Rdmsys

Hey all. I have a 2012 GT, put a few mods on it one being Borla Axel backs. Probably my favorite one actually.

I've been reading around on exhausts and I gotta say I'm pretty confused. I'm not mechanically ignorant but this has me wondering what is going on.

I know there's headers...seen the cat backs and the H, X, Y, pipes. Then theres this resonator delete.

Now there's short and long headers. So, needless to say I'm clueless. I know headers are better than stock exhaust manifold.

I guess what I'm asking is, what is the best route do you think for an upgrade here? I have a tune and I've read that headers require a tune update. I'm not sure if that is true.

I'm looking for some extra performance, however I'm not looking for a way loud, droning exhaust either.

Can I just go with headers without anything else? Would it add decibels or just performance benefits?

If I go cat back I would lose the Borlas?

Just looking for advice, or straightening out lol.

Thanks...

Mark_K

There's a lot there to unpack.

The Borlas are most likely a catback system. Catback refers to the portion of the exhaust system behind the catalytic converters. They can start right behind the cats, or further back, like after the rear axle (although technically those are axle-back systems). On the stock system, there are resonators behind the catalytic converters. They are there to mellow out the tone of the exhaust. think rice-rockets that sound like echoing beer cans. Resonators help with the brappy tinny noise, although decent mufflers can eliminate the brapp sound without resonators.

Y pipes are used to merge 2 pipes into one, typically converting a V-type engine into a single exhaust system. H pipes are what usually comes stock on dual exhaust cars. It connects the 2 sides of the exhaust system together using a little section of pipe that connects the 2 sides. X pipes are sort of like dual y pipes. The 2 sides of the system come together sort of like in a Y pipe, then separate again using a 'backwards Y pipe'.


Y-pipe

H-pipe

X-pipe

X pipes create a different sound than H pipes, and 'allegedly' produce more horsepower. When I replaced the factory H pipe on my Corvette with a Borla X pipe, the car gained a cool burble sound, but I didn't notice any change in power.

Headers come in 2 basic styles, shorty headers, and long tube headers. Shorty headers will usually bolt directly into a stock system without cutting and welding. Long tube headers require customizing the front of the exhaust system. Long tube headers will typically get you more horsepower, but at a higher cost. Also, headers can be tuned or not tuned. That refers to the length of the tubing for each cylinder. On tuned headers, each tube is the same diameter and length, just bent differently so they fit under the hood. Untuned headers are usually better than manifolds (but not always), but not as good as tuned headers. Headers are also tuned for specific uses. RVs need more torque at low end than dragsters, so they are probably a bigger diameter tube and maybe shorter than race headers.

So, what all this comes down to is how much money do you have to spend, and how much do you hope to gain with just exhaust upgrades. Exhaust is the first thing people notice about a car, but just exhaust upgrades, without induction and cam upgrades can only get you so much. The real power upgrades don't come from the exhaust, but the sound satisfaction does.

Bert

I think Mark covered most of the basics; nice job Mark, that took some time and effort.

back to the OP, Rdmsys -- you are looking for a performance boost, not sound, correct?

If so, I think long tube headers are still good for around 20 HP increase, if done right. To go with the headers you will need:

• a tune -- to adjust computer to get the performance benefit
• a new mid-pipe -- to fit with the headers
• new catalytic converters -- assuming you want to remain legal; you want a catted mid pipe; because the factory cats won't fit with the long tube headers

Even with the new catalytic converters, the system is borderline illegal because technically any change to the catalytic converters is illegal. Depending on the inspections they do where you live, you might get away with it., You also need to get the rear O2 sensors to give the right signal to indicate that the cats are working, to pass the most common emissions inspection where they check to make sure this is all good, using the OBD2 port. Kooks "green" cats are said to be about the best for this.

You can connect the new mid-pipe to your existing over-axle pipe and mufflers. I'm pretty sure the stock resonators are part of the stock mid-pipe, so they would be removed/replaced by the new mid-pipe.

m05fastbackGT

Actually, the stock exhaust manifolds are really efficient and flow pretty well when compared to the previous SN-95 generation and older 2 valve cars. Therefore, unless your looking to just improve sound? upgrading to short tube headers won't provide any noticeable performance gains over the stock manifolds. If your looking for both sound and performance gains, your best options are going with long tube headers and resonator deletes. But keep in mind that if your state requires emissions inspection? long tube headers will not pass the OBDII emissions test. As for long tubes requiring a tune update? I'm not quite sure if they do on the Coyote 5.0 motors, but they do require a tune update on the older 2005-10 3 valve S197 cars. Personally, if your 2012 GT were my car? I would start out by upgrading to resonator deletes first.. If your not satisfied, then consider going with an axle back delete setup.. If you don't want to go with the axle back delete option, then I would consider the short tube header upgrade only as a last resort, but once again short tube headers are only good for changing the sound of the exhaust. Cat back exhausts also provide very little performance gains over stock.. So once again, unless your looking to just improve the sound of the exhaust, don't expect any performance gain benefits. As for losing the Borla's if you go cat-back? lets just say that most cat-back exhaust systems usually include axle backs, I know that Borla does anyhow lol. If you really like the Borla axle-backs that you currently have, then in my honest opinion, upgrading to a cat-back system is just plain overkill and a waste of your hard earned money.

That being said, other than upgrading to long tube headers or running straight pipe with no cats? your not going to notice any real performance gains over the stock exhaust, and also as mentioned, neither will pass OBDII emissions testing..

Meanwhile, hope the info provided is useful and best of luck in finding the right solution for your particular application needs.

Bert

I'm pretty sure the tune is required with long tube headers because the front O2 sensors are relocated and that affects the signal, which must be "recalibrated" in the tune

and just confirming what was already said -- long tube headers should give some performance gain (but you need all that other stuff to go with them) ; any other exhaust modification is for sound only

m05fastbackGT

I also wouldn't waste forking out the additional costs for the Kooks green cats either.. I've read on several other Mustang forums they have not passed OBDII emissions testing. So just something more to keep in mind

Rdmsys

Wow, thanks guys, seriously. Like @markk said, there is a lot going on. @Bert excellent advice as always.

Maybe I should just think about sound as opposed to performance gains? It sounds too crazy to me to do the headers thing.

So a resonator delete would be in essence scrapping my Borlas? And just running straight back from the catalytic converter?

So, it goes like this: Exhaust --> Cat Converter - H pipe ---Axle Back (resonators)?

I don't want to get rid of my Borlas (plus they were a lotta $$), so barring that adding an H pipe will just make it growl more? Thus I imagine louder in cabin?

What is in your opinions the best modest thing to do here?

Bert

The resonators are up forward in the mid-pipe, removing them does not affect the mufflers which are at the extreme rear. But I'm pretty sure it is a cut-and-weld job, meaning if you want to put them back, then you need to pay some to cut-and-weld again. The resonators are sort of like mini-mufflers, upstream of the axle.

If you can get the car up on ramps or something, and look at the bottom to see how the exhaust is routed and put together, that might help. Basically I think it goes:
Manifolds/headers => Catalytic converters => mid-pipe/resonators/H => over-axle pipe => muffers aka 'axle back" => tips/exit

You already have an H-pipe, it is part of that mid-pipe.

Resonator delete is pretty common on these cars, I guess if you want it a little louder, that would be an easy thing to do. there are lots of threads on hear about this, if you want to read more of them, try the "search" feature.

Rdmsys

OK thanks Bert! I will check it out!

Again, thanks everyone for your comments...

m05fastbackGT

Just as Bert mentioned, the resonators are located upstream in the mid-pipe. Apparently, you didn't read the entire post which clearly stated

Nobody mentioned anything about having to get rid of your Borlas unless you choose to go with the axle-back delete option which replaces the axle back mufflers located downstream from the over the rear axle pipes. Perhaps you were thinking an axle-back delete system and resonator delete systems are one in the same, however they're completely different systems from one another.

That being said, you've been provided with some very valuable info from 4 different members on this forum that recommend the best modifications for your particular application..

Just to clarify once again..

1- retain stock mid-pipe
2- resonator deletes, upstream before the rear axle, attached to the stock mid-pipe section (sound only)
3- retain stock tail/over the axle pipes
4- retain your Borla axle-backs
5- short tube headers (sound only)
6- long tube headers (up to 20HP performance gain and sound improvement) but will not pass OBDII emissions testing and also illegal for use on all public roads/highways.
7- axle-back deletes (sound only) eliminates your Borla axle-back mufflers downstream after the rear axle with either resonated or non-resonated exhaust tips.

Personal recommendation, if your looking for just a louder/more aggressive exhaust tone and still able to pass OBDII emissions test/inspection, then I would strongly suggest the resonator delete option while keeping your Borla axle-back mufflers and stock exhaust in place.. If still not loud enough? only then would I consider or recommend doing the shorty header mod as a last resort.

Siber Express

Still trying to grasp the Short Tubes are for Sound only, Short tubes do offer more power than the stock logs and even the stock unequal length headers the 5.0 has from the factory, just because is is not at peak HP at the very end does not mean it is not there.

m05fastbackGT

Lets just say even if the short tubes make up to 5-7hp over stock, is such a minimal gain worth justifying the cost? You certainly aren't going to notice nor feel it where it counts most..LOL

Rdmsys

@m05fastbackGT yes I did read Mark k's post (many times). Like I said I'm trying to grasp all of this but I think I got it know. I spent a few more days looking at diagrams and watching YT videos.

I was not aware that the resonators were in the mid pipes until I found the LMR and Borla Over The Axel pipes. I would like to replace them but keep the resonators but I couldn't find any.

And you were right a lot of people say the stock manifolds are very good so maybe I shouldn't mess with it.

Also, I have thoroughly looked at the whole H vs. X pipes and am convinced that H is more what I'm looking for. However, I can't seem to locate any. I found I think 2 but both were catted.

That being said, 75% of guys with the resonator deletes said it was way too loud so I think I should forgo that as I'm not really looking for that, as an ahem, older guy.

So in the end I'm thinking maybe I should just try an X pipe and see how it sounds. Seems reasonably priced and I can always sell it if I don't like it and put back the stock one.

The problem is too is that there's a ton of them. Anyone have an experience with a good one?

Thanks again everyone.

m05fastbackGT

Just an FYI: I wasn't referring to Marks post, I was referring to my initial post which also brought up the resonator delete vs axle-back delete debate. I'm also not following your statement regarding the H is what your looking for.. The stock exhaust on all 2005-14 GT models are equipped with a catted H-pipe. As for X pipes? just keep in mind they produce a slightly higher exhaust tone over an H-pipe and they also produce a raspy type sound. Therefore, if you prefer that deeper/throatier, muscle car sound? then stick with your stock H-pipe

Needless to say, I have a spliced-in Pypes cut'n'clamp X-pipe to my stock cats that I've been running with my stock over the axle pipes and Borla ATAK axle-backs.. Thru my personal experience, the X crossover has more of a refined tone, produces a slightly higher exhaust pitch and most of all, the X crossover produces a raspy type exhaust sound.. Personally, I don't like the higher exhaust tone and especially don't care for the rasp, so I plan on reinstalling the stock catted H-pipe which I have a spare stored in my basement.

Also, as I mentioned in my initial post, if your state requires emissions inspection? I would not recommend operating your car without the stock catted H-pipe in place, otherwise, your car will not pass OBDII emissions scan

That being said, I also don't see any real benefit in replacing the stock over the axle pipes with aftermarket, unless they offer larger diameter tubing that allows for more airflow, otherwise, why even bother

Bert

there is not much difference between X-pipes -- they are just a hunk of pipe with an X-intersection in the middle; as long as they fit in the space and have the right end connections, I'd probably just go with the cheapest one, as long as it doesn't look like it has any really stupid design flaws

However I think most X-pipes are "off road X-pipes" which means that they replace the cats with a section of straight pipe; if you need to pass emissions then you need to keep the cats and you might need cut & weld x-pipe because of the way the original pipes are designed and put together. I would avoid cutting and welding because I'd rather keep the original clamped connections so I can easily make changes later. Except maybe to delete the resonators; that seems fairly safe and simple.

But bottom line, personally, I would not mess with the X-pipe -- I like the H-pipe sound better (exactly as m05 described above) and I don't want to mess with the cats or cutting and welding

changing the over-axle pipes is a complete waste of money in my opinion, unless you are doing the entire system starting with long tube headers and all the way back

if I was in your shoes I'd probably just try the resonator delete

Rdmsys

Yeah, I may at some point. "Why even bother"? Cause I'm a dope who loves to blow money lol.

I'll go back to my other mods.

Bert

LOL, yeah this is all for fun anyway; what better way is there to blow money? when considering any of these mods, I always remind myself:

"don't expect much, and you won't be disappointed"

m05fastbackGT

If you really think going with resonator deletes would be too loud? then going with an aftermarket X or H-pipe without cats will be twice as loud and will drone inside the cabin like crazy.

If your looking to increase the sound and stay emissions legal? then go with either the resonator delete or equal length, shorty header mod!

Rdmsys

Bert, good advice brother! I spent a lot of money on it already. Sometimes I wonder if it's worth it. It's just a plain GT, not even premium.
I know a few guys who told me I won't get my money back on it cause it's 'not original'. Well I don't even care about it really. I consider it as a hobby albeit a really expensive one.

@m05fastbackGT thanks, If I do end up doing anything I will definitely go this route. BTW I forget to always mention, yes I'm in PA and we have emissions so.

OK, my next thing is a throttle body. Yeah or nay? Intake manifold? Much like this topic this seems to be either do it or don't waste your money.

This is why I come here cause I know you guys know your s***. I know I should probably create new thread?

Bert

yes it usually works better if you create a new thread, with a specific title, in the relevant sub-forum, and I'd probably go with the 2010-2014 "general" forum (top level of this sub-forum, for maximum visibility, though it might not matter)

and also feel free to use the "search" tool before posting a new thread, you should find quite a bit on throttle bodies . . . .

general consensus is that aftermarket throttle body is useless, stock throttle body is fine, bigger throttle body not needed unless you are already pushing big numbers like 600 HP ballpark and looking for more

regarding intake manifold, I guess you are thinking Boss? I think that is good for a small HP improvement in the high RPM's with a little sacrifice of low end