ShaneN.

I've got a 2012 that came with resonators deleted for straight pipes and I wanted the car a bit louder, but I also felt like some of the low end throttle response was missing. Making it louder being the primary goal I decided to have those straights turned into an H pipe with a connecting 2" diameter piece and at the same time I had the secondary cats deleted with straight pipe. I'm greatly disappointed. The car sounds good (although i thought it did before too) but it's considerably more quiet than it was before. I wanted the cross pipe of the H pipe put in closer to that cross member that goes underneath the exhaust but it was put on about 2/3 of the way toward the end of the new pipe section (closer to rear of car). Does placement of the H make a difference in how loud the car will be? I chose this route after reading countless threads and watching many videos but I'm really unhappy with how much quieter it got. I'm weighing out my options and open to suggestions - I'm thinking about going back to straight piped reso section and having an H pipe made for where the cats were, as I assume my cats couldn't be welded back in very easily to return it back to how it was. Would creating an H pipe where the cats were and having a straight pipe section to the muffles be any louder for whatever reason? The only other option I have is going straights for both the secondaries and resos but they don't seem to sound good IMO, based on the videos I've seen. Or I could do some sort of X pipe setup but it sounds like they make the car even quieter. On a side note, I think that low end throttle response improved but I don't want to say for sure until I have more seat time, although I would have preferred how it sounded before at the expensive of how it felt before.

MTV10

My current setup is just that. H-Pipe at secondary cats, straight pipes at Resonator. Sounds perfect. My old C63 had straight pipes in both sections and I found it a touch too raspy. This is a nice balance.

Jasonoff

Did you post a vid of each setup?

MTV10

I did not.

deadlyvt

Crossovers will lower the exhaust sound levels doesn't really matter where you move the H the sound is going to be the same
IF you want more noise you'll need to take out the primaries or do a muffler delete unless you want to remove the H
could put in some electric cutouts and then only have the car louder when you feel like it

bentz69

Glad you posted this. Ive been debating adjusting my H pipe for a little while now. Ill start by saying that your 2" diameter H is too big. I will bet that the exhaust note/tone has slightly smoothed out VS the prior straight pipe right? Remember that the stock resonator has the tiny crossover pipe OR H pipe inside it. It has a diameter of roughly 0.5". It does balance the flow to some degree but many have always said that the exhaust note that this car is known for mainly generates from the design of the resonator. That little tiny H pipe does wonders for sound.

I started my exhaust adventure with a 2nd cat delete with straight pipes first. Sounded louder then stock but retained that nice tone/bark/grunt. Next move was removing the resonator, adding straight pipes with a small .75" diameter H where the resonator was. The volume of the exhaust increased a little bit more BUT still retained that nice tone/bark/grunt. Then I put catless headers, catless midpipes, going to an X pipe that bolted up to where I had the H pipe installed. Granted there were headers on the car but the sound completely smoothed under heavy throttle. The crossover section in the X pipe is rather large (similar in size to your 2" H). Drove around for about a day and hated it. Removed the X pipe, put straight pipes in its place BUT still have that small H pipe where the oem resonator was. Car is back to sounding like before with that nice bark/grunt but obviously sounder louder.

Every little adjust to your exhaust will change the sound/volume/tone etc but if I were you, I would not be concerned so much with the actual placement of the H but rather the diameter of the H. Grab some .5" or .75" diameter stainless steel and replace that 2" H. Going to a smaller H from a larger H may not be as easy as cutting the old one out and replacing with a smaller one because the steel on the straight pipe would have already been removed to allow for the larger H already on there. May have to cut out both straight pipe sections and redo it with the smaller H.

For my catless header setup, I'm debating going to a slightly larger H (maybe 1.25") just see if there are any changes in the mid range. My car doesn't feel flat at all but I wonder If Im maximizing back-pressure/flow with a .75" pipe

So after all that, dont use the X pipe option and use a smaller H

bentz69

What diameter H are you using?

MTV10

2.5'' I believe.... almost same size as the piping going front to back.

NotABaller

You want a smaller crossover diameter for the H pipe. The placement doesnt matter.

bentz69

Everyones opinion of sound will obviously be different BUT a smaller diameter H is what you want

julours

Thanks a lot for sharing this experience playing with different setups. I am now considering headers and wanted an H pipe to keep the original tone, but I didn't knew about the H pipe diameter influence.

julours

If you have some photos of your setup available, could you please share some?

ShaneN.

I'm just wondering if it's any louder than how my car is now, the only difference is my h pipe is back where the resos were. If I can confirm it's loud enough I'll have him do a nice stainless h pipe by the secondaries and run it all the way back to the mufflers. Nice and clean

I was really happy with just the reso delete, I just wanted it slightly louder. I don't want to do cutouts or all straights just because I don't think it will sound good and i don't want it THAT loud. I think my current setup with headers might be perfect but by the time I got them into canada and installed i'd be looking at 5-6k CAD which is crazy to me. I also don't know if I want it loud ALL the time.

So at some point you had secondaries deleted and reso deleted with a .75" h pipe in reso section? Have you ever had it side by side with only a reso delete car? I have a feeling a reso delete car (only) is louder than most of this variations unless the diameter of the connecting H portion places into volume as much as it does how the car sounds.

I can't comment to how the car sounds now with the 2" connecting piece versus stock as I never had resos but yah it smoothed it out a bit versus just reso delete. The thing I'm more disappointed with is how much more quiet it got though. I had a hard time picking that diameter, it seemed like most people in these threads tried about a 1.5". Some of the videos I found sounded amazing but my car is much quieter in person than those videos made it seem. I'd be willing to cut it all out and do a clean stainless setup of straights all the way through with a tiny .5-1" connecting h pipe in a specific area if I KNEW it would be louder. The whole reason I stayed away from doing an X pipe was because I had read it would smooth it out even more, like you said. It sound great, just more quiet and slightly less pops and burbles on slowing/downshifts too.

When I bought my car the other week it came with just aluminized steel straights so that's what I put in yesterday for the secondaries/h pipe portion, so I have no problem getting rid of it all and going with a full stainless build if I know for sure it's going to be at least as loud as just my reso delete was with a .5 or 1" h pipe in it. I even just called back the shop to see if he could connect the secondaries again and just go back to straight pipe to the mufflers. Would cost a lot of money to have it back to how the car was when I first bought it though, all for nothing. Also the mentioned he's doing a reso delete on my same car next week so I might be able to scoop up those resos and just do secondary delete with straights and weld in some resos again but I have a feeling secondary delete with reso is quieter than just a reso delete like I had before.



So my current setup with a .5" crossover H versus the 1.5" will be much louder? Louder than a resonator delete ONLY car? I'm not concerned about the sound as much as the loudness. It sounds a bit different now than before but equally as good, just more quiet, which baffled me as I figured getting rid of cats would make it much louder than just having no resonators.

ShaneN.

I guess what I'm getting at is, what's the loudest setup we can do short deleting secondaries/reso with straights since I don't think that's the sound I'll be going for. And without doing headers.

bentz69

So at some point you had secondaries deleted and reso deleted with a .75" h pipe in reso section?
YES

Have you ever had it side by side with only a reso delete car?
NO

I have a feeling a reso delete car (only) is louder than most of this variations unless the diameter of the connecting H portion places into volume as much as it does how the car sounds.
I doubt it. 2nd cat delete with resonator in place will be louder then leaving the 2nd cats in place and deleting the resonator. Your removing a cat converter that restricts flow VS a hollow resonator. Location of H is not as important as the diameter as the H.

I can't comment to how the car sounds now with the 2" connecting piece versus stock as I never had resos but yah it smoothed it out a bit versus just reso delete.
Trust me, the 2" is too big for the type of sound your going after

The thing I'm more disappointed with is how much more quiet it got though. I had a hard time picking that diameter, it seemed like most people in these threads tried about a 1.5". Some of the videos I found sounded amazing but my car is much quieter in person than those videos made it seem. I'd be willing to cut it all out and do a clean stainless setup of straights all the way through with a tiny .5-1" connecting h pipe in a specific area if I KNEW it would be louder.
It will be, lets make a paypal bet LOL.... make a before and after video and post to youtube making sure the camera placement is the same distance each time and you rev to the same rpm each time

The whole reason I stayed away from doing an X pipe was because I had read it would smooth it out even more, like you said. It sound great, just more quiet and slightly less pops and burbles on slowing/downshifts too.
Exactly, the X smooths the tone. Many people like it that way but I can tell your after the same type of sound I was and Ive been there and done it, like many others

When I bought my car the other week it came with just aluminized steel straights so that's what I put in yesterday for the secondaries/h pipe portion, so I have no problem getting rid of it all and going with a full stainless build if I know for sure it's going to be at least as loud as just my reso delete was with a .5 or 1" h pipe in it.
DO IT

bentz69

2nd cat delete with straights
resonator delete with small .5 or .75" H
over n done with

ShaneN.

I appreciate the replies guys, it's hard to make a decision without being able to hear cars in person and I only want to do this one more time.



So you really think simply changing the 2" piece to .5" or 1" will make it much louder rather than just changing the sound? That's promising then because it wouldn't be easy to get the cats back in.

Now, how would that /\ compare to putting the stock resonator in and getting ride of the H pipe again, both setups without secondaries, because this shop has an appointment to take the resonators out of an identical car in the next week or two, so maybe I can scoop them up.



Just to be clear, that's my current setup only it's 2" H. Are we sure it's going to be at least as loud or louder than when I had reso delete ONLY?

ShaneN.

Would secondary delete with straights and putting back in resonators be louder than secondary delete and reso delete with an H pipe in reso locatoin with a .75" piece of pipe? Looks like I might have a chance to scoop up some resonators off another car.

bentz69

Save your money and don't buy the resonator. Deleting second cats with straights and putting the H in place of the resonator will be louder then just using the resonator instead if the H

NotABaller

I have done countless hours of researching the interwebs, listening on youtube, going to other owners' cars and comparing, and even testing on my own car. I had similar goals to yours, so I believe you will find my conclusions applicable:

For the loudest sound and best note, you want straight pipes all the way to the muffler, with an H crossover (0.5" - 1" max) as "high up" as possible. For us, this means where the secondary cats are. So replace secondary cats with an H. Replace resonator with straight pipes. Enjoy your sound.

If any of you are ever in Toronto, you're free to come check out my car and lose some of your hearing.

ShaneN.

That's what what I have now though, it's quieter than reso delete only. I just can't imagine the 2" h pipe I used making the car much quiter than if I went with a half inch diameter piece. I guess all I can do is try it.


​​​​​​​I might have to give this a try next, hopefully I can cut out and cap off where the 2" H is that I have now and try a smaller one where the secondaries were.

bentz69

Agreed on the H with straights for being the loudest. BUT how can you compare the placement of the H to achieve the loudest volume? Have you had it far downstream and then moved it closer to the motor?

ShaneN.

I know I keep bringing this up but we haven't really acknowledged it, the straights and H is the exact setup I have now and it's not loud at all. My prior reso delete only was louder (and sounded better). So unless going from a 2" H piece down to a .5 or .75" makes a very large difference in how loud it is then....

bentz69

I think I addressed that in my first post. Your 2" diameter H is robbing you of the noise/sound/volume you want. I used the X pipe when I put headers on as an example. Although it is a X pipe and not an H pipe, the cut-out inside the X is rather large. 2" to 3"

I think this is my last post in this thread until you get rid of the 2" and add a .5 -.75" pipe in its place

Post back after you get it done

ShaneN.

My bad, I thought you were just referring to the note rather than the volume level. Going to book an appointment for next week. Cheers