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Thread: I can hardly think with all this DRONE...

  1. #46
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    Apr 2002
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    Update: Ok so I was finally able to get it to a custom exhaust shop. I was told that the new Magnaflow resonator was already blown out. So I'm actually happy that this was probably a big contributor to the loudness/ drone.

    I'm going to order those brick style universal cats from Summit, and bump up the resonator from 18" to 24". With me supplying just the cats, should be around $300 (plus my cat cost) to get it all done.

    But now my buddy is telling me to go one step further and get rid of the center pipe out of the resonator and just go true dual. So I may do that as well...

    Going to leave the mufflers/tail pipes alone for now. I'll post back in the next week or two when it's finished!

  2. #47
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    Longer resonator under the car is not really the answer, and a true dual will be worse than either. Just replace the resonator with the same unit that was in there and get the new cats. A burned out resonator is a sign of unburned fuel getting into it and probably happened before the car was fully tuned. On high HP SC's I've run into this issue due to camshaft overlap and excessive scavenging of the cylinders, often partially aggravated by longtube headers. The cam in that car doesn't have any overlap, so I don't think that is the issue and I don't think you'll have any more problems burning out resonators, at least not so quickly, as long as it's properly tuned.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  3. #48
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    Quote Originally Posted by XR7 Dave View Post
    Longer resonator under the car is not really the answer, and a true dual will be worse than either. Just replace the resonator with the same unit that was in there and get the new cats. A burned out resonator is a sign of unburned fuel getting into it and probably happened before the car was fully tuned. On high HP SC's I've run into this issue due to camshaft overlap and excessive scavenging of the cylinders, often partially aggravated by longtube headers. The cam in that car doesn't have any overlap, so I don't think that is the issue and I don't think you'll have any more problems burning out resonators, at least not so quickly, as long as it's properly tuned.
    Appreciate the guidance Dave! But not following why cats + 24" resonator would be worse than cats + 18" resonator? (18" is what's on there now). Wouldn't the longer resonator just be quieter and more resistant to blowing out (the latter why the exhaust shop recommended it).

    Also, don't a lot of 94-95 SC owners go with true dual? Why wouldn't a dual in/out X pipe resonator along with cats be a reasonable way to go?

    Dave, any plans to go back to Carlisle this year?

  4. #49
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    Quote Originally Posted by joenintiesc View Post
    Appreciate the guidance Dave! But not following why cats + 24" resonator would be worse than cats + 18" resonator? (18" is what's on there now). Wouldn't the longer resonator just be quieter and more resistant to blowing out (the latter why the exhaust shop recommended it).

    Also, don't a lot of 94-95 SC owners go with true dual? Why wouldn't a dual in/out X pipe resonator along with cats be a reasonable way to go?

    Dave, any plans to go back to Carlisle this year?
    I didn't realize you were contemplating replacing the whole exhaust. I thought you were talking about replacing the resonator with dual pipes. I don't see any benefit to replacing the exhaust unless you just want to.

    I recommended the same size resonator because you don't need a bigger one. The fact that the other one was empty probably made the car miserable. You can add a bigger one of course but it's not necessary. If you are generating enough heat to burn out the packing from the resonator, then having a bigger one isn't going to help much and if you are burning out resonators then you need to correct the tune rather than put a bigger muffler on it. As I said, I suspect the resonator issue dates backward to before the car was tuned properly.

    Whether or not I make Carlisle has a lot to do with whether or not I have a Pearl white SC to deliver at that time.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  5. #50
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    Quote Originally Posted by XR7 Dave View Post
    I didn't realize you were contemplating replacing the whole exhaust. I thought you were talking about replacing the resonator with dual pipes. I don't see any benefit to replacing the exhaust unless you just want to.

    I recommended the same size resonator because you don't need a bigger one. The fact that the other one was empty probably made the car miserable. You can add a bigger one of course but it's not necessary. If you are generating enough heat to burn out the packing from the resonator, then having a bigger one isn't going to help much and if you are burning out resonators then you need to correct the tune rather than put a bigger muffler on it. As I said, I suspect the resonator issue dates backward to before the car was tuned properly.

    Whether or not I make Carlisle has a lot to do with whether or not I have a Pearl white SC to deliver at that time.
    Gotcha. I don't really want to hack into a brand newish custom exhaust (and pay extra to do it), so I'm going to leave the configuration as is, add the cats I ordered, and let the exhaust shop put in the size resonator that they recommend. Call it a day. Since this is the kind of stuff I have to pay a shop to do, and it's $$ and a hassle, I guess I tend to over think it and explore every possibility since I want to get it as right as possible the first time. Thanks again for your guidance, and everyone's input!

    I'll email you next month to see if you will be at Carlisle and might have time for some fine tuning!

  6. #51
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    Ok, listen!

    First exhaust I installed, 2 1/4" down pipes, no cats into 2.5" dual in/out magnaflow X resonator, true dual 2.5" pipes into large case known to drone magnaflows I bought from fellow inmate. Drone got to me. Horrible in back ok in front. Car sounded good inside but not good outside. Year later I get back to WA to my best friend/ exhaust guy. The 2.5 dual in/out magna res is hollow, blown out. Done. So we try single res per side into x pipe. Only slightly less drone and car sounds like a goose with its head in a vise. So I think, its the mufflers. They started the drone. Research turned up the dynomax vt series mufflers. Bought them and installed they are awesome! A year later NO DRONE! Car sounds good inside and out! The same gear head friend who said my bird sounded like a goose with its head in a vise, said it sounded good with my current set up. He's a ford guy with a 800hp stang and tuned my stang so he knows his stuff.
    So current set up is 2 1/4 down pipe, no cats into single 2.5 magnaflow res' per side, to 2.5 true dual pipes, to dynomax VT mufflers for 4-6cyl. It is ~~~~ing nice! I will do an exhaust clip for you if you like. No drone! And sounds good!
    Last edited by sc91gt; 04-19-2014 at 02:51 AM.

  7. #52
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    Quote Originally Posted by sc91gt View Post
    First exhaust I installed, 2 1/4" down pipes, no cats into 2.5" dual in/out magnaflow X resonator, true dual 2.5" pipes into large case known to drone magnaflows I bought from fellow inmate. Drone got to me. Horrible in back ok in front. Car sounded good inside but not good outside. Year later I get back to WA to my best friend/ exhaust guy. The 2.5 dual in/out magna res is hollow, blown out. Done. So we try single res per side into x pipe. Only slightly less drone and car sounds like a goose with its head in a vise. So I think, its the mufflers. They started the drone. Research turned up the dynomax vt series mufflers. Bought them and installed they are awesome! A year later NO DRONE! Car sounds good inside and out! The same gear head friend who said my bird sounded like a goose with its head in a vise, said it sounded good with my current set up. He's a ford guy with a 800hp stang and tuned my stang so he knows his stuff.
    So current set up is 2 1/4 down pipe, no cats into single 2.5 magnaflow res' per side, to 2.5 true dual pipes, to dynomax VT mufflers for 4-6cyl. It is ~~~~ing nice! I will do an exhaust clip for you if you like. No drone! And sounds good!
    For me it came down to either/or. Either add cats, or change the mufflers. My problem is inside the car, I can hear the loudness/ drone coming from right beneath me. Finding the resonator blown out made the exhaust guy, who spent some time under the car in thoughtful assessment, advise adding cats to quiet AND dissipate some of the heat that probably blew out the res and of course replacing the res with a bigger one. Neither he nor I considered the pre-tune driving as a cause of the res getting cooked, because neither one of us was as familiar with the car as David Dalke was, since DD helped build and tune the car with the previous owner.

    If it ended up being a better, more cost effective solution to leave the front alone (if the res was still intact) and replace the mufflers/ tailpipe, I was going to order two Dynomax VT mufflers (17949) that were a match to the dimensions/ inlet/ outlet of the mufflers currently installed. With coupon I could have gotten them shipped from Advance Auto for total of $150.

    If/ when it comes time to replace the mufflers, I am eager to try out those VT's.

  8. #53
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    Looking forward to seeing results! Inside drone sucks!

  9. #54
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    Mount Vernon, WA
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    Cool.

    I went from single dual in out magnaflow res (didn't change from new to blown out packing), to dual magnaflow res and x pipe and didn't change the drone only made car sound worse outside. My drone was so bad anyone in back seat would be bleeding from the ears after a ten minute drive. And only barely tolerable in the front seat Drone started with the magnaflow mufflers and completely gone with the VTs'... Cats are spendy and not needed where I live...

  10. #55
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    Quote Originally Posted by joenintiesc View Post
    For me it came down to either/or. Either add cats, or change the mufflers. My problem is inside the car, I can hear the loudness/ drone coming from right beneath me.
    I have to offer again, that while it's not an SC, on my 3.8 Mustang, that after i'd put in an h-pipe, it took away all the drone. The sound, like you said, when it was droning, sounded/ felt like it was coming from right below me, whereas after the h-pipe, it sounded like it was coming only from the back of the car, from the mufflers. This was a MAC catback 2.5" true dual setup where the mufflers are situated pretty much right under the foot area of where a passenger would be in the back seat. The h-pipe mellows out everything that is behind it in the exhaust chain. The MAC was V8 type loud, but before the h-pipe, it was evident that it was a 6 at lower RPM's. There's a nice low end rumble to it. It's not until you get past 2500 RPM's or so, where it reveals itself as a 6.

  11. #56
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    s91gt, I am contemplating a single 3" dual inlet Dynomax VT after the cats and just a single 3" tail pipe on my 93. Do you think that would be crazy loud with no resonator at higher rpms when the baffle opens?
    Last edited by Ngrimm; 04-21-2014 at 12:06 PM.

  12. #57
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    Update

    So I just got back from the exhaust shop. Originally I was quoted $700 to add cats and replace resonator using the shops parts. Cost dropped to $300 with me supplying the cats, but unfortunately those brick style universal cats from Summit I bought were too big - they would have sat 1.5 to 2 inches lower than the lowest part of the undercarriage (the resonator). I did not feel good about that, so I was back to using the shops spun metallic bullet style cats and $700. I definitely did not feel good about that either so I ended up just replacing the blown out res with a longer one (Magnaflow).

    I think it is slightly less droney, but barely. I guess the headers are just that much louder then stock manifolds, so I'm not eve sure if the cats would have quieted it too much more, at lest not the style that the shop had available.

    I'm going to Hushmat the interior next, and then maybe later this year I will look back onto swapping the mufflers for those Dynomax VT's.

  13. #58
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    I too am having to think about exhaust. http://www.sccoa.com/forums/showthre...3-Strange-Miss
    Mine hasn't been too bad but I think I am ready for more quiet.
    Current : 2.5 downpipes (necked for 2.25 stock manifolds) - 2.5" Cats - 2.5 Dynomax Ultra-Flo x Muffler - Dual back to 2.5" Dynomax Ulta-Flo Mufflers.

    I had an exhaust off of Charles Brown's car out back so I put that on. Yuck. 2.25" down - no cats - 2.5" Magnaflo Dual in/Dual out - Dual back to Borla ProXs Mufflers.
    All the screws are now loose inside the car. And my fillings.

    Since it has a problem, I have an excuse. I want quieter and I am not sure if the raspy sound I got at about 2200 was the x Muffler or out back. So the testing begins.
    95 SC Auto
    95 SC 5-speed Toy
    Rodney

    Best time 95 5spd 14.58 @ 93.50 totally stock and tired.

  14. #59
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    The spun metallic cats are a waste of time, sorry to say. They don't work that well and do nothing for drone. They sure do flow well though! Since that is done now though, suggest you forget about the part you just replaced and just get some new mufflers out back. Hushmat isn't going to do anything for you. The SC is well insulated in the first place. Go ahead and get the VT's. Do it sooner than later too, there are few things worse than a loud droning SC.

    PS. Headers have no appreciable affect.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  15. #60
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    Feb 2014
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    Quote Originally Posted by XR7 Dave View Post
    PS. Headers have no appreciable affect.
    In the past, i've only gone shorty ceramics, but that was mostly to keep engine bay temps down.

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