FR-S / BRZ Big 3" Cat Back Exhaust

[Jesse]

2.5 seems fine, if your lowered the ground clearance could be a problem too.

[Thatruth2001]

Northwest meet up video and 3" exhaust demonstration on shop car over Memorial Day weekend

http://www.ft86club.com/forums/showt...t=35860&page=4

[Splat]

I ran a few 1/4 drags... and never did a muffler still on do better than opening the headers. I don't think running 3-4" can hurt your performance at all ..

[ramiram1984]

Originally Posted by DarthThinmints

http://www.perrinperformance.com/brz...t-back-exhaust


Does anyone have any sound clips for this exhaust yet?
Pros/Cons?

Dude there's vid on the same ad page u were on.

[GTM_Challenge]

From what I've heard from a few exhaust builders (won't name them here), the FA20 can flow enough air to warrant a 3" exhaust - but its so loud that most people would probably be turned off.

The F20/F22 motors from the S2000 work best with a 3" exhaust, just FYI.

[SuiSid3l]

Originally Posted by chadstyle

With NA and 3" exhaust on this car you will LOSE power. FA20Club built a full 3" system and it lost substantial power. If you go turbo then it will help out but until then don't waste your money.

I'd like to know where you saw this or at least some dyno numbers to back it up. Especially since there are a couple Vendors on this very forum that say the exact opposite of what you just said and have dyno runs that show gains from stock. I'd agree its not ideal for an n/a setup, but having a 3" exhaust on N/A is more for future proofing. I dont want to buy a 2.5 when I fully plan on going f/i and then later on decide I wanna run 400hp and have to drop another grand on a new exhaust. Now I dont have to worry about the exhaust EVER bottlenecking my build.

[chadstyle]

Originally Posted by SuiSid3l

I'd like to know where you saw this or at least some dyno numbers to back it up. Especially since there are a couple Vendors on this very forum that say the exact opposite of what you just said and have dyno runs that show gains from stock. I'd agree its not ideal for an n/a setup, but having a 3" exhaust on N/A is more for future proofing. I dont want to buy a 2.5 when I fully plan on going f/i and then later on decide I wanna run 400hp and have to drop another grand on a new exhaust. Now I dont have to worry about the exhaust EVER bottlenecking my build.

I heard it directly from FA20Club while he was dyno tuning my car. He built a full 3" exhaust for his personal car as he was prepping for the turbo install. He lost a nice bit of power (he said around 10 HP if I recall correctly) while still NA.

[SuiSid3l]

Originally Posted by chadstyle

I heard it directly from FA20Club while he was dyno tuning my car. He built a full 3" exhaust for his personal car as he was prepping for the turbo install. He lost a nice bit of power (he said around 10 HP if I recall correctly) while still NA.

I only ask because Ptuning has their dyno posted of their 3" and they are showing a 5hp gain from stock. Still like to see some legit dyno of a 3" cause a loss of power on the fa20, regardless of who's mouth it came from.

[PERRIN_Chris]

Stay tuned guys, we are working on dynos comparing the 2.5" to the 3" on NA and on the Vortech kit soon!

[FR-S Matt]

Originally Posted by PERRIN_Chris

Stay tuned guys, we are working on dynos comparing the 2.5" to the 3" on NA and on the Vortech kit soon!

Thanks! Can't wait to see the results. I'm hoping to see no power loss unlike many that are claiming it will lose power.

[SuiSid3l]

Originally Posted by PERRIN_Chris

Stay tuned guys, we are working on dynos comparing the 2.5" to the 3" on NA and on the Vortech kit soon!

This is really what people want to see. I'm curious to see when/if the 2.5 starts losing out to the 3".

[Turbowned]

Very interested to see dyno, sound clips, and weight differences. I'm definitely going FI, just not this year. I want to buy a Perrin exhaust ASAP but I don't want to buy the 3" and have to deal with noisy farty boxer engine sounds for a year while I'm waiting to go turbo. The alternative is to buy the 2.5" for now and if it's determined to be a restriction, sell it and replace it later.

Originally Posted by frslee

3" exhaust for this small engine? Even Audi S4 V8 guys run 2.5 and 2.25 at the end.

They have dual exhausts though, do they not? 2.25 x 2 = 4.5.

[mad_sb]

Originally Posted by Tansey86

Well a naturally aspirated car wants back pressure. .

No, it does not. What every engine wants is the lowest back pressure with the highest exhaust gas velocity in the rpm range you want the biggest gains. Often times going larger kills velocity and hence the myth about back pressure.

[Tansey86]

Originally Posted by mad_sb

No, it does not. What every engine wants is the lowest back pressure with the highest exhaust gas velocity in the rpm range you want the biggest gains. Often times going larger kills velocity and hence the myth about back pressure.

You are right, I stand corrected. In a world of trying to make as much power and flow as much air as possible, you want no back-pressure or restriction in the exhaust. i.e. open downpipes and open headers

But on certain situations n/a cars will retain a little back-pressure on purpose to maximize torque in a given rpm range, mainly DD situations.