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  1. #1

    Default Mac Prochamber Or High-Flow Cats?

    Okay, so my latest flight of fancy is quieting down my exhaust. Right now, I have an off-road H-pipe that I've mangled for various reasons and is a different size from my catbacks, which bothers me. It's bigger. The catbacks are Flowmaster Super 44s for LX 5.0 Mustang and are non-negotiable at this point. They're staying. My headers are Ford Racing shorties for P heads.

    I've started looking around at my options. I'd thought about adding some resonators to the H-pipe (which I'd really like to replace with the proper size). But it doesn't seem like something many people do, so I'd be in uncharted territory.

    Another option is a used original h-pipe, but I just don't like that plan very much because who knows what I'd be getting. The cats could be plugged or whatever. Plus that just seems like it would be a big jump backwards in power.

    After that, we have a new catted h-pipe. It will definitely quiet the car down, and would still flow better than stock. And the car would stink up the garage less. But those are WICKED expensive. A BBK is like $500! SVE offers a kit that includes high flow cats and an off-road H-pipe and it's up to you to splice them in, which would be an acceptable option.

    Then, I was thinking about it, and since it's a box in your exhaust kind of like a muffler/resonator, is the Prochamber. It's pricey too, but I did read a review that said it quieted down his car with Flowmasters coming from a normal off-road h-pipe. And in theory, I wouldn't lose any power.

    But I put it to you, FEP. What do you think? The car's just too loud for me to drive a lot. And it scares my kids, haha.
    Last edited by ZephyrEFI; 06-02-2017 at 06:48 PM.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  2. #2
    FEP Super Member erratic50's Avatar
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    Default

    Put tail pipes on it. Even just 9" with a turndown makes a huge difference.

    i have pipes from an old MAC kit on mine which has a flange behind the tires for the tips. The car is way louder without the last 18" of pipe.

    high flow cats on a 2.5" X pipe vs off-road pipe makes almost zero difference in my experience.

    my car runs 2.5" 2 chamber series 44 flowmasters. It was nearly NASCAR loud without tailpipes. Is not much past stock with full tailpipes. I got pulled over with the turn downs above the axle for being too loud but it was far quieter than dumps right off the mufflers were.

  3. #3

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    Probably should've mentioned that she's already got tailpipes. We cut the Flowmaster Mustang catbacks and extended them before the mufflers and then again after the axle to fit the longer car.



    So, high flow cats actually DON'T quiet the car down, huh? That's good to know...
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  4. #4
    FEP Super Member erratic50's Avatar
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    Not really. Barely if at all with the Mac X pipe I run now vs an off-road H.

    My headers are BBK 2.5" with 1 5/8" equal shorty setup. Heads are just stock E6's. Was WAY obnoxious without the tail pipes.

    You might try turndown style tips.

    I helped do a few V8 cars with nothing but straight pipes and turn downs -they ran them for years before they got any crap for it. Much quieter than the burned out glass packs (expansion tubes) we used to do.

    You know that drill drill I am sure.... Pour full of diesel and let sit overnight then burn. When they burn out throw them in ice cold water. Shake any crap you can out of them, rattle can them, and put them on..... loud as hell. Makes a small block sound like a giant big block stroker too. Especially is she's lean and generating stupid hot exhaust gas temps.


    Love your car BTW - one hell of a sleeper.

  5. #5
    FEP Super Member mustangxtreme's Avatar
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    Brad you need to replace the Flowmaster mufflers. I bought a set of cat back flows from a gal who had them on their 88 GT. Using the decibel meter on her i-phone she was getting 103db in the drivers seat. The new Flowmaster cat back she put on also hit 103db.
    Dave

    If common sense was common wouldn't it just be sense?

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  6. #6

    Default

    Thanks Erratic. Not so much a sleeper with the loud exhaust, haha. That's part of the reason I want a change. So it better fits the sleeper theme. The other part being long term comfort. I know guys ride open pipe Harleys all their lives or whatever, but I guess I'm just not that hardcore.

    Dave, I knew someone was going to say that. I do remember being a bit underwhelmed by them when I first put them in with the stock h-pipe (quieter than i expected). They are 44s, not 40s, so they're a bit better than typical. I just would rather not go back to the stock h-pipe, like I said above. The mufflers are staying for now, they just sound too damn good. I'll explore other avenues first before I give up on them. I also know i DON'T like the way Magnaflows sound.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  7. #7
    FEP Super Member erratic50's Avatar
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    The Dynomaxes I had before the Mac kit actually sounded better than my flowmasters 40's or the Mac mufflers.

    ive been tempted to throw on an SLP kit just because I can.

  8. #8
    FEP Senior Member danco86's Avatar
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    Brad,
    I spent quite some time researching changing out my exhaust last year.
    I have BBK shorties, and off road 2.5" h-pipe. I had the same flowmaster American thunder super 44 polished stainless tip catback system you have.
    I too, loved the sound, especially at idle. The wife hated that she could hear me coming home a mile away.
    For me, the 2k rpm drone was the killer. I could not take it anymore.
    Anyways, I was also getting sensitive to the exhaust smell. Even tuned and dialed in, you won't lose the smell with no emissions.
    So, to get to my point, the first thing I did was buy a set of magnaflow metallic spun cats, and installed them into my off road h. The part number for the cats is 59956, and they are available cheapest on amazon.

    https://www.amazon.com/gp/aw/d/B000V...fXL&ref=plSrch

    These babies are awesome. They fit in the limited space I had, and took away all the smell, and don't need thermactor air. BUT they did nothing to quiet down the exhaust at all. I ended up cutting out just the mufflers and installing dynomax vt's in the end as well.
    I did up a thread on the whole deal here:

    http://vb.foureyedpride.com/showthre...ax-VT-mufflers
    Last edited by danco86; 06-06-2017 at 06:21 PM.
    Dan

    http://vb.foureyedpride.com/showthre...ng-GT-restomod


    1986 Mustang GT Cobra
    Lotsa stuff, lotsa work. Check my thread above.

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  9. #9

    Default

    Thanks for the input so far. Nice to know the Dynomax worked out well for you guys. And those cats are pretty cheap, aren't they?! Nice!
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  10. #10

    Default

    So, here's a question. Take these for example.

    https://lmr.com/item/FLO-2230125K/Mu...tic-Converters

    Notice they have a rather large area to slide onto the other pipe. What's to stop a guy from just using band clamps instead of having them welded in? American Muscle even sells their way-more-expensive Pypes universal cats along WITH band clamps.

    http://www.americanmuscle.com/pypes-...converter.html

    I notice the Magnaflow cats offer much less area for that's so i could see needing to weld those in, but not so the Flowmaster and Pypes ones. What do you think?
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  11. #11
    FEP Senior Member danco86's Avatar
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    Agreed. I wanted to use those clamps too. Standard muffler clamps barely fit the magnaflows. I had to weld them in. The big thing for me is that the magnaflows are metallic spun cats, which do not need the air pump.
    Note the pypes are ceramic substrate. Not sure about the flowmaster she, I think ceramic too.
    But substrate material was the determining factor for me.
    Dan

    http://vb.foureyedpride.com/showthre...ng-GT-restomod


    1986 Mustang GT Cobra
    Lotsa stuff, lotsa work. Check my thread above.

    Daily drivers
    2002 F-350 7.3 Powerstroke crew 4X4
    2012 F-150 Ecoboost Screw FX4

  12. #12
    FEP Super Member gr79's Avatar
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    Have been using band clamps for a few years now.
    Can be used for either lap seal or butt connections.
    When torquing down band, it will adjust to slightly different tube dia.
    Very strong neat looking connection without welding.
    Reuseable, much easier to install than u clamps.
    Many variations.
    Stainless is worth the extra coin.
    Car/Truck makers use different styles and custom variations per ap. That is what really sold me on them.
    http://www.normaamericasds.com/brand...haust%20Clamps

    Welding is fine if you know how or have the time to have someone do it.

    Old tech plain steel generic U clamps can pinch and distort tubing, do not seal or clamp that well, or last long.
    HD versions ok for low torque universal hanger clamp duty.

    As usual, the hardware will eventually rust in some climates.
    Anti-seize helps prolong remove ability.

  13. #13

    Default

    That's certainly a good question to be asking, Dan. Looks like the Pypes ones are ceramic though, and according to a question answered by the AM staff, they say it does not require the air pump, and even go so far as to tell them to remove it. It's not addressed on the LMR page, so I have an email in to their customer service about that.

    gr, thanks. That's what I thought. Wish I'd known about those back when i had to extend my catbacks.

    I'm still curious about the Prochamber though if there's anyone that has input about that.
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  14. #14

    Default

    Here's the answer I got.

    Jay Walling (LMR.COM)
    Jun 9, 10:40 AM CDT

    No, these are considered a high flow unit and will not be required to have the factory air injection on them. As long as this is being used on a N/A application and not supercharged, turbo, or nitrous you will be good to go.
    Thank You,

    Jay Walling
    Lead Customer Care Rep

    (254) 296-6518
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

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