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Focus ST Flowmaster American Thunder Cat-Back Exhaust System Install Video 2013-2014

18613 Views 32 Replies 13 Participants Last post by  NimbusST

817637 Mustang Flowmaster Cat-Back Exhaust System American Thunder 2-1/4" with Polished Oval Tips Stainless Steel Focus ST 2013-2014 | CJ Pony Parts

This Flowmaster American Thunder Stainless Steel Cat-Back Exhaust System is for the 2013-2014 Focus ST. It features 2-1/4" mandrel bent stainless steel tubing and delivers a moderate to aggressive exhaust sound. Also, dual polished oval 3-1/4"x3-3/4" tips exit the center of the rear bumper, and the system is dyno tuned for maximum performance.

Flowmaster's cat-back bolts in place of your original exhaust. For installation, you'll first want to remove the stock system, and then the rear muffler and tip assembly. Put your new Flowmaster exhaust up into place on the Focus and after that the s-shaped pipe. Then, install the tailpipe, hooking it up to the original hanger, and then move on to the tailpipe. Tighten all bolts, secure the exhaust tips, and return the front brace, finishing up your installation.

The American Thunder cat-back is perfect for the person looking for moderate to aggressive sound levels with all of the performance benefits that you would expect from Flowmaster. Total installation takes around two hours.

See more Flowmaster Parts from CJ Pony Parts:
Flowmaster | Ford Mustang Exhaust | CJ Pony Parts
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Here's a follow up with a video for those that want to hear how it sounds.

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I love the sound... But how is it for daily driving? Do you feel increased vibrations on the interior or anything?
2 1/4 inch"? Why?
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2 1/4 inch"? Why?
Because it's a tiny little 2.0 engine. Any increase you would get from 2.5 or 3" pipe would not be noticed until a turbo upgrade. Which means 2.25" is adequate for 99% of ST owners. And it weighs less. And it's cheaper for Flowmaster. :)
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I love the sound... But how is it for daily driving? Do you feel increased vibrations on the interior or anything?
I don't have any interior vibes with mine, but it is kinda loud. I recently unplugged the ASS and it actually helped some in city driving. The only time it really becomes intrusive is in hard acceleration in 6th gear, say like going from 60mph to 80mph with anything more than 40% throttle. Other than that it's not bad at all. Silent while cruising on the highway. I like it. I wouldn't, however, recommend a downpipe with it tho. I can see it being extremely loud with one, considering it only has one resonator and no muffler.
Focus ST Flowmaster American Thunder Cat-Back Exhaust System Install Video 20...

I love the sound... But how is it for daily driving? Do you feel increased vibrations on the interior or anything?
I felt a little tiny bit of vibrations with mine but only when you are more than 1/3 of the way on the throttle. Now I don't feel it at all cause it's so little.

I was shocked by the loudness of the exhaust for having small piping. When you are on the throttle it is quite loud which I love. However, just like falcon said it is near silent when cruising below 2,500rpm.

I also like the size of the tips and how they fit in the rear bumper. They aren't too small or too unrealistically large.

The only negative I would say is the bass/drone noise when cruising between 67mph and 70mph. Once above 70 it quiets down again. This was expected because I don't believe any exhaust can be 100% drone free and it is such a small window of noise that I just stay out of it so I don't hear it.

I underestimated this exhaust greatly before installing it because of the size of piping. Overall, I would give it an 8.5/10 and would recommend it for anyone not power hungry since it won't be a good fit with a large turbo.

I am not sure how a DP will react with this system but I am going to get a high flow catted DP eventually so we will find out.


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Because it's a tiny little 2.0 engine. Any increase you would get from 2.5 or 3" pipe would not be noticed until a turbo upgrade. Which means 2.25" is adequate for 99% of ST owners. And it weighs less. And it's cheaper for Flowmaster. :)
Stock size is mostly 2.5 inches I believe with a smallish section of 2.1 or 2.2 " OD. Any turbo application vehicle, even a 2.0 with our punt k03 will benefit from a larger exhaust/better flow....to a point or course.

But what ever..more options for people is good.
Stock size is mostly 2.5 inches I believe with a smallish section of 2.1 or 2.2 " OD. Any turbo application vehicle, even a 2.0 with our punt k03 will benefit from a larger exhaust/better flow....to a point or course.

But what ever..more options for people is good.
So your saying 2.5" pipe with sections that reduce down to 2" with 2 large mufflers/resonators will flow better than 2.25" straight thru pipe?
Not saying that at all. Didn't mean to offend u or knock their product. I actually didn't see there was only a small resonator/no muffler. Just seems odd they went with 2.25 when stock is bigger in most sections and I could just remove the muffler from the stock system and its basically the same thing.

To each is own.
I don't care either way. I'm not a flowmaster fan boy or anything, I just liked the sound and it was a good price. I don't plan on going crazy with the car, I just wanted some more noise. The car will never see the track so I'm not worried about big HP numbers. At the end of the day I'm happy with it and that's good enough for me.

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Stock size is mostly 2.5 inches I believe with a smallish section of 2.1 or 2.2 " OD. Any turbo application vehicle, even a 2.0 with our punt k03 will benefit from a larger exhaust/better flow....to a point or course.

But what ever..more options for people is good.
I know you prob don't care, but I was just cutting up my stock exhaust so I can fit in in the garbage, and the only section of the exhaust that is 2.5" is the downpipe and into the resonator, the resonator outlet is where the 2" pipe starts. So you're looking at maybe a 2foot section of pipe that is 2.5" where as the rest of the system is a hair over 2".
Anyone have any videos with sound clips? Lots of the videos on YouToob have horrible mics and the feedback on the exhaust is terrible. So far I like the Flowmaster but I can't tell how loud it is. It that a resonator or a chambered muffler right after the downtube? The Cobb sounds nice as well. Can't find any vids on the Ford Racing setup but $900 is a bit steep when the Flows sound good to me especially at the $550 price tag :) This is my first 4 banger coming from the world of Mustangs so I'm trying to avoid the dreaded fart machine! Thanks for the info all!

- James
Anyone have any videos with sound clips? Lots of the videos on YouToob have horrible mics and the feedback on the exhaust is terrible. So far I like the Flowmaster but I can't tell how loud it is. It that a resonator or a chambered muffler right after the downtube? The Cobb sounds nice as well. Can't find any vids on the Ford Racing setup but $900 is a bit steep when the Flows sound good to me especially at the $550 price tag :) This is my first 4 banger coming from the world of Mustangs so I'm trying to avoid the dreaded fart machine! Thanks for the info all!

- James
http://www.focusst.org/forum/cj-pony-parts/15546-focus-st-exhaust-sound-clip-video-2013-2014-a.html
Tanks Steve. Probably one of the best compilations of exhaust vids for the ST online. Thanks for putting this together.

The only ones it doesn't address are the Cobb, Roush, and the new Ford Racing cat-back kit that just came out.

I like the Flowmaster sound and it sounds good in your video but in the video Flowmaster released it sounds a bit too loud and raspy. Ugghh ... tough decisions!!! :shocked::shocked:

Thanks again!

- James
I also got a Thundercat down pipe, it came with a sword of Omens.
Tanks Steve. Probably one of the best compilations of exhaust vids for the ST online. Thanks for putting this together.

The only ones it doesn't address are the Cobb, Roush, and the new Ford Racing cat-back kit that just came out.

I like the Flowmaster sound and it sounds good in your video but in the video Flowmaster released it sounds a bit too loud and raspy. Ugghh ... tough decisions!!! :shocked::shocked:

Thanks again!

- James
Personally having heard all three of these I would go with MBRP. I have not heard the Cobb or others yet but I am sure as we get settled into the ST game that will change.
Exhaust sounds are so subjective, and if you don't hear them in person it's hard to tell. I personally think the MBRP sounds the worst out of all of them, just seem like it has no tone to it at all. Pretty much the same reason why I don't like magnaflows on 4 cylinder cars, just all bass. The vids that roush put out of theirs I thought sounded great, then I heard the production version and it didn't sound anything like the video, made me really glad I didn't go with that one. I really want to see what the Injen sounds like...I've heard them before on other cars and they've always sounded great. I do tend to change up my exhausts pretty often so I may end up with something else down the line. I still like the tone that the flowmaster gives and I'm pretty happy with it. I finally found a decent exhaust shop around me and I think I'm going to get them to make me a triple tip like the agency power catback just as long as it's not too costly.
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Would not buy as its too small and not ideal for when I would want to upgrade later on. IMO
I also got a Thundercat down pipe, it came with a sword of Omens.
so you got the flowmaster exhaust and downpipe? sound clip with both please!! to my knowledge ive just heard the exhaust - the flowmaster downpipe
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