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16 ST, 93 oct, FRPP, RS ac K&N filter, Forge FMIC, Mountune Recirc, CNT cat, 3" pipe, Steeda RMM
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Discussion Starter · #1 ·
As I mentioned in another post, I'm considering an MBRP 3" exhaust, or an Accelatec 2.5". As an old time hot rodder who's primarily had 8 cylinders, but also had turbo 4's, I got to thinking 2-1/2 inch exhaust just doesn't make sense for a car putting out over 250 HP. The stock exhaust narrows down even smaller in some areas, closer to 2 inch. It's seems like a miracle that it makes over 250 hp with the stock exhaust.

Anyway, a couple of things I found, one is an exhaust chart that reinforces the 3" as well as a link to a ZZP video covering exhaust where it recommends 3" for turbo cars.

Has anyone here gotten much more than stock horsepower running less than 3 inch exhaust?

Thanks!

Here's those sources:

 

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As I mentioned in another post, I'm considering an MBRP 3" exhaust, or an Accelatec 2.5". As an old time hot rodder who's primarily had 8 cylinders, but also had turbo 4's, I got to thinking 2-1/2 inch exhaust just doesn't make sense for a car putting out over 250 HP. The stock exhaust narrows down even smaller in some areas, closer to 2 inch. It's seems like a miracle that it makes over 250 hp with the stock exhaust.

Anyway, a couple of things I found, one is an exhaust chart that reinforces the 3" as well as a link to a ZZP video covering exhaust where it recommends 3" for turbo cars.

Has anyone here gotten much more than stock horsepower running less than 3 inch exhaust?

Thanks!

Here's those sources:

Stock 2.5" is good to 350hp. There's no limit unless you go BT.
 

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^^^What he said^^^ Unless you are going for a bigger turbo, the factory exhaust is not a limiting factor, the little tiny KO3 is the bottle neck.
 

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Hmmm. I think my Ford Performance Exhaust by Borla is still 2.5"... I wonder if that's going to be an issue when when slapping on my 2867 Gen2 on full aux.

Sent from my ONEPLUS A6003 using Tapatalk
 

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16 ST, 93 oct, FRPP, RS ac K&N filter, Forge FMIC, Mountune Recirc, CNT cat, 3" pipe, Steeda RMM
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Discussion Starter · #7 ·
This is with a 2.5” exhaust. I was told by my turbo manufacturer I need a 3”. My tuner said it isn’t necessary. I believe my tuner.
View attachment 394422
Wow over 450 hp and almost 450 Ft lbs? Dang I'm a believer!

What do you have done to that car to make so much power?
 

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This is with a 2.5” exhaust. I was told by my turbo manufacturer I need a 3”. My tuner said it isn’t necessary. I believe my tuner.
lol, way to mic drop...don’t you have some blue-haired litttle old ladies to go chase 😂

Wow over 450 hp and almost 450 Ft lbs? Dang I'm a believer!

What do you have done to that car to make so much power?
all of it, that’s what he’s done 🙃
 

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2018 Focus ST1
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BNR 3071 turbo. Cobb 3” catted downpipe. FSwerks 2.5” stealth exhaust. Mishimoto hot side charge pipe. JBR cold side charge pipe with Tial bov. 2 port stratified aux fuel kit & split second controller. Tuned by Alan at EdgeAutoSport. Had to upgrade the clutch, stock won’t grab anything over 420wtorque. Spec 3+ with lightweight flywheel installed Saturday.
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Wow over 450 hp and almost 450 Ft lbs? Dang I'm a believer!

What do you have done to that car to make so much power?
Dyno was done today as well
That's wild! Big turbo. Makes me want one now. That must be a blast to drive.
absolutely, I’ll post videos of me giving sauce to V8s lol
 

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@Tunapish , that exhaust looks like a straight pipe with a resonator, lol. I'm not seeing any restrictive 'muffler' looking object, but I realize that cylinder supposedly is one.
Is it this one?
 
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Discussion Starter · #15 ·
Downpipe next logical upgrade for me? If so, what defouler would I need with a high flow cat? J type or ?
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Discussion Starter · #17 ·
That will work fine. I use a CP-e one that they provide with their High Flow/Catless DPs - straight with no angle - works without a problem. I use a high flow cat with the medium insert for the defouler.
I can get a decent deal on a lightly used cpe... If I get it, the angled extension works as the defouler so I don't need an extra? Thx
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I can get a decent deal on a lightly used cpe... If I get it, the angled extension works as the defouler so I don't need an extra? Thx View attachment 394429
You will still need a de-fouler; I would ask the seller if they have the one that came with the downpipe.
 
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I can get a decent deal on a lightly used cpe... If I get it, the angled extension works as the defouler so I don't need an extra? Thx View attachment 394429
The defouler I referenced was a CP-e one that they make - the J-style defouler will work fine with any downpipe. I'm not sure about the CP-e one, but I would assume it would be the same size - just not angled.
 

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2017 Kona Blue ST1
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People on the stock K03: "I need a 3" exhaust"
Your K03:
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"No, no you don't"...
 
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