[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
4000sq exh. thanks
A few weeks ago when I was even more of a newbie on this list, I
posted a question regarding exhaust mods for an 85 4ksq. One of the
questions I asked was: Will the rear muffler from the TQC work as the
only difference appears to be pipe diameter?
Another question was: If the center muffler is omitted and only the
rear muffler and cat are used, will there be sufficient back pressure
as to have decent bottom end power?
I received many different replys. Some yes, some no, etc.........
Now that I have finally finished the exhaust,I would like to post my
findings on this subject.
First, those of us who thought the rear muffler from the TQC would
drop right in the 4000 were wrong.
The only major difference between the two mufflers is that the muffler
for the coupe, (which in this case is an ASNA) has 2 outlet tubes
where the muffler for the sedan has one outlet that splits into 2
tips. The 2 outlets are also nearly center on the cpe., where the sdn.
has them way off to the driver side.
Since the body of the muffler for the cpe. fits perfectly in the
hangers on the sdn., I hung it in the car and proceded to re-bend the
outlet tubes to clear both the floor pan where the spare sits and
clear the valance on the left. Also, where the factory rear meets the
center has a slightly different angle on the cpe. than the sdn. That
was put in the pipe bender as well. (very small adjustment here)
That was the most difficult part of the install.
The cat I used was a new unit designated for a TQC. The differences
here are that the cat on the turbo does NOT have an O2 sensor port in
it and the cat for the non-turbo does. Also, the cat for the turbo has
a small plate IN the front of it which would not allow the sensor port
from the defective cat to be put here. So I put it in the end of the
What supprised me the most here is that the two converters have the
EXACT same internal diameter. Both at inlet and outlet. But, the pipe
that meets the cat on the 4000 has an end that is flanged to a
diameter that is larger than the rest of the pipe.
From here, all that was left was to bend a pipe to fit between the two
The result, the car now has a complete 2& 1/2" exhaust that flows much
better with only a slight increase in loudness. Also, I don't think
that I lost much, if any bottom end. Must be all the bends around the
drivetrain provide enough back pressure.
Now I'm all set exh. wise when I do the turbo!
p.s. I'm sorry about length of the post, but I thought someone may
find this info usefull.