Exhaust Pressure Testing

[engineermike]

Just an update....I spent Saturday morning welding up numerous cracks in my friend's Stainlessbros resonator. The center piece/wrap of the body is super thin and the welds cracked top, bottom, and the longitudinal seam. I'm 100% sure pressure didn't cause this because the rest of his exhaust is dual 3" straight through. I welded on some reinforcement, so he's probably good to go. But for anyone else looking to go this route I would consider that Jones MF2469 that @TEXAS HEAT recommended.

@TEXAS HEAT you're 100% sure it's a full dual 3" all the way through and doesn't bottleneck at the "waist" of the internal X?

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[Joshinator99]

Just an update....I spent Saturday morning welding up numerous cracks in my friend's Stainlessbros resonator. The center piece/wrap of the body is super thin and the welds cracked top, bottom, and the longitudinal seam. I'm 100% sure pressure didn't cause this because the rest of his exhaust is dual 3" straight through. I welded on some reinforcement, so he's probably good to go. But for anyone else looking to go this route I would consider that Jones MF2469 that @TEXAS HEAT recommended.

@TEXAS HEAT you're 100% sure it's a full dual 3" all the way through and doesn't bottleneck at the "waist" of the internal X?

We had a multi-page discussion about this exact same muffler over on the Camaro6 forum. The Jones MF2469 is a true 3” X all the way through (not a double Y) but apparently for a while they were mistakenly packing and shipping the slightly more restrictive double Y version in the box. Supposedly that’s been figured out and corrected but you’re probably on the right track to double check when you receive the muffler.

I’m still running the Magnaflow double Y version at 1059 WHP but thought about swapping it out for the Jones true X version listed above… the double Y version has to be a restriction at some point, right?!?

 

[TEXAS HEAT]

Just an update....I spent Saturday morning welding up numerous cracks in my friend's Stainlessbros resonator. The center piece/wrap of the body is super thin and the welds cracked top, bottom, and the longitudinal seam. I'm 100% sure pressure didn't cause this because the rest of his exhaust is dual 3" straight through. I welded on some reinforcement, so he's probably good to go. But for anyone else looking to go this route I would consider that Jones MF2469 that @TEXAS HEAT recommended.

@TEXAS HEAT you're 100% sure it's a full dual 3" all the way through and doesn't bottleneck at the "waist" of the internal X?

@engineermike

The Jones resonated muffler is a dual 3" tru-x and does not neck down once inside the case. I think I posted images of mine, and it is clearly designed an x-pipe

 

[K4fxd]

I just got one today and it is not an X pipe center. It has 2 3 in pipes on one side they stop about 6 inches into the muffler to an open chamber then there are 2 3 in pipes going out of the case.

Is yours a true X?

@TEXAS HEAT

 

[K4fxd]

Here is a crude drawing of the muffler MF2469

Looks to me like this is going to cause a bunch of turbulence or back pressure.

What do you think @engineermike

 

[engineermike]

Does it not look like post 363 anymore?

 

[K4fxd]

Does it not look like post 363 anymore?

Kind of

 

[K4fxd]

 

[engineermike]

I replaced my friends busted stainlessbros resonator+H pipe with the Jones equivalent this morning and we were both shocked as to the sound level. His car is full dual 3”/no cats from the collectors back, Jones muffler with built-in X, and corsa touring mufflers. It’s very quiet at light loads through the full rpm range, possibly as quiet as stock. At wot it’s a bit louder but that’s to be expected. This is my new favorite combo. When my stainlessbros fails I’ll install one as well, as it should be even quieter with the cats.

 

[cbrtrx]

A sound clip would be nice. I think the Jones will become a littler louder in about 1000 miles.

The Jones is just a stamped X/H section like the Magnaflow which is the worst version of an X pipe but common for cost reasons, I wish a company made a true resonated x section.

 

[engineermike]

I believe the stamped x to be lower restriction vs a true x because it doesn’t neck down so much at the “waist”.

Conversely, I think the magnaflow is the worst because it’s a double Y meaning there’s a short section of single exhaust in there in some models.

 

[cbrtrx]

I believe the stamped x to be lower restriction vs a true x because it doesn’t neck down so much at the “waist”.

Conversely, I think the magnaflow is the worst because it’s a double Y meaning there’s a short section of single exhaust in there in some models.

It's not just about the neck down it's about turbulence. The stamped Xs are turbulent especially at lower rpms because of the exhaust pulses tumbling all around, that's why they are usually quieter as well. A proper sized true X increases velocity as the pulses go through creating slightly more power just like a true merge collector on a header they increase velocity at the neck down then flare out again. The gains aren't huge either way but I've tested every X/H version back in the day at around 500 rwhp and the formed x pipe had the least peak hp. Also on s550s the crossover is placed way too far back to offer much difference except for sound.

 

[18psi]

this is the one you're discussing? https://www.mustang6g.com/forums/th...-too-loud-or-drones-too-much-try-this.133777/

 

[GregO]

I replaced my friends busted stainlessbros resonator+H pipe with the Jones equivalent this morning and we were both shocked as to the sound level. His car is full dual 3”/no cats from the collectors back, Jones muffler with built-in X, and corsa touring mufflers. It’s very quiet at light loads through the full rpm range, possibly as quiet as stock. At wot it’s a bit louder but that’s to be expected. This is my new favorite combo. When my stainlessbros fails I’ll install one as well, as it should be even quieter with the cats.

Will you retest your exhaust back pressure test after installing the Jones mid-muffler ?

 

[cbrtrx]

I tested at 12 lbs with a centrifugal. Catless longtubes to a completely stock catback with internal 2 inch neck down then tested a full 3 inch straight through exhaust set up, results were about 25 rwhp at peak rpm (7800). Gains started around 5k on up. Also it was almost 30 pounds less weight then stock. That being said though I'm not sure if the cost and in my opinion poor sound is worth the 20 to 25 hp. In this application I didn't add any timing because I've found no significant gains by doing so. This was on E85 where I'm not knock limited either.


Also Flowmaster FX series makes a 409 stainless perforated core muffler with identical specs as the Jones but it's almost double the price. I called Jones and they said his has no connection between theirs. His is made in China, I'm guessing the flowmaster is as well because they only offer a 1 year warranty on the FX series.

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