Gains from front pipe and cat back? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

trippinbillies40 · 07-14-2015, 11:15 PM

Hi all!

Right now I have an HKS EL header with no cat, Motiv overpipe, stock front pipe, and a muffler delete. I'm also on a Moto East tune.

Any idea of how much I stand to gain by replacing the front pipe? Two options would be:

1. JDL front pipe with both cat & resonator, and keep muffler delete

2. Any hi-flow catted front pipe and a cat-back exhaust.

Has anyone done a before & after dyno in this situation and want to chime in with expected gains? Any help is appreciated!

ramiram1984 · 07-14-2015, 11:21 PM

Try both out.

Wayno · 07-15-2015, 03:06 AM

For NA, shit all. Less than 5hp with FP, less than 2hp with cat back. The more you increase the exhaust volume closer to the header, the less benefit a cat-back becomes. You could test it yourself by swapping between your muffler delete and your oem mufflers. With an aftermarket catted FP I'd wager either would be as much of a restriction as an aftermarket cat-back.

Basically, you'll get much more value hp/$ from a catted FP, than changing anything after the cat.

The only ones you'll find with dynos are likely vendors like perrin, who test their system on a stock car with stock header and stock tune, which is apples and oranges compared to yours.

sw20kosh · 07-16-2015, 01:28 AM

A high end header + e85.

07-14-2015, 11:15 PM	#1
trippinbillies40 Senior Member Join Date: Mar 2013 Drives: '22 WRB Location: US Posts: 863 Thanks: 201 Thanked 1,227 Times in 405 Posts Mentioned: 37 Post(s) Tagged: 0 Thread(s)	Gains from front pipe and cat back? Hi all! Right now I have an HKS EL header with no cat, Motiv overpipe, stock front pipe, and a muffler delete. I'm also on a Moto East tune. Any idea of how much I stand to gain by replacing the front pipe? Two options would be: 1. JDL front pipe with both cat & resonator, and keep muffler delete 2. Any hi-flow catted front pipe and a cat-back exhaust. Has anyone done a before & after dyno in this situation and want to chime in with expected gains? Any help is appreciated!

07-15-2015, 03:06 AM	#3
Wayno Senior Member Join Date: Apr 2014 Drives: Toyota 86 GTS Location: Australia Posts: 1,129 Thanks: 453 Thanked 896 Times in 424 Posts Mentioned: 211 Post(s) Tagged: 0 Thread(s)	For NA, shit all. Less than 5hp with FP, less than 2hp with cat back. The more you increase the exhaust volume closer to the header, the less benefit a cat-back becomes. You could test it yourself by swapping between your muffler delete and your oem mufflers. With an aftermarket catted FP I'd wager either would be as much of a restriction as an aftermarket cat-back. Basically, you'll get much more value hp/$ from a catted FP, than changing anything after the cat. The only ones you'll find with dynos are likely vendors like perrin, who test their system on a stock car with stock header and stock tune, which is apples and oranges compared to yours. __________________ rom downloads, information and examples Toyota 86 GTS OFT - Guide To Dialling In OTS Base Tune OFT - Example Alternate Maps for AT, 98RON, E85, MAF Scales

07-16-2015, 01:28 AM	#4
sw20kosh Senior Member Join Date: Jul 2012 Drives: 2013 Black FR-S Location: SF Posts: 3,030 Thanks: 881 Thanked 2,014 Times in 990 Posts Mentioned: 153 Post(s) Tagged: 1 Thread(s)	A high end header + e85. __________________ 86DRIVE Challenge

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