Need some opinions on overpipe/catbacks - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

RedRez86 · 02-07-2017, 01:18 PM

So I was thinking about running a 2.5 inch cat back and will eventually be throwing a turbo in my frs. My question is would it make sense and would it work to run a 3 inch over pipe with a 2.5 inch catbacks or will that cause issues? Not sure if it will fit or if it even makes sense. I was thinking more air flow where it tends to be more congested and the bring it back down to 2.5 catbacks after that to keep some back pressure and not be too free flowing with only around 300-350 hp. (That's the goal) let me know your thoughts on this please and any recommendations on overpipe and catbacks that will give me a nice growl and not sound like a ricer. Please be respectful I am simply trying to think outside the box, if I am way off kindly inform me. Thanks guys!

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Tcoat · 02-07-2017, 01:48 PM

Here is some light reading for you.
http://www.ft86club.com/forums/showthread.php?t=81491
http://www.ft86club.com/forums/showthread.php?t=6064

Keep in mind that exhaust flow is based on the smallest part of the system. Other than sound there is really no benefit to go from 3" and then drop down since you are still restricting the flow with the smaller pipe.

RedRez86 · 02-07-2017, 02:15 PM

So you think I just need to decide between either 2.5 or 3 inch and call it a day? Also I don't see many 3 inch options to choose from?

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Tcoat · 02-07-2017, 02:30 PM

Quote:

Originally Posted by RedRez86

So you think I just need to decide between either 2.5 or 3 inch and call it a day? Also I don't see many 3 inch options to choose from?

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I would.
Some more info for you.

http://www.ft86club.com/forums/showthread.php?t=12530
http://www.ft86club.com/forums/showthread.php?t=48704
http://www.ft86club.com/forums/showthread.php?t=75516

RedRez86 · 02-07-2017, 02:57 PM

So since I plan on going turbo later on it seems the wiser choice would be to go 3 inch overpipe/catback?

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8RZ · 02-07-2017, 03:00 PM

Yes, 3" for boosted applications.

RedRez86 · 02-07-2017, 03:34 PM

Awesome, thanks for the help fellas!

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Xxyion · 02-07-2017, 03:37 PM

Quote:

Originally Posted by RedRez86

Awesome, thanks for the help fellas!

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If you are planning on going FI definitely go with 3" piping for better airflow and performance. I made the mistake of not planning ahead so i wasted money on a few revisions but right now i'm using the Namless Axelback 3" with 5" mufflers. Should have also gotten the 3" JDL UQ Front Pipe but ah well.

RedRez86 · 02-07-2017, 03:47 PM

I don't see many 3 inch options, could you guys give some suggestions on what to look for and where? I've been mainly looking on ft86 speed factory and the only one I remember seeing was perrin I belive, also need help finding a 3 inch overpipe.. One thing I was sure about was if a catback system includes the front pipe?

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Nothingman · 02-07-2017, 04:06 PM

Quote:

Originally Posted by RedRez86

I don't see many 3 inch options, could you guys give some suggestions on what to look for and where? I've been mainly looking on ft86 speed factory and the only one I remember seeing was perrin I belive, also need help finding a 3 inch overpipe.. One thing I was sure about was if a catback system includes the front pipe?

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Check out jdlautodesign, I recently got a frontpipe (ultraquiet version) from them. They make 3" OP, FP, and Catbacks. As a welder/fabricator myself, I was very impressed with the welding and overall quality of the product (mostly everything is made to order). Frontpipes are typically not included in any catback that I know of. People love the perrin catbacks and I think CZP has groupbuy pricing in the classifieds section.

RedRez86 · 02-07-2017, 04:36 PM

Quote:

Originally Posted by Nothingman

Check out jdlautodesign, I recently got a frontpipe (ultraquiet version) from them. They make 3" OP, FP, and Catbacks. As a welder/fabricator myself, I was very impressed with the welding and overall quality of the product (mostly everything is made to order). Frontpipes are typically not included in any catback that I know of. People love the perrin catbacks and I think CZP has groupbuy pricing in the classifieds section.

Thanks brother much apprecieated

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02-07-2017, 01:18 PM	#1
RedRez86 Member Join Date: Feb 2017 Drives: Red Scion Frs Location: Lutz, Florida Posts: 79 Thanks: 13 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Need some opinions on overpipe/catbacks So I was thinking about running a 2.5 inch cat back and will eventually be throwing a turbo in my frs. My question is would it make sense and would it work to run a 3 inch over pipe with a 2.5 inch catbacks or will that cause issues? Not sure if it will fit or if it even makes sense. I was thinking more air flow where it tends to be more congested and the bring it back down to 2.5 catbacks after that to keep some back pressure and not be too free flowing with only around 300-350 hp. (That's the goal) let me know your thoughts on this please and any recommendations on overpipe and catbacks that will give me a nice growl and not sound like a ricer. Please be respectful I am simply trying to think outside the box, if I am way off kindly inform me. Thanks guys! Sent from my SM-G935T using Tapatalk

02-07-2017, 01:48 PM	#2
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,841 Thanks: 61,656 Thanked 108,295 Times in 46,456 Posts Mentioned: 2499 Post(s) Tagged: 50 Thread(s)	Here is some light reading for you. http://www.ft86club.com/forums/showthread.php?t=81491 http://www.ft86club.com/forums/showthread.php?t=6064 Keep in mind that exhaust flow is based on the smallest part of the system. Other than sound there is really no benefit to go from 3" and then drop down since you are still restricting the flow with the smaller pipe. __________________ Racecar spelled backwards is Racecar, because Racecar.

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02-07-2017, 02:15 PM	#3
RedRez86 Member Join Date: Feb 2017 Drives: Red Scion Frs Location: Lutz, Florida Posts: 79 Thanks: 13 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	So you think I just need to decide between either 2.5 or 3 inch and call it a day? Also I don't see many 3 inch options to choose from? Sent from my SM-G935T using Tapatalk

02-07-2017, 02:57 PM	#5
RedRez86 Member Join Date: Feb 2017 Drives: Red Scion Frs Location: Lutz, Florida Posts: 79 Thanks: 13 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	So since I plan on going turbo later on it seems the wiser choice would be to go 3 inch overpipe/catback? Sent from my SM-G935T using Tapatalk

02-07-2017, 03:34 PM	#7
RedRez86 Member Join Date: Feb 2017 Drives: Red Scion Frs Location: Lutz, Florida Posts: 79 Thanks: 13 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Awesome, thanks for the help fellas! Sent from my SM-G935T using Tapatalk

02-07-2017, 03:47 PM	#9
RedRez86 Member Join Date: Feb 2017 Drives: Red Scion Frs Location: Lutz, Florida Posts: 79 Thanks: 13 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	I don't see many 3 inch options, could you guys give some suggestions on what to look for and where? I've been mainly looking on ft86 speed factory and the only one I remember seeing was perrin I belive, also need help finding a 3 inch overpipe.. One thing I was sure about was if a catback system includes the front pipe? Sent from my SM-G935T using Tapatalk

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