'04 Liberty

[Shane White]

Has anyone noticed how the Liberty has dual exhaust outlets but only a
single exhaust pipe from the engine to the rear? This seems as though
the dual exhausts are for vanity reasons only.... Can anyone provide a
functional reason?

Shane.

 

[H. Whelply]

I think that's true for many (most?) cars that have dual exhaust, though I'm
reflecting only on my now-departed '99 Honda Acord V6. Reason? I'd guess
it's cheaper than running real dual exhaust.

HW

 

[Stu Hedith]

I would imagine it's to reduce the backpressure of one muffler.

Stu

 

[CW]

On the great majority of cars, it's for show only. Kind of sucks when
they ultimately rust out and both become liabilities.

CW

 

[C Bell]

I would imagine it's to reduce the backpressure of one muffler.

Stu

Two mufflers will have more backpressure than one....
No, there are no practical reasons for running this dual-tip system. It's
purely for vanity reasons, as the original poster said.

Cam

 

[Gerard]

From what I gather the dual exhaust system was to increase ground clearance
under the middle. The mufflers in the new Outback are no longer the lowest
part.

Gerard...

 

[Forg]

Two mufflers will have more backpressure
than one....
No, there are no practical reasons for running
this dual-tip system. It's purely for vanity
reasons, as the original poster said.

....

There _could_ be practicality behind it, although I doubt it
.... the AE82 Corolla Seca Twin Cam had dual tips when the
Hatch had a single; Toyota claimed the duals were a little
bit quieter, which ws why the Seca had them. The Seca was a
bit quieter, but then it was a coupla inches longer; which
could've made that amount of difference.

I reckon Subaru would advertise if they were using the
block-one-exit system that BMW were using (dunno if they
still do).


-Forg

 

[Charlie]

Has anyone noticed how the Liberty has dual exhaust outlets but only a
single exhaust pipe from the engine to the rear? This seems as though
the dual exhausts are for vanity reasons only.... Can anyone provide a
functional reason?

on my rx7 it looks like they've done it so they can fit more emissions /
muffling gear in!

Charlie

 

[C Bell]

There _could_ be practicality behind it, although I doubt it
... the AE82 Corolla Seca Twin Cam had dual tips when the
Hatch had a single; Toyota claimed the duals were a little
bit quieter, which ws why the Seca had them. The Seca was a
bit quieter, but then it was a coupla inches longer; which
could've made that amount of difference.

I reckon Subaru would advertise if they were using the
block-one-exit system that BMW were using (dunno if they
still do).


-Forg

True, good points. What is this BMW system you speak of? I could find out...

Cam

 

[Richard Fay]

True, good points. What is this BMW system you speak of? I could find out...

Cam

The 6 cylinder BMWS (mainly 3 series) have a flap in one of the exhaust pipe
exits that remains shut at low engine speed to reduce exhaust noise. It is
opened at higher engine speeds to reduce back pressure.

 

[Stu Hedith]

Two mufflers will have more backpressure than one....
No, there are no practical reasons for running this dual-tip system. It's
purely for vanity reasons, as the original poster said.

Cam

That makes no sense. If you have a fixed volume of air leaving through
a restriction, and you double the size of the restriction, you
essentially halve the backpressure created by the restriction. If
you've ever designed an irrigation system, the priciples are similar.
Suppose you have one sprinkler head on a line that sprays a diameter of
30 feet (diameter is directly related to water pressure = backpressure).
Add a second head and they still likely go almost 30 feet since the
water supply should be able to maintain the back pressure. At some
point, the number of heads will allow enough water out to exceed the
water supply's capacity. and the back pressure will be less and the
heads will no longer spray 30'. Now on a car the supply air is fixed so
as soon as you add a second muffler, there will be a reduction in
backpressure, assuming the mufflers are all of the same design and
exhaust pipes are the same diameter.

Stu