Truck Muffler Installation Questions

[edwardb]

Working around part issues and decided to get serious about the muffler installation on my truck build. The engine and trans are mocked into their final positions. So no reason not to get this all sorted out and ready to bolt in for good later during the build. I'm trying to use all the kit supplied parts per the manual. In doing so, three questions for you builders past this point:

1. After some work, I now have the supplied pipes coming off the LS headers and spacers to where the muffler height is (1) the same on both sides, and (2) approx. 1/2" from the underside of the floor. Does this sound about right? Don’t see how it can be any different with the parts provided plus any lower and would be lower than the frame. With the double floor and insulation between, plus whatever insulation I add in the cockpit plus carpet, seems it would be OK. But would like to confirm.

2. I’m not too happy about how the manual shows putting the last section inside the frame by the rear lower control arm mount. Requires a somewhat sharp angle off the ball joint and just not sure it’s necessary. Is there any reason the mufflers couldn’t be rotated and complete the last section from the other side? The inlet at the front is in the center. So doesn't matter on that side. Would be a straight shot and IMO a better setup. As shown in this picture. Would turn the muffler over and put the exit where the arrow is. Then through the frame and straight back.



3. Finally, the manual shows a muffler hangar on each side of the muffler body itself. (Which will require some mods not shown in the manual. But OK...) But then on the last page of instructions shows another one on the last section with the turndown. Seems like that would be necessary. The two pieces making up the last section aren’t light and don't think you'd want that much unsupported. But the kit only comes with 4 hangars. Not 6. Am I missing something? Maybe put only one on the engine side of the muffler and then another at the back as this page shows? What have you guys done?



Thanks in advance. Appreciate the feedback.

[House Money]

1) My mufflers are also about one inch from the floor. I ended up just using one hanger for the mufflers, at the rear. Seems rock solid.
2) I have my mufflers mounted as shown in your first picture. The pipes that mount to the rear have a pretty good jog in them to allow fairly straight connection to the mufflers.
3) I too only received 4 hangers. I purchased these for supporting the tail pipes: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
and I bolted the part of the un-used hangers with rubber bushings to the 1.5" tube running across the chassis right at the rear of the battery tray.DSC_0780.JPGDSC_0781.JPG

One thing to watch, I had a hard time fitting the parking brake cable bracket on the passenger side, you might want to mock that up before final attachment of the exhaust on that side.

Gary

[Robodent]

I used the supplied items from the kit once it’s bolted up it’s pretty much rock solid . Yes it’s a very tight fit to the floor and the location of the mufflers your sitting right on top of them. After talking with Erik T. I removed my exhaust system and wrapped it from the collectors back to the tailpipe. I have one of the early trucks and only one piece floor pans not two .
Rob

[edwardb]

Thanks for the feedback guys. Very helpful! I like those different hangars a lot.

[jmccrack]

Just finished my muffler system today. All went well. Used only the parts FFR supplied and the fit is rock solid. The only mod I made was to make 4 -1/2" Lg spacers to but under the bolt on the hanger that fits by the tranny support. This dropped the tranny down enough to get my fingers between the floor and the muffler. I have a new floor so it has the foam core but I still think I will wrap the muffler for heat retention.

IMG_1150.jpgIMG_1151.jpgIMG_1152.jpgIMG_1153.jpg

[jmccrack]

That should say dropped the muffler down.

[edwardb]

Just finished my muffler system today. All went well. Used only the parts FFR supplied and the fit is rock solid. The only mod I made was to make 4 -1/2" Lg spacers to but under the bolt on the hanger that fits by the tranny support. This dropped the tranny down enough to get my fingers between the floor and the muffler. I have a new floor so it has the foam core but I still think I will wrap the muffler for heat retention.

Nice. Thanks for sharing. Very helpful. Your pictures confirmed a couple things for me: (1) For my LS3 and the headers/downtubes that Factory Five supplied, my mufflers are further to the outside of the chassis. There's no way I can orient the mufflers with the exits on the outside and route the last tubes without hitting the LCA mounts. Yes the pipes jog but not enough. I've mocked it up with the exits on the inside and it fits fine. No downside to doing it that way that I can tell. Also because of the wider placement, the provided hangars don't reach anything solid to attach to around the transmission mount. Still studying that one. (2) I see you don't put the hangars where Factory Five showed. The front ones yes. But the back ones all the way at the back instead of the other side of the muffler. I just don't see the rationale of having a hangar on each side of the mufflers and then leaving the last two sections hanging in space. I like what you did and I'm planning to have hangars back there too and skip at least one of the muffler hangars. Maybe both. (3) I can just get my fingers around mine too. So that's about the same. I'm going to leave it as is for now. If there's a problem, I'm thinking I would add some reflective heat barrier material between the muffler and the floor. Several products available. Rather than wrapping the mufflers.

[VIRGIN MIKE]

Similar to what House Money did (post 2, this thread); welded ⅜ nut to diagonal frame member, for hanger mount, welded other end of hanger to exhaust tip. Surprisingly solid, was able to do pull-ups on pipe without issueex hanger.jpg No additional bracing needed