be too expensive to to a custom oval tune is chamber 1. The sound sure intoxicating and worth it to me.

[Mywifes335]

Originally Posted by dd1981

It's sounds very good without the muffler, but same reason I avoided it, the drone. I get a bit of drone now with the down pipe but nothing even close to annoying.

I'd stick with your plan, open it up and have them replace the tubes. Maybe it won't be too expensive to to a custom oval tune is chamber 1. The sound sure intoxicating and worth it to me.

So basically the stock can and chambers is enough to combat the drone?

[Jadar]

Originally Posted by Mywifes335

So basically the stock can and chambers is enough to combat the drone?

With a stock downpipe yes, it won't be a huge difference inside the cabin.

[Mywifes335]

What about catless downpipe?

[Mr_White]

Just had my muffler modded by welding the perforated holes in the two outside chambers. It was a good cheap mod, and the exhaust note sounds excellent. I would say only 25% louder outside of the car, and barely any noticeable difference with the windows up. Absolutely no drone whatsoever at any RPM.I'm still finding it too quiet, so I will do a resonator delete + downpipe + Enzo tune.

[Drpoomanchu]

Originally Posted by Mr_White

I will do a resonator delete + downpipe + Enzo tune.

Good choice