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Hate my 3" thermal exhaust

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Sorry didn't realize thermodynamics knew how many spark plugs, and whether the fuel has octane or cetane.
You made a ridiculous statement and you knew it was ridiculous when you posted it.
 

TMac

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Waah, I posted something ridiculous and stupid and got called on it. (For about the 3rd time). I'll show you, I'll just keep digging deeper 'cuz I work on a tractor dammit.
 

TMac

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Sorry didn't realize thermodynamics knew how many spark plugs, and whether the fuel has octane or cetane.
Really informative and useful. :rolleyes: I'm kinda interested in what you're drinking...or smoking!
 

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FYI the oem system is fully mandrel bent with straight through mufflers.
Good to know about the mufflers! The OEM system may be mandrel, it wasn't such a great job then. Some spots are good, like right past the resonator and the mid pipes leading up to it. On my OEM exhaust, particularly as it heads towards the mufflers, it looks like the shoe they uses may not have fit all that well. There's some ripples and obvious crimp areas on some of the bends. So I figured it was a nicely done crush-bend, as opposed to a mandrel. Either way :)
 

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I have a question.... for you AND @mcglsr2 ... i haven't seen much mention of the cats. With stock downpipes, isn't all of this exhaust discussion a moot point? isn't the stock downpipe and cat going to be EVERYONE's limiting factor, no matter the catback system chosen? so there really would be zero difference between stock/2.5/3.0 on the dyno OR the track until you change downpipes, AND THEN, there would be zero difference between those with 2.5" and 3.0" if they were both running the same aftermarket downpipes?
I'm not sure the cats are as restrictive as some people think- we've seen over 50lbs/min airflow through stock exhaust with stock cats. At that point, you probably at the limit of the stock turbos. I've always recommended changing cats when you change the turbos.
Agreed with TMac. Cats - at least modern ones - aren't that restrictive. Older model ones may not have been either but I honestly don't know. As a cat ages, it has a chance to become contaminated and/or clogged. If this happens you will most likely notice it, as performance will be done quite a bit (depending on how bad the clog is). If the cat is free and clear (whether OEM downpipes or aftermarket high flow ones like the Fenfab), it really won't hurt performance significantly.
 

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Agreed with TMac. Cats - at least modern ones - aren't that restrictive. Older model ones may not have been either but I honestly don't know. As a cat ages, it has a chance to become contaminated and/or clogged. If this happens you will most likely notice it, as performance will be done quite a bit (depending on how bad the clog is). If the cat is free and clear (whether OEM downpipes or aftermarket high flow ones like the Fenfab), it really won't hurt performance significantly.
Dyno numbers and track times show that on this platform, they can hold you back a little. 20-28whp gains for the average aftermarket DP's, even with stock turbos on 93. I think it's the usual "value" prop for you and you're setup (or wallet, lol) to determine if you're going to do them or not. I found a crack on the wife's stock DP's, so I'm using that as an excuse to swap them out when I put on the cat-back.
 

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Hey I have a nearly brand new Borla S-type less than 300 miles on my 2022 ST would you like to trade?
Why would you trade for the crappy thermal?? You have the best sounding (bolt on) exhaust already!
 

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Why would you trade for the crappy thermal?? You have the best sounding (bolt on) exhaust already!
That’s what makes exhaust fun…everyone has an opinion on what sounds best or worst. I think the Borla S is second to worst sounding only to their Atak system. Other people love it…
 

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Dyno numbers and track times show that on this platform, they can hold you back a little. 20-28whp gains for the average aftermarket DP's, even with stock turbos on 93. I think it's the usual "value" prop for you and you're setup (or wallet, lol) to determine if you're going to do them or not. I found a crack on the wife's stock DP's, so I'm using that as an excuse to swap them out when I put on the cat-back.
Oh, interesting, good to know! I guess those Fenfabs are looking even better! Also, just FYI, there's a recall on the cat/downpipes for cracking :(
 

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Oh, interesting, good to know! I guess those Fenfabs are looking even better! Also, just FYI, there's a recall on the cat/downpipes for cracking :(
Ya, I’m aware of the recall, but would rather “upgrade”.


Sent from my iPhone using Tapatalk
 

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Ya, I’m aware of the recall, but would rather “upgrade”.
Sent from my iPhone using Tapatalk
Understandable :)


Why would you trade for the crappy thermal?? You have the best sounding (bolt on) exhaust already!
Personally, I think the Thermal sounds really good.
 

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Thinking about doing a muffler delete (removing the Borla Atak rear mufflers) and doing straight pipe from the mid x pipe I had fabricated. Anyone have an idea what to expect? I presume the exhaust will get louder and more raspy. I'm trying to get the tone deeper but still loud. Anyone know if glass packs would work?
How about a recommendation for a mid high flow resonator just in case I get to much raps and drone?
Spoke to a few shops to get their opinion and everyone said not to do the mid x pipe to straight pipe because "it will sound like trash". So I asked for an alternative to achieve the sound I'm aiming for and was told "ecoboost 3.0L aren't very good sounding".
Now I've heard some nice v6 Camaros and Mustangs but those are 3.7L which seem to sound close to a v8 if done right.
Long story short - how do I get the closest thing to a V8?
Tks in advance.
 

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Thinking about doing a muffler delete (removing the Borla Atak rear mufflers) and doing straight pipe from the mid x pipe I had fabricated. Anyone have an idea what to expect? I presume the exhaust will get louder and more raspy. I'm trying to get the tone deeper but still loud. Anyone know if glass packs would work?
How about a recommendation for a mid high flow resonator just in case I get to much raps and drone?
Spoke to a few shops to get their opinion and everyone said not to do the mid x pipe to straight pipe because "it will sound like trash". So I asked for an alternative to achieve the sound I'm aiming for and was told "ecoboost 3.0L aren't very good sounding".
Now I've heard some nice v6 Camaros and Mustangs but those are 3.7L which seem to sound close to a v8 if done right.
Long story short - how do I get the closest thing to a V8?
Tks in advance.
It will sound like complete shit and drone. You can’t make this sound like a v8 period.

custom exhaust to make it sound like a GTR is the best you’d get. Something like FenFab did for Kevin’s cars with a single 4 inch mid pipe that goes back to 2 mufflers.

or unbroken’s custom 3 inch vibrant setup.
 

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It will sound like complete shit and drone. You can’t make this sound like a v8 period.

custom exhaust to make it sound like a GTR is the best you’d get. Something like FenFab did for Kevin’s cars with a single 4 inch mid pipe that goes back to 2 mufflers.

or unbroken’s custom 3 inch vibrant setup.
I've had comments telling me it sounds like a GTR now tbh. It screams on WOT and on cold starts it does have a V8 rumble. Problem is the 2 to 3k rpm range 1-4 gear at regular speed that sounds terrible.
Sigh...
Single 4" mid pipe to 2 mufflers hmm.
That sounds interesting.
 

TMac

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IMHO, you can never get a turbocharged even-fire V6 to sound like a NA V8. Think about it. The V8 has a cross-plane crank meaning that the separate 4 cylinder banks are NOT even fire. The ST has two separate 3 cylinder even-fire banks. One can certainly lower the tone through some creative acoustics. A larger diameter exhaust will add a lower tone, and eliminating any crossover in the midpipe will lower the frequency. But it cannot sound exactly like a V8.
 

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I've had comments telling me it sounds like a GTR now tbh. It screams on WOT and on cold starts it does have a V8 rumble. Problem is the 2 to 3k rpm range 1-4 gear at regular speed that sounds terrible.
Sigh...

Single 4" mid pipe to 2 mufflers hmm.
That sounds interesting.
Dual 3" to Single Muffler 4" Mid back to Dual 3"

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Oh, a follow up to the whole the "the stock flows fine" discussion, and that it's already high flowing, mandrel bent, etc.

It has a flapper valve in it. I was getting my old OEM ready today to try to sell it (anyone want to buy an OEM exhaust in great condition?) when I noticed a little knob looking thing. I played with it to see what it is/does.

It's literally a blocker valve thing on a spring. Like a throttle body plate. Presumably when there's enough exhaust flow, it forces the valve open. It's positioned right after the mid pipes, before the central muffler/resonator thing.

The valve closed, with a flashlight on it (it has a little hole in it):
Flap 01.jpg

The valve open half-way, I'm twisting it against the spring tension:
Flap 02.jpg

The valve just about all the way open:
Flap 03.jpg

There's a little ball on the opposite of this plate, it looks like a flapper valve from a toilet. This device is called an Adaptive Valve, and its job is to attenuate low frequency sound in the exhaust. It works to keep the exhaust quiet. These valves do increase backpressure, though they maker claims only a "moderate" increase.

It's worth mentioning that aftermarket exhausts, such as ones from Thermal R&D, do not have these devices in them.
 



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