Which is better: welded on exhaust system by muffler shop or bolt on kit system to replace factory system?

Thanks

 

Well, the bolt on kit will not require any special tools to install and can be removed later, but the bolts rust, the flanges sometimes aren't stainless either. Depending on your year, sometimes bolt on means clamp on. Welds can rust too, but welds don't tend to trap water.

Most bolt on kits tend to be pretty expensive. You can often get a complete system bent up by a shop for less than a bolt on kit runs. And some bolt on kits are not as bolt on as you might think. If there is a hanger that changes location, or a pipe that has a slightly different bend, then a pro is required to fix the problem. Just because its a well known brand name doesn't mean that it will fit perfectly either.

On the plus side, the bolt on kits are usually mandrel formed, which does look nicer, and in theory flows better. The actual difference between crush bends and mandrel bends is ignorable on a street vehicle however.

So just a quick summary

Bolt on kits
Pros:
often stainless steel pipe
can be installed by a DIYer
often mandrel formed
muffler and tips are often included
can swap back to the stock setup relatively easily

Cons:
expensive
non always perfect fit
flanges or slip joints can sometimes rust
bolts can rust
expensive to ship
Muffler and tip choices are limited by brand
when an imperfect fit does occur, the kit must often be installed by a pro

Custom made system
Pros:
Low cost
local shop stands behind their work
perfect fit
can supply any muffler and tip combination
can make custom variations
can use any desired pipe size
pros can install flanges or slip joints that can be disassembled

Cons
usually aluminized pipe
few shops have mandrel benders
welds can be difficult to remove or alter once the system is assembled
harder to restore back to stock unless special care is made to that end

 

Thanks for the complete info. I bought a set of Doug Thorley headers and a Heartthrob cat back for my '91 F250, 460, 4x4...pretty nice stuff. I thought that the Heartthrob kit, properly installed, may be more durable and maintainable.

Thanks

Bob

 

I use stanless U-bolt style clamps from jegs and Summit for the connections I can't tig weld easy or on the mufflers.(They sometimes go bad) A tack or two on the clamped connection helps to insure they stay in place. I usually like the converter inputs and outputs welded though. The thing I like a lot about the cat-back kits you buy is the mandrel bent tubing and the design is usually checked on a dyno.