[Formulajones]

Originally Posted by 69 Limelight

Formulajones, do both these cars (one with 20" Ultraflows and 14" Ultraflows) have the Dr. Gas X? Just wondering, if they do, that's maybe why you have unduplicated success eliminating drone with Ultraflows. Know I had a conversation with the owner of Dr. Gas sometime back and he claimed his X's are not just 2 curved pipes with holes in them welded together, like other brands, that his have been engineered and tested.
s

Both have X's, One is a Dr. Gas and the other is a BBK.

I liked the Dr. Gas stuff. Made specific per application. Too bad he's not around anymore.

[Formulajones]

Originally Posted by Firebob

Allenga, you want the best of both worlds? Cool at the car show and quiet when you don't need to be so cool. Boom! Here you go.
https://youtu.be/JOM7uA22Z3o

3 electric cutout cars here, and they are an absolute ball. Highly recommend it.

[nmoreilly]

Originally Posted by allenga

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

I had the xcelerators on 66 Bonneville 421 HO with the RA big exhaust manifolds. I thought they were perfect for that car but I don't I'd like them on a GTO for some reason

[cnc]

Originally Posted by Formulajones

It's a Chevelle, so it's made for dual mufflers under the floor. Is that what you're looking for??

Sorry misunderstood thought it was on a bird..

[Lee]

Originally Posted by BAD2000TA

The problem is that I have a terrible resonance/drone. However, it's only really bad in gear at idle. My idle is set at 750 and the sound at a light is extremely annoying.

Do you have access to your timing tables with that Sniper system? If so, try changing the timing around, and see if the drone improves.

[Formulajones]

That's what I figured CNC with a picture of a bird on your post. On the F and X bodies I stick to the transverse systems, but if you want 3 inch your kind of backed into a corner. 20" Ultraflows would be a task trying to tuck them under the floors of an F-body, especially with 3" piping. I'm sure it could be done but I'm betting they'll hang down a good bit when viewed from the back of the car.

They are pretty big, but fit fine on an A=body, used the factory hangers at the rear of the mufflers and the pockets in the floor pans were more than generous enough to fit the mufflers with room to spare. I just simply had to shorten up the pipes in front of the mufflers a bit, do a little welding and bolt it back together.

[BAD2000TA]

How should I change them?

[tom s]

Im going to bring this to the top to post some new results I have had.69 Bird and have had 14in Walker ST mufflers with 2 diff engines.366 RA V with headers and a 455 with a SP II and long branch.Both setups with a H pipe and 2 1/2 back over the axles.No issue with drone at 2000 or anywhere else.Fast forward to last week.I pulled the 455 and put in a 434 RA V with a 239-245 cam and a set of shorty custom headers.HUGE diff in sound level.86 dec at 2000 in 4th or 5th gear.My shop wanted me to try the 18in Walkers,better but not much 84 dec at same RPMs.He is going to pull them and put on a non performance set of mufflers.Will report back.The 18s made a lot of diff at idle over the 14s.FWIW,Tom

[Lee]

Originally Posted by BAD2000TA

How should I change them?

Note where you are on the timing table when the drone is occurring. Try adding a few degrees timing and see if the drone changes. Or take out some timing. Just play around and see what happens.

You can do things with timing table tuning that could NEVER be done with a mechanical/vacuum advance distributor (not without adding complications that would make a watchmaker gasp).

[tom s]

I have the timing where I and the engine likes it,im done with performance mufflers with this compo.If stock type mufflers cost me 50 HP I care less.Comfort of driving at my age is way more important.Just posting as I really think the issue is the shorty headers and the cam.I have had this car for a long time with MANY diff engine combos and diff mufflers and both X and H pipe.This is the first combo that has really sucked!Tom

[allenga]

Do you think shorty headers contribute to drone. Thinking about pulling shorty headers, going back to stock manifolds or to RAM Air factory headers.

Also, thinking, keep my too quiet mufflers on and going with exhaust cut-outs for when I want some rumble.

[napster]

Allenga,

I use to have a 1969 Grand Prix and had the Spintech Sportsman XL mufflers on it. I will never get a Spintech again. The resonance gave me a headache.

Here is the formula for the exhaust system I like. Ram Air III or IV manifolds and Dougs long tube headers into Flowmaster American Thunder series with H-pipe and Texas TA mufflers.

Ram Air IV Manifolds:
https://www.youtube.com/watch?v=IsmQXWoIMSU
https://www.youtube.com/watch?v=AXveB8zehOw

Dougs Headers:
https://www.youtube.com/watch?v=QVzzzFoUWPg
https://www.youtube.com/watch?v=OjFDfmyE7lQ

I have other cars with the Dougs headers and a Pypes system with an X-Pipe and still think they sound good, but really like the way the H-pipe makes the the exhaust note sound along with an accent on the lope of the cam.

Jim

[moontower69]

Simple answer: YES Headers contribute to overall noise and drone. Hard to say exactly in what percentages based on other factors like pipe diameter and mufflers and placement and install and X or H pipe placement, etc.

For Pontiacs, the stock logs are quietest and good for any daily driver that doesnt race or need to rev regularly past 5200-5500. I love them.

For quiet and added performance, the Ram Air Restoration "headers" are still VERY quiet and can scream to 6000 rpm without choking performance.

Pair with 17749 20" Dynomax Superturbos with 2.5 inch pipes and an "X" pipe and you get low stock muscle car rumble, NO drone and great performance. Don't waste your time worrying about "mandrel" bends in the pipe unless you care about racing and squeezing that extra 1/10th of a second or two in quarter mile times...drive and enjoy like the cars were designed to do....

For that extra rumble I guess the Magnflows can't be beat but then there's a risk of drone at around 1600-2200 RPM, been there done that.....

[allenga]

Originally Posted by moontower69

Simple answer: YES Headers contribute to overall noise and drone. Hard to say exactly in what percentages based on other factors like pipe diameter and mufflers and placement and install and X or H pipe placement, etc.

For Pontiacs, the stock logs are quietest and good for any daily driver that doesnt race or need to rev regularly past 5200-5500. I love them.

For quiet and added performance, the Ram Air Restoration "headers" are still VERY quiet and can scream to 6000 rpm without choking performance.

Pair with 17749 20" Dynomax Superturbos with 2.5 inch pipes and an "X" pipe and you get low stock muscle car rumble, NO drone and great performance. Don't waste your time worrying about "mandrel" bends in the pipe unless you care about racing and squeezing that extra 1/10th of a second or two in quarter mile times...drive and enjoy like the cars were designed to do....

For that extra rumble I guess the Magnflows can't be beat but then there's a risk of drone at around 1600-2200 RPM, been there done that.....

I would think the headers would vibrate easier and transmit that vibration though the whole system.

[Tom Vaught]

I would agree that the shorty headers and your engine are not happy with each other.
would go with the production mufflers and if necessary get rid of the shorty headers.
Put some regular RA-V manifolds on the car if you have them.

Tom V.

[389]

X pipes made these cars sound like *****... Just run two pipes out to the back and use the Dynomax Super Turbo and you have an excellent exhaust system..

[The Champ]

Originally Posted by 389

X pipes made these cars sound like *****... Just run two pipes out to the back and use the Dynomax Super Turbo and you have an excellent exhaust system..

The DynoMax Super Turbos sound great with the X pipe. Been running those mufflers for 7 years with an X pipe.

[David Jones]

We rode 50 miles down to lock 17 On the Warrior river in the GTO this afternoon. Had a great picnic, then rode 50 miles back. In the woods. BEAUTIFUL day. 70. Sun. We talked the whole way. Dynomax Super Turbo’s.

[Formulajones]

Agree with Champ. We run X pipes on everything here, Fords, Chevrolets, and the Pontiacs. Most with Dynomax Ultraflows, some with a handful of other brand mufflers. No complaints from anyone in our camp about sound quality.

[NeighborsComplaint]

Goerlich has been gone for years. The brand was bought by AP Exhaust Technologies. They are called AP Xcelerators now. I have them on my '71 and they drone with an H pipe I am switching back to Flowmaster 40's for that sound. I was willing to compromise on tone for no drone, but it didn't work out that way.