Delete secondary cats? - Page 2 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

CamaroFred · 08-12-2017, 05:12 AM

O Pipe (Dual Exhaust)

$125.00

You've heard of the Y pipe.. the X pipe.. the H pipe.. nothing can touch the O pipe!!! It provides 100% back pressure feedback on ALL engines!! Torque increase and kuneutson valve float brings in much lower revs so you don't hurt your motor! Not CARB Legal. Please specify standard or polished finish. Product shown is dual input O-Pipe with standard finish.

christianchevell · 08-12-2017, 08:04 AM

Your mechanic is right, it is a $10000 fine per case of removing cats, you should start from the front and use high flow cats with long tubes and a tune. The increased flow speed from removing the cats will cause codes if you go messing with one and not the other. The fronts do adjust the AFR, the rears tell the ECU how well the fronts are doing with the amount of fuel left over to the rears to help, that's why you can delete the rears, but also have to do the remove the "DELAYED RESPONSE"" code that comes up with long tubes as the first sensor is moved further back on the headers.'

Back pressure is overrated but its a case of what ever you do to the exhaust you will be decreasing it most likely and you really do not need to worry about it as its not your daddies 65 Ford.... If your going to have to tune it and do it do it right the first time. Some on here have done Solo high flow cats or shortie headers, I do not recommend either but do work and have much less gain that makes the money not so worth it if you really want to throw money around. Once again there is no substitute for doing the job right the first time IMO.

""The astute exhaust designer knows that you must balance flow capacity with velocity. You want the exhaust gases to exit the chamber and speed along at the highest velocity possible - you want a FAST exhaust stream. (see below ) If you have two exhaust pulses of equal volume, one in a 2" pipe and one in a 3" pipe, the pulse in the 2" pipe will be travelling considerably FASTER than the pulse in the 3" pipe. While it is true that the narrower the pipe, the higher the velocity of the exiting gases, you also want make sure the pipe is wide enough so that there is as little back pressure as possible while maintaining suitable exhaust gas velocity. "
* So your messing with backpressure may screw things up, sure he is right there as your still using the stock exhaust manifolds not designed to go without the first cat, will it make it really bad..??? But just because they make a piece to replace another does not mean its a good idea. And a pair of nice designed long tube headers will decrease the back pressure but also keep the velocity you need to clean out the cylinders...... And less back pressure is good, too much back pressure bad... but it really depends on your exhaust and its functioning and messing with it ... not such a good idea. And removing the cats will always throw a code...... you have to delete them and their needed response in the ECUs software VIA good tuning..............There is a reason people pay $500 plus for a good dyno tune with HP tuning way beyond a dyno sheet............

flynhawaiianss · 08-12-2017, 09:06 AM

I suppose in the meantime I can have the muffler delete and the x-pipe out on for now and I can always delete the secondary cats later if need be. LT's are in the near future plan (probably purchase this winter) and I wasn't planning on going with any cats at all from there on out. So basically the exhaust would be 1 7/8" LT's, no cats, x-pipe, with a muffler delete. Yes it will be loud and I know that from my '96 Z28 that has LT's, Y-pipe, no Cats, and muffler delete

I'm almost positive I have read about quite a few other members that have a similar exhaust to this. I'm not worried about having to pass emissions and the car will not be driven year round either. Guess I'm just trying to make it scream and not lose any performance because I still think the back pressure argument is crap even when I go to the future exhaust plans.

08-12-2017, 05:12 AM	#15
CamaroFred Drives: Miss Con Ception Join Date: Aug 2016 Location: Chicagoland Posts: 2,998	We don't need no stinkin' backpressure! O Pipe (Dual Exhaust) $125.00 You've heard of the Y pipe.. the X pipe.. the H pipe.. nothing can touch the O pipe!!! It provides 100% back pressure feedback on ALL engines!! Torque increase and kuneutson valve float brings in much lower revs so you don't hurt your motor! Not CARB Legal. Please specify standard or polished finish. Product shown is dual input O-Pipe with standard finish. __________________ 2011 1SS/RS LS3 CGM

08-12-2017, 08:04 AM	#16
christianchevell old school chevy rodder Drives: 2021 zl1 a-10 WildCherry Join Date: Jul 2012 Location: Oregon Posts: 5,622 View My Garage	Your mechanic is right, it is a $10000 fine per case of removing cats, you should start from the front and use high flow cats with long tubes and a tune. The increased flow speed from removing the cats will cause codes if you go messing with one and not the other. The fronts do adjust the AFR, the rears tell the ECU how well the fronts are doing with the amount of fuel left over to the rears to help, that's why you can delete the rears, but also have to do the remove the "DELAYED RESPONSE"" code that comes up with long tubes as the first sensor is moved further back on the headers.' Back pressure is overrated but its a case of what ever you do to the exhaust you will be decreasing it most likely and you really do not need to worry about it as its not your daddies 65 Ford.... If your going to have to tune it and do it do it right the first time. Some on here have done Solo high flow cats or shortie headers, I do not recommend either but do work and have much less gain that makes the money not so worth it if you really want to throw money around. Once again there is no substitute for doing the job right the first time IMO. ""The astute exhaust designer knows that you must balance flow capacity with velocity. You want the exhaust gases to exit the chamber and speed along at the highest velocity possible - you want a FAST exhaust stream. (see below ) If you have two exhaust pulses of equal volume, one in a 2" pipe and one in a 3" pipe, the pulse in the 2" pipe will be travelling considerably FASTER than the pulse in the 3" pipe. While it is true that the narrower the pipe, the higher the velocity of the exiting gases, you also want make sure the pipe is wide enough so that there is as little back pressure as possible while maintaining suitable exhaust gas velocity. " * So your messing with backpressure may screw things up, sure he is right there as your still using the stock exhaust manifolds not designed to go without the first cat, will it make it really bad..??? But just because they make a piece to replace another does not mean its a good idea. And a pair of nice designed long tube headers will decrease the back pressure but also keep the velocity you need to clean out the cylinders...... And less back pressure is good, too much back pressure bad... but it really depends on your exhaust and its functioning and messing with it ... not such a good idea. And removing the cats will always throw a code...... you have to delete them and their needed response in the ECUs software VIA good tuning..............There is a reason people pay $500 plus for a good dyno tune with HP tuning way beyond a dyno sheet............ __________________ 2021 Wild Cherry ZL1 A10, Sunroof, Data,Red Carbon Interior, Nav, RotoFab Big Gulp , Elite x2ultra, Borla ATAK, Driveshaft shop, BMR susp, Speed covers, intercoolers, ATI , 2650 MAG, DSX lid, 103 NW, TSP Longtubes & cats, LPE, 1le mods, ,LME cover, Katech pump and chain, Trunnions, BTR stage 2, LPE boostapump, Gforce, Speed eng , Granetteli, etc etc Last edited by christianchevell; 08-12-2017 at 08:17 AM.

08-12-2017, 09:06 AM	#17
flynhawaiianss Drives: 2011 Chevy Camaro SS Join Date: Jun 2017 Location: IL, US Posts: 57	I suppose in the meantime I can have the muffler delete and the x-pipe out on for now and I can always delete the secondary cats later if need be. LT's are in the near future plan (probably purchase this winter) and I wasn't planning on going with any cats at all from there on out. So basically the exhaust would be 1 7/8" LT's, no cats, x-pipe, with a muffler delete. Yes it will be loud and I know that from my '96 Z28 that has LT's, Y-pipe, no Cats, and muffler delete I'm almost positive I have read about quite a few other members that have a similar exhaust to this. I'm not worried about having to pass emissions and the car will not be driven year round either. Guess I'm just trying to make it scream and not lose any performance because I still think the back pressure argument is crap even when I go to the future exhaust plans.