Devon why so angry... No glue tube here just wanted to elaborate on a particular item that 4 friends of mine have installed on there cars. I know it works from experience. Now understand most people that use them have cars with MDS, so when the engine turns into a weedeater you get that anoying buzz everyone hates. You will get a bad review on any product on the market. I hear grannies apples have worms in them... But I digress. Davy wish you much luck to you on your endeavor
Davy, In one of your earlier posts you touched on the solution when you mentioned how it used to be when it didn't drone, but no one jumped on it. The solution is going back to 2.25" pipes. I have a V8 Buick with 2.5" pipes and it has the drone you are talking about, and I had another Buick (sold it to a board member) with identical drivetrain, but 2.25" pipes and it was drastically different with no drone. The drone is coming from the large pipes. If you drop back to 2.25" pipe between the headers and the mufflers, it will go away. You can keep your 2.5" tail pipes--they will affect the sound outside the car. The pipes between the headers and mufflers are what affect the sound inside the car. The large pipes act like an echo chamber that amplifies the sound, and with it being right under the floor, it transfers right into the passenger compartment.
I forgot where I mentioned that but you have a good point. Directly following my engine build about 10 years ago the engine shop patched up my new shorty headers to my old exhaust system. It was Shorty headers, 2.25 inch pipe all the way back, no X pipe and generic super turbo mufflers. That was the last time I truly had no drone. I know I said I didn't have a drone after I cut off my tail pipes however.... After this last test I realized that I did still have a drone but it was only at a different RPM range at about 800 RPM. Meaning my car while at idle or being driven was rarely at that range so it wasn't an issue. So I am at a place again of not knowing what my next step should be. I hear a lot of people suggesting I put on resonators and a lot of people suggesting that those wouldn't solve my problem. People suggesting I should get rid of the Flowmasters and put in quieter mufflers and now the idea that I should go back down to 2.25 inch pipe before the mufflers. I think all of these ideas are valid and are worth a try. Now I am asking my self where do I go from here?
Just as a side note there is a LOT of info. on this subject over on the Turbo Buick Board. Those guys fight this all the time. Some of that info. might cross over. Just a heads up. Mike D.
I think you are coming to the same conclusion that I did, mentioned back in #51. 2.5" exhaust pipes to Walker Super Turbos, then 2.25" tailpipes with glasspacks in the stock resonator location. Result is little to no drone. Still sounds ok, but not aggressive. I loved the sound with no tailpipes also, but I couldn't take the fumes. It's a resonance in the boattail bodystyle that we are dealing with. If it sounds aggressive, it's going to have drone. You have to choose between relatively quiet with little drone, aggressive with drone, or asphyxiation and no drone.
Very true, Looks like we both have had a very similar situation. Am I reading this right? You had 2.5 inch pipes with the super turbos and there was too much drone..... Then went to the 2.25 inch pipe with the same mufflers and added the glasspacks? I'm now wondering what I should try first. Going back to 2.25 inch front pipes sounds like a great choice but I know it will be the most expensive. Also I am wondering what kind of performance losses I would see? If David P. was running the super turbos and still had the drone that doesn't seem like it will solve my problem by swapping my flowmasters with super turbos. Im thinking resonators might be my next choice. From what I have read some people are really for them and some don't think they are the solution. If I did get resonators is there a specific brand or size I should get?
The automakers are going to active noise suppression. They find the sound they want to get rid of and apply a sound through speakers that cancels it. Must be someone here that wants to play with that. Just need a wave file to analyze. I have an idea that is super cheap but will require a lot of experimentation. Get some stick on wheel weights and apply to different places on the tailpipe. The whole problem is sympathetic resonance. If you can dampen the vibration that causes the drone it should be reduced. I did this on the case of my supercharger to try to reduce gear whine. Helped a little, at least lowered the tone a bit. What can it hurt at this point? They also do this with snow skis to dampen vibration.
Pypes street pro mufflers are nice. No resonance at all on my Regal with an xpipe and those mufflers.
Some kind of active cancellation is what it would probably take to have loud exhaust on a boattail. As for the pipe size, I tried many combinations that I didn't mention. For any muffler, the biggest drone reduction came from the change to 2.25" tailpipes. My opinion is to leave the size ahead of the mufflers 2.5", as changing that to 2.25" will cost horsepower. I have 2.5" there. I tried 2.5" glasspacks with 2.5" tailpipes and it was still too bad. I tried 2.5" glasspacks with 2.25" tailpipes and the glass packs didn't help at all beyond 2.25" tailpipes with no glasspacks. It took 2.25" tailpipes and 2.25" glasspacks. I would try 2.25" tailpipes with the combo you have to see if that helps enough. If not, add the glasspacks where they pretty much have to go in the straight runs along the gas tank. Still too loud, change your mufflers to the Walker long case super turbos. I almost stayed with the Edelbrock SDT muffler, but I needed just a little more reduction for long trips. The cheapest "resonators" to experiment with are generic glasspacks from Summit racing, etc.
That's what I've been doing for years. It's called dual amplifiers, subwoofer and Eric Clapton. Thanks to it I cannot hear my exhaust system at all. Of course, I also can't hear anything else, but trade-offs must be made in life. Davy77, I hope you get it figured out. I know better than anyone how irritating it is when your car won't cooperate.
The pipe dia makes perfect sense, as does your shortening the tailpipe making a difference in the "tune" of your exhaust. You are apparently accomplishing what a "tuned" header is supposed to accomplish; I have heard some "tuned" headers and they make a lot of noise when they are in their tuned RPM. I will speculate the power increase you notice may be real because that same annoying drone is helping your exhaust scavenge. If that is all correct speculation, you have the perfect exhaust for your engine combination and best efficiency if you could stand to drive it at that RPM. That said, it is odd that the x-pipe didn't change the harmonic intensity or RPM of the drone. It is somewhat odd that the tailpipe modifications did change the drone as most harmonics are dampened by the muffler enough that I wouldn't guess the tailpipe "tune" would have that much effect but I don't know. Maybe some of the reason why these cars did use a resonator when some others did not is the muffler location and tailpipe length created a resonance? (not to mention the specific name "resonator" which alludes to it being there to eliminate something similar to your problem.) I don't know what a OEM resonator looks like (assuming like a small glasspack), but is there any chance you can add from your collection of mufflers one of them onto the tailpipes toward the rear where the factory resonator would be and see what happens? Maybe a cut and clamp temporary setup to test the idea? FWIW, the x-pipe virtually fixed the drone on my Skylark with 3"full-lenth pipes and long-tube headers.
Resonators installed Resonators installed just before the tips. Cut the drone by about 50%. It quieted the over all exhaust sound a little but at least the drone is manageable. My exhaust guy had a set of late model stock resonators he had cut off a mustang last week. He gave them to me for free and installed them for only 50 bucks.
Update. My previous statement about the resonators reducing the drone by 50% was incorrect. After driving it around for a few days I believe the reduction was more like 20%. I still could not handle the drone so I broke down and bought some new mufflers. I went from Flowmaster Super 44's 2 chamber to Flowmaster Delta Flow 50's 3 chamber. How is the 2000 rpm drone? STILL THERE! If not ever so slightly worse. Latest.... Shorty Headers, 2 1/2 in pipe all the way back with X Pipe, 2 Delta Flow 50's, 2 resonators in the tail pipes.
God willing, I am installing Dynomax VT 'Drone free' mufflers this weekend. http://www.v8buick.com/showthread.php?251623-Advice-Needed-Get-Rid-Of-Exhaust-Drone I'll let you know how I make out.
I actually was considering those but I read some very bad reviews so I decided against them. Please let us all know how they work for your car!
Will definitely do! The real 'litmus test' will be the > 900 mile cruise out to Ohio at the end of this month. I don't have a drone issue at highway RPMs, just cruising RPMs. The bad reviews I read were the 'early versions', that had a weak(er) spring and a miss-cut valve that made noise. They redesigned this muffler since then...so I'm told by tech support and I've read online. Having a 455 motor with ported manifolds, X-pipe, and 2.5 mandrel pipes, it was recommended to get the 17959 mufflers by tech support (stronger spring). They thought the 17159 would fully open 'too soon' on a 7.4L motor with free-flowing exhaust.
My tach works, but reads waaaaay high (better high than low for a manual trans) starts about 2300 (which I'll guess is about 2K) up to 2800 (which I guess is about 2400-2500). This is 4th gear cruising in a 35-45 MPH speed zone...VERY ANNOYING. Sometimes I'll shift into 3rd to get RPMs up just to get rid of the drone. Again, highway speeds there is no done and the car sounds great. I'm told that 60MPH is 3K on the tach.
