Exhaust Repair Question

[Whistler]

Have a question For the "real" mechanics here; neighbor has a Ford Expedition he managed to rip the exhaust pipe in half & asked if I'd weld it up for him. It's a bit mangled, needs to be trimmed back to square and sleeved so here's my question; should I sleeve it on the inside or the outside? Would the wall thickness of an inside sleeve impact the back pressure enough to affect performance?

Not a huge deal just helping a neighbor but it's as easy to do either way and want to do it right for him.

Thanks guys.

[clublights]

Not a " real" mech here but I'm assuming only a foot or two or even 3 foot of replacement pipe, the increase of back pressure ( by reducing inner diameter ) or the decrease ( by increaseing inner diameter ) mathmatically is so insignificant that there will be no to EXTREMELY minimal performance impact either way .

Assuming a 16th or so of an inch either direction .... I don't think performance would take hit till you got at least in to the 1/4 of an inch range

[spleify]

Would the wall thickness of an inside sleeve impact the back pressure enough to affect performance?

Not on a Ford Expedition....

Sleeve it however its easier, I would assume an inner sleeve will be easier

[ray1970]

I'd just wrap some old beer cans around that sucker and secure them with hose clamps.






(Seriously, it doesn't really matter how you do it. Personally, I would get a replacement piece from the parts store that is the same size that is expanded on both ends to slip over the existing pipe.)

[Mtn.man]

First off it's a FORD.

So just cut it off and let her roar.

Or go the beer can route.

[UncleDave]

Is this a single or dual exhaust system? If it is stock single side exhaust then unless the owner is very sensitive to performance he will not notice a difference. Me I have high flow systems on every vehicle I own, and can tell the difference. If you want to do it right, weld replacement pipe replacing everything downstream of the damaged area. The replacement sections are flared on one end to fit over the old pipe. That is his call though. BTW I was in the service side of the business for over a decade myself a master level tech, and grew up in the business.

[Whistler]

Single, stock 3" broken between the cat & muffler. He wants to patch it, guess by "right" I meant "better than a beer can" or flex

T'was mine I'd... what am I talking about I don't drive Fords!

Thanks for the replies one and all, about a 4" long internal sleeve welded solid is the route I think I'll take.

[UncleDave]

Sounds like the perfect time for a flowmaster upgrade to me!

[Cman]

Im a "real" mechanic been at it 40 years. Weld it up the easiest way it wont make any differance in performance.

[soldier-of-the-apocalypse]

Sleeve the outside