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Flowmaster muffler overheating

Discussion in 'The Hokey Ass Message Board' started by johnod, Aug 5, 2012.

  1. johnod
    Joined: Aug 18, 2009
    Posts: 780

    johnod
    Member

    Has anyone had a problem with this?

    Mine burned a hole thru the carpet, thru 2 layers of insulation.

    After lowering the mufflers , you can still not touch the floor as its still way hot.
     
  2. Flipper
    Joined: May 10, 2003
    Posts: 3,312

    Flipper
    Member
    from Kentucky


    Yep, they do get hot.
     
  3. Deuces
    Joined: Nov 3, 2009
    Posts: 18,816

    Deuces
    Member
    from Michigan

    Sounds like your running your motor waay too lean.. Fatten up the jetting on your carb!! And redo the timing... I'm running a set of Flowdaddys on my '91 Fox car and never had that problem...
     
  4. GassersGarage
    Joined: Jul 1, 2007
    Posts: 4,729

    GassersGarage
    Member

    I ran the 3 chambered Flowmasters with no problems.
     
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  5. I've run them for years and havent even browned the paint on them.
    Too lean as stated above?
     
  6. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,262

    Gman0046
    Member

    They also sell muffler heat shields.
     
  7. Deuces
    Joined: Nov 3, 2009
    Posts: 18,816

    Deuces
    Member
    from Michigan

    That's what I have on mine and they're still freakin' loud... :eek:
    Must be that .542" lift cam I'm running.. :eek::rolleyes:
     
  8. shmoozo
    Joined: Aug 14, 2007
    Posts: 672

    shmoozo
    Member
    from Media, PA

    Yeah, that sounds like a likely source of the problem. At the very least get a tuning expert to look at that jetting and timing, and don't be disdainful of the use of an exhaust gas analyzer to sort it all out.
     
  9. oldolds
    Joined: Oct 18, 2010
    Posts: 2,993

    oldolds
    Member

    Some cars seem to do that. It may be lean jetting. It also may be the way the air flows under your car. Heat shields may be needed.
     
  10. Really, you guys determined the condition of his engine by this diagnosis?

    So tired of hearing "lean" conditions for every ailment.

    Seriously; hot mufflers are not uncommon. Flowmasters take the sound wave energy and reflect them against each other and that causes heat. Therefore, this type of muffler will always run hotter than "traditional" mufflers.

    If your floor insulation/carpet is burning because of this, the mufflers are far too close to the floor. Use a one hand rule. You should be able to able to get one hand between the exhaust and the floor at a bare minimum.
     
  11. johnod
    Joined: Aug 18, 2009
    Posts: 780

    johnod
    Member


    Flat hand?
     
  12. gas pumper
    Joined: Aug 13, 2007
    Posts: 2,952

    gas pumper
    Member

    I can't resist this anylonger:D.... The wrong weight oil in the muffler bearing can cause overheating. unless it's the multiple bearing design that uses silicon grease.
     
    buymeamerc likes this.
  13. johnod
    Joined: Aug 18, 2009
    Posts: 780

    johnod
    Member


    Well duh, even i know this.
    Thats why I use the new sealed bearing design from Dewey and Scruem.:p
     
  14. 41woodie
    Joined: Mar 3, 2004
    Posts: 1,064

    41woodie
    Member

    I run them on the woodie without problems. Of course they are wrapped with thermal wrap and there are two layers of foil/bubble insulation under the fiber pad and carpet. I would think that if the muffs are getting that hot you'd see problems under-hood also. Are you running headers? If you are running headers that are thermal wrapped it's possible that it's carrying the heat further into the exhaust system and the first "outlet'' for all of that heat is the mufflers.
     
  15. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,084

    Ebbsspeed
    ALLIANCE MEMBER

    They also run hotter the closer they are to the motor. Not much, but it does make a difference.

    What kind of insulation are you using?
     

  16. Yeah, flat. should be able to reach all around the muffler or components. Without forcing of course.
     
  17. isky1843
    Joined: Feb 3, 2011
    Posts: 157

    isky1843
    Member

    This!!! It could also be the lack of ZDDP in the oil used to lube the muffler bearing.
     
  18. Hyway Hauler
    Joined: Aug 31, 2009
    Posts: 670

    Hyway Hauler
    Member

    Could be a timing issue...If your engine timing is retarded even a few degrees, your exhaust will run way hot. Check to see if your headers or manifolds are glowing at high RPM...
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 46,447

    squirrel
    Member

    Just wait a few months, you'll be glad for the heat.

    Seriously....yeah, mufflers get hot. Yeah, engine tune can affect how hot they get, as well as other variables.

    Pictures?
     
  20. drptop70ss
    Joined: May 31, 2010
    Posts: 1,149

    drptop70ss
    Member
    from NY

    Flowmasters on the Buick are spray bombed black and they havent gotten hot enough to wrinkle the paint. Maybe you have a mouse nest in there :)
     
  21. 1964countrysedan
    Joined: Apr 14, 2011
    Posts: 1,131

    1964countrysedan
    Member
    from Texas

    Check for a small leak at muffler joints. Let us know what you find.
     
  22. Carnuba
    Joined: Mar 19, 2012
    Posts: 430

    Carnuba
    BANNED

    OK, I read every response and no-one suggested this. Flowmasters will run blistering hot and burn flooring even when properly spaced from the floor if they're installed BACKWARDS. They are directional, and it's very important they get installed correctly. I had a car that with no interior was smoking the POR 15 off the floor on one side only. THAT Flowmaster was installed backwards....and the prob gone after I switched it around
     
    Last edited: Aug 5, 2012
  23. The "1 hand" rule is what we used when I worked in muffler shops. If you can pass your hand between the pipe, muffler and whatever, you should be okay.

    Bob
     
  24. squirrel
    Joined: Sep 23, 2004
    Posts: 46,447

    squirrel
    Member

    You're right...the big orange INLET sticker needs to go towards the front of the car. I forgot all about that.
     
  25. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    Member
    from Wisconsin

    I had my Borla mufflers getting very hot and I found that mice had put dog food in them.
     
  26. 1964countrysedan
    Joined: Apr 14, 2011
    Posts: 1,131

    1964countrysedan
    Member
    from Texas

    To the original post...

    What was the solution?
     
  27. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,262

    Gman0046
    Member

    Gas pumper, in Kentucky we use KY Jelly.
     
  28. Use some Porters and forget about all the other problems
     
  29. Deuces
    Joined: Nov 3, 2009
    Posts: 18,816

    Deuces
    Member
    from Michigan

    Thank you sir!.. I'm glad you agree with me on that.. :)
     
  30. johnod
    Joined: Aug 18, 2009
    Posts: 780

    johnod
    Member

    Well the solution has not been arrived at yet.
    But I think this is the solution I'm going to be using.

    http://www.spintechmufflers.com/700...000-round-cruiser-series-muffler/cat_120.html

    It will solve proximity problems.
    I need to get under the car and take some measurements.

    Mufflers are not in backwards, I think they're just too close to floor, and I have seen some stuff on the web about them running hot too.

    Also will be installing AFR gauge so that should help with getting mixture right as well , should that be part of the problem.
     

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