Is a cat-back without a tune safe to do? (SS with AFM)

dperrone · 10-06-2018, 01:33 PM

Trying to decide between borla atak axle back and cat back. I have an SS with active fuel management. Im not looking to tune the AFM out and possibly void my warranty. I know the v4 mode has valves to help with the back pressure.

If i get a cat back which replaces the valves with straight pipes, can any damage come to the engine with a less restrictive exhaust? The car will still be free to cut off half the engine

The catback is way more expensive so I want to be sure

drperry · 10-06-2018, 01:52 PM

Might throw codes with the AFM valves being disconnected.

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dperrone · 10-06-2018, 02:03 PM

Quote:

Originally Posted by drperry

Might throw codes with the AFM valves being disconnected.

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Pretty sure you plug them into dummies or something like that to not throw error codes

drperry · 10-06-2018, 02:14 PM

Quote:

Originally Posted by drperry

Might throw codes with the AFM valves being disconnected.

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Then you should be good.... V4 mode can sound odd, though

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MrRuss · 10-06-2018, 06:38 PM

You can't get dummy plug in's and most who take the AFM exhaust valves out leave the valve solenoid/motor pugged in and tucked up out of the way, zip tied or clamped.

Tuning is the only way to remove them altogether and not get CEL's. You can disable the AFM with a Range OBDII plug in, no tune and keeps the warranty. The Range still won't allow you to remove the AFM exhaust valves without CEL's but eliminates the V4 issue.

dperrone · 10-06-2018, 06:48 PM

Quote:

Originally Posted by MrRuss

You can't get dummy plug in's and most who take the AFM exhaust valves out leave the valve solenoid/motor pugged in and tucked up out of the way, zip tied or clamped.

Tuning is the only way to remove them altogether and not get CEL's. You can disable the AFM with a Range OBDII plug in, no tune and keeps the warranty. The Range still won't allow you to remove the AFM exhaust valves without CEL's but eliminates the V4 issue.

Okay I guess just keeping them intact and hiding them away is what I meant by "dummy". I saw an installation but I didnt realize they just kept it intact.

I've just been worried because I haven't seen much information and I figure most people who did the catback actually tuned or disabled AFM.

Im really trying to decide between the borla atak axle or catback lol

CodeCody · 10-07-2018, 10:19 AM

I got the catback when EFI tuning was still selling the AFM plugins that got rid of the check engine light but kept the functionality. I could have sworn Borla mid pipes had AFM actuator mounts.

enzia35 · 10-07-2018, 02:26 PM

With Borla, you get the axle back then the correct midpipe that keeps the AFM. That makes it the cat back package.

JT58 · 10-08-2018, 09:53 AM

Yes it is safe to do on any car and despite what you read it will increase performance and gas mileage (if you keep your foot out of it). I have installed CAT backs on a lot of cars I have owned over the last 40 years and always see immediate results in performance and gas mileage. Most recent was my 2016 Miata ND- performance increase I noticed idling and starting off and all throughout the RPM range and MPG went up 4 MPG. And on my 2017 FIST- much more upper end and gained at least 2 MPG. And of course as an added benefit you get sound. My favorite and best mod I always do first.

Spartan268 · 10-08-2018, 11:20 AM

ATAK catback includes AFM valves if you get that option. You would have nothing to worry about if that's the one you're planning to pull the trigger on.

cellsafemode · 10-09-2018, 09:28 AM

all of the passive valves related to AFM are for aesthetic sound purposes. They serve no performance purpose.

Remove them if you want, you just start hearing a slightly different tone when you switch to V4 mode.

Since you're only ever in v4 mode when cruising at no throttle, who cares what it sounds like. 1 less obstruction is worth it. Tuning it out fully is only something i'd consider if you never drove on the highway. Contrary to some forum opinion, V4 mode does save significant fuel while cruising and it's worth retaining. Plenty of ecu tuning options out there and it is possible to have afm tied to a switch. That's how I'm setup.

gmw0181 · 10-10-2018, 11:19 AM

Stainless Works has cat back with afm delete and with afm valves. You choose. I have the Stainless Works cat back with afm delete. The motors bolt to the exhaust to ground them. The car does not know any the valves are gone.

10-06-2018, 01:33 PM	#1
dperrone dp77 Drives: camaro Join Date: Apr 2018 Location: toronto Posts: 30	Is a cat-back without a tune safe to do? (SS with AFM) Trying to decide between borla atak axle back and cat back. I have an SS with active fuel management. Im not looking to tune the AFM out and possibly void my warranty. I know the v4 mode has valves to help with the back pressure. If i get a cat back which replaces the valves with straight pipes, can any damage come to the engine with a less restrictive exhaust? The car will still be free to cut off half the engine The catback is way more expensive so I want to be sure

10-06-2018, 06:38 PM	#5
MrRuss Drives: 2016 Camaro 2SS Join Date: Mar 2018 Location: Chandler, AZ Posts: 207	You can't get dummy plug in's and most who take the AFM exhaust valves out leave the valve solenoid/motor pugged in and tucked up out of the way, zip tied or clamped. Tuning is the only way to remove them altogether and not get CEL's. You can disable the AFM with a Range OBDII plug in, no tune and keeps the warranty. The Range still won't allow you to remove the AFM exhaust valves without CEL's but eliminates the V4 issue. __________________ Mr Russ Tim "the tool man" Taylor is my hero My Garage: '16 Chevrolet Camaro 2SS, Summit White, Adrenaline Red -- Rotofab CAI, Soler TB, 1 7/8 coated LT's, Full 3" mids, 3" Stainless Works NPP mufflers, Flex Fuel, E85/91 tuned '20 Honda Oddysey Elite 25th Anniversary Edition --wifes car, she said "No more SUV's" after the 2 CX-9's totaled

10-07-2018, 02:26 PM	#8
enzia35 Drives: '16 Garnet Red 1SS Join Date: Mar 2014 Location: College Station, TX Posts: 3,450	With Borla, you get the axle back then the correct midpipe that keeps the AFM. That makes it the cat back package. __________________ '16 Camaro 1SS '18 Miata GT Gone: '01 Camaro, '14 Camaro, '90 Miata

10-08-2018, 09:53 AM	#9
JT58 Drives: Former 2016 Camaro 1LT Join Date: Jan 2017 Location: Naples, FL Posts: 760	Yes it is safe to do on any car and despite what you read it will increase performance and gas mileage (if you keep your foot out of it). I have installed CAT backs on a lot of cars I have owned over the last 40 years and always see immediate results in performance and gas mileage. Most recent was my 2016 Miata ND- performance increase I noticed idling and starting off and all throughout the RPM range and MPG went up 4 MPG. And on my 2017 FIST- much more upper end and gained at least 2 MPG. And of course as an added benefit you get sound. My favorite and best mod I always do first. __________________ 2006 C6 Corvette Manual, 2019 Silverado, 1997 Jeep Wrangler

10-06-2018, 01:52 PM	#2
drperry Drives: Chevy Blazer Join Date: Sep 2009 Location: Grande Prairie, AB Posts: 300	Might throw codes with the AFM valves being disconnected. Sent from my SM-G930W8 using Tapatalk

10-07-2018, 10:19 AM	#7
CodeCody Drives: 2017 Camaro 2SS Join Date: Mar 2017 Location: IL Posts: 88	I got the catback when EFI tuning was still selling the AFM plugins that got rid of the check engine light but kept the functionality. I could have sworn Borla mid pipes had AFM actuator mounts.

10-08-2018, 11:20 AM	#10
Spartan268 Drives: HB 2SS Join Date: Apr 2017 Location: Vancouver, BC Posts: 518	ATAK catback includes AFM valves if you get that option. You would have nothing to worry about if that's the one you're planning to pull the trigger on.

10-09-2018, 09:28 AM	#11
cellsafemode Drives: 2016 Camaro 1LT Join Date: Jan 2016 Location: California Posts: 3,491	all of the passive valves related to AFM are for aesthetic sound purposes. They serve no performance purpose. Remove them if you want, you just start hearing a slightly different tone when you switch to V4 mode. Since you're only ever in v4 mode when cruising at no throttle, who cares what it sounds like. 1 less obstruction is worth it. Tuning it out fully is only something i'd consider if you never drove on the highway. Contrary to some forum opinion, V4 mode does save significant fuel while cruising and it's worth retaining. Plenty of ecu tuning options out there and it is possible to have afm tied to a switch. That's how I'm setup.

10-10-2018, 11:19 AM	#12
gmw0181 Drives: 2017 Camaro 2SS A8 Join Date: Dec 2017 Location: Ohio Posts: 137 View My Garage	Stainless Works has cat back with afm delete and with afm valves. You choose. I have the Stainless Works cat back with afm delete. The motors bolt to the exhaust to ground them. The car does not know any the valves are gone.

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