Taming Coupe Exhaust

[JimStone]

There have been plenty of threads bemoaning the loudness and harshness of the FFR kit supplied stainless side pipes. But there seems to be very little information on modifications to the FFR pipes that actually help.

Inevitably, the solution seems to be "buy Gas'N or Boig pipes", which isn't really a solution at all

Yes, I know, it will be loud no matter what. But even a few decibels lower can make a difference in tolerability. And improving tone and cutting drone is also beneficial.



Has anyone actually done anything that resulted in real, long-lasting improvement?


Things that seem to be potential options:

1) adding Car Chemistry inserts

2) adding auger style inserts

3) adding outlet diffuser plates, like these https://www.dkcustomproducts.com/thunder-torque-inserts-158-model-family-dk-tti-158.htm

4) adding baffled inserts

5) repacking the core with better materials like stainless wool or basalt fiber wrap

6) others?

A combination of above?


Cutting the pipes apart is not optimal, but probably necessary for access to achieve a sufficient fix

Would love to hear from those who have experience working on exhaust. (I have none), whether you have a Coupe or not

[Cobraman]

I'm at this stage also and would like to get this done before I ceramic coat the ffr sidepipes. I have looked at all the same options you have and I still:confused: have questions if it really changes the dB that much. I've seen some posts on this subject from a while back but I've been unable to find them again. Hope someone with experience chimes in.

[JTG]

Thank you for starting this thread, as it has been high on my list of things to figure out.

We haven't really started exploring this yet, but one consideration is using forward facing headers with a crossover pipe, into cats, and out to the side pipes. This will require moving the battery somewhere else. The crossover is because I prefer the sound of all 8 cylinders together vs two separate 4 cylinders. The cats will also cut down on sound and it would make me feel better having them. I know it's not necessary, but neither is this car. I found a picture or two of someone who fabricated something like this in a Gen 2 Coupe, so it seems possible.

Will it fit? Don't know.
Will it help with the sound levels? Not a clue.
Will I be able to shield the cats enough to not bake something else nearby? Possibly.
Will it make me happy trying to figure this out? Yup!!

At any rate, I look forward to seeing what others with actual experience have to say about this.

[burchfieldb]

Greg from the Cobra Daytona Build has several videos on this topic with different attemps on things. Here is one of them.

https://youtu.be/avJwAMHT92I?si=ABSNzv5M5agkcLvq

[JimStone]

Thank Brent,

I went back and found Greg's video with the dual pipes that he modified. https://m.youtube.com/watch?v=6cDpWwb-Yfc&t=11s

In my opinion, only the dual pipes look right and are a must for me.

Basically Greg put new glass pack and baffled pipes in. Seemed to help. Still loud, but maybe that truly is the best that can be done if sticking with dual pipes

[JimStone]

Thank you for starting this thread, as it has been high on my list of things to figure out.

We haven't really started exploring this yet, but one consideration is using forward facing headers with a crossover pipe, into cats, and out to the side pipes. This will require moving the battery somewhere else. The crossover is because I prefer the sound of all 8 cylinders together vs two separate 4 cylinders. The cats will also cut down on sound and it would make me feel better having them. I know it's not necessary, but neither is this car. I found a picture or two of someone who fabricated something like this in a Gen 2 Coupe, so it seems possible.

Will it fit? Don't know.
Will it help with the sound levels? Not a clue.
Will I be able to shield the cats enough to not bake something else nearby? Possibly.
Will it make me happy trying to figure this out? Yup!!

At any rate, I look forward to seeing what others with actual experience have to say about this.



I saw that photo of the Coupe with the crazy forward facing exhaust with X pipes. That certainly could be an option if you're willing to make that effort. Looking at my engine bay with even the "small" LS in there, I can't even imagine how to make the necessary room for it though.

[Skuzzy]

Could always do what Superformance does. Use the side pipes as an exhaust pipe which has fake exits at the end and turns back into the body and exits at the rear of the car. I think they use a Corvette style muffler at the back. I do not know if this is possible with the FFR design, but it is worth consideration.

All the appearance of the dual side pipes with none of the noise.
221403

[lewma]

Jim

GasN has really helped with the noise levels in my car. I still use noise cancelling earbuds every time I'm in the car but the sound is not as harsh as it was with the standard FFR pipes. I've done a couple of multi hour highway trips with the GasN pipes and my head/ears are not ringing in any way with that setup.

mark

[JTG]

I saw that photo of the Coupe with the crazy forward facing exhaust with X pipes. That certainly could be an option if you're willing to make that effort. Looking at my engine bay with even the "small" LS in there, I can't even imagine how to make the necessary room for it though.

We haven't test fit the Coyote yet, but I will probably have a similar reaction once we do. It may be trying to stuff 50 lbs. worth of stuff into a 10 lb. bag.

That being said, I won't be satisfied until we try! We going to start with a crude pool noodle mockup before moving onto any sort of hard pipes. I'll post up in our build thread whether it's a success or failure.

[JimStone]

Could always do what Superformance does. Use the side pipes as an exhaust pipe which has fake exits at the end and turns back into the body and exits at the rear of the car. I think they use a Corvette style muffler at the back. I do not know if this is possible with the FFR design, but it is worth consideration.

All the appearance of the dual side pipes with none of the noise.
221403


I had no idea Superformance did rear exhaust. Interesting. For the FFR coupe it'd be difficult. But when there's a will, there's a way.





Lewma,

I'm trying to avoid resorting to Gas'N. I'm glad to hear they help, but with all the talk recently about the issues with communication and delays, as well as the cost (of course), I'm trying to find a way to make the FFR pipes work.

In Greg's YouTube video that I linked above, he thought the new packed 3 inch tubes he used from Classic Chambered Exhaust were probably similar (or the same) as what Gas'N uses. He says they were "custom" so I don't actually see them for sale on Classic Chambered Exhaust 's website so you have to call, but he said 4 of the packed tubes were $380 (a a year or two ago).

Trouble for me is I don't TIG weld. I'd either have to learn and get the equipment (fun, but expensive) or pay someone (I hear prices that are kinda asinine)

[JimStone]

Here's a screenshot from Greg's Youtube of the new packed 3 inch tubes with baffles from Classic Chamber Exhaust. They're a few inches longer than FFR 's

https://thefactoryfiveforum.com/attachment.php?attachmentid=221422&d=1762984675



And a view of the inside. Said it's 2.25" inside, which is same as FFR 's

https://thefactoryfiveforum.com/attachment.php?attachmentid=221423&d=1762984675


He showed improvement from 112 decibels to 102 decibels with the new mufflers




Edit:

Emailed with Eric from Classic Chamber Exhaust and he only does mild steel (16ga), not stainless, so that may change how I feel about them...

[Bob Brandle]

Here's some ideas that I considered a ways back during my Gen 3 Coupe's build. Add inline a small catalyst converter such as a Pypes 3 in. High Flow Mini-Cat F144757942 or similar unit. Yes, some significant cutting of header of exhaust pipe and welding is required.

https://thefactoryfiveforum.com/attachment.php?attachmentid=221442&d=1763009434

Another similar mod is what was accomplished in the Mercedes SLR McLaren Renntech where both the required mini cat. and a small muffler were mounted within the engine compartment. Likely the Merc had much more room than a FFR Gen 3 Coupe.

https://thefactoryfiveforum.com/attachment.php?attachmentid=221443&d=1763009434


The twin very small diameter Daytona coupe sidepipes are simply very to too small a diameter to contain much in the way of sound muffling yet be open enough to free flow the exhaust. They due have The Look, however.

I ultimately made the choice of going with Boig Quiet Pipes for the Coyote mounted in my Gen 3 Coupe.

https://thefactoryfiveforum.com/attachment.php?attachmentid=195400&d=1707256899

https://thefactoryfiveforum.com/attachment.php?attachmentid=169586&d=1658196721
https://thefactoryfiveforum.com/attachment.php?attachmentid=221445&d=1763009434

[AaronR]

... but one consideration is using forward facing headers with a crossover pipe, into cats, and out to the side pipes. This will require moving the battery somewhere else. The crossover is because I prefer the sound of all 8 cylinders together vs two separate 4 cylinders. The cats will also cut down on sound and it would make me feel better having them. I know it's not necessary, but neither is this car. I found a picture or two of someone who fabricated something like this in a Gen 2 Coupe, so it seems possible.



This is exactly what I've been scheming to do with mine. Forward facing turbo headers with an "X" pipe, resonators, and then mufflers, but no cats. I have also thought about dumping it out right at the fender hole instead of routing out along the side (after crossing over the front). I will have the "small" LS, so I'm hoping I can figure out the routing in a way that works. I don't have the coupe yet, so it's all just a bunch of hopium at this point. We'll see if reality comes crashing down when I see how small of a space there actually is to work with in there.

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[JimStone]

The forward X pipe exhaust is definitely possible if you plan it from the start. You could even bring some of the exhaust out into the radiator tunnel to make more room. It's not for me, but definitely doable. I saw a picture at some point of someone who did it several years ago, but for the life of me I can't find it now

[turbodon]

This is my solution on this current build. The first Coupe I built did not have the performance cats but did have the Burns Stainless mufflers.

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