I may be alone in this, but I really despise the stock exhaust
system setup on the Austin Healey. Especially on a BJ8. The
factory exhaust exit location looks like a serious afterthought, and the
additional resonators completely ruin the sound. Not to mention the tiny
size of the pipe at the exit, progressively getting smaller from the
1-3/4" at the front. I wanted to do something about this... but didn't
want to spend a whole lot of money :)
I looked around at some of the aftermarket exhaust
systems out there, but really didn't like what I saw. They all
seemed to keep the same lousy tailpipe outlet configuration, and there'd be other
problems getting some of the non-resonator models to fit on a BJ8.
And there was no way I was going to spend nearly a thousand bucks buying
a whole new system, or more if doing something custom. So....
The stock system that was on my car was a bit old,
but was still in pretty decent shape. So I figured it wouldn't
cause me a whole lot of heartburn if I completely ruined it. So
off I went, hacking away!! I'm calling it a MacGyver'd exhaust
system because it ended up being a pretty major "rig job", but managed
to work beautifully, and looks pretty cool as well. And it was
cheap, too! All totaled, including new flex sections that didn't
really have anything to do with the "custom" part, I ended up spending
around $120. Here's the ingredients I started with...
-
My original stock style BJ8 exhaust system (with
all the standard brackets).
-
Some new exhaust-to-manifold gaskets.
-
QTY 4 - 20° bend elbows, 1-3/4" ID-OD, Walker P/N
41814.
-
QTY 2 - 90° bend elbows, 1-3/4" ID-OD, Walker P/N
41000.
-
QTY 2 - 1-3/4" flex pipe (stainless bellows
wrapped in stainless braid),
universal 12" overall length, 8" flex portion, Walker P/N 41452.
-
A couple pieces of straight pipe section, 1-3/4"
ID-OD.
-
Some thin stainless steel flat stock to make some small
angle brackets from.
-
Several 1-3/4" exhaust clamps (for temporary
fitment prior to welding).
Here's the basic layout showing what I did....
My original flex sections were leaking pretty bad,
especially at the connection to the mufflers, so that's why I replaced
those here as well. The new sections I bought I think are way
better than original, with a stainless inner bellows wrapped in a
stainless braid. I decided to weld up both ends of the flex
section - as well as every joint in the system - to insure I was (and
would remain) free from leaks. I'm afraid I didn't take too many
photos during the build process, but here's a few as I was getting
started, doing the flex sections...
Building the exhaust system simply involved various
iterations of measuring, cutting, marking and test fitting, essentially
following my diagram above. I used exhaust clamps to hold the
joints firmly together as I moved from front to back, enabling me to
take the system back off the car without loosing position or orientation
in order to do the welding. Once welding was done, all the clamps
were then removed. I used an angle grinder to clean up some of the
welds (though there are still a few ugly ones that I didn't bother
with... I'm not a very good welder), and then actually pressurized the
whole exhaust system to search for leaks. I did this by capping
off the flange end, and pressuring through the outlet with about 10 psig
through a hole in a rubber stopper that I jammed into the pipe.
Once under pressure, I just listened and used water to find the big
leaks, and re-weld as needed. There were still several super-tiny
leaks in some of the weld areas that I didn't bother with, because those
would quickly close up once exhaust gases and moisture started flowing
through the system.
FYI... those 20° elbows actually weren't quite at
20°... either that, or 20° just wasn't quite right... because I ended up
have to "massage" them quite a bit in order to tuck the pipes up close
to the body and bumper like I wanted. My massaging ended up
ovaling the pipes pretty good, but that actually worked out even better,
and gave the exhaust outlets a cool slightly oval shape.
All of the original mounting brackets remained in
place, except for the brackets that formerly held the resonators at the
rear. They weren't in a position where I could use them, so I
removed them (leaving the bolts in place, capped off, in case I ever
wanted to change things in the future).
I therefore needed some type of mounting support for
the pipes at the rear of the system. Well, I didn't necessarily
"need" additional mounts, because once every joint was welded the system
was extremely rigid, but I opted to add them anyway just for piece of
mind. I oriented the exhaust outlets on each side of the license
plate strategically positioned right next to the bolts that stick out
through the floor from the gas tank straps. I bought aftermarket
straps for my tank, and the bolts were really long, so I had a good 5/8"
or more of thread sticking down. Using this as my mounting point,
I made some simple angle brackets that I welded to the exhaust pipes,
and drilled a hole in the other side to fit over the end of the gas tank
strap bolt. I installed some rubber washers first (two on each
side) to minimize vibration, then the bracket went on, then a
self-locking nut... and you can see here....
Once the exhaust was all welded up and I made the
welds as pretty as they were going to get, I then had to figure out
painting. I didn't want the tailpipe sections black, since they
run up the back of the body, but didn't want the underneath portion of
the system to be silver either, since that makes it stand out more.
So I simply did both... I used some VHT high heat black up front, before
the mufflers... then from the mufflers back to the sections that come
out from under the car I just used Krylon Rust-Tough semi-flat black...
then for the portion that stuck out the back, I painted it with
Duplicolor silver caliper paint (which works extremely well on exhaust
systems). Yeah, I know, I could have done a better job with the
paint division between the silver and black, but you can't really notice
it unless you crawl under the car to look at it. From the outside,
it ended up looking pretty good.
And lastly, here it is with chrome tips added to give it a nice finish....
All in all, I am EXTREMELY pleased with how this
turned out. I think having tailpipes exit in this manner is a
really great look on a Healey. Oh, and the SOUND!!! It
sounds really amazing now... partly from removing the rear resonators... partly from maintaining the 1-3/4" size all the way out the back...
and partly from the tailpipe exits being further apart, giving it more
of a "stereo" sound.
It has a really full, rich sound now that was simply absent before, at a
really nice "classic sports car" volume (sounding especially
awesome when you get in the pedal a bit!).
I've uploaded a video to YouTube now (mainly
to show off the brake light mod),
but you can hear the sound as well....
check it out here!
If anyone has any questions about any of this, feel free to
send me an email!
