Magnaflow exhaust

[monte0185]

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.

[tommy217xxx]

No advice on pipes here, but I sure like that truck. What year?

[monte0185]

Originally Posted by tommy217xxx

No advice on pipes here, but I sure like that truck. What year?

1991 454 4l80e

[monte0185]

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

[Katrina/10]

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.

[Tilt]

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.

[lowridergmc]

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

[monte0185]

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.

[LuvNLife]

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

[Tilt]

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.

[SkinnyG]

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.

[monte0185]

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.

[monte0185]

Ended up getting 70 series Big Block FlowMasters!! I love the sound of them. Quiet but still rumble some with no drone!!

[riz]

Video of exhaust would be interesting.

RIZ

[79sierra]

Has anybody tried 50 series Flowmasters? I love the sound of the 40's but the drone is killer.

[IHOutlaw]

Chevy k30 flowmaster super 10s - YouTube

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.

[68Timber]

Do you know how long those Magnaflows were? I have a new pair in my parts pile I'm wondering about now. Thanks.

[KQQL IT]

Originally Posted by monte0185

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.

I have a pair of 70's dual 3" on my 73 and love em

[68Timber]

Originally Posted by lowridergmc

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

What size Magnaflows are you running?

[RodsGreen10]

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!

[monte0185]

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.

[bowtiebubba]

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.