Exhaust Debate

[Koreandude]

For those with catless secondaries, installing a set of Flowmaster HPII resonators will absolutely kill the rasp. Back in the day I ran a full header and MBRP CBE on my Tiburon GTV6 and it was raspy as heck just like I've been hearing on vids in here. After purchasing the HPII resonator and getting an exhaust shop to weld it in the same spot the secondary cat would've been, it smoothed the exhaust note out tremendously w/ zero power loss. Matter of fact it dyno'd about 210whp with a NGM Stage 4 IM, CAI, full exhaust and a custom tune with that resonator (stock it dyno'd 145whp). At this point, the exhaust never sounded better.

So I have no doubts a pair of HPII's would do the trick on the catless secondaries and improve the sound significantly. The cross-section of the HPII's is a pretty neat, flow through design. The Dbx might work as well although I've never installed it. Both the HP2 and Dbx use laminar flow technology to minimize backpressure and keep the exhaust moving.

 

[Toddasaurus]

Flowmaster has a lot of products that utilize sound cancellation at the expense of gas flow. Their laminar flow design may improve flow compared to their other multi-chambered mufflers, but it's still restrictive compared to even a louvered straight through design.

Even so, I'll admit that I'm fairly biased against Flowmaster. I've used their mufflers in the past, along with one of their highflow catalytic converters, and the quality and performance was disappointing. Of course my experience could just be a fluke, as I'm sure other people had disappointments with other exhaust products. Even so, I've used a few other generic brands, but mostly Magnaflow, and I've had excellent results with them.

Even so, I'll admit that Flowmaster products usually have a unique sound, and some people (I think) love them because of that. They certainly perform better than stock applications, but other designs (again, I personally prefer Magnaflow) perform even better. My point is, that much of choosing an exhaust comes down to personal preference.

 

[Koreandude]

Their laminar flow design may improve flow compared to their other multi-chambered mufflers, but it's still restrictive compared to even a louvered straight through design.

This is 100% false. Look up "laminar flow" lol.

Laminar flow by design and definition will always flow better than a louvered straight through design (or chambered for that matter). Louvered cores are trash when it comes to "straight through" flow due to the turbulence it creates (which is the complete opposite of "laminar").

If you're worried about "restriction", these will flow better than the secondary cats, not to mention the OE piping has that tight kink before entering the cats (vs aftermarket downpipes + HP2 resonators). I can't speak for other Flowmaster products as the only thing I've owned was the HP2 resonators and they absolutely worked with negligible penalty.

 

[Toddasaurus]

This is 100% false. Look up "laminar flow" lol.

Laminar flow by design and definition will always flow better than a louvered straight through design (or chambered for that matter). Louvered cores are trash when it comes to "straight through" flow due to the turbulence it creates (which is the complete opposite of "laminar").

If you're worried about "restriction", these will flow better than the secondary cats, not to mention the OE piping has that tight kink before entering the cats (vs aftermarket downpipes + HP2 resonators). I can't speak for other Flowmaster products as the only thing I've owned was the HP2 resonators and they absolutely worked with negligible penalty.

Laminar flow, in this case, is just a patented name for their muffler design. Nothing about that thing actually promotes laminar flow. If it did, all those circles would be facing in the exact same direction on both sides, they would line up perfectly, and they'd have to be connected by individual tubes. The way they have it now just induces turbulence.


Also, this...

...the only thing I've owned was the HP2 resonators and they absolutely worked with negligible penalty.

....the fact is that you haven't compared them directly to anything else with reputable evidence (ie before and after dyno), so all you're going on is butt dyno and sound. I don't doubt for a second that it sounds great and has less restriction than stock, I mentioned that above, but my argument is that there are better flowing mufflers out there, and in fact, a well made, louvered style straight through muffler, specifically from Magnaflow, would perform better (ie cause less restriction) - their louvered design is much more efficient than you'd think, and not to be confused with other, poorly designed tubes that have way too much turbulence via those overly huge flaps sticking out into the exhaust stream. Chances are the real world differences here would be negligible, but that's part of my point now, isn't it? So much about choosing an exhaust is subjective, because of stupid and sometime blatantly false advertising that companies, in this case specifically Flowmaster, shows.

 

[NismoDPB]

This is 100% false. Look up "laminar flow" lol.

Laminar flow by design and definition will always flow better than a louvered straight through design (or chambered for that matter). Louvered cores are trash when it comes to "straight through" flow due to the turbulence it creates (which is the complete opposite of "laminar").

If you're worried about "restriction", these will flow better than the secondary cats, not to mention the OE piping has that tight kink before entering the cats (vs aftermarket downpipes + HP2 resonators). I can't speak for other Flowmaster products as the only thing I've owned was the HP2 resonators and they absolutely worked with negligible penalty.

Quite the opposite. The point of straight through exhausts is to be less restrictive and is ideal for performance. Chambered designs are intended to be a compromise to offer as much performance as possible while reducing as many undesirable frequencies as possible at the cost of creating back pressure. Ironically the straight through design is the one that would actually have something that more closely resembles a laminar flow profile. Why flow master decided to use that to describe their chambered muffler I cannot understand.

 

[Aarvix]

as AvE would say.....marketing wank.

 

[Koreandude]

...the fact is that you haven't compared them directly to anything else with reputable evidence (ie before and after dyno), so all you're going on is butt dyno and sound.

Oooook. So I guess in my first paragraph where I said I dyno'd the vehicle doesn't count? You do realize that I had a 31% increase in power from intake, headers, a HP2 in place of the cat, an MBRP CBE, a Stage 4 NGM IM and a NGM stage 1 reflash tune? These things stock only produce 145whp and getting these older 2.7 Delta V6's over 200whp is tough, requiring to address the choke points in the intake plenum and inefficient exhaust system. It's why anything short of a NGM Stage 4 IM and full exhaust system on top of the other bolt ons would just fall flat on it's face. The fact it's making that kind of power up top, peaking closer to 7k indicates the engine is breathing way more efficiently.

louvered style straight through muffler, specifically from Magnaflow, would perform better (ie cause less restriction) - their louvered design is much more efficient than you'd think, and not to be confused with other, poorly designed tubes that have way too much turbulence via those overly huge flaps sticking out into the exhaust stream.

The HP2 is just a fancy glasspack resonator with more science involved for sound wave attenuation. The critical key is it has a perforated core which, it is absolutely, 100%, been documented to the moon and back, more EFFICIENT than louvered cored resonators. To make a claim that "louvered cores from Magnaflow" will outflow a perforated core is just nonsense as you can look it up yourself.

Also, Flowmaster doesn't have a patent on "laminar flow". Their specific design is probably patented though. I don't mean to sound crass but are you just making this stuff up?

Btw, I uploaded my personal dyno run I was referring to along with another dyno (not from my car) of a typical stock 2.7 with a Injen CAI install on an otherwise stock 2.7 for reference.

The whole point of this is: I think the HP2 (or S-HP2 these days) would be an efficient and effective addition for maintaining power and smoothing sound should anyone need it.

 

[Koreandude]

Quite the opposite. The point of straight through exhausts is to be less restrictive and is ideal for performance. Chambered designs are intended to be a compromise to offer as much performance as possible while reducing as many undesirable frequencies as possible at the cost of creating back pressure. Ironically the straight through design is the one that would actually have something that more closely resembles a laminar flow profile. Why flow master decided to use that to describe their chambered muffler I cannot understand.

What chambered muffler? Chambered mufflers aren't part of this discussion. Just their perforated core resonators which cannot be and aren't chambered.

 

[NismoDPB]

What chambered muffler? Chambered mufflers aren't part of this discussion. Just their perforated core resonators which cannot be and aren't chambered.

You attached a video where one muffler is chambered and one is straight through. You do realize that what flowmaster is showing is a chambered muffler right? You seem to be getting wrapped up in their marketing wank.

 

[SKStinger]

I'm not sure why we're talking about any of this here. I don't have rasp with my secondary pipes and MBRP exhaust.

 

[Toddasaurus]

Oooook. So I guess in my first paragraph where I said I dyno'd the vehicle doesn't count? You do realize that I had a 31% increase in power from intake, headers, a HP2 in place of the cat, an MBRP CBE, a Stage 4 NGM IM and a NGM stage 1 reflash tune? These things stock only produce 145whp and getting these older 2.7 Delta V6's over 200whp is tough, requiring to address the choke points in the intake plenum and inefficient exhaust system. It's why anything short of a NGM Stage 4 IM and full exhaust system on top of the other bolt ons would just fall flat on it's face. The fact it's making that kind of power up top, peaking closer to 7k indicates the engine is breathing way more efficiently.



The HP2 is just a fancy glasspack resonator with more science involved for sound wave attenuation. The critical key is it has a perforated core which, it is absolutely, 100%, been documented to the moon and back, more EFFICIENT than louvered cored resonators. To make a claim that "louvered cores from Magnaflow" will outflow a perforated core is just nonsense as you can look it up yourself.

Also, Flowmaster doesn't have a patent on "laminar flow". Their specific design is probably patented though. I don't mean to sound crass but are you just making this stuff up?

Btw, I uploaded my personal dyno run I was referring to along with another dyno (not from my car) of a typical stock 2.7 with a Injen CAI install on an otherwise stock 2.7 for reference.

The whole point of this is: I think the HP2 (or S-HP2 these days) would be an efficient and effective addition for maintaining power and smoothing sound should anyone need it.

Okay, I can see that this discussion is going nowhere. I'm not going to readdress my points. You evidently believe in Flowmaster's marketing, whereas I take it with a grain of salt. The end.

Sorry to the OP for changing the subject.

 

[Koreandude]

You attached a video where one muffler is chambered and one is straight through. You do realize that what flowmaster is showing is a chambered muffler right? You seem to be getting wrapped up in their marketing wank.

Well, ignore the chambered mufflers? I can't edit videos just to showcase a perforated core design. The rest of the video is irrelevant. I guess you just didn't read the full discussion?

I'm not sure why we're talking about any of this here. I don't have rasp with my secondary pipes and MBRP exhaust.

Perhaps you don't (and that's great!) but it's been discussed that some people do, so this is for them. Besides, I have a feeling some members aren't reading everything through and jumping to conclusions causing confusion. I've provided dynos and as far as perf. vs louvered cores are concerned, anyone can Google their designs and see louvered cores are at a disadvantage. Short answer is they cause turbulence. It makes them better at quieting things but at a cost of flow. Magnaflow makes both perforated and louvered core resonators for this reason. If you need more hush, get louvered (although I'd highly advise you don't). If you want some quiet with max flow, get perforated.

Simple as that.

 

[NismoDPB]

Well, ignore the chambered mufflers? I can't edit videos just to showcase a perforated core design. The rest of the video is irrelevant. I guess you just didn't read the full discussion?

Im following the discussion just fine. I am going to return you to your very own post were you start to tell people they are incorrect and are very indignant about it.

This is 100% false. Look up "laminar flow" lol.

Laminar flow by design and definition will always flow better than a louvered straight through design (or chambered for that matter). Louvered cores are trash when it comes to "straight through" flow due to the turbulence it creates (which is the complete opposite of "laminar").

If you're worried about "restriction", these will flow better than the secondary cats, not to mention the OE piping has that tight kink before entering the cats (vs aftermarket downpipes + HP2 resonators). I can't speak for other Flowmaster products as the only thing I've owned was the HP2 resonators and they absolutely worked with negligible penalty.

1) Here in this post you tell Mr. Toddasaurus that what he said is 100% false. However your basis for saying such a thing is you clearly conflate the fluid mechanical behaviour of "laminar flow" with flowmaster's demonstration jargon "Laminar Flow Technology" as stated in the video. Interestingly enough that is the only time the video even mentions "Laminar Flow" yet none of the explanations fo into how it even promotes "Laminar Flow."

2) Based on this conflation of terms you then go on to say that clearly the "Laminar Flow" from flowmaster will always be better than the louvered straight through. The problem with this of course is that you are describing the Flowmaster as a simple perforated straight through muffler when in fact it is just a fancy chambered muffler. This leads us back to why we had to make clear the Flowmaster was showing a chambered design.

3) You keep bringing up the fact that "perforated is better than louvered." No one is actually disputing this fact though because that comparison is undoubtedly true when you are comparing a glasspack perforated with a glass pack louvered. See point 2 as to why the discussion is really about a chambered muffler compare to a straight through louvered.

 

[xot1]

Please someone split this thread.

 

[cncBilly]

Well, ignore the chambered mufflers? I can't edit videos just to showcase a perforated core design. The rest of the video is irrelevant. I guess you just didn't read the full discussion?




Perhaps you don't (and that's great!) but it's been discussed that some people do, so this is for them. Besides, I have a feeling some members aren't reading everything through and jumping to conclusions causing confusion. I've provided dynos and as far as perf. vs louvered cores are concerned, anyone can Google their designs and see louvered cores are at a disadvantage. Short answer is they cause turbulence. It makes them better at quieting things but at a cost of flow. Magnaflow makes both perforated and louvered core resonators for this reason. If you need more hush, get louvered (although I'd highly advise you don't). If you want some quiet with max flow, get perforated.

Simple as that.

The title to thread is “MBRP EXHAUST”. Please spare the rest of us and start your own thread. This thread has been hi-jacked long enough.

 

[NismoDPB]

The title to thread is “MBRP EXHAUST”. Please spare the rest of us and start your own thread. This thread has been hi-jacked long enough.

This is a discussion about the exhaust system. Specifically about the best way to address a supposed "rasp" the sound has.

 

[AdamNZ]

Looks more like yet another pointless pissing contest between Akshually Internet Geniuses to me.

 

[cncBilly]

Looks more like yet another pointless pissing contest between Akshually Internet Geniuses to me.

I agree. A thread should be started called “SAND BOX” They can go play there

 

[SteveCo]

Please someone split this thread.

I just got here, but believe me I'm splitting ...

 

[SKStinger]

This is a discussion about the exhaust system. Specifically about the best way to address a supposed "rasp" the sound has.

Great. Please create a thread in the DIY section called “how to deal with a raspy exhaust” because it’s generic and not specific to the MBRP exhaust.