2.5" Exhaust W/ LSA? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

ARrado15 · 06-30-2017, 09:47 PM

Hey all. Currently contemplating on going with an LSA blower. I currently have full intake/ full exhaust and a cam swap. I have 1 7/8" Kooks LTH with the HFC and a Solo Mach XL Catback (2.5"). Would it be mandatory to swap over to a 3" exhaust from the headers back, or can I just swap to off road connection pipes and call it a day? I ask because I absolutely love my exhaust right now and would like to keep it as long as it isn't steeling a ton of power.

Devcon 7 · 06-30-2017, 11:20 PM

I doubt your exhaust is robbing a bunch of power, certainly not worth the extra $$.

pyroguy · 07-01-2017, 07:01 AM

I hope it doesn't rob power, or at least too much because I have the exact same exhaust setup as you. I'm sure there would be some power gains by going 3", but I don't know if there'd be enough to justify switching most of my exhaust.

Also, others may correct me if needed, but I think having cats last all depends on the tune. I'm hoping to leave my cats on because I need them for PA inspections, but if I have to then I'll punch the guts out of mine.

jrhagen · 07-01-2017, 09:35 AM

I have 2.5 exhaust, no issues. Gut the cats.

dentnshell · 07-01-2017, 10:14 AM

2.5" NPP - No Cats - LSA conversion with Stainless Power Headers. 91 Octane is my power limiter...

bayarea408 · 07-01-2017, 11:10 AM

Cut outs

frankwjr · 07-01-2017, 11:43 AM

HFC will last with a "stock" type F/I setup...once you start to turn up the wick is when the cats need to go....higher temps eventually melt them into a nasty mass...have read where cat went completely clogged....not pretty...

BTW - how is the Legal Weed going? lol...

jrhagen · 07-01-2017, 06:07 PM

Quote:

Originally Posted by dentnshell

2.5" NPP - No Cats - LSA conversion with Stainless Power Headers. 91 Octane is my power limiter...

You should be able to squeeze more than 579 out of that set up.

ARrado15 · 07-01-2017, 09:46 PM

Quote:

Originally Posted by frankwjr

HFC will last with a "stock" type F/I setup...once you start to turn up the wick is when the cats need to go....higher temps eventually melt them into a nasty mass...have read where cat went completely clogged....not pretty...

BTW - how is the Legal Weed going? lol...

Couldnt tell ya. My job forbids it :P. I think i'll just gut my cats, because the off road connection pipes are like 3-400 bucks.

shibbs · 07-01-2017, 09:51 PM

2.5" exhaust isn't robbing you of much. You ditched the stock cats, that's where most of the restriction is.

Not worth it since you sound like you really love your current exhaust.

dentnshell · 07-02-2017, 01:53 AM

Quote:

Originally Posted by jrhagen

You should be able to squeeze more than 579 out of that set up.

GPI dyno is a little stingy on cold days. I am stuck with 91 octane. Ryan says there is at least 20 more HP with 93. Also the SS1 cam is not a zero overlap cam. It is a great NA cam but a little lacking with some boost.

hammdo · 07-02-2017, 11:58 AM

2.5" on mine...

645\605 vvt ss1 cam also

-Don

SSyclone · 07-09-2017, 09:01 PM

Just get the ADM kit and don't look back. The no cats runs well but it smells like an old musclecar. I get a fair amount of deceleration pop. That's pretty much inherent of a free flowing exhaust.

EV1L SS · 07-09-2017, 09:24 PM

I have a Magna charger with header , gutted cats , & 2.5" exhaust. Honestly I can't even see picking up 20rwhp going to 3" so not worth it for me. If you were building a 1000hp or max effort car than go for it but at your level nope.

06-30-2017, 09:47 PM	#1
ARrado15 Drives: 2011 Camaro 2SS Join Date: Jan 2017 Location: Las Vegas Posts: 145	2.5" Exhaust W/ LSA? Hey all. Currently contemplating on going with an LSA blower. I currently have full intake/ full exhaust and a cam swap. I have 1 7/8" Kooks LTH with the HFC and a Solo Mach XL Catback (2.5"). Would it be mandatory to swap over to a 3" exhaust from the headers back, or can I just swap to off road connection pipes and call it a day? I ask because I absolutely love my exhaust right now and would like to keep it as long as it isn't steeling a ton of power. __________________ 2011 Camaro SS - Kooks 1 7/8" LTH - Kooks HFC - Solo Mach XL Catback - CAI Intake - VMAX TB - Howards ASA Cam

07-01-2017, 07:01 AM	#3
pyroguy Started#gottalovethatblue Drives: ABM #831 Join Date: Apr 2013 Location: TN Posts: 6,943 View My Garage	I hope it doesn't rob power, or at least too much because I have the exact same exhaust setup as you. I'm sure there would be some power gains by going 3", but I don't know if there'd be enough to justify switching most of my exhaust. Also, others may correct me if needed, but I think having cats last all depends on the tune. I'm hoping to leave my cats on because I need them for PA inspections, but if I have to then I'll punch the guts out of mine. __________________ '10 Camaro 2SS/RS \| Aqua Blue #831 of 3,903 \| Silver Stripes Check out my build thread

07-01-2017, 10:14 AM	#5
dentnshell Drives: Black 2014 2SS Join Date: Apr 2015 Location: Oologah, OK Posts: 454 View My Garage	2.5" NPP - No Cats - LSA conversion with Stainless Power Headers. 91 Octane is my power limiter... __________________ 2014 L99 2SS. 595HP/571ft-lbs Mods: LSA Conversion 2.5" Upper Pulley, 65# injectors, GPI SS1 Cam, SP Long Tubes, ADM Race Scoop & CAI, NPP exhaust (DIY control), BMR 1" lowering springs, ZL1 Rear Differential / Axles, CF Side Strip / Hood Spear, Tint - Windows / Tails / Sidemarkers, Splash Guards, ADM Boost Gauge, ABL Dashkit, '68 Script Badges, ACS T4 Splitter, ZL1 Rockers from Gary's, Z28 Spoiler, Carbon Fiber Hood Vent, Summer - MRR FS01 Satin Black (10" Front 11" Rear) Winter, pictured-Drag DR 64's Satin Black (9" Front-10" Rear.)

07-01-2017, 11:43 AM	#7
frankwjr Drives: 2010 SS 2SS M6 Join Date: Aug 2016 Location: Smithsburg, Md. Posts: 2,445	HFC will last with a "stock" type F/I setup...once you start to turn up the wick is when the cats need to go....higher temps eventually melt them into a nasty mass...have read where cat went completely clogged....not pretty... BTW - how is the Legal Weed going? lol... __________________ 2010 SS 2SS M6 - Tune by RDP dynoSteve!(Woot) - Daily Driver - *150K!* - All work by me...

07-02-2017, 11:58 AM	#12
hammdo 'It's an experiment' Drives: [COTW 2/09/15] '11 GPI LSA SC Z/LE Join Date: May 2014 Location: Dallas TX Posts: 8,695 View My Garage	2.5" on mine... 645\605 vvt ss1 cam also -Don __________________ 747 RWHP 794 RWTQ "Horsepower sells cars, torque wins races." - Enzo Ferrari See My Build: http://www.camaro5.com/forums/showthread.php?t=385577

06-30-2017, 11:20 PM	#2
Devcon 7 Drives: 15 camaro Join Date: Nov 2016 Location: Wichita, Ks Posts: 131	I doubt your exhaust is robbing a bunch of power, certainly not worth the extra $$.

07-01-2017, 09:35 AM	#4
jrhagen Banned Drives: Camaro Join Date: Mar 2013 Location: USA Posts: 2,701	I have 2.5 exhaust, no issues. Gut the cats.

07-01-2017, 11:10 AM	#6
bayarea408 Drives: T Join Date: Mar 2015 Location: CA Posts: 803	Cut outs

07-09-2017, 09:01 PM	#13
SSyclone Drives: 2011 2SS Inferno Orange Join Date: Oct 2013 Location: Cedar Hill, MO Posts: 60 View My Garage	Just get the ADM kit and don't look back. The no cats runs well but it smells like an old musclecar. I get a fair amount of deceleration pop. That's pretty much inherent of a free flowing exhaust. __________________ 2011 Camaro SS Buckets of money under hood!

07-09-2017, 09:24 PM	#14
EV1L SS Drives: 2010 ss , cam, magnacharger , etc Join Date: Jul 2017 Location: Nj Posts: 94	I have a Magna charger with header , gutted cats , & 2.5" exhaust. Honestly I can't even see picking up 20rwhp going to 3" so not worth it for me. If you were building a 1000hp or max effort car than go for it but at your level nope.