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#1 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Magnaflow exhaust
Well I sold my dually cause a friend of mine just had to have it so I went and bought a new one. Its not as fancy but it will be. Anyway It needed exhaust desperately So i had a new set of 2.5" pipe and magnaflows ran with turndowns right after the muffler. Although it was alot better than it was I get a glasspack sound when accelerating. Any Ideas why? Maybe I need some tail pipes with magnaflows? This is my first experience with them.
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#2 |
Registered User
Join Date: Oct 2014
Location: mi
Posts: 359
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Re: Magnaflow exhaust
No advice on pipes here, but I sure like that truck. What year?
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TJ 76 gmc 1500 swb patina finish Dropped 4/5, 350/4 speed 80 Chevy c10 lwb 305/350 |
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#3 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Re: Magnaflow exhaust
1991 454 4l80e
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#4 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Re: Magnaflow exhaust
This was my dually I sold. Kinda wish I hadnt but it allowed me to get a better setup for my 8.1L swap and I got my son his first car with the money as well so It wasnt in vain for sure. LOL
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#5 |
Registered User
Join Date: Oct 2010
Location: Ocean Springs, MS
Posts: 1,746
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Re: Magnaflow exhaust
I put a set of Magnaflows on one of my trucks, and it had that same glasspack blap sound under acceleration. I do have tailpipes. It also had a drone at about 65 mph, and I did not like it. The only thing I could come up with was to replace the mufflers. The exhaust shop said the only thing they had that would be quieter was stock mufflers, so I had them put on. I'm much happier with them. It's still louder than you would think with stock mufflers.
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Gary 1971 Chevrolet C/10 1951 GMC 100 1977 GMC C15 1955 Chevrolet 3100 |
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#6 |
Registered User
![]() Join Date: Jul 2014
Location: Dayton, TX
Posts: 335
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Re: Magnaflow exhaust
I just had dual 3" Magnaflows put on my LS swapped '86. Tail pipes go out the back corners. It sounds good while idling, a little quieter than I was looking for, but has the popping you describe when you get on it. I may swap them out for something different latter on.
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'83 Silverado Step Side '85 GMC short bed. '86 Chevy Step Side Custom Deluxe LQ9/4L80 swap (SOLD) |
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#7 |
Registered User
Join Date: Dec 2012
Location: saskachewan
Posts: 150
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Re: Magnaflow exhaust
just put full 3" exhaust with magnaflows on mine and i absolutly hate it.it is so loud and raps like glasspacks.i have heard a h pipe will help but i am just going to replace them
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#8 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Re: Magnaflow exhaust
Sounds to me like I'm not the only one that dosent like it. Think I may go to 70 series flows. I don't mind the loud part just hate the droning sound at low rpms that the 40 series has. I really thought the MagnaFlow wouldn't do that but my best guess is they are all tuned with catalytic convertor to supply some back pressure.
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#9 | |
At the body shop.
Join Date: Aug 2009
Location: Land of fruits and nuts.
Posts: 5,211
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Re: Magnaflow exhaust
Quote:
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" That didnt make it any newer " " Dont antique the equipment " |
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#10 |
Registered User
Join Date: May 2010
Location: Crossville, TN
Posts: 142
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Re: Magnaflow exhaust
Add me to the "not too happy" list. When I first had the Magnaflows put on, with 2.5" pipes behind the rear wheels, I though he'd installed Magnapacks by mistake, so I crawled under to take a look - he'd used the right ones. The half throttle rap was so loud, it had to be obnoxious to anyone I was passing.
Now for the irony: I just had a new crate 350/260 installed with full length Hedman headers, and it's quiet as heck. I only have about 40 miles on the engine, and it's still in breakin mode (ported vacuum, 8 degrees timing). Even at full throttle, there's only a very slight bit of rap. I kinda suspect it's running lean now, so once it's re-jetted properly, I wonder if that sound will be back... Jerry |
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#11 |
Registered User
![]() Join Date: Jul 2014
Location: Dayton, TX
Posts: 335
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Re: Magnaflow exhaust
I've only been able to drive mine just a few miles with the exhaust on, but didn't notice any drone at all. It does have an H-pipe. Taking it Tuesday to put it on the dyno and finish the tuning, so I should get a better idea of what it sounds like when we're done. If the popping is too bad, guess I'll look at some Flowmasters, as much as I don't want to.
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'83 Silverado Step Side '85 GMC short bed. '86 Chevy Step Side Custom Deluxe LQ9/4L80 swap (SOLD) |
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#12 |
I know the pieces fit
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
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Re: Magnaflow exhaust
What size Magnaflows are you running?
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#13 |
Registered User
Join Date: Jun 2015
Location: Richmond,KY and Knoxville,TN
Posts: 1,584
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Re: Magnaflow exhaust
Borla is the only thing I will run. My setup is 3" from collector back with a x pipe no reducers in my setup. And unless you have over 500hp dual 3" is bigger than you need. That's not my opinion that is fact google it lol. Or call any real muffler/exhaust company. Not a local shop 99% of those people are idiots. Just sayin.
If you want high flow no drone look at the Borla Pro XS line. Nice smooth sound and scream when you stand on the skinny pedal. If you want high flow race with a little drone look at Borla XR1. Sounds pissed off at idle and when you stand on the skinny pedal hell will be unleashed. Lol. Sound is subjective some like some don't. And opinions are like assholes. Good luck man! |
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#14 |
Registered User
Join Date: Feb 2012
Location: Beautiful BC, Canada, eh?!
Posts: 2,227
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Re: Magnaflow exhaust
A Magnaflow is essentially an oval body glasspack - it is straight-through design, hence the sound. The larger body helps absorb more sound at a low speed than a glasspack, and you still get a lot of sound at full throttle.
I am running Dynomax Super Turbos on mine - throatier than a stock muffler, but no annoying drone.
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1961 Apache: "Grabber Orange" Shortboxed, pancake, step-notch, air-ride, boosted-LS 1977 Silverado: Shortboxed & dropped, potato-potato V8 Pontiac Firefly (Chevy Sprint): The ultimate engine swap: 5.7L in a 1.0L bag Lotus Super 7 Replica: Scratch-built street-legal rollerskate |
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#15 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Re: Magnaflow exhaust
Well I'm glad I'm not the only one with this problem. Not that I like the fact we are having this issue giving the money we all spent but I'm glad I'm not crazy and its just me. lol I really think I'm going to go with some 70 series flowmasters.
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#16 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Re: Magnaflow exhaust
Ended up getting 70 series Big Block FlowMasters!! I love the sound of them. Quiet but still rumble some with no drone!!
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#17 |
Registered User
Join Date: Oct 2011
Location: hudson,wi
Posts: 805
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Re: Magnaflow exhaust
Video of exhaust would be interesting.
RIZ |
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#18 |
Registered User
Join Date: May 2015
Location: Parma, Ohio
Posts: 35
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Re: Magnaflow exhaust
Has anybody tried 50 series Flowmasters? I love the sound of the 40's but the drone is killer.
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#19 |
Registered User
Join Date: Dec 2014
Location: Texas
Posts: 30
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Re: Magnaflow exhaust
I hated the sound of magnaflows on a 454 w/carb. glass packs was a high school fad and when I graduated, I graduated to flowmasters. Have an '83 C20 with 350HO with 30 series flowmasters, w/ X pipe. they were dumped behind the muffler and turned out 45*. ran it like tat for 10 years, got tired of the reverb and ran 2.5" pipe out to the corners with 4" tips. K30 I went with flowmaster 10 series, 2.5" pipe, 4" tips out the corners. |
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#20 |
Registered User
Join Date: Oct 2008
Location: Brighton, TN
Posts: 1,267
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Re: Magnaflow exhaust
I really like my 70 series flows I swapped to. Im only running 2.5" but it sounds great. Ill eventually add a H or X pipe at some point but probably not till I swap in my 8.1L. Ill get a video soon for those asking.
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A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together. |
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#21 |
Registered User
Join Date: Jun 2008
Location: joplin mo
Posts: 37
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Re: Magnaflow exhaust
Anyone selling their hated magnaflows? I like them and have them on 4 vehicles. shoot me a txt if for sale 417/291/0912 phill.
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#22 |
I know the pieces fit
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
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Re: Magnaflow exhaust
Do you know how long those Magnaflows were? I have a new pair in my parts pile I'm wondering about now. Thanks.
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