As the subject states... I'm now working on my 3rd repair to my 4 year old Dynomax Ultraflo's. I've popped the welds at the end caps to the case on both mufflers (about 3" lengths have popped) and now on one of the mufflers I have about a 4" crack over the "Dynomax" stamped logo in the main body, which is tracking the letters and making its way up the "A" at the moment.

I really like the sound (and quiet cruising) but I'm somewhat disappointed with the lifespan of these suckers. Anyone else have this problem?

So, I'm looking to replace them. This time I want 3" inlet & outlet, offset/offset configuration (on different sides) and I want a case length between 16"-20". I'm currently running the 14" case Ultraflo's and get a lot of popping on overrun, a bit more muffler volume will help in that department so I want to go with larger case size.

I see Dynomax offers a 20" case Ultraflo in the configuration I want but given the rather short lifespan of my current mufflers I was hoping to find something matching my specifications in stainless. Any suggestions? Definately want a straight through perforated core design. I see Magnaflow offers a 22" case muffler but given my current exhaust configuration I can't quite swing that and I don't feel like reworking my system. I really wanted a set of Borla XR1's but they are center/center only and would require substantial pipe rework to get them to fit, so they're out too unfortunately.

Any other suggestions?

Thanks...

I've been using the Dynomax Ultraflos for 4 yrs or so and no problems with them. I'm using 3" pipes, 3" H pipe, with mufflers at the rear with dumps. No problems here at all.

I'm running 3", 18" cased Magnaflows. They are off/off. I really like they way it sounds (quiet at cruise, loud wot). These are stainless...they didn't have the regular finish in this config. Plus, they have stainless steel packing instead of the fiberglass/wool..should last alot longer.

I loved my Dynomax ultra flow's. I was severely disappointed when the muffler shop that I have been using for years told me that they weren't carrying them anymore.

When I asked why he said that the Dynomaxs used too thin of a shell and they were tired of replacing them for people.

They suggested the Magnaflows as very similar in sound as they are both straight pass thru's but told me the Magnaflow utilized a heavier gauge case and a steel wool type insulation instead of the glass packing in the Dynaflows and would last much longer.

I've used them on two vehicles now, my V8 Grand Cherokee and now my Buick Special. Even though the shop has started carrying Dynomax's again due to popular demand, I've decided to stick with the Magnaflows.

Actually I've not had a failure with either brand personally.

Greg

I'm running 3", 18" cased Magnaflows. They are off/off. I really like they way it sounds (quiet at cruise, loud wot). These are stainless...they didn't have the regular finish in this config. Plus, they have stainless steel packing instead of the fiberglass/wool..should last alot longer.

Cool, another option. I didn't even bother looking at the polished page but you're correct, they don't offer a 3" offset/offset 18" case in the satin finish but do in polished (wonder why?) I could always scotchbrite or mediablast them and bring them back to satin.

Still soliciting ideas, keep them coming...

No problems with mine (yet).

Have you checked to make sure you don't have excessive backpressure for whatever reason? Unlikely, but who knows?

What about some Hooker maxflows??? Supposed to flow 595cfm and have a straight through design similar to dynomax. But the case is very beefy.

I've been using the Dynomax Ultraflos for 4 yrs or so and no problems with them. I'm using 3" pipes, 3" H pipe, with mufflers at the rear with dumps. No problems here at all.
Same here...no problems! :thumbsup:

I ran some for several years, everything was fine.

First time I had an ignition problem, and raw fuel from a non- or poorly-running cylinder got dumped in the exhaust, it was all over with. They ballooned up like any other muffler when the fuel exploded inside them.

I'd be inclined to suspect that something along those lines is happening; either you're way rich at WOT, or have an intermittent miss, or way rich on decel, or something like that. Especially with a blower, it's pretty easy to end up with an unexpectedly rich tune under some condition(s) or other. At some point, for some reason, you have raw fuel passing through the engine and ending up in the mufflers, and subesquently igniting and blowing up the muffler. You might be able to hear it as a loud popping noise in the exhaust.

NO muffler will stand up to that for very long.

I ran some for several years, everything was fine.

First time I had an ignition problem, and raw fuel from a non- or poorly-running cylinder got dumped in the exhaust, it was all over with. They ballooned up like any other muffler when the fuel exploded inside them.

I'd be inclined to suspect that something along those lines is happening; either you're way rich at WOT, or have an intermittent miss, or way rich on decel, or something like that. Especially with a blower, it's pretty easy to end up with an unexpectedly rich tune under some condition(s) or other. At some point, for some reason, you have raw fuel passing through the engine and ending up in the mufflers, and subesquently igniting and blowing up the muffler. You might be able to hear it as a loud popping noise in the exhaust.

NO muffler will stand up to that for very long.

Car runs about 11.5:1 at WOT (wideband A/F sensor) and is dead lean on decel-- the WBO2 goes off scale lean and pegs at 16:1 when I back off the gas. I've got it set for almost zero fuel on the VE table and very high timing (50+ degrees) during decel conditions.

If the car were carb'd or someone elses, just as you said I would suspect an overly rich/fuel dump/poor ignition condition initially as the cause too (a friend and I use to purposely grenade mufflers on his flatbed by revving it up, shutting the key off, pumping the gas like crazy then switching the key back on) but I'm 99% sure that's not my problem. The pops I get out the back during overrun are more pronounced than a glasspack "burble" but definatley aren't "pump the gas with the key off" kabooms that would indicate a dead-rich overrun condition and the condition of the mufflers don't indicate that as they are not ballooned in any way; either the case welds split or as I have now just a crack in the case. The case isn't bent/distorted/balooned at the crack either, appears to simply be a fatigue/stress crack in the case.

Still, won't hurt to do some checking and just make sure there isn't another cause.

I just took off a pair of the 20" case, 3" in/out, offset/center Dynomax Welded Ultraflow mufflers. They can't be made of thin materials as they weighed 17 lbs a piece! The weight was the only reason I took them off. Great mellow sound. I ran them for three seasons and they still looked new when i took them off. Not heard of anyone splitting cases on them here locally.

Magnaflow. Strong azz mufflers.

I use the Sears Muzzler for $24.99, full lifetime warranty.

I use the Sears Muzzler for $24.99, full lifetime warranty.

Get out of here :eek: .

I use the Sears Muzzler for $24.99, full lifetime warranty.

How do they compare to Midas or Meineke? I really dig the "leaf blower pushing air through a bendy-straw" sound.

How do they compare to Midas or Meineke? I really dig the "leaf blower pushing through a bendy-straw" sound.


LOL....Can't beat the Muzzler !!!!

I use the Dynomax Super Turbo's and do not have a problem with them. I was interested in your post as I was surprised to hear a problem with the ultra flows.

I used 3" hooker maximum flows on my sbc for years very durable muffler and at idle and part throttle are fairly quite as opposed to the chambered mufflers they replaced.

Shawn

Magnaflow and Borla XR-1 mufflers are popular among rotary guys. They are one of the very few (only?) universal fit mufflers that can withstand the heat and backfiring tendencies of a rotary engine. If they can survive in that environment, they can live a long happy life behind any piston engine.

Have you had a chance to check out some Spintechs?

I bought a pair of Sportsman XL's. They are built very strong & weigh about 15lbs. each. If you blew one of these you might get some shrapnel.

I'd like to tell you that they sound great(and they do at idle)but I don't have enough engine to fill them yet. After I had the new exhaust installed I had to turn the idle down some because it idled faster than the old pipe.

Saw a chart floating around the 'net that made the Hooker muffs look real good.

~JM~

Yes, I did briefly consider Spintechs. A couple friends have them (and another friend owns a muffler shop that's a dealer for them) and while I love the sound and tone they are too loud for my tastes-- especially in the car. That's what I like about my current Ultraflos, they are loud and nasty when I'm on it but are nearly silent in the car at steady-throttle cruise. My friends cars with Spintechs (both with and without X-pipes and with and without catalytic converters) tend to drone and are always more audiable than I prefer even at cruise inside the car.

Also, I've heard several reports where they lost HP to a straight through style muffler; 66 283 (on this board) saw them sap over 40hp (albeit on a 1000hp car.)

Right now I'm leaning towards the 18" case Magnaflows-- hoping for a tone similar to my current Ultraflo's but with a overall lower SPL because of the larger case volume.

[QUOTE=Gokou] Yes, I did briefly consider Spintechs...
...I've heard several reports where they lost HP to a straight through style muffler; 66 283 (on this board) saw them sap over 40hp (albeit on a 1000hp car.)
[QUOTE]

Hmmm... 40hp? That's not good.

Mine's pretty quiet & no drone but it might be a different story when the 406 replaces the 305.

Here's that chart I was talking about. Of course I didn't see it until after I bought what I have now.

http://www.broaderperformance.com/muffler_flow_tests.htm

~JM~

Quiet? Spintech? I didn't know you could say those in the same sentence unless they were seperated by "not". :p

Then again all my friends have the itty-bitty "Pro-Streets" -- I've never heard the Sportsmans or what I was considering, the Sportsman XL or the Truck/SUV models.

I've not had any problems with mine when I had a pair of Ultraflows on my last hot rod.

I happen to have a pair sitting in the garage awaiting for me to do something with them.....maybe I oughta send 'em back to Summit?

Magnaflows, Magnaflows, Magnaflows. Very well built mufflers, a similar sound to what you already have and they come with a LIFETIME WARRANTY. How can you go wrong?

the stainless dynomax ultraflo i put on my tow vehicle isnt holding up well at all.
They must have used the cheapest stainless on the planet. It looks terrible in comparison to the type 304 tubing infront and behind it.

If you use a stainless muffler, make sure its a 300 series stainless, if they dont specify its probably 400 series which will last a long time, but will have a corroded look to it.

I have a pair of steel Ultraflos on the Camaro, and they're holding up well. just under 3 years on them now and they dont show any sign of weakness :D

I recently built a stainless exhaust system and used a set of Magnaflow stainless mufflers for my Boss' Camaro. They're an extremely nicely built muffler. We'll see how they hold up.

Kooks makes nice stainless mufflers also, but i dont know if they will be quiet enough.
Brian

I've pretty much decided on the 18" case offset/offset 3" Magnaflows. Just need to place an order with Summit and will put them on on next Friday (my day off.)

Wish they made them in Satin, I don't feel like paying extra for the polished cases when the first thing I plan on doing is taking scotchbrite to them. The only thing polished on my car is the lips on the wheels and that's as much as I want to be polished. :p

I didn't want pay for the stainless/polished also, but I has no choice. BUT...the finish has grown on me. I'm usually irritated when I'm under my car. When I see the muffs, they look so good that it makes me feel better.

I got Summit to drop 25 bucks for the pair of muffs to lessesn the pain a little. Do a google search for the cheapest price, Summit will match it.

Let us know how you like them and how they compare to the Ultra's.

Some good reading:

http://www.chevelles.com/forums/showthread.php?t=108790&highlight=pypes

http://www.chevelles.com/forums/showthread.php?t=107370&highlight=pypes

http://www.chevelles.com/forums/showthread.php?t=108614&highlight=magnaflows+installed+perfect

http://www.chevelles.com/forums/showthread.php?t=107555&highlight=magnaflows+summit

Try these guys:

http://www.performancepeddler.com/search_results.asp?txtFromSearch=fromSearch&txtsearchParamType=ALL&txtsearchParamMan=ALL&txtsearchParamVen=ALL&txtsearchParamCat=ALL&subcat=&iLevel=1&txtCatName=&txtsearchParamTxt=14264&x=5&y=7

Wish they made them in Satin, I don't feel like paying extra for the polished cases when the first thing I plan on doing is taking scotchbrite to them. The only thing polished on my car is the lips on the wheels and that's as much as I want to be polished. :p


Why, your car never gets dirty anyway! :waving:

Jody

Why, your car never gets dirty anyway! :waving:

Jody

My car? Dirty? LOL!

I should have taken pictures of the foilage that I extricated via the rust hole in the bottom of my front fender a couple weeks back. I started looking for a pine tree growing in the cowl because of how many pine needles fell out... I parked under a large pine tree for all of high school, tells you how long those pine needles have been in there!

Now I'll have to buy one of those pine-tree shaped air fresheners and chuck that down the "no mans land" between the fender and cowl to replace the smell of the real thing.

Your cars on the other hand are never dirty. :p

I have ultra flows behind my 540 and really like them. They have only been on fo about 3 months though. For the first time in years my head was not ringing after a 3 hour road trip, I had flowmasters in the past. I was told from dyonmax they have a lifetime guarantee to save my reciept.

Today I put my car up on the lift and welded up the crack in the one muffler, chances are I'll be installing the new Magnaflows next Friday morning.

Here's the interesting part... I stop drilled the crack first with an 1/8" bit. I drilled 3 holes and I didn't get ANY fiberglass packing material out of any of the holes on the bit and I didn't see any when I looked into the case with a flashlight. Couldn't get any out by fishing around with a real small hook either!

Seems there is none or next to no packing left in the mufflers.

When I change the mufflers I'm going to cut them up and see what is left. I don't expect to find much, if anything. Amazing they're quiet at cruise right now if indeed all the packing is gone.

Also, surprised that the case cracked, it's pretty thick! Probably 16 or 14 gauge body. The stamped "Dynomax" logo is obviously effective as a stress riser. LOL!

Hey, I saw your car at Friday night live the other nite. I like the new wheels. Looks killer. I had the gray/silver 69 Camaro up by the sign in booth.

Hey, I saw your car at Friday night live the other nite. I like the new wheels. Looks killer. I had the gray/silver 69 Camaro up by the sign in booth.

Thanks! Saw your Camaro too, very nice. Thinking of going charcoal gray / silver on mine too, but don't know yet.

These Mufflers wasn't mentioned so I'll bring them up.

http://www.pypesexhaust.com/mufflers.html