Is cutting up a catback wrong?
Is cutting up a catback wrong? This is just a thought and I am not sure if it is a stupid idea and I would ruin my exhaust. I bought my car with a slp loudmouth cat back w/ a bullet resonator which I don't like the sound (I assume it is stainless). I think a transverse muffler (like a dynomax) will give me more of that old school muscle car sound I am looking for. Can I have an exhaust shop cut out the resonator and add regular straight pipe and add a y after the axle to go into the muffler or would this be a disaster and I should leave it alone?
by the time you've paid a shop to do all that work you might just be better off buying a different cat-back that more flows with what you're looking for and selling this one off.
edit: and if you really want that old school muscle sound you need a big cam.
edit: and if you really want that old school muscle sound you need a big cam.
I thought so but I just feel better knowing that I asked smart people and I'm making the right decision to do nothing. I can live with the sound, there are many other things that I can spend money on that will make a bigger difference in the car. A small cam is in my plans but my motor is basically stock and I need to keep my cats for the wonderful emissions in my state. Thanks guys.
Swapping out the SLP LM1 resonator for a bullet muffler (Magnaflow 14419 or Dynomax 24219)is a common modification with the LM1 cat-back exhaust. Now if you're set on having a oval muffler in the stock location then, yeah I have to agree with the others; sell it.
I should also point out that I had the LM1 with long tubes, ORY and HCI setup...it was frigging horrible lol. Had the MagnaFlow 14419 put in place of the LM1 and it made a big difference...love it now
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From: Schiller Park, ILL Member: #317
No cam swap is needed for an old school muscle sound. Only the very high end muscle car engines had lopey cams stock; most of them, even the big blocks, idled pretty smooth with just a little burble.
To get as close as possible to this "old muscle" sound you would need a true dual exhaust, preferably without a crossover, no cats, and chambered mufflers of some sort. They never sound "old" to me when they have cats, doesn't matter how lopey or even if there is no muffler at all - with cats they always have a tell-tale "mellowness", even when loud, vs. a sharpness that can only be attained with a catless system.
The GMMG catbacks are close to this, but they have a horrible rasping sound when connected to an ORY. You can tame this with various types of bullet mufflers in the Y-pipe and/or I-pipe, but true duals sounds even better.
To get as close as possible to this "old muscle" sound you would need a true dual exhaust, preferably without a crossover, no cats, and chambered mufflers of some sort. They never sound "old" to me when they have cats, doesn't matter how lopey or even if there is no muffler at all - with cats they always have a tell-tale "mellowness", even when loud, vs. a sharpness that can only be attained with a catless system.
The GMMG catbacks are close to this, but they have a horrible rasping sound when connected to an ORY. You can tame this with various types of bullet mufflers in the Y-pipe and/or I-pipe, but true duals sounds even better.
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I bought a Borla XR-1 muffler and cut the SLP LM1... expansion chamber(theres no "muffling" in there it's basically straight pipe) out of the LM1 catback and welded the XR-1 in on my Camaro Z28. Worked great and sounded awesome!
And I cut the tips off of my LM1 catback on my T/A and put Corsa Clones on it. Planning on doing the XR-1 in the near future again haha!
And I cut the tips off of my LM1 catback on my T/A and put Corsa Clones on it. Planning on doing the XR-1 in the near future again haha!
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From: Bucks County, Pa.
Another point is that basically NO run of the mill muffler shops would be able to properly weld stainless tubing, let alone bend it if necessary (Mufflex might be the exception to this rule, at least as far as the welding goes, but they are anything but 'run of the mill', and even they cannot actually bend stainless tubing).
A word of caution about the Borla ZR1 mufflers; they ARE a full race muffler, so if you want to keep your hearing past 22 years old (the average age on here??), I would avoid them on a daily driven, everyday, street car (my hearing is PERMANENTLY damaged from using one on a 3.5" Mufflex system daily, for less than a year, and the resultant tinnitus is maddening, so TO HELL with those who say "If it is too loud, you are too old", as that is about as shortsighted as one can be (unless they don't plan to live past 30 years old).
A word of caution about the Borla ZR1 mufflers; they ARE a full race muffler, so if you want to keep your hearing past 22 years old (the average age on here??), I would avoid them on a daily driven, everyday, street car (my hearing is PERMANENTLY damaged from using one on a 3.5" Mufflex system daily, for less than a year, and the resultant tinnitus is maddening, so TO HELL with those who say "If it is too loud, you are too old", as that is about as shortsighted as one can be (unless they don't plan to live past 30 years old).
Im 48 and want to keep my cats & oe manifolds. To me my car sounds like rice with a deeper tone or a garbage can not a loudmouth, my po even put the tips on reversed. It looks like my only two choices are to live with it or get another cat back that will cost hundreds. This one will be worth bupkis. There are so many other things I would rather pay for like sfc's or a cam. 
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
I seem to remember the I-pipe portion of the LM systems being the cheaper 409 stainless, welding this should be no problem as 409 stainless, and aluminized 409 stainless, is pretty much standard issue on most new cars these days.
Borla XR-1 is still quieter than an LM1 resonator, which isn't really all that loud when put behind stock manifolds and cats. Sure, it's loud at WOT, but normal daily driving won't often take you above 2500-3000rpm, unless you have a huge stall speed, so really I don't see this causing hearing issues. I'm closer to 40 than 30 myself, and have daily driven cars this loud or louder, and my hearing is just fine.
If you are insistent on keeping cats, then you'll never get an "old car" sound, as the cats have a smoothing effect even with no muffler at all.
I think something like the GMMG system, or perhaps a custom system using a Flowmaster 10-series race muffler, will get you as close as possible to what you want. Neither of these will be raspy or excessively loud with stock manifolds, cats, and a stock engine.
Borla XR-1 is still quieter than an LM1 resonator, which isn't really all that loud when put behind stock manifolds and cats. Sure, it's loud at WOT, but normal daily driving won't often take you above 2500-3000rpm, unless you have a huge stall speed, so really I don't see this causing hearing issues. I'm closer to 40 than 30 myself, and have daily driven cars this loud or louder, and my hearing is just fine.
If you are insistent on keeping cats, then you'll never get an "old car" sound, as the cats have a smoothing effect even with no muffler at all.
I think something like the GMMG system, or perhaps a custom system using a Flowmaster 10-series race muffler, will get you as close as possible to what you want. Neither of these will be raspy or excessively loud with stock manifolds, cats, and a stock engine.
Last edited by RPM WS6; Jun 23, 2015 at 12:45 AM.
A word of caution about the Borla ZR1 mufflers; they ARE a full race muffler, so if you want to keep your hearing past 22 years old (the average age on here??), I would avoid them on a daily driven, everyday, street car (my hearing is PERMANENTLY damaged from using one on a 3.5" Mufflex system daily, for less than a year, and the resultant tinnitus is maddening, so TO HELL with those who say "If it is too loud, you are too old", as that is about as shortsighted as one can be (unless they don't plan to live past 30 years old).
If you want a quieter 3.5" muffler that'll fit in the stock location, this is what you want.
http://www.summitracing.com/parts/mpe-12909/overview/
Another point is that basically NO run of the mill muffler shops would be able to properly weld stainless tubing, let alone bend it if necessary (Mufflex might be the exception to this rule, at least as far as the welding goes, but they are anything but 'run of the mill', and even they cannot actually bend stainless tubing).
A word of caution about the Borla ZR1 mufflers; they ARE a full race muffler, so if you want to keep your hearing past 22 years old (the average age on here??), I would avoid them on a daily driven, everyday, street car (my hearing is PERMANENTLY damaged from using one on a 3.5" Mufflex system daily, for less than a year, and the resultant tinnitus is maddening, so TO HELL with those who say "If it is too loud, you are too old", as that is about as shortsighted as one can be (unless they don't plan to live past 30 years old).
A word of caution about the Borla ZR1 mufflers; they ARE a full race muffler, so if you want to keep your hearing past 22 years old (the average age on here??), I would avoid them on a daily driven, everyday, street car (my hearing is PERMANENTLY damaged from using one on a 3.5" Mufflex system daily, for less than a year, and the resultant tinnitus is maddening, so TO HELL with those who say "If it is too loud, you are too old", as that is about as shortsighted as one can be (unless they don't plan to live past 30 years old).
the problem with the "if it's to loud you're to old" line is people don't understand QUALITY over QUANTITY, it doesn't have to be loud to sound good and just because it's loud doesn't mean it sounds good, personally I'm a huge fan of the sound of the Borla cat-backs and the Hooker cat-back (which is fairly cheap as far as cat-backs go).
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
...your issue likely comes from more then your exhaust unless you drive around NEVER letting your foot off the floor, even the loudest exhaust have trouble reaching 90db at your head position in the car under wide open throttle.
the problem with the "if it's to loud you're to old" line is people don't understand QUALITY over QUANTITY, it doesn't have to be loud to sound good and just because it's loud doesn't mean it sounds good...
the problem with the "if it's to loud you're to old" line is people don't understand QUALITY over QUANTITY, it doesn't have to be loud to sound good and just because it's loud doesn't mean it sounds good...
I also agree about sound quality. Loud can be good or bad, and so can quiet. Volume is not a direct indicator of good or bad quality, IMO.
"even the loudest exhaust have trouble reaching 90db at your head position in the car under wide open throttle"
That's very incorrect .
At the drivers head position my car idles at 90db, driving through city traffic with the engine rpms no greater than 2500 rpm it's around 100db, at WOT hauling *** down the road it's even louder at about 106db. Now strap it down in a shop on the Dyno an do a WOT pull it's a lot louder yet.
Furthermore, my car with H/C/I w/LT headers, an a ORY-pipe is actually rather quiet sounding for what it is.
My suggestion to you is go to shop when they're having a Dyno day with a spl/db meter, you'll be surprised how loud it gets .
That's very incorrect .
At the drivers head position my car idles at 90db, driving through city traffic with the engine rpms no greater than 2500 rpm it's around 100db, at WOT hauling *** down the road it's even louder at about 106db. Now strap it down in a shop on the Dyno an do a WOT pull it's a lot louder yet.
Furthermore, my car with H/C/I w/LT headers, an a ORY-pipe is actually rather quiet sounding for what it is.
My suggestion to you is go to shop when they're having a Dyno day with a spl/db meter, you'll be surprised how loud it gets .
I seem to remember the I-pipe portion of the LM systems being the cheaper 409 stainless, welding this should be no problem as 409 stainless, and aluminized 409 stainless, is pretty much standard issue on most new cars these days.
Borla XR-1 is still quieter than an LM1 resonator, which isn't really all that loud when put behind stock manifolds and cats. Sure, it's loud at WOT, but normal daily driving won't often take you above 2500-3000rpm, unless you have a huge stall speed, so really I don't see this causing hearing issues. I'm closer to 40 than 30 myself, and have daily driven cars this loud or louder, and my hearing is just fine.
If you are insistent on keeping cats, then you'll never get an "old car" sound, as the cats have a smoothing effect even with no muffler at all.
I think something like the GMMG system, or perhaps a custom system using a Flowmaster 10-series race muffler, will get you as close as possible to what you want. Neither of these will be raspy or excessively loud with stock manifolds, cats, and a stock engine.
Borla XR-1 is still quieter than an LM1 resonator, which isn't really all that loud when put behind stock manifolds and cats. Sure, it's loud at WOT, but normal daily driving won't often take you above 2500-3000rpm, unless you have a huge stall speed, so really I don't see this causing hearing issues. I'm closer to 40 than 30 myself, and have daily driven cars this loud or louder, and my hearing is just fine.
If you are insistent on keeping cats, then you'll never get an "old car" sound, as the cats have a smoothing effect even with no muffler at all.
I think something like the GMMG system, or perhaps a custom system using a Flowmaster 10-series race muffler, will get you as close as possible to what you want. Neither of these will be raspy or excessively loud with stock manifolds, cats, and a stock engine.
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From: Bucks County, Pa.
Sorry to hear you permanently damaged your hearing, but sometimes you have to learn things the hard way, and I'm sure you are now aware of ear plugs, sound deadening, and yes even a quieter 3.5" in/out muffler, and that continuous sounds of 90db or greater WILL damage your hearing.
If you want a quieter 3.5" muffler that'll fit in the stock location, this is what you want.
http://www.summitracing.com/parts/mpe-12909/overview/
If you want a quieter 3.5" muffler that'll fit in the stock location, this is what you want.
http://www.summitracing.com/parts/mpe-12909/overview/
Sadly, yes, somehow I misjudged the damaging sound level of the XR1 in this system, and the above bolded TRUTH is TOTALLY lost on most of the young and 'indestructible'/immortal self image types on here.
I can't see how one's hearing could NOT be damaged PERMANENTLY from even just one single, ONE HOUR cruise with a longtube, catless, loudmouth system (or the like)!!
(And some of those same types have insanely loud, mega thousand watt amped, I.C.E. systems on top of their deafening exhaust systems. 
) Last edited by dailydriver; Jun 25, 2015 at 10:13 PM.
Joined: Nov 2001
Posts: 34,629
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From: Schiller Park, ILL Member: #317
Borla XR1 isn't any louder than a Flowmaster 10-series, LM1 resonator, Dynomax race bullet, or anything else along those lines. All of these are often used in "street" applications for stock engined, stock manifold/cat cars without any mass reports of considerable and rapid hearing damage.
There may be a genetic predisposition that increases susceptibility to noise induced hearing loss, and/or other environmental factors adding to a daily total of noise experienced by a given individual on average, as the exhaust system described (stock mainfolds/cats, stock LS1 with full interior and rear bumper exit tail pipes using a "race" muffler) when used under normal daily driving circumstances isn't going to cause a rash of hearing loss.
Considering the 2+ decades and 10s of thousands of miles I've logged with exhaust systems similar to what is being blamed for damage above, I'm certain that if this was the norm then I too would be suffering from some form of untimely hearing loss, though I am not.
Perhaps caution should be exercised by persons who have a family history of premature hearing loss, but I don't think there is any blanket statement to be made here in terms of risk for the average individual with a stock LS1 using a Loudmouth system.
There may be a genetic predisposition that increases susceptibility to noise induced hearing loss, and/or other environmental factors adding to a daily total of noise experienced by a given individual on average, as the exhaust system described (stock mainfolds/cats, stock LS1 with full interior and rear bumper exit tail pipes using a "race" muffler) when used under normal daily driving circumstances isn't going to cause a rash of hearing loss.
Considering the 2+ decades and 10s of thousands of miles I've logged with exhaust systems similar to what is being blamed for damage above, I'm certain that if this was the norm then I too would be suffering from some form of untimely hearing loss, though I am not.
Perhaps caution should be exercised by persons who have a family history of premature hearing loss, but I don't think there is any blanket statement to be made here in terms of risk for the average individual with a stock LS1 using a Loudmouth system.