Hi All,
I've only been a member for a short while though I've had
my '00 5 spd for over three years now. I have tried
various changes to the vehicle to improve it. Some helped,
some bombed and I changed them back. I guess this will
be my first posted mod to contribute to this knowledgeable
and enlightened group that I have the good fortune to be
a member of. This mod does work. Many thanks and
acknowledgment to cakley for his original thought and
inspiration. All I've done is to glean more info and take
it a step further. All suggestions for improvements from
my fellow members are to be looked forward to. Happy
to be part of the team. Oh well, here goes:
Did a modified cakley muffler mod to the '04 inside the
muffler. Wanted to do it in a way your average driveway tech
could do it without a welder and do it on the car. If your
going to do it you probly will want to clean the muffler (I
used brillo pad and soapy water. Then sand or file the area
your going to work on(easier done before). Took a while
since I had to cut the muffler wide open so we could get pics
of everything in there. I need to find a way to post them. As
the pics are over 1 mb each I'll try to find a photo album
sight (or other) where I can post them and link to, help
appreciated. Till then I'll post another message explaining as
best I can what's actually in there. I had the good fortune to
meet Willie(Little Red Rocket) at the time I decided to do the
mod. His advice was the best. If you want improvement you
have to take a chance and initiate change. So, if it doesn't
work I'm out 180 bucks for a new exhaust. Fortunately it has
improved mpg somewhat and testing is ongoing. There
are three chambers in the muff. The mod only needs to be
done in the third or rear chamber so work is minimized.
Basically, the tail pipe goes into the muff and continues on
to the first chamber. By observing where the tail pipe
enters the muff you can cut a three sided "square"
hole on the drivers side of the muff(I used a handheld 4"
grinder w/1/16" cutting blade). Two vertical cuts. One 3/4"
in from the rear surface (Note: rear surface is indented)
of the muff and 3" long. Second like the
first but 4" in from the rear surface. Third cut to connect the
first two at the top(creates a door). Bend the door down so you
can see and get to the tail pipe inside the muff. Make two
vertical cuts in the tailpipe 2" apart and remove the cut out
pipe(I used a Keyhole saw to make these cuts, Ace Hardware).
EDIT: 7/5/4 While in the muff would also cut the small end off
the restrictor. Checked before I closed it up and you can reach it
with the keyhole saw. WHY: When I mod'd the '04 I went into
the other side of the muff(pics) so had to mod a little different.
To reproduce mod as suggested here for ease and simplicity
had to come up with approximating same relief for other side
of muff. Testing so far is showing more relief may be necessary.
If youv'e already done the mod you can get to the restrictor
thru the opening suggested for the second tail pipe which will be
installed away from the exhaust in for less effect on reverse pulses.
DETAILS for second tail pipe worked out. It will be fully adjustable
for exhaust flow and relatively simple to reproduce. Since removing
the rear bumper or dropping the exhaust may be needed, those of
you interested may want to wait before cutting as much more
testing is needed. The Good Side: It does work. The mpg #'s so far
are heartening. Honda engineering made a high quality and fairly
elaborate muf(tuned, but restrictive, thanks Cakley).
As is obvious here and is unfortunate for engineers everywhere
at times, Marketing had a hand in developing this muff.
To close it back up I bent the door closed, used a few 1/8"
pop rivets to hold it in place. At Willie's recommendation used
J.B. Weld(Ace again) to seal it shut. This stuff drips like
crazy but Willie helped me again. After mixing let it sit for about
30 or 40 minutes till it JUST Starts to get pasty. I used a hair
dryer to speed the process. Then used the dryer on the muff
to speed curing. Let the car sit for at least a day before running
motor. Run motor to final cure J.B. and check for leaks. I had
none. You can lightly sand and add more J.B. as needed.
Important, before you start the muff mod. Drill a water drain
hole in the FRONT surface of the muff at the bottom(low point).
I used a 5/64 titanium bit(Ace again). This muff gets ALOT of
H2O in it. If you don't care to leave the hole you can always
stick a screw in it afterwards. I like the hole(lots h2o comes out).
After all done ran motor to heat muff and sprayed it with black
Rustoleum barbeque paint(that Ace place again), looks OK.
Tentative results from testing. Moderate improvement in
acceleration(results appear to be a bit different than cakleys).
Improved highway mpg. Lean burn at higher speed(for me).
Cut off point seems to be between 72 & 73 actual mph (w/out tail
wind or drafting although head wind will slow you down
of course). By actual mph I mean checked against my gps. If the
speedometer says 70 my gps tells me I'm doing just over 71. I've
heard with some insights it's the other way round but the gps
seems to be working OK. I'll let you know more as I learn more.
Testing is tuff around here on turnpike. One minute your free and
clear and the next your surrounded by cars and you can throw
the test out the window. I did go ahead(since the noticeable
improvement) and do the mod to the '00 as prescribed
above for her next owner. There are 3 pics. I'll try to post as
previously stated. Please let me know what you think & if I may
have missed anything.
Thanks, Jack Lee
Jack.mpgtech@verizon.net
P.S. Did the cakley throttle cable mod to the '04, you can dial
in the mpg you want and rest your foot. Don't have any good
results yet on it's effect w/lean burn. Will post when I do.
Modified Cakley Muffler Mod, Edit 7/5/4
