Anyone need a (higher-end) 105 downpipe?

[jkeithw]

I met with my fabricator buddy/mentor today about the general quality of the 105 downpipe and the feasibility of modifying it to add O2 bungs and a cat. As a result, we're now jigging up to make a proper, repeatable, in-frame solution for the FZJs.

This is going to cost me some coin to set up, so if anyone is interested in getting in on it (to spread the pain, so to speak), I'm happy to make one for you as well. - I'm making two for our family FZJs, regardless.

These will be 304, tigged, v-bands on every section after the factory manifolds, a decent 2-1 collector (vs the 105), with Toyota-specific O2 bungs and separate cat & muffler sections - and will completely replace the portion of the exhaust between the stock manifolds and the stock post-muffler tailpipe section. (The cat and muffler sections will be serviceable for future-proofing.)

That's where I am at the moment (just committed to it today). As I test-fit the 105 pipe and measure component clearances, I welcome your opinions on available/existing cat & muffler options. I know some of you have more experience in these areas, and I'd like to hear your perspectives.

I don't want car-show noise or drone (although I don't mind a decent exhaust tone), but space is limited down there, so real-world experience is appreciated.

 

[Rusty Cruiser]

I love the idea and could possibly be interested sometime in the future but I replaced my entire exhaust from the manifold back earlier this year. I would love an option that doesn't cross the frame rail and would tuck up nice and tight for max ground clearance.

 

[Kernal]

Maybe run it by OTRAMM, he might have some insight as he made custom FZJ80 Stainless exhaust systems for awhile (not any more).
Then there was someone else maybe ?10 or so years ago that made a stainless system for the FZJ80 but it had a ton of issues IIRC

 

[lumbee1]

@jkeithw I don't mind crossing the frame rail as long as it goes up and over and not below. Inside the frame rail is certainly interesting but I worry about clearance and heat. There's some main engine harness connectors on the trans that will be right beside the exhaust.

My Cruiser is supercharged. Are you thinking 2.5" piping for this project?

 

[jkeithw]

@jkeithw I don't mind crossing the frame rail as long as it goes up and over and not below. Inside the frame rail is certainly interesting but I worry about clearance and heat. There's some main engine harness connectors on the trans that will be right beside the exhaust.

My Cruiser is supercharged. Are you thinking 2.5" piping for this project?

2.5, yes.

 

[Marvelicious]

@jkeithw I don't mind crossing the frame rail as long as it goes up and over and not below. Inside the frame rail is certainly interesting but I worry about clearance and heat. There's some main engine harness connectors on the trans that will be right beside the exhaust.

My Cruiser is supercharged. Are you thinking 2.5" piping for this project?

Get it ceramic coated. Problem solved.

Edit: also, I won't say I'm definitely on board, because I'm contemplating a motor swap, but I'd be at least curious. That exhaust needs to wind up in a different location one way or another.

 

[voodu3]

I thought about this too but I don’t have the resources to make one. I have the 105 down pipe and it was and is a challenge to get it installed. I’m still working on catalytic converter placement. I have 93 so it’s a bit easier with the upstream O2 sensors in the manifold. I had to modify my stock muffler pipe to get the down pipe to mate up. If I had to do it over again I’d get a shop to build a custom pipe. I’d be interested in a plug and play option if it included a cat. I haven’t noticed any more heat but that may change when the cat is installed.

 

[BlueCruiser84]

Is this still moving ahead? I literally just ordered a 105 downpipe and then saw this post. We’ll see if it gets processed and shipped.

I need a solution relatively “soon” as my current exhaust is a mess. I’m going to patch it up while I wait for the new downpipe, but would love to hear more about what you’ve got cooking.

 

[jkeithw]

Is this still moving ahead? I literally just ordered a 105 downpipe and then saw this post. We’ll see if it gets processed and shipped.

I need a solution relatively “soon” as my current exhaust is a mess. I’m going to patch it up while I wait for the new downpipe, but would love to hear more about what you’ve got cooking.

Yes, sir, but it's going to be a Q1 2026 project. Too much frontend investment for the holidays.

(plus, Julia wants her 80 back on the road, so I'll have to switch it out with mine to start jigging & measuring)