Announcement

Collapse
No announcement yet.

Exhaust diameter question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Exhaust diameter question

    Hey, i searched a bunch on the forum but the question seems to be only answered for people looking for more power or with larger motors. I found a bit on google but for other cars and im not sure how well it applies to festivas specifically. My question is what diameter exhaust is best for a stock festiva 1.3L with no plans to make more power? Mine is kinda bashed up and rotted out. I have 2 parts cars so i took the exhausts off both. The one is the standard 1.5in OD but no muffler and the flange is cut off back there. Couple pinholes throughout the pipe and the resonater would have to be replaced but the pipe is not squishable by hand. The other one is out of a carbed festiva so its got the cat with the heat pipe. The outside diameter is 2.1in. Resonater seems in ok shape and it has a flange for the muffler. I have a good muffler with a flange but no brackets, i have to weld them on. So anyway, the 2 inch exhaust is obviously (to me) less work and cheaper to make work- and thats the goal, im not lookin to spend money on it or else i would buy a whole new exhaust. However i do not want to loose any power. *My concern is does the 2.1inch slow the velocity of the exhaust down enough that you loose power on the n/a 1.3L? Or will there be no noticable power difference? The muffler is the stock 1.5in.*
    Thanks


    Sent from my iPhone using Tapatalk

  • #2
    Originally posted by ryanprins13 View Post
    Hey, i searched a bunch on the forum but the question seems to be only answered for people looking for more power or with larger motors. I found a bit on google but for other cars and im not sure how well it applies to festivas specifically. My question is what diameter exhaust is best for a stock festiva 1.3L with no plans to make more power? Mine is kinda bashed up and rotted out. I have 2 parts cars so i took the exhausts off both. The one is the standard 1.5in OD but no muffler and the flange is cut off back there. Couple pinholes throughout the pipe and the resonater would have to be replaced but the pipe is not squishable by hand. The other one is out of a carbed festiva so its got the cat with the heat pipe. The outside diameter is 2.1in. Resonater seems in ok shape and it has a flange for the muffler. I have a good muffler with a flange but no brackets, i have to weld them on. So anyway, the 2 inch exhaust is obviously (to me) less work and cheaper to make work- and thats the goal, im not lookin to spend money on it or else i would buy a whole new exhaust. However i do not want to loose any power. *My concern is does the 2.1inch slow the velocity of the exhaust down enough that you loose power on the n/a 1.3L? Or will there be no noticable power difference? The muffler is the stock 1.5in.*
    Thanks


    Sent from my iPhone using Tapatalk
    Depends where you want the torque peak. Bigger will give more top end, and smaller should help with cruise. Specially if you have a header. Primary exhaust diameter is a big deal for torque peaks. Well that mixed in with runner length

    Sent from my SM-G900V using Tapatalk

    Comment


    • #3
      Also be sure the 2.1" that you are measuring isn't a double wall exhaust (common).
      Trees aren't kind to me...

      currently: 2 88Ls (Scrappy and Jersey), 88LX, 90L(Pepe), 91L, 91GL (Skippy) 93 GL Sport (the Mighty Favakk), 94 (Bruce) & 95 Aspire SEs, 97 Aspire (The Joker),
      94 Justy 4WD, 87 Fiero GT, plus 2 parts cars. That's my fleet.

      Comment


      • #4
        Here is a good read on how to calculate exhaust size needs. I'm assuming it is accurate. I'm not sure how many muffler shops carry 1.75" pipe but I think I may try to get installed from the Manifold back to a Borla muffler in a couple of months.

        http://www.exhaustvideos.com/faq/how...pipe-diameter/
        "The White Turd" 1993 Festiva 144k miles. (Winner of FOTM November 2016)
        sigpic
        "The Rusty Banana" 1990 Yellow 5 Speed Mud Festiva (Lifted with 27" BKT Tractor Tires)(Winner of "Best Beater Award" - Madness 12 - 2018)

        "Papa Smurf" 1992 Blue 5 Speed Shell
        "Cracker?" (name pending) 1992 White Auto Shell (Future BP Swap)
        "Green Car..." Scrap Car that Runs?!?
        "Red Car..." Complete Scrap Car

        "El Flama Blanca" 1993 Festiva 104k miles. (Lil Brothers Car)
        https://drive.google.com/file/d/0BzM...ew?usp=sharing

        Comment


        • #5
          Thanks for the help and the links. I know 2 inch is way overkill, just not sure if it will cause a loss in power. It is not double wall. I decided that i will just install it and see what it does. If its bad i will look for another 1.5 inch exhaust. Its the stock manifold and 'downpipe' to cat, stock cat and stock 1.5in muffler. So i dont know what going from 1.5 to 2 and back to 1.5 will do but i will find out. Just need to find some time to install it. Oh, and theres no issues putting a cat from a carbed car onto an efi car right?
          Thanks again


          Sent from my iPhone using Tapatalk

          Comment


          • #6
            You can't swap cats, they are not compatible due to the PAIR system pipes. Also they are constructed differently.
            Trees aren't kind to me...

            currently: 2 88Ls (Scrappy and Jersey), 88LX, 90L(Pepe), 91L, 91GL (Skippy) 93 GL Sport (the Mighty Favakk), 94 (Bruce) & 95 Aspire SEs, 97 Aspire (The Joker),
            94 Justy 4WD, 87 Fiero GT, plus 2 parts cars. That's my fleet.

            Comment


            • #7
              im in the same boat. mine fell off the other day....been running open down pipe for the past few days....hahaha

              Comment

              Working...
              X