4000sq exh. thanks

["Todd Candey" <tcandey@usr.com>]

        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 
     down pipe.
        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 
     ends.
     
     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.
     
     ToddC.
     tcandey@usr.com