[OCMDGTO]

I've got 2.5" pipes with an X and Ultra Flows and it drones like crazy at 2k rpms. Outside of the drone zone they sound great.

[nmoreilly]

PYPES X system in both cars - 66, 69 GTO - with the Race Pros which I like a lot. There is a bit done but definitely not fatigueing

[BLANK1]

Jones Max Flow mufflers or the new Flowmaster FlowFX mufflers.

[DOC]

Not sure where you are located but I have a 3" Pypes w/ X pipe, Dynomax ultraflows from headers to tailpipes in good condition I just took off a 78 T/A because I wanted to go back to a cross flow muffler. If your interested. PM me. Located in Jacksonville Fl

[allenga]

Originally Posted by JLMounce

I'm a little confused. Your picture shows an X pipe, but you state you had an h pipe installed. Is the picture you posted not of your car and just a stock image of a like system?

There is a general rule of thumb on muffler type that fits different cross-overs. If you go with an H, you typically want a chambered muffler like a Flowmaster. If you go with an X pipe, you generally want a packed muffler like what pypes sells, or a magnaflow etc.

Putting a chambered muffler behind an x pipe is a recipe for massive drone.

Spinttech doesn't really say on their site if their mufflers are a straight through packed design or if it is a chambered design, or a hybrid of the two.

Regardless, if the car is rattling itself, that is also some of the resonance you're getting. How you deal with that is by adding a constrain layer to the body panels (usually floor boards) that are resonating. This is your typical dynamat product. 70% coverage on large flat panels will reduce harmonic resonance by quite a bit.

Follow with a mass loaded vinyl on top of areas around the mufflers and you'll knock down a good bit of the sound that the muffler is putting off itself.

Thank you. Sorry, I meant I have X pipe. Floor boards are covered with dynamite like product and another layer of heat insulation.

[allenga]

Originally Posted by coonhunter70

Dynomax or Goerlich xcellerator

These Xcelerators are interesting but no one promotes them but RamAir Restorations.

[allenga]

Thank you. There is a hands width between floorboard and muffler.

[allenga]

I would love this sound. https://www.youtube.com/watch?v=BoQdGQpwZk0

[wovenweb]

Originally Posted by allenga

Floor boards are covered with dynamite like product and another layer of heat insulation.

Be careful!!!!! Oh, dynomat, lol.

[Chris-Austria]

Originally Posted by BLANK1

Jones Max Flow mufflers or the new Flowmaster FlowFX mufflers.

I use the FlowFX on my 66 GTO (462cui) and there is very little drone, nothing I would complain. I use an H-Pipe and 2.5" piping.
Just a nice deep sound

[Larry Navarro]

Jones Max flow mufflers are similar to the dynomax or goerlich designs, oval case, offset or straight through, perforated tube surrounded with noise suppression packing. I use the ones available on ebay. About $40 each. Sound great with no drone.

[Lee]

Originally Posted by allenga

These Xcelerators are interesting but no one promotes them but RamAir Restorations.

Tom Hand recommended these to me over 15 years ago. I've used two sets, one on a low-11 Pontiac and the other set on a mid-10 stroker Ford Windsor. Great performance, surprisingly quiet (for the large case versions, at least).

[Navy Horn 16]

This thread makes me appreciate my military related hearing loss.
I run 3 inch electric cutouts, and they dumb right behind the driver's door. I made a 3 hour road trip yesterday with them open, and it didn't bother me a lick. I really like the stupid face I get from Prius drivers when I drop a gear and pass em at WOT. It's only when the sound bounces off their car that I really notice it.

[allenga]

Originally Posted by Lee

Tom Hand recommended these to me over 15 years ago. I've used two sets, one on a low-11 Pontiac and the other set on a mid-10 stroker Ford Windsor. Great performance, surprisingly quiet (for the large case versions, at least).

Do they sound like this? . https://www.youtube.com/watch?v=BoQdGQpwZk0

[Lee]

Originally Posted by allenga

Do they sound like this? . https://www.youtube.com/watch?v=BoQdGQpwZk0

Yep, pretty much sound the same on my cars. Here is an in-car video, from the track. https://youtu.be/tHpXgrPAKmE?t=16

[Dick Boneske]

I installed a 2 1/2" Pypes X pipe system on my '64 GTO in 2010. I used the Pypes mufflers, the quietest of three they offer. It's a 4 speed, 428, with '67 HO cast iron exhaust manifolds, 3.23 gears, so I'm running about 3000 rpm at 70 mph.

There is no drone whatsoever. The sound is a little "raspier" than stock OEM mufflers, but quiet inside the car while on the highway.

[HWYSTR455]

Originally Posted by allenga

Do they sound like this? . https://www.youtube.com/watch?v=BoQdGQpwZk0

I use the XLerators a lot, as well as the Dynomax Super Turbos. The Goerlich's have a more raspy sound and do wake up when you stomp on it. The Super Turbos are more quiet than the XLerators. Either in a short case get louder, obviously. Both last about the same time.

Another example of the XLerators:

https://www.youtube.com/watch?v=R2Od_KQq1ms

It does boil down to personal preference at some point, but with H or X pipe, either I have never had any drone with over the axle tailpipes.


.

[63gpman]

Maybe I missed it, but I assume you have tail pipes and not just dumps at the mufflers?

[allenga]

Yes, tail pipes and X pipe.

[moontower69]

The Dynomax Ultra flow will still drone.

Get the #17749 DM super turbo (offset/offset) with 2.5 pipes and it will rumble like stock muscle from 70s and still roar a bit when you mash it down.

Its the only way to go if you value your ears, sanity and want to be comfortable on long trips talking to people in your car or on phone.