• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Anything wrong with flexible exhaust pipe?

H

HenryKrinkle

NAXJA Forum User
Location
WI
I'm doing my exhaust manifold and would like to use a section of flexible exhaust pipe to connect the downpipe to my cat. Do these things leak excessively? It would be pretty protected down there, so getting smashed up shouldn't be an issue. Anyone see anything wrong with using the 2 feet or whatever of pipe and just using those u-bolt clamps to secure it?
Thanks for any help...
 
It'll work but when the exhaust starts getting old you'll know which section will start leaking first.
 
I don't see as you'd need two feet of the stuff - when I get my refit going, I'm going to have a six-inch or so section put in the downpipe on my 88.

"Restriction" in the typical spiral flex pipe is largely caused by internal turbulence - the longer them section of pipe, the more "restrictive" it will be. You don't need much to have the desired effect (the typical desired effect being cheap insurance against exhaust manifold collector failure shortly after engine mount failure...)
 
5-90 said:
I don't see as you'd need two feet of the stuff - when I get my refit going, I'm going to have a six-inch or so section put in the downpipe on my 88.

"Restriction" in the typical spiral flex pipe is largely caused by internal turbulence - the longer them section of pipe, the more "restrictive" it will be. You don't need much to have the desired effect (the typical desired effect being cheap insurance against exhaust manifold collector failure shortly after engine mount failure...)
Click to expand...


I will have a gap from just after the downpipe becomes parallel to the ground all the way to the front of the cat. I hadn't thought of the restriction aspect- that's something to consider. Would it matter if I ran a high-flow cat and muffler? I'm thinking not because the flow would be bottlenecked ahead of them...
 
HenryKrinkle said:
I will have a gap from just after the downpipe becomes parallel to the ground all the way to the front of the cat. I hadn't thought of the restriction aspect- that's something to consider. Would it matter if I ran a high-flow cat and muffler? I'm thinking not because the flow would be bottlenecked ahead of them...
Click to expand...

You are correct - it wouldn't matter. The "restriction" (the material isn't restricting the flow, but the configuration has a restrictive effect) is going to be upstream of the cat and muffler. Doesn't matter what they do, provided they don't add further to the restriction.
 
I have a short section before my cat. I got it so if I hit the pipe it can flex rather than mess up seals. But it's straight not bent
dpgright.jpg
 
winkosmosis said:
I have a short section before my cat. I got it so if I hit the pipe it can flex rather than mess up seals. But it's straight not bent
dpgright.jpg
Click to expand...

I could be wrong but I do not think this is the type of flex pipe he is talking about....I do not see anything wrong with that at all....I think he is talking the cheap bendable spiral stuff that you buy by the foot. Which I would avoid and go with something like this or what Joe linked to.

Tory
 
outkast7222 said:
I could be wrong but I do not think this is the type of flex pipe he is talking about....I do not see anything wrong with that at all....I think he is talking the cheap bendable spiral stuff that you buy by the foot. Which I would avoid and go with something like this or what Joe linked to.

Tory
Click to expand...

That is the same thing I linked to, and what I used.

I would avoid the "by the foot" crap, however my experience with that stuff it was all supposed to be galvanized and it was the first thing to rust out.
 
You must log in or register to reply here.

Similar threads

X
Redoing my entire Exhaust
Replies
7
Views
4K
XJEEPER
XJEEPER
L
1994 XJ 4.0 exhaust down pipe size/flange?
Replies
3
Views
2K
Lordhelemt
L
X
Help me my Obi Wan Kenobi's
2 3
Replies
47
Views
13K
75SV1
7
K
TUPY head on 01 Cherokee
Replies
11
Views
3K
75SV1
7
M
2000-01 Exhaust Header on a 99'
2
Replies
22
Views
4K
75SV1
7
Back
Top