I have the Flowtech Afterburners on my riviera and the sound is O k for mi.Good sound for that price. Inge.
OK so on my 350 I have headers, an x-pipe from Jegs, flowmaster 40's, and tailpipes from Jegs. All mandrel bent (no kinks). These are all choices that as I understand it allow the pulses of the exhaust to flow best maximizing HP. The purpose of an x pipe is for the exhaust pulse from one side of the engine to scavenge flow off the pulse that just went thru the x from the other side. (Now I am talking actual pipe, not the mufflers with an x inside them) The resonators and glasspacks and mufflers that are filled with a stuffing material are said to deaden the pulse of the exhaust and therefore slow it down. Inside a flowmaster 40 is only metal angles (baffles). Anyone else comment on this aspect?
The baffles deafen the sound somewhat(like the stuffing), but flow better. Plus there is less chance the metal baffles will deteriorate like the packed ones. I have the 40's...they sound good at idle, but when cruising, thay do have a natural resonance that gives that droning sound.
Mine do too. If I didn't change mufflers, or add a resonator.. is there a fix for that? Does unsulating the floor under the rear seat help? Adding a resonator would defeat the purpose of having the pulses flow well.
I'm hoping the crossover pipe will help, but I'm going add the Dynamat Xtreme Trunk Kit (expensive) or something along this type, because the noise is coming from the trunk area.
What is your car? My 72 Skylark has the mufflers under the rear seat area, I believe the resonance comes off the body of the muffler no?
70 Skylark 350. Yeah. But it has many factors, engine size, engine speed..ect. I thought that running the pipes out to the rear would help this. Not. I believe the sound is traveling through the pipes up through the trunk...big hollow area. So the rear firewall is what I will seal first.ray:
I just had this system put on my GS 350 a couple weeks ago and love it! nice take off sound, nice idle, but at cruising, its nice and quite. Zero drone. I have some video clips on my blog http://72buickgs.blogspot.com/2010/09/exhaust-is-on.html
Flowmasters get my vote though I do like the sound of the Dynomax. Here is my GS 350 with flowmaster 40's,2.5" mandrel,and x pipe. <object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/WhxGVSd5OC8?fs=1&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/WhxGVSd5OC8?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
I put hooker aero chambers on my wifes caprice wagon, they sounded great with no drone at reasonable speeds, once you hit 3500 cruising a drone came around, all in all a good muffler though
Glasspacks and Cherry Bombs are only good for obnoxious noise levels, nothing else. 1st choice: Walker/Dynomax Super Turbos are great performance mufflers for value; I've used them on all of my Skylark/GS's, and a few Trans Am's, and noticed performance improvements every time, with each vehicle, using H-pipes (before X-pipes were thought of)! I'd also trust Flowmasters, by reputation, as they usually get good reviews, too!
JIM HAND (do a search) published a drag strip test of several mufflers. He printed the results for Torque Techs' newsletter; also added it to the book he wrote on Building High Performance Pontiacs. At the drag strip: The top two, were the Walker Dynomax Super Turbo "Hemi" muffler # 17749, and the Flowmaster. ET and MPH were dead even and the Walker was way quieter. (& way cheaper) Got'em on my 67 GS and can hear the radio too. MY FAVORITE MUFFLER...again; that's 17749 (originaly called the "HEMI" muffler)
I'm going on 2 years with my Cherry Bombs and I am far beyond ready to get rid of them. They are just annoyingly loud at all times. There's a drone at 50-60mph that vibrates the roof of the car and causes an even more annoying sound. I can hear the rods in my headliner vibrating as well. I've got shorty headers, 2.5" pipe running back and the Cherry Bombs sit right under the back seat of the car and the ends of the pipes are dumped right after the axle. No X or H. Just 2 pipes and glasspacks. When I first did it, I thought it would be cool. Thought it would sound cool. Now, I just know that I made a mistake. They will come off and ill put some quiet Walkers on there. ...and judging by how my Sanderson Headers are holding up, I may just put my stock manifolds back on as well.
I just added Flowmaster 40s on my 455 and am very happy. It has the crossover. Sounds like a musclecar should.
My friend installed Flowmasters and they were really LOUD. He installed an X pipe and he is much happier now. Took away some the noise when cruising and rattle when backing off the throttle.
3" Duals with x-pipe, T/A Tail Pipes with 64-65 extension and Dynomax Super Turbo Mufflers: <iframe width="560" height="315" src="http://www.youtube.com/embed/54cOWJ8UtB8" frameborder="0" allowfullscreen></iframe>
