PSA for those with Aftermarket Exhaust

MrBigglesworrth · Apr 6, 2024

This might be common knowledge and I might just be an idiot, but if you have aftermarket exhaust you might want to consider adding weep holes. I have Thermal 3” and I had to remove the resonators and they were absolutely filled with water. If I had to guess I’d say 16-20oz’s, maybe more. It did not disappear by running the vehicle. I always thought it sounded kind of raspy under hard acceleration. I’m guessing this is why. It no longer sounds that way and sounds as it should. I live in Florida so your mileage may vary.

UNBROKEN · Apr 6, 2024

I’ve been doing that for decades…try to tell people but usually nobody listens.

2020FordRaptor · Apr 6, 2024

UNBROKEN said:

People not listening to something that makes sense NEVER! I know our Raptor spits out a lot of water sometimes from the exhaust and after putting in weep holes it sounds better too.

THNX SVT · Apr 9, 2024

I’ve been meaning to post on this issue for awhile. I have CVF DP’s and a Thermal 3” exhaust, and there’s definitely water in there since the ST sees more than its fair share of in-town trips. I’d greatly appreciate it someone provide some input on how many weep holes I should drill, what size to drill them and approximately where I should locate them.

Cblue · Apr 9, 2024

I mean a good WOT pull should get that exhaust hot enough to evaporate any water in the system.

UNBROKEN · Apr 9, 2024

Cblue said:

You would think…but it doesn’t always work that way. There’s a reason factory mufflers have weep holes.

UNBROKEN · Apr 9, 2024

THNX SVT said:

3/16” is more than enough…either the front or lowest end of the muffler right at the seam and in the center.

MrBigglesworrth · Apr 9, 2024

Cblue said:

Well, it didn’t. Sooo….

MrBigglesworrth · Apr 9, 2024

THNX SVT said:

What Unbroken said. I’ll take a picture in a little of where I put mine. But I just put my finger in the resonator to find where would make the most sense and drilled there.

Eljaber · Apr 9, 2024

Interesting. Looking forward to some pics of where people put theirs!

MrBigglesworrth · Apr 9, 2024

THNX SVT said:

I’ve been meaning to post on this issue for awhile. I have CVF DP’s and a Thermal 3” exhaust, and there’s definitely water in there since the ST sees more than its fair share of in-town trips. I’d greatly appreciate it someone provide some input on how many weep holes I should drill, what size to drill them and approximately where I should locate them.

THNX SVT · Apr 10, 2024

Thanks @UNBROKEN and @MrBigglesworrth for the input. I can also tell I have some water at the bottom of the DP’s as I can see the nasty stainless/exhaust drippage spots on my garage floor. Do you or anyone else have any thoughts on adding weep holes somewhere closer to the DP’s in addition to the ones in the mufflers?

CoHPhasor · Apr 10, 2024

Closer to the downpipes? I don't know that I'd advise that.
1. You would be letting out exhaust gas under the cabin, which is a nono and will fail inspections
2. Exhaust is far louder when you're closer to the engine, so you'll be letting out noise
3. Turbos work best when exhaust flow is smooth, as interference messes with the pressure differential - it may be minimal but I wouldn't add any possible issues

Generally speaking, air tubes are water tubes, so when going uphill, the water flows towards the back anyway (Which is where I would put my holes - towards the back of the muffler).

StarWhite22 · Apr 10, 2024

Curious why most aftermarket exhausts don’t come with them? Seems like something that would make sense to do but I’m sure there’s a cost benefit analysis that wins out.

Eljaber · Apr 10, 2024

Curious, what are the long term effects if water continues to buildup? Besides the obvious of possibly rusting/corroding?

CoHPhasor · Apr 10, 2024

Eljaber said:

Just that, really.
You are unlikely to build up enough water to cause water to roll down the pipes to the exhaust manifold and get in, as you usually drive forward, pushing water to the back, allowing it to exit. You are not going to fully block exhaust from escaping, as your muffler does not vertically exit, so water levels can't be higher than the bottom of the exhaust tube.
It's just nice to not be carrying water, and it doesn't hurt that you don't form a lot of rust or corrosion. (Even stainless steel is susceptible)

THNX SVT · Apr 17, 2024

Thanks all for the input. I drilled two weep holes in the mufflers and drained just over 15 fluid ounces from the exhaust. Pics attached, and I promise it’s not pee.

CoHPhasor · Apr 17, 2024

That, is a lot of fluid!
still soundd good, right?

Tracked · Apr 17, 2024

THNX SVT said:

Was there a noticeable change in volume after draining the water?

I have thermal and DPs and swear the turbo whistle at idle isn't at loud as what I've heard in videos online from others with the same setup... this has me wondering if I have water in my rear mufflers.

Dale5403 · Apr 17, 2024

THNX SVT said:

Can you post a picture of where you drilled the holes? It might help other members if you would, thanks.

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