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Why do my flowmaster 40s sound funny?

Discussion in 'The Garage' started by Muddin_Mavric, Jun 1, 2004.

  1. Muddin_Mavric

    Muddin_Mavric Registered Member

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    I just installed a header back 2.25 dual exhaust with an h pipe on my k5. I used duel flowmaster 40s (the original ones) and it sounds really tiny and its not deep and rumbly at all.

    it use to have a single 3 chamber on there im not sure wich one but it sounded a lot deeper and louder.

    now when it idles it sounds like tong,tong,tong, and its not loud at all. when i step on it, it gets loude and starts to sound a little better but it sounds like a giant exhaust leak. when i drive down the highway at 60 mph i cant even hardly hear it and thats with 31" all terains.

    do you guys have any advice? would taking the H pipe out help or should i just go buy the cheapest and shortest glass packs i can.

    thanks for any advice you can give me


    justin
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    It's the small pipe. I have 2 1/4" and it's the same way. Makes me sick in a way but it just doesn't roar until I really get on it.

    I wish I had flowmasters on my tow rig and glasspacks on my big truck instead of the other way around /forums/images/graemlins/angryfire.gif
     
  3. white-rhyno

    white-rhyno 1/2 ton status

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    It is possible to put them on backwards. They do sound funny then. Just a thought.

    Dont ask how i know they sound weird backwards.......
     
  4. ntaj*ep

    ntaj*ep 1/2 ton status

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    Why are you using and where is your H pipe?
    It will make the system "quiet" at low rpm...
     
  5. 79Stomper

    79Stomper 1/2 ton status Premium Member GMOTM Winner

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    I am running dual 40 Series Flowmasters through 2 1/4" exhaust and I have no complaints. Roars when I romp on it and quieter at highway speeds and at idle. Maybe the crossover pipe is where it is going. Not sure but mine has set off alarms going down the road.
     
  6. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    The length of pipe behide the mufflers make a hugh diffrence. If you want it deeper add some 2 1/2" from the mufflers back.
     
  7. sr175

    sr175 Registered Member

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    I just put a new exhaust system on my newly installed rebuilt 350. I have a 2 1/4 y pipe going to 3" into a high flow cat and then into single 3" in and dual 2.5 out 2 chamber series 40 flow. This is the original that will start getting hard to find. At first I had the same complaint as you. This last weekend was the first off road outing with my rig. I had to drive 250 miles to get there and back. By the time I got back the thing was roaring like it should. My buddy made the comment that his did the same thing. There seems to be a little break in. I thought he was smoking something but it happened to mine. Give it some time and if sounds the same then the pipe size may be an issue. The last point was right on. Extending the dual out will increase the noise. I left just a few inches on the end of mine so as to not catch on objects going under truck /forums/images/graemlins/peace.gif. I did not want any spare rice rocket parts stuck in my muffler /forums/images/graemlins/yikes.gif, just under my tires /forums/images/graemlins/whistling.gif
     
  8. Muddin_Mavric

    Muddin_Mavric Registered Member

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    Thanks for all the replies. My H pipe is right under the back of my t-case and about 8 to 12 inches from the mufflers.

    I dont think they are on backwards. right now the exhaust goes in the side marked inlet.


    I think i will try and remove the H pipe and see how it sounds i just have to get some pipe to go in there place.


    Getting 2.5 tialpipes is not really an option since this is a kit i got from summit and since i have no cats i dont think i will ever find an exhaust shop to work on it. and i was not able to find any kits that were 2.5 or i would have gotten that. How would it sound with just turn downs or somthing and no tail pipes after the mufflers?


    One of my friends brother in law has a 93 suburban with a cat and a flowmaster 40 (stock exhaust piping) and i herd it while back before i order mine and his was louder than mine and sound a lot better too /forums/images/graemlins/angryfire.gif



    Justin
     
  9. ntaj*ep

    ntaj*ep 1/2 ton status

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    Are you running a "large" profile cam? You really won't need a crossover under certain conditions. My brother had a fullsize J.E.E.P with a stock 360 and 2 40s and it was quite loud, a co-worker just put a Delta flow 40 on his Avalanche and that is loud as hell.
     
  10. sled_dog

    sled_dog 1 ton status

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    don't know what to tell you. Exhaust systems can be odd. On my 89 Burb I ran Ypipe, to stock cat, to flowmaster 40 series(not delta) and it was SO quiet, it barely barely sounded anything above stock. Remove the flowmaster and BAM its loud so the muffler is whats doing the muffling. My 95 K2500 had Y pipe, to a flowmaster 40 delta flow, single in dual out. That thing was LOUD. One of the louder gas trucks in the area. Added a high flow cat and it quieted it down just a little bit. Enough that I wasn't as worried about the cops pulling me over(which did happen before). I got the truck up to about 1600 RPMs pulling out of a parking spot, and a cop pulled me over for piping my truck up with her sitting right there.... When I sold it I put 2.25" dual pipes(factory ones actually) on it. They quieted it down a lot. But its still very deep. I can hear it coming from a ways off, it went past my work today and the resonance of how deep it was reverberated in my work(probably used some terms wrong there but you get the idea). Exhausts seem to be hit or miss for people. I can't figure out what I want to do on my 97 C2500. Its got true dual exhaust with factory high flow cats going all the way back to the muffler. True 3" the whole way too. Tempted to slap two mufflers or just one with a single outlet on.
     
  11. Muddin_Mavric

    Muddin_Mavric Registered Member

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    I just took off my tailpipes and WOW! it got a lot more deep and rumbly with a lot less of that tinny sound but its still there a little. But when i step on it it doesnt seem like it gets that loud when it winds up. it sounds pretty loud inside i just wish it sounder louder outside. i guess when my brother gets home i will have to let him drive it so i can here what it sounds like from outside. now if it would just sound like that with tail pipes so i dont die from the fumes when i got my back window open.

    Now im not sure what to do because my mufflers are to far back to have a short 2.5' tialpipe exit before the tires. maybe ill just have to go with turns downs and not open my back window much.

    I just put the H pipe in there becuase i herd it helps with low end tork and flowmaster recomends one. For now its got a stock 305. i just got headers and duel exhaust for when i get a 350 with a fairly mild come in there.
     
  12. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    Mine has turndowms and I run with the back window open a lot. I don't smell the fumes /forums/images/graemlins/dunno.gif
     

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