New Flowmaster FX "Magnaflow-style" straight-through mufflers?

So I'm about to replace both cats on my '96 Roady Wagon with Magnaflow cats I bought on Ebay.  One of my original cats is broken inside and rattling.   They are on order now.  Since I'm doing these, I'm considering upgrading the mufflers next.

I've recently removed the stock resonators, and it's louder now...and I like the sound, but sure-enough, I have some "Flowmaster-drone" at around 50-60mph now.   I'm thinking of replacing those 11-year-old Flowmaster 40's soon, and my exhaust guy is pitching me on the new Flowmaster FX, which is a Magnaflow-style straight-through design, not a traditional chambered Flowmaster like my 40s.   The main attraction here is that these are cheaper than both the Magnaflow or the Dynamax.  

Anyone have any experience/heard these?    I'm told they should be a little quieter than the 40's, but will help with the drone and will still sound moderatly loud.    

https://www.flowmastermufflers.com/flowfx/

I was also considering having them modify my stock pipes by adding a crossover pipe to balance the sound, but not sure of that's worth doing on stock pipes.  Has anyone done this, and where did they add the pipe?

Thanks All!

-Texas Mike

Never heard these, but I ran Dynomax straight throughs similar to those on the 94, and should help some with the drone. These cars pick up drone like crazy tho. Sounded fantastic, just a little head rattley.

On the 93 (TBI single pipe) I replaced my stock muffler with a glasspack, and no resonator and it droned. Catalytic clogged and no checks around here, so that became a glasspack too. Droned like crazy! Replaced the original resonator with another glasspack. Now the drone is effectively gone, but it's also much quieter outside than I wanted. (Methinks I need side exit pipes behind the front wheels. Can't resonate with the body if it's not near the body for long!)

Sounds good, but to get rid of drone I had to make it quiet. That rear section of the car resonates like crazy even with the dynomat all over the floor of the car.

The crossover might make it better, but I've never tried it on one of the wagons.

I guess I'll see. I may try these new FX mufflers. Did some reading on them and like what I read.

We'll see.

-Mike

On a 1996 Roadmaster and 1996 Caprice, I used 3" pipe from the cats back, Walker muffler of the same OAL as the stock muffler, 2.5" H-pipe connection before the mufflers, and deleted the resonators. No drone whatsoever. Nice low frequency rumble outside when you step on it. Relatively quite inside at cruising.

I think you'd be happy with an X-pipe system, Mike. They are a little quieter than straight back duals.

If you really want to go first class, you'll need the O-pipe from Kale.  See:  http://kalecoauto.com/index.php?main_page=product_info&products_id=41

Amateur hour.

First class is direct exhaust injection. 100% efficient:

I have a pair of Magnaflows on my 454, and it still drones (or is just loud). I dumped them in front of the rear axle. I am considering over the axle and behind the wheel exit pipes. I read somewhere that someone did that, and it cured the drone. He discovered it when the drone stopped on a steel grid bridge.

The kalecoauto.com site is simply wonderful. If they don't have what you need, you don't need it.


The DEI system was actually under development by the Nazis (really) for submarines. The gas analysis instruments available at the time were not reliable enough to precisely meter in the pure O2 to prevent the engines from grenadeing, and the system never made it into production.

It's been my experience that these cars drone whenever the resonators are removed simply because of the pipe length between the mufflers and the exit causes a resonance around 1400-1500rpm. If you look at ANY new vehicle, they all have mufflers or resonators within 18" of the tailpipe exit for this reason. If I had to do it all over again, I'd choose a nice muffler and then leave resonators in place. Any aftermarket muffler can be used as a resonator, just something to break up the standing waves before they reflect off the tailpipe exit.

Quote :

It's been my experience that these cars drone whenever the resonators are removed simply because of the pipe length between the mufflers and the exit causes a resonance around 1400-1500rpm.

See earlier post: With 3" pipe from the cats back, this has not happened with a resonator delete on either my Roadmaster or my Caprice wagon.

dmg4 wrote:

See earlier post: With 3" pipe from the cats back, this has not happened with a resonator delete on either my Roadmaster or my Caprice wagon.

Yes but can you coherently explain why your setup doesn't have drone? Are you using the stock 1.875" over the axle pipes and tails? I'm not trying pick a fight but there's a reason every single OEM does it the way I described.

Quote :

Can you coherently explain why your setup doesn't have drone?

I didn't mean to sound terse.

How about a tautology rather than a coherent explanation: I don't know why it doesn't drone, but it doesn't.  The pipes are a full 3" and they follow the OEM path up and over the axle and end just short of the rear bumper.  The tips are directed 45 degrees outward at the very end.

Perhaps it's like a weak-winded kid try to get sound from a tuba. The cross-sectional area of the 3" pipe is nearly 3 times that of a 1 7/8 pipe.

Source for those pipes,Dave?

DERP! I just measured the pipes and they are 2.5", not 3".

No wonder women mistrust me.

So, the increase in cross sectional area is about 1.75X over OEM. However, the OEM pipes are sometimes flattened on top immediately behind the cats; not the case with mine, so mine are full diameter from front to back.

My local Monroe Muffler shop mandrel bent and welded both systems for me. So long as they are matching an OEM system part, you are just charged a bit extra for the upsized stock for the pipes.

That's pretty impressive that they have a mandrel bender. No accordion marks on the insides of the pipes?

On the exterior of the pipes there are no accordion marks on the insides of the various bends. I can't see inside the assembled system, but if there is none on the exterior, then I don't see why they would form on the interior of the tube.

There is only one Monroe shop in this area that offers the service, and only one guy in the shop who operates the machine.

The pipes bent on a mandrel have some compression in the area bent, so the size is slightly smaller, even though there are no accordion marks. Hydroformed tubing not only has no accordion marks, the diameter is maintained through the bent parts. Hydroforming requires that the tube is first bent on a mandrel, and then is put in a mold. The tube is sealed, then high pressure water is forced into the tube, and the tube expands to fill the mold. Hydroforming is the premier method of making a high flow system.

So, does anyone have personal experience with FlowFX mufflers? How's their sound?

I have the Flow FX mufflers on my '96 wagon now, replacing the old Flowmaster 40's I'd had on since about '09.   Frankly...I don't like them.   I liked the 40's better.   They have a good burble at idle but are raspy on acceleration.   I'm told I should add a crossover pipe somewhere near the transmission to "balance" the sound...   Regardless...the only realy plus to adding these was the fact that I now have sharp chrome exhuast tips....done at the same time....    





Flow FXs seen here. And YES the welds are ugly. The old Flow 40s were longer. It is what it is...


I installed two new Magnaflow free-flow cats when doing this work.   One of my stocks was rattling so just did both to be safe.


One thing to point out, you will see there is a big metal weight on one pipe.   I at-first removed it, but the re-added it.   You could actually feel a vibration or resonance when driving that is totally gone when that weight is installed.  Many folks told me they just left it off when doing exhaust work, but one of the things I love about my Roadmaster is how SMOOTH it is.   This is part of that!   I've since learned that the Fleetwoods have the weights on BOTH pipes, not just one like the Buicks, and some folks have added the second weight to their Roady after nabbing one at the junkyard.   Gotta be smooth!



I did drive it for a week with no resonators...and hated it, so I did put resonators back on in the stock locations.   It sounded like crap to me without them...booming inside the car at certain speeds.   Sadly the resonators I cut off were trashed, so I had brand-new ones installed.   I will never run without them again.  Learned that lesson the hard $$$ way.   Ouch.



I do think it now LOOKS great even if the sound is not exactly what I was hoping for.   I may try a crossover or add Magnaflows later.   For now I'll live with the FXs.  




-Texas Mike

Video clips? I'd like to hear what your setup sounds like!

brokecello wrote:

Video clips?  I'd like to hear what your setup sounds like!  

Didn't take any...don't like how it sounds!  Ha!   I think I may do a crossover pipe and see if that helps anything.  Pretty sure that would be a cheap mod, rather than changing the mufflers to something else.   Spring project maybe.

81X11 wrote:

brokecello wrote:

Video clips?  I'd like to hear what your setup sounds like!  

Didn't take any...don't like how it sounds!  Ha!   I think I may do a crossover pipe and see if that helps anything.  Pretty sure that would be a cheap mod, rather than changing the mufflers to something else.   Spring project maybe.

Lol..gotcha. I have a X pipe (just bought a generic one from Summit) and they always seem to really help smooth things out / drone. I don't have resonators though. I signed up for Power Tour today and realize I need to reroute my exhaust before then. Your way / stock exit really keeps the fumes from getting sucked back into the car. Debating adding resonators too.

Yikes, those connections and welds at the muffler are horrible looking. Amazed your OCD isn't triggered by that chicken scratch

Not surprising to hear that the mufflers suck. Most all of those "straight through" types are raspy and full of cackle. They are just square glass packs. Worst thing I ever did was to use the magnaflow versions.

94Woody wrote:

Yikes, those connections and welds at the muffler are horrible looking. Amazed your OCD isn't triggered by that chicken scratch

Not surprising to hear that the mufflers suck. Most all of those "straight through" types are raspy and full of cackle. They are just square glass packs. Worst thing I ever did was to use the magnaflow versions.

Yep I'm not happy with the welds on the mufflers, especially the driver's-side one. Normally that shop does great work, but the FX mufflers were shorter than the 40s, and they had to space them...and it was just generally frustrating. The resonators and chrome tip welds look much better. It is what it is.

-Mike

81X11 wrote:

94Woody wrote:

Yikes, those connections and welds at the muffler are horrible looking. Amazed your OCD isn't triggered by that chicken scratch

Not surprising to hear that the mufflers suck. Most all of those "straight through" types are raspy and full of cackle. They are just square glass packs. Worst thing I ever did was to use the magnaflow versions.

Yep I'm not happy with the welds on the mufflers, especially the driver's-side one.   Normally that shop does great work, but the FX mufflers were shorter than the 40s, and they had to space them...and it was just generally frustrating.  The resonators and chrome tip welds look much better.  It is what it is.

-Mike

Yes, the rest of it looks much better. It's like one guy did everything but that last muffler, lol.

94Woody wrote:

81X11 wrote:

94Woody wrote:

Yikes, those connections and welds at the muffler are horrible looking. Amazed your OCD isn't triggered by that chicken scratch

Not surprising to hear that the mufflers suck. Most all of those "straight through" types are raspy and full of cackle. They are just square glass packs. Worst thing I ever did was to use the magnaflow versions.

Yep I'm not happy with the welds on the mufflers, especially the driver's-side one.   Normally that shop does great work, but the FX mufflers were shorter than the 40s, and they had to space them...and it was just generally frustrating.  The resonators and chrome tip welds look much better.  It is what it is.

-Mike

Yes, the rest of it looks much better. It's like one guy did everything but that last muffler, lol.

I thought about grinding it myself to make it look a bit better, but have not messed with it yet. Never done!

-Mike

81X11 wrote:

94Woody wrote:

81X11 wrote:

94Woody wrote:

Yikes, those connections and welds at the muffler are horrible looking. Amazed your OCD isn't triggered by that chicken scratch

Not surprising to hear that the mufflers suck. Most all of those "straight through" types are raspy and full of cackle. They are just square glass packs. Worst thing I ever did was to use the magnaflow versions.

Yep I'm not happy with the welds on the mufflers, especially the driver's-side one.   Normally that shop does great work, but the FX mufflers were shorter than the 40s, and they had to space them...and it was just generally frustrating.  The resonators and chrome tip welds look much better.  It is what it is.

-Mike

Yes, the rest of it looks much better. It's like one guy did everything but that last muffler, lol.

I thought about grinding it myself to make it look a bit better, but have not messed with it yet.   Never done!

-Mike

Never is right. I have a giant list of things to do to mine. One of those is to pull the exhaust for some new mufflers. Mine is home made and held together with band clamps though.

Turning wrenches for a living kills any desire to work on things at home so my progress is very slow.

Hey mike I watched the video on your flo 40’s and liked that a lot and wondered why you didn’t go with them again, are they not made any more.

rxxdr wrote:

Hey mike I watched the video on your flo 40’s and liked that a lot and wondered why you didn’t go with them again, are they not made any more.

michael-massey

When my catalytic converter failed it clogged one of the 40's. I liked the 40's, but they could be a bit raspy and boomy at certain rpms, and these new FX mufflers were presented to me as Flowmater's version of Magnaflow mufflers. Everyone said how great the Magnaflows were, so I tried the new FX's.

That's my answer. You live and learn.

The STUPID thing is all this came about because I wanted to add chrome exhaust tips, and decided to remove the resonators at the same time... They used a saws-all to cut the pipes off, and I'm convinced the jarring of the exhaust rattled the converter so much it crumbled, leading to clogging up the 40, leading to new cats, then mufflers, and then installing new resonators because the drone was terrible.

Moral of the story....should have just left everything ALONE.

-Texas Mike