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    Catalytic convertors

    My cat's are original and probably clogged from what I can tell at this point. Could be something else, but it seems like it since this car lacks power until its at high speeds. I have a new dual exhaust system from the cats back, so I'm not going to replace the whole system. Still have to take the car through emissions, so I can't just cut them off. What would be a good option, this motor will stay stock and I don't want to do the HO conversion (except the intake/tb). Too much of a risk this year and I have other problems with the car to take care of first.

    1) Buy shorty headers, use the mustang catted h-pipe I have, and have someone fabricate it to work on my existing dual exhaust system.

    2) Buy new oem cataytic convertors and use the stock manifolds.

    3) High flow cataytic convertors with 90 Towncar mainfolds (if I can find either).

    The mustang h-pipe I got is used with around 80-90k on it, but I can also sell it for more than I paid for it. I don't know if it would weld easily to my current dual exhaust system, the lower flanges will have to be cut off for it to work.
    Current rides - 1991 Ford Thunderbird 3.8 v6 (gas saver/DD) - New Heads/Headgaskets with ARP studs, Air Silencer Delete, 70mm MAF, Plasti-dipped Matte Black with a Silver Metalflake Overlay, Muffler Delete, some LED's, 30.233 MPG for high MPG average!
    2006 Jeep Wrangler 4WD (fun vehicle/backup DD) - 4.0/6spd - too many mods to list.

    Associated Panthers:
    Father's 1994 Ford Crown Victoria - Stock, 45,000 miles.
    Sold in 2007 - 1987 Mercury Grand Marquis LS "Grandpa Special" 2 door.
    http://www.cardomain.com/ride/2128327

    #2
    Also, with the mustang h-pipe don't I still need a smog pump? I think it had the smog tubes on it the last time I looked at it. I'm really looking to ditch the smog pump since I'm fixing the AC soon.
    Current rides - 1991 Ford Thunderbird 3.8 v6 (gas saver/DD) - New Heads/Headgaskets with ARP studs, Air Silencer Delete, 70mm MAF, Plasti-dipped Matte Black with a Silver Metalflake Overlay, Muffler Delete, some LED's, 30.233 MPG for high MPG average!
    2006 Jeep Wrangler 4WD (fun vehicle/backup DD) - 4.0/6spd - too many mods to list.

    Associated Panthers:
    Father's 1994 Ford Crown Victoria - Stock, 45,000 miles.
    Sold in 2007 - 1987 Mercury Grand Marquis LS "Grandpa Special" 2 door.
    http://www.cardomain.com/ride/2128327

    Comment


      #3
      From my experince with bad cats, I had zero power from above 1500rpms, the opposite of what is happening to you. You might want to look into that.

      If you decide to replace the coverters, I think I'd find some shorty headers to go with your Mustang H-Pipe. If you are going to run cats, you'll need the smog to cool the cats and complete the chemical reactions going on inside to their fullest.

      There are some cats that run without the smog so I guess you could run them without the smog.

      You have several options here.
      1990 Country Squire - weekend cruiser, next project
      1988 Crown Vic LTD Wagon - waiting in the wings

      GMN Box Panther History
      Box Panther Horsepower and Torque Ratings
      Box Panther Production Numbers

      Comment


        #4
        It depends on the specific type of catalyst whether or not it needs air piped in. Usually the system will actually shut the airflow off once the engine is warm anyway, so its not critical. Its intendted to make the cats heat up faster by pumping air in them in order to burn off the junk in the exhaust. The catalysts only work once they're hot so warming them up faster means less pollution. A Mustang H wont bolt to your existing duals. You really wouldn't want it to anyway. The spacing is all wrong and ot would require some strange connector pipes to be made up in order to salvage the stock H pipe. I'd ditch it and just do S10 mid pipes and keep the tailpipes you have now.
        86 Lincoln Town Car (Galactica).
        5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

        91 Lincoln Mark VII LSC grandpa spec white and cranberry

        1984 Lincoln Continental TurboDiesel - rolls coal

        Originally posted by phayzer5
        I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

        Comment


          #5
          Sorry, I forgot to mention that I don't have an stock h-pipe on my car, it has midpipes with no crossover welded about 2 inches above where the stock h-pipe (for stock cat-back duals) would have bolted up. I couldn't afford to purchase the h-pipe and I had a friend custom bend the entire exhaust system. Even if I go with stock cataytics, it will have to be cut and welded to work with the existing exhaust system.

          Im going to have to get under the car again and look at it, but I think it was done that way because the mufflers were 2.25 inch with 2.25 inch tails.

          Im trying to plan what to do this summer to help performance and handling, and the exhaust still needs some work. The car doesn't have much power when driving in the city (0-35) and the gas mileage varies from 8mpg to 12mpg with light driving. Highway is fine, but also varies in gas mileage. I suspect the o2 sensors are bad and the cats are clogged from running it rich last year.
          Current rides - 1991 Ford Thunderbird 3.8 v6 (gas saver/DD) - New Heads/Headgaskets with ARP studs, Air Silencer Delete, 70mm MAF, Plasti-dipped Matte Black with a Silver Metalflake Overlay, Muffler Delete, some LED's, 30.233 MPG for high MPG average!
          2006 Jeep Wrangler 4WD (fun vehicle/backup DD) - 4.0/6spd - too many mods to list.

          Associated Panthers:
          Father's 1994 Ford Crown Victoria - Stock, 45,000 miles.
          Sold in 2007 - 1987 Mercury Grand Marquis LS "Grandpa Special" 2 door.
          http://www.cardomain.com/ride/2128327

          Comment


            #6
            Your lack of a crossover is killing your torque output. The crossover balances out the backpressure and helps maintain torque. Have a crossover pipe welded in, and I'm sure you'll notice a difference. Straight pipes are fine for light weight, high speed applications. With our big ass cars though, we need as much torque as possible to get rolling.
            Save a seal, club a liberal.

            Comment


              #7
              87mefull im having the exact same problem, mileage and all, I JUST cut out my cats, (I could see light through them, didnt look that bad in there )

              Do these H pipes make that big of a difference, im buying some mufflers tomorrow, and dont have alot of cash, is there like small H pipe adapters you can buy. I never thought it would make that much of a difference.

              Comment

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