I removed the rear resonators and first replaced them with Monza
dual chrome tips. Shown here, they are detailed with white paint
inside the tips for show--a nice display touch, but for obvious
reasons, not practical for day-to-day use.
However, over two years of year round driving, these beautiful tips
rusted out.
Here is a picture of the muffler shop
welding on the new Ansa tips, but I am
getting a little ahead of myself. In addition to replacing these rusted tips,
I wanted to increase the
bore of the stock 1 7/8" pipes to as large as was practical. And, although
the stock 11+ year old factory Jaguar mufflers seemed to be holding up OK,
it seemed practical to augment the new pipes to a 'high performance' muffler.
(See other steps below)
Exhaust--Step 2
Modification:
Removed the front resonators with straight pipe.
Effect:
Added about 10 more Horsepower. Increased the exhaust note
to a purring rumble that plays musically, especially as the RPMs are incresed.
This is a very worthwhile mod for any XJS Owner looking for a cheap
way to grab some free Horsepower. Plus, you'll like the sportier sounding
exhaust note.
Exhaust--Step 3
Modification:
I replaced entire exhaust system from the catalytic converters back
with 2 1/4" stainless steel and
installed a Flowmaster 'performance' muffler.
Effect:
Increased Horsepower by about 10 HP, but kept
the exhaust note at about the same level.
Due to the clearance between a chassis rail and the automatic transmission,
the maximum diameter pipe that can be put into an XJ-S (assuming the pipes are
placed in the same location as the original pipes) is 2 1/4". A 2 1/2"
pipe was too big and presented some potential clearance/banging problems.
As you can see from these photographs, the factory stock exhaust is an over-axle
design, but in taking this to my local muffler shop, they immediately
suggested a 'Corvette style' under differential approach. So far, I have had
zero problems with ground clearance, and I like the looks of the new system
better.
I also had a Flowmaster Muffler
installed with the new tubing. It is hard to say what came first, as the
saying goes, the chicken or the egg. Are the differences in exhaust note
due to the muffler or new tips? Perhaps both. Here is what I've perceived
so far.
The new system has a very pleaseing backpressure popping when letting
off the throttle, and especially when down shifting and engine breaking--
the last incarnation with the stock muffler and Monza tips didn't do that.
The Monzas had a 'boomier' sounding exhaust note with some un-even
sonic hot spots as you ascended the rev range. However, the new Ansa tips are
a bit sharper in sound, and have a consistant sound throughout the
entire rev range. I like the sound of the Ansa over Monza, but I think
I like the tucked in, closer together look of the Monzas as opposed to the
more splayed out Ansa tips. Also, because of their width, they had to be mounted
farther out from the body. Which one do you prefer?
Regardless of the new tips, the car is still realtively very quiet. I wanted the
car to remain 'Jaguaresque' and not sound like a rumbling big block
Mustang with headers. I've achieved this goal, and so can you if you
follow the above steps.
Effect:
Increase Horsepower by an additional 15-30.
Add a more agressive exhaust note.
