Question for MRTv2 owners who had Hemholtz Resonators (J-pipes) installed.

[Marklar]

Did you have to do anything special to get your j-pipes to fit? My car is currently at the shop getting my Axle-back welded on and quad tips added. The technician said there's no way he could fit 29" of pipe under my car without serious modification.

I followed this guy's build thread to come to 29", even did my own frequency measurement to confirm 120Hz is the problem area.

https://www.camaro5.com/forums/showt...=182467&page=4

I showed the tech the pictures, but still he said the best he can do is 8". Which if you understand how Helmholtz resonators work, you'll know that won't work. He said if they had a mandrel bender they may be able to custom make a pipe, but even then it would be expensive.

I'm honestly shocked. This exhaust shop has a good reputation in the area and was recommended to me by my local Camaro club owner. I'm at a loss if this place is refusing to do this seemingly-straight-forward weld job. All I feel like I can do now is ask around for to see if any shops have a mandrel bender.

[Rahnok]

I don’t really see the need for J-pipes. The drone isn’t that bad anyways and from what I’ve read, a Magnaflow X-pipe will fix it.

[Marklar]

Originally Posted by Rahnok

I don’t really see the need for J-pipes. The drone isn’t that bad anyways and from what I’ve read, a Magnaflow X-pipe will fix it.

Thanks for your opinion, but that doesn't really answer my question.

[DSX_Camaro]

Originally Posted by Marklar

Did you have to do anything special to get your j-pipes to fit? My car is currently at the shop getting my Axle-back welded on and quad tips added. The technician said there's no way he could fit 29" of pipe under my car without serious modification.

I followed this guy's build thread to come to 29", even did my own frequency measurement to confirm 120Hz is the problem area.

https://www.camaro5.com/forums/showt...=182467&page=4

I showed the tech the pictures, but still he said the best he can do is 8". Which if you understand how Hemholtz resonators work, you'll know that won't work. He said if they had a mandrel bender they may be able to custom make a pipe, but even then it would be expensive.

I'm honestly shocked. This exhaust shop has a good reputation in the area and was recommended to me by my local Camaro club owner. I'm at a loss if this place is refusing to do this seemingly-straight-forward weld job. All I feel like I can do now is ask around for to see if any shops have a mandrel bender.

Bold part. Yes. It has to (or should) be mandrel bent. You cut a hole in the pipe before the mufflers and snake the tube around the muffler and up parallel with the mufflers and then up behind the diffuser. You can use Solo's pictures as a reference for what I'm talking about, but there's multiple ways to get it done, design doesn't matter, pipe length does. I'm guessing you knew that though, so yes, you need to go elsewhere.


I kinda can't believe they can't bend pipe like that. On that topic, I really don't have a comment. I'd think any exhaust shop with any kind of reputation would have a mandrel bender. Since you're in Ohio obviously I can't help location wise, but definitely start calling around. Any shop with a mandrel bender can get it done, certainly isn't hard.

[Marklar]

Originally Posted by DSX_Camaro

design doesn't matter, pipe length does. I'm guessing you knew that though, so yes, you need to go elsewhere.

Yup. That is why I told the shop to not bother with it when they suggested 8" pipes instead. I was surprised even by that comment. 8" will not work for what I need. I feel like they should know how Helmholtz resonators work given how common they are now. I see them on off-the-shelf cat-back systems for all sorts of cars now. Both techs said they hadn't heard of "Helmholtz" or "J-pipe" before. Said they always called them "drone cones".

Originally Posted by DSX_Camaro

I kinda can't believe they can't bend pipe like that. On that topic, I really don't have a comment. I'd think any exhaust shop with any kind of reputation would have a mandrel bender. Since you're in Ohio obviously I can't help location wise, but definitely start calling around. Any shop with a mandrel bender can get it done, certainly isn't hard.

Do they even really need a mandrel bender? The guy from the thread I linked above said he bought stock pipe from E-Bay. I'm honestly incredulous that this shop is refusing to do this work. I'm looking around for new shops now.

[DSX_Camaro]

Strictly speaking, mandrel is "correct", and I personally don't know of another way to bend pipe with a machine. You can do it by hand with heat and what not, but mandrel bending is the only way that I know of to not crimp / kink the exhaust. However, on topic, yes, you could buy stock pipe and cut it to what you need / weld the portions together and then when you weld the portions up around the mufflers maybe tack a small steel rod (like the exhaust hanger rods) to the j pipe and the muffler pipe to keep it a solid unit.


I can't lie, not having a mandrel bender, not knowing what J pipes are. This is all weird to me. I've been through a few exhaust shops, some of them good with their hands and some more upkept and professional, but I literally thought everyone knew what J pipes were. Lol.


Maybe the shop you went to has stock sections of pipe and doesn't want to chop them up is all? Like maybe they don't have 90 degree bends pre made? I just don't know.

[Marklar]

Originally Posted by DSX_Camaro

This is all weird to me. I've been through a few exhaust shops, some of them good with their hands and some more upkept and professional, but I literally thought everyone knew what J pipes were. Lol.
Maybe the shop you went to has stock sections of pipe and doesn't want to chop them up is all? Like maybe they don't have 90 degree bends pre made? I just don't know.

Sounds like you're as flabbergasted as I am lol

[1LEJNG]

I had my exhaust guy make and weld on a set. Lots of room behind the diffuser. Its not rocket science, mandrel bends are not important as no exhaust flows through the J

[DSX_Camaro]

Yo. Did you ever get this worked out?

[Marklar]

Originally Posted by DSX_Camaro

Yo. Did you ever get this worked out?

I did not. I just told them to go ahead with the install without the J-pipes. I haven't talked with any other shops yet.