[Diy_efi] Re: Can constant WOT operation destroy a muffler?
Andy Harvilla
higrafey
Thu Jun 15 14:49:33 UTC 2006
Those are some good exhaust mounting tips. It's true the exhaust
systems on these Jeeps aren't set up very well. The cat and muffler
are within six inches of each other, there being a support at the cat
(into the transmission mount) and one behind the muffler on the
body. Even so, I'm not sure if it's really a lack of suitable
mounting that's causing the mufflers to blow out (the motor mounts
are pretty new, too). Here's a picture I took this morning showing
how the metal is degrading. The silvery band along the center is
usually first to deform; the arrow shows where it typically develops
a crack. The pipe ends never give me trouble, only the metal
underside of the muffler. In another month I'll be ready to replace
this one again (good thing for lifetime warranties!).
http://www.pitt.edu/~ajh32/etc/yjmuffler.jpg
This being an off-road vehicle and all, sloshing through the mud and
muck isn't good for the exhaust... especially water, which cools down
the metal relatively quickly. However, the four-wheeling in my area
has all but dried up in the past year and I haven't been out in quite
sometime.
Depending on the situation, I see a wide range of rpm at full pedal.
Driving up a steep hill, I'd usually be in third gear and turning
maybe 3000-3500 rpm. Highway driving at 65 mph is around 2500 rpm in
fifth, but most often I'm using fourth gear (3000 rpm) because
there's not enough power. I've already regeared from 4.10's to
4.56's (what a difference!). On-road driving is the only power issue
I have with the Jeep. Off-road, there's more than enough juice to
get around due to all of the gearing.
Again, I've only started having this problem after I installed a
converter. The original muffler lasted 65,000 miles with a hollowed
cat, but I'm on my fourth muffler only 30,000 miles later. Just
kinda seems weird. I'm wondering if it's possible for a cat to heat
up enough to damage a muffler... or maybe if prolonged high
temperatures (aggravated by a cat) can kill it. Assuming I'm
entering WOT mode, of course.
Andy
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