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#101
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I liked the Dr. Gas stuff. Made specific per application. Too bad he's not around anymore. |
#102
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#103
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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
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#104
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Sorry misunderstood thought it was on a bird..
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1973 Firebird Navajo Orange w/shaker,1973 400/461,1972 Intake SD CNC'd,1977 Q-Jet 800 CFM w/ Cliffs Kit,Tanks Inc PA4 255 Walbro intank pump ,-8an feed/return,RobbMc Regulator,RobbMc 40 micron filter,253 CFM 6x-8's w/H.S 1:5 Roller Rockers,SD Stump Puller H/R Cam 230/236 @.050 112 lobe separation 565/.570 lift,Crower Solid Rollers,28150 Hedman Headers,3" exhaust,full tailpipes,350 Turbo,9.5" 3200 Converter,3:42 gear,8.5 posi,C/E slide-alinks,Koni adj frt shocks,Best 12.18@110.55 Lookin for 11's |
#105
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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.
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust |
#106
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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. |
#107
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How should I change them?
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2001 Pontiac Trans Am WS6, 6-Speed, LS6 block, TEA LS6 heads, 4" SCAT forged crank, SCAT H-Beam rods, 226/234 cam, McLeod RST clutch, SLP Lid, SLP Power Flo Catback 1980 Pontiac Trans Am Y-84 Bandit WS6, 455 (.030 over), #96 Heads, Hedman headers, Wolverine 234/244 cam, Performer intake, Holley Sniper "Need a car to run blocker. Speedy car. Speedier than that....." |
#108
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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
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#109
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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).
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust |
#110
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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
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#111
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Still planning next exhaust move..
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. |
#112
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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 |
The Following User Says Thank You to napster For This Useful Post: | ||
#113
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Headers & drone
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.....
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1974 Lemans Sportecoupe GT (daily driver) .030 over 354, #47 heads (84cc), Lunati voodoo 700 camshaft (207/213 @ .050), logs, 2.5 duals, X-pipe and Dynomax super turbo mufflers, 3.08 rear Last edited by moontower69; 10-03-2020 at 04:11 PM. |
The Following User Says Thank You to moontower69 For This Useful Post: | ||
#114
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#115
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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.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
The Following User Says Thank You to Tom Vaught For This Useful Post: | ||
#116
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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..
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The Following User Says Thank You to 389 For This Useful Post: | ||
#117
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The DynoMax Super Turbos sound great with the X pipe. Been running those mufflers for 7 years with an X pipe.
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#118
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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.
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frittering and wasting the hours in an off hand way.... 1969 GTO, 455ci, 230/236 Pontiac Dude's "Butcher Special" Comp hyd roller cam with Crower HIPPO solid roller lifters, Q-jet, Edelbrock P4B-QJ, Doug's headers, ported 6X-8 (97cc) heads, TKO600, 3.73 geared Eaton Tru-Trac 8.5", hydroboost, rear disc brakes......and my greatest mechanical feat....a new heater core. |
#119
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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.
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#120
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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.
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Triple Black 1971 GTO |
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