Dual-mode track and street pipes - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Hags86 · 10-11-2017, 05:10 AM

Thought someone might be interested in my custom exhaust.

It is a turbo with a 3" all the way through (including dump pipe and overpipe) with just a high-flow cat and no mufflers. An exhaust bypass cuts this out for 'street' mode and exits via the other exhaust tip which is 2.5" and has a muffler.

An aftermarket ECU allows one dash switch to both open the valve and set a new ECU map. It goes in for dyno tuning next week - we think we'll get a few more degrees of ignition timing with the open pipes. Let's test the theory and see if it actually makes more power.

Cat is installed such that it can be removed relatively easily.

Video of the bypass valve testing

Boomerang · 10-11-2017, 07:09 AM

Take my money and sell me one...

churchx · 10-11-2017, 07:15 AM

I wonder how did you made ecu tune also actuate straight exit exhaust valve?

Tcoat · 10-11-2017, 07:38 AM

Very nicely done. In for the test results.

femaledog · 10-11-2017, 08:51 AM

Nice man. I wish there were more valved options for this car. I may need to have something made as well.

churchx · 10-11-2017, 09:14 AM

There are several valve options, if one searches, that can be welded in. Electric or mechanical wire actuated. IIRC i've seen here another one or two similar setups on this forum. But actuated by ECU tune sounds something new.

cbryant514 · 10-12-2017, 12:18 PM

Thoughtful solution and it appears to be well executed! I'd like to hear the difference via a test video...

Barefootdan · 10-12-2017, 03:34 PM

Quote:

Originally Posted by Boomerang

Take my money and sell me one...

I’ll be second in line!

CSG Mike · 10-12-2017, 03:42 PM

Clean!

Pat · 10-12-2017, 04:19 PM

Looks pretty cool. Why does the valve open past 90 degrees? It seems like 90 would be best.

Hags86 · 10-12-2017, 04:42 PM

Quote:

Originally Posted by Pat

Looks pretty cool. Why does the valve open past 90 degrees? It seems like 90 would be best.

It does open to 90 degrees. The camera angle makes it look weird.

Quote:

Originally Posted by cbryant514

Thoughtful solution and it appears to be well executed! I'd like to hear the difference via a test video...

It makes a large difference in volume but i haven't rev’d it past 3500 yet - still has a NA map. Goes for dyno next week - I'll report back then together with any differences in HP a video with the valve open and closed.

Hags86 · 10-12-2017, 05:24 PM

Quote:

Originally Posted by churchx

I wonder how did you made ecu tune also actuate straight exit exhaust valve?

That is the easy part. The MoTeC ECU is very configurable. A 10 position Driver Rotary Switch enables Auxiliary Output to switch to ground which then then operates a relay to drive the servo motor of the valve.

That one Driver Rotary Switch can operate several software options at once. for example:

Switch Pos Ex Valve Rev Limit Timing
Pos 1 - Valet Closed 3500 Map 1
Pos 2 - Daily Closed 7000 Map 1
Pos 3 - Track Open 7500 Map 2

I can even operate outputs based on GPS position. One track I got to has a restrictive noise limit. I'm thinking of programming the ECU to close the valve as the car approaches the Decibel meter and then opening it back up when I'm further away.

It's only really limited by your imagination - it could open based on engine RPM, throttle position etc etc.

imnotsureaboutbrz · 10-12-2017, 06:08 PM

I would love to have a dual mode exhaust for everyday driving and track/autox days... most options are too expensive or custom. And here's the perfect spot for that switch...

I can't wait to hear how yours turns out!

ichitaka05 · 10-12-2017, 06:17 PM

Impressive! Interested to see the vid & result as well

10-11-2017, 05:10 AM	#1
Hags86 Senior Member Join Date: Mar 2013 Drives: Toyota GTS 86 Location: Melbourne Australia Posts: 243 Thanks: 21 Thanked 118 Times in 65 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Dual-mode track and street pipes Thought someone might be interested in my custom exhaust. It is a turbo with a 3" all the way through (including dump pipe and overpipe) with just a high-flow cat and no mufflers. An exhaust bypass cuts this out for 'street' mode and exits via the other exhaust tip which is 2.5" and has a muffler. An aftermarket ECU allows one dash switch to both open the valve and set a new ECU map. It goes in for dyno tuning next week - we think we'll get a few more degrees of ignition timing with the open pipes. Let's test the theory and see if it actually makes more power. Cat is installed such that it can be removed relatively easily. Video of the bypass valve testing Attached Images Last edited by Hags86; 10-12-2017 at 04:43 PM.

10-11-2017, 07:38 AM	#4
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,845 Thanks: 61,656 Thanked 108,286 Times in 46,456 Posts Mentioned: 2497 Post(s) Tagged: 50 Thread(s)	Very nicely done. In for the test results. __________________ Racecar spelled backwards is Racecar, because Racecar.

10-12-2017, 06:17 PM	#14
ichitaka05 Site Moderator Join Date: Oct 2009 Drives: ichi 86 Project Location: Middle of No where Posts: 20,976 Thanks: 7,673 Thanked 19,101 Times in 8,333 Posts Mentioned: 679 Post(s) Tagged: 27 Thread(s)	Impressive! Interested to see the vid & result as well __________________

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10-11-2017, 07:09 AM	#2
Boomerang 86 Join Date: May 2016 Drives: 2015 Toyota GT86 MT UEL E85 RSR CWP Location: Perth, Western Australia Posts: 3,293 Thanks: 3,553 Thanked 4,850 Times in 2,166 Posts Mentioned: 28 Post(s) Tagged: 0 Thread(s)	Take my money and sell me one...

10-11-2017, 07:15 AM	#3
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,086 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	I wonder how did you made ecu tune also actuate straight exit exhaust valve?

10-11-2017, 08:51 AM	#5
femaledog Member Join Date: Sep 2017 Drives: 2017 BRZ Perf. Pkg. Location: NYC Posts: 67 Thanks: 93 Thanked 32 Times in 25 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Nice man. I wish there were more valved options for this car. I may need to have something made as well.

10-11-2017, 09:14 AM	#6
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,086 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	There are several valve options, if one searches, that can be welded in. Electric or mechanical wire actuated. IIRC i've seen here another one or two similar setups on this forum. But actuated by ECU tune sounds something new.

10-12-2017, 12:18 PM	#7
cbryant514 Member Join Date: Apr 2017 Drives: 2016 Scion FR-S Location: Senoia, GA Posts: 56 Thanks: 73 Thanked 18 Times in 17 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Thoughtful solution and it appears to be well executed! I'd like to hear the difference via a test video...

10-12-2017, 03:42 PM	#9
CSG Mike Join Date: Jul 2012 Drives: S2000 CR Location: Orange County Posts: 14,536 Thanks: 8,929 Thanked 14,183 Times in 6,838 Posts Mentioned: 966 Post(s) Tagged: 14 Thread(s)	Clean!

10-12-2017, 06:08 PM	#13
imnotsureaboutbrz Senior Member Join Date: Jan 2017 Drives: between cars... Location: Ohio Posts: 498 Thanks: 192 Thanked 263 Times in 158 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	I would love to have a dual mode exhaust for everyday driving and track/autox days... most options are too expensive or custom. And here's the perfect spot for that switch... I can't wait to hear how yours turns out!

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