J dot Miller
Registered User
I was told one time not to waste money on high flow cats. Just buy larger truck cats and reduce them down. It should be less expensive and still flow...
Speaking of drone, I went to Indiana to pick up my 89. I had discussed finishing the exhaust on it. I was told it had headers to a flowmaster muffler for a resonator. I figured it had a pipe running to the back of the car but it did not. The muffler dumped under the car.....headers>flowmaster>nothing.....no pipes, nothing.
I drove the car for 13hrs like that. The drone was so loud that it vibrated the dash, side mirrors. I bought ear plugs and they did nothing to stop the noise. Took close to two hrs for my ears to stop ringing and playing tricks on me when I got home. It sounded like a alien mothership was trying to land on my roof!!!
Interesting - you have super turbos on one end, but no headers on the other. I wonder which is the bigger drone killer?
The sound tubes do not have to be welded at 90 degree angles. The sound waves can turn and bend. Some of the examples in the that thread I posted. They lay at angles and even parallel the exhaust under the car. The best example is the intake tube resonater on like every intake tube made.
SWS
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?
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.
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.
PS. Headers have no appreciable affect.