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Exhaust Set Up

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Withe the way the muffler is setup, guaranteed gains for spool, power and lighter weight with an aftermarket setup. Problem will be, to gain it, there's really no room for a muffler. A car running this much boost (25 psi), will gain plenty of power from opening up the exhaust. For every psi into the engine, there is almost double that coming out. Since the valve doesn't open until 3k rpm, iirc, you are losing spool. A down pipe should help, but I don't know the specs of it stock. A 260+ whp car needs a minimum of 2.5" through to be ok performance and 3" for maximum. Running a 3sgte at different power levels, you could gain 20 whp with 3" exhaust because stock bottle necked down to 2" in places. Straighter is better too. Imo, I'll probably do double 3" straight pipes out the back and hopefully get to 400+ whp
 

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I think that's only the GR Yaris because of European regulations...
I'd definitely like to see the entire length of the exhaust for confirmation. However, every single one of these cars I've seen pics of dirty (after drive events, or the Canadian press cars that got driven for longer periods of time, or that guy who signed up who's neighbor has been driving that white one). The exhaust tips are 100% spotless. No soot buildup whatsoever.


EGR is making a comeback, and GPFs are getting installed on vehicles more and more in the US market these days.
 

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Withe the way the muffler is setup, guaranteed gains for spool, power and lighter weight with an aftermarket setup. Problem will be, to gain it, there's really no room for a muffler. A car running this much boost (25 psi), will gain plenty of power from opening up the exhaust. For every psi into the engine, there is almost double that coming out. Since the valve doesn't open until 3k rpm, iirc, you are losing spool. A down pipe should help, but I don't know the specs of it stock. A 260+ whp car needs a minimum of 2.5" through to be ok performance and 3" for maximum. Running a 3sgte at different power levels, you could gain 20 whp with 3" exhaust because stock bottle necked down to 2" in places. Straighter is better too. Imo, I'll probably do double 3" straight pipes out the back and hopefully get to 400+ whp
Don't think the stock turbo will do 400+whp without E85. Think the record is like 380ish.
 

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08 STI / 85 CB650SC Nighthawk (kinda cafe)
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Tempted to stay oem and just add a down pipe since the exhaust setup kinda grew on me, but if I do anything it’d be a dual outer setup. Hopefully still around oem-ish look/sound wise to open it up and drop some lbs
I design exhausts for my current car and after 2 years just threw the OEM exhaust back on it to test a different product. OEM is kinda nice, haha.
 

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Tempted to stay oem and just add a down pipe since the exhaust setup kinda grew on me, but if I do anything it’d be a dual outer setup. Hopefully still around oem-ish look/sound wise to open it up and drop some lbs
Very possible that the DP will give the biggest bump. These cars run 25 psi. More flow = more power, but also less lag and better transient response. In NA cars, a little backpressure isn't bad. In turbo cars, you always gain with more flow. Straight open dump makes the most power, while being loud af. lol
 

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Very possible that the DP will give the biggest bump. These cars run 25 psi. More flow = more power, but also less lag and better transient response. In NA cars, a little backpressure isn't bad. In turbo cars, you always gain with more flow. Straight open dump makes the most power, while being loud af. lol
This isn't always true. I've tested this theory with an EJ and a SR20. It was really noticable at the lack of power from open DP.
 

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15 WRX, Sienna, GR86
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This but loose the center and add euro trailer mount
Yay, at least one other person thinking like me! I was planning to modify the stock muffler to remove the center tip just after the valve mechanism and put a down-spout type tip on there. Then install the hitch for the regular Corolla hatchback. If the receiver sits low enough, I'll cut/weld to shorten it so it tucks nicely into the center tip cutout.

Unfortunately it doesn't look like there's any room to keep the valve mech with a hitch. I don't want to hack up the OEM muffler either so I'll probably go for an aftermarket exhaust. From all I've heard the stock exhaust on this thing is about all I'd want.. hopefully there will be some mellow dual/side tip options.
 
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