12-16-2009, 04:04 PM | #1 |
Drives: 2010 CGM 2SS/RS Join Date: Jul 2008
Location: .
Posts: 80
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High Flow Cats with Shorty Headers?
I am installing a catback system. I would love to also install some long tube headers, but since I live in the golden state I won't pass a smog inspection with them. I don't really feel like swapping out the headers before every smog inspection.
From everything I've seen on the forums, it looks like most people are seeing 25-30 HP gains with longtubes and high flow cats, and people with shorties and stock cats are getting 4-9HP. It seems like the most restrictive part is the stock cats. Has anyone tried just replacing the stock cats, or shorty headers with high flow cats? What type of gains have you seen? If shorties and high flow cats worked well, it would be pretty easy to just swap the cats with a couple bolts prior to the inspection. Thoughts? |
07-02-2010, 03:46 AM | #2 |
nobody?
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07-02-2010, 03:55 AM | #3 |
On the wrong side of town
Drives: Pontiac G8 GT Join Date: Jun 2010
Location: Bay Area Cali
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Different cars but a buddy of mine with a G8 has shorty headers with stock cats and a corsa catback and made 20 less rwhp than myself with solo high flow cats, stock manifolds and solo catback. We have got our tunes from the same dyno also. Personally I think you may gain a little power in the mid range but not enough to warrant the cost of shorties unless you want more sound to go with your high flow cats. Well if you plan on going the maggie route you may have to get shorties anyway to get as much flow as possible.
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07-02-2010, 05:54 AM | #4 |
first u dont have to smog ur car for atleast 5 years since its new. 2nd tons of smog shops out there look to see if u have cats, thats it. not if theyre relocated not if u have LT's. if you have cats then ur good. u just need to find one. and u can install LT's and Catted mid pipes.
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07-02-2010, 06:53 AM | #5 |
Drives: 10 SIM 2SS/RS LS3 Join Date: May 2008
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check my thread out aaron, you may find it helpful. I have DT shorty headers and SOLO hiflow cats.
http://www.camaro5.com/forums/showthread.php?t=91945
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5th Gen Camaros of the Carolinas SIM, 2SS/RS LS3 5/7/11 453.9 RWHP 427.5 RWTQ
VMS Stage 2.5 Comp Cams kit, Cold Air Inductions intake, ADM race scoop, DT 1 3/4" headers, Solo cats, 3" Magnaflow catback, Pypes cutouts, HP tune, H&R SuperSport springs, Eibach sways/spacers, TexasSpeed UD pulley, LSR tensioner pulley, Barton shifter, skip shift eliminator, powder-coated calipers, R1 concept rotors, StopTech pads, Granatelli wires, Lloyds mats, tint, AAC afterburner taillamps, AAC scanner/sidemarkers, SRP pedals, custom engine cover, black bowties, Ridergraphix hood spears.... |
07-02-2010, 10:15 AM | #6 |
Search Ninja
Drives: 2010 Black 2SS/RS A6 Join Date: Oct 2009
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Regardless of what "some shops" may do/say, the letter of the law states that if you move or replace FUNCTIONAL cats, you are in violation of the inspection. Take it for what's worth and make your own decision from there.
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07-02-2010, 10:25 AM | #7 |
"Silver Street"
Drives: 2010 2SS/RS L99 Join Date: Oct 2009
Location: Franklin, TN
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I am hoping the Magnaflow replacement cats I am getting will fool the visual inspection, since they look identical and flow a bit better, or so they say. I won't know until I get them installed (parts are ordered, install not scheduled, yet) and go through inspection (September).
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Silver Street - 2010 Camaro 2SS/RS, SIM, Gray, Cyber Gray Rally Stripes, Polished Wheels, Automatic (L99) - 553 RWHP/510 RWTQ
CAI Inc., ARH LT Headers with Cats, Borla Touring Cat-Back; Pfadt Coil Overs, Sway Bars, End Links, and Trailing Arms; Comp Cams Blower Cam, Dual Springs, Push-Rods, and Lifters; GM LS2 Lifter Trays, 6.2 MLS Head Gaskets, Crank Bolt, and LS2 Front Cover; 3-Bolt Conversion Timing Gear, Katech C5R Timing Chain, ARP LS2/LS3 Head Bolt Kit, Melling Hi Volume Oil Pump, TVS 2300 Supercharger (Black); Build by Vengeance Racing; Custom Tune by Vengeance Racing |
07-03-2010, 07:54 AM | #8 |
Think With Your Dipstick!
Drives: 1997 Camaro Z28 Join Date: Jul 2010
Location: Spokane, WA
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Gen III/IV engines essentially have shorty headers from the factory. In other words it's a gigantic waste to buy an aftermarket set. I am just starting to really learn about the 5th gen so I don't know what all is available at this point, but if there is a 50 state legal (C.A.R.B. approved) mid length header available that may be something you want to check into. Those will not move the cats back like LTs do and would be 100% legal. Also, as true as it is that swapping working cats is illegal, good luck to any inspector that tries to prove they didn't replace dysfunctional cats or ones that were removed by another owner. If you have cats and EGR you can often pass a visual with LTs too but with that one you're really at the mercy of the inspector. If they look for the C.A.R.B. sticker on the headers you will have a problem. Granted nothing stops you from going to as many shops as you need to in order to pass. If you don't mind some possible hassle I'd get LTs with emissions hookups and some high flow cats.
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07-03-2010, 08:43 AM | #9 |
"Silver Street"
Drives: 2010 2SS/RS L99 Join Date: Oct 2009
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Not a gigantic waste since. The DT Shorties are lighter weight, look better and because of the ceramic coating, will allow less heat into the engine compartment. That is why I am going with them.
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Silver Street - 2010 Camaro 2SS/RS, SIM, Gray, Cyber Gray Rally Stripes, Polished Wheels, Automatic (L99) - 553 RWHP/510 RWTQ
CAI Inc., ARH LT Headers with Cats, Borla Touring Cat-Back; Pfadt Coil Overs, Sway Bars, End Links, and Trailing Arms; Comp Cams Blower Cam, Dual Springs, Push-Rods, and Lifters; GM LS2 Lifter Trays, 6.2 MLS Head Gaskets, Crank Bolt, and LS2 Front Cover; 3-Bolt Conversion Timing Gear, Katech C5R Timing Chain, ARP LS2/LS3 Head Bolt Kit, Melling Hi Volume Oil Pump, TVS 2300 Supercharger (Black); Build by Vengeance Racing; Custom Tune by Vengeance Racing Last edited by bi11ymc; 07-03-2010 at 08:44 AM. Reason: waste (not waist) lol |
07-03-2010, 09:23 AM | #10 | |
Think With Your Dipstick!
Drives: 1997 Camaro Z28 Join Date: Jul 2010
Location: Spokane, WA
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Quote:
2. If a $500 (plus hassle or cost of install) under-hood decoration is your thing that's your business. This is America. 3. Lower temps in the engine bay are a plus, but assuming the current heat is not causing any problems I don't see how this is a major factor? If it was you would see it reflected on dynos. On a stockish car the only purpose I could see it serving is maybe (big maybe) helping hoses last longer. Those should really be changed long before they have a chance to be a problem though. I will concede that they are at least a little better than stock manifolds and may manifest a more notable gain over stock manifolds on a decently modded engine or a high RPM application than they do stock. I do see that you have a cam coming soon so maybe that will make them a bit more useful. Just speculation there. But what is not speculation is the for the cost/hassle involved I personally find shortys on LSx engines extremely underwhelming. Its not my goal to attack you dude and sorry if my opinion offends you but it is my opinion. I like mods that actually make my car do something notably different than it already does. If you're into paying $100/hp that's your business.
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- Willy
1997 Camaro Z28 (LT1/T56): K&N CAI | Kooks 1 3/4" LTs | 3" Custom Duals | UMI LCAs w/ relocation brackets | UMI adj. panhard bar | UMI adj. torque arm | Koni SA shocks | Strano Springs | Ram Powergrip clutch | Pro 5.0 shifter | skip shift eliminator kit | WS6 Store rotors | Hawk HPS pads |
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07-03-2010, 10:43 AM | #11 | |
"Silver Street"
Drives: 2010 2SS/RS L99 Join Date: Oct 2009
Location: Franklin, TN
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Quote:
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Silver Street - 2010 Camaro 2SS/RS, SIM, Gray, Cyber Gray Rally Stripes, Polished Wheels, Automatic (L99) - 553 RWHP/510 RWTQ
CAI Inc., ARH LT Headers with Cats, Borla Touring Cat-Back; Pfadt Coil Overs, Sway Bars, End Links, and Trailing Arms; Comp Cams Blower Cam, Dual Springs, Push-Rods, and Lifters; GM LS2 Lifter Trays, 6.2 MLS Head Gaskets, Crank Bolt, and LS2 Front Cover; 3-Bolt Conversion Timing Gear, Katech C5R Timing Chain, ARP LS2/LS3 Head Bolt Kit, Melling Hi Volume Oil Pump, TVS 2300 Supercharger (Black); Build by Vengeance Racing; Custom Tune by Vengeance Racing |
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07-05-2010, 06:51 AM | #12 | |
Drives: 10 SIM 2SS/RS LS3 Join Date: May 2008
Location: Winston-Salem, NC
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Quote:
yes
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5th Gen Camaros of the Carolinas SIM, 2SS/RS LS3 5/7/11 453.9 RWHP 427.5 RWTQ
VMS Stage 2.5 Comp Cams kit, Cold Air Inductions intake, ADM race scoop, DT 1 3/4" headers, Solo cats, 3" Magnaflow catback, Pypes cutouts, HP tune, H&R SuperSport springs, Eibach sways/spacers, TexasSpeed UD pulley, LSR tensioner pulley, Barton shifter, skip shift eliminator, powder-coated calipers, R1 concept rotors, StopTech pads, Granatelli wires, Lloyds mats, tint, AAC afterburner taillamps, AAC scanner/sidemarkers, SRP pedals, custom engine cover, black bowties, Ridergraphix hood spears.... |
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07-05-2010, 09:08 PM | #13 |
speed freak
Drives: 2015i Cadillac Escalade,10 IOM 2ss Join Date: Jun 2009
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My shorties gave the the car a little bit more growl out of the Solo exhaust and look great for only $200 new.
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07-05-2010, 11:33 PM | #14 |
Drives: '15 Z06, '01 NBM SS, '97 SS Join Date: May 2009
Location: Rio Rancho, NM
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Definitely replace the Cats with some high flow/spun units to realize better HP gains.
Agreed, the factory manifolds are not bad at all. The Shorties Def give a better look, just don't look for LT Header performance out of them. Best of luck to you sir! Ivan |
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