Removing the Cats?

[blackZbandit]

Originally Posted by Bell040

If you decide to use cut-outs, do you still have to get the PCM tuned?

I like the idea of the cutouts, but I dont want to be driving around in a brand new car with the check engine light on.

Good question... can anybody tackle this one?

[CamaroSpike23]

Originally Posted by TAG UR IT

Do it right and put on high flow cats. You are sure to trigger codes (lights) and that might even have an effect on the way it drives....who knows right now.

Best bet is to jump on a vette forum and ask those who deal w/ the LS3's on a daily basis.....or just call CamaroSpike!

Originally Posted by MerF

Mustangs always have, and probably alwasy will, sound better than F-bodys. It's just the way it is. You can not compare the two, one is about show and the other is about go.

while I agree with the last part of your statement, I do have to disagree with the rest. SOME mustangs sound better than SOME f-body's and vice versa.

Flowmaster exhaust on mustangs sound awesome, but on camaros, it sounds like liquid hot ass magma.

just depends on the setup.

Originally Posted by 2010_5thgen

it shouldnt throw any codes. the o2 sensor still gets plugged into the new spot on the y or x pipe. its not really going to make it that much louder unless you use resonator mufflers instead of a regular muffler. the cats are for emmisions not sound.

it will throw codes. with 4 o2 sensors on the car, the front ones do the actual air/fuel measurements of the exhaust to tell the computer whether its running rich or lean. the rear 2 measure the noxious fumes in the exhaust to tell the computer whether or not the catylitic converters are working. unless you buy them used from someone, you wont find o2 sims on the market anywhere as they have been deemed illegal because they directly affect the emissions equipment of the car. same way that gutting your cats or removing them is illegal except for off road only vehicles. now, before you get pissy and tell me that you are running with no cats and have been pulled over and they didnt say anything, I am running long tube headers with a custom y-pipe without cats and an electric cutout right off the Y. is it legal? no. is anyone going to do anything about it? no.


going off the o2 sensor part. most emissions facilities these days are switching to a computer read only setup. where instead of doing a full sniffer test, they hook up a scanner to your diagnostic port and run the motor, and based off the readings you either pass or fail. and some places can even scan to see if you've deleted the emissions stuff from the programming and will fail you for that.

with this new camaro, unless you are planning on making it a track queen, either leave the stock cats or replace them with hi-flo cats. make power and be legal all at the same time.

Originally Posted by Bell040

If you decide to use cut-outs, do you still have to get the PCM tuned?

I like the idea of the cutouts, but I dont want to be driving around in a brand new car with the check engine light on.

depending on where you put the cutout will decide that. you can run dual cutouts right after the cats and be just fine, tho you might burn up the o2 sensors from too much ambient air coming back into the exhaust.

tho most people run cutouts right before the regular mufflers and dont have a problem.



honestly, with the way this exhaust is setup. if you want to make it louder. unclamp the stock mufflers, cut them open, pull out all the baffles, then weld them back shut. look stock, pass emissions, and sound bad ass.


or replace the exhaust with a cat-back system and get the same results.

[knowitman]

Originally Posted by SoFlaZ

As for F-bodys, LT1's have the greatest sound you can hear besides a full blown race engine at the drag strip.

I must say that I completely agree with you about the LT1. I don't know if it is because I grew up with an LT1 car, but in my opinion the LSX motor, or any other motor, doesn't sound nearly as good as an LT1, even with stock exhaust.

[Camaro_Corvette]

Originally Posted by LSxJunkie

Ummm....why don't Ford and GM stop competing and just sell the same cars?

Sorry, I just hate it when some things could be easily worldwide standard, but yet all the sudden, oh well we started numbering the cylinders from the right.

[Crowley]

Originally Posted by Bell040

If you decide to use cut-outs, do you still have to get the PCM tuned?

I like the idea of the cutouts, but I dont want to be driving around in a brand new car with the check engine light on.

Typically your cutouts will be after the Last O2 sensors (after the cats). That being said, you should not get a check engine light .. however, I am not sure about optimum exhaust flow. Im sure whoever installs the cutout would know what they are doing so you do get maximum power out of it.

In my experience ... (in regards to cats) .. unless you are running very high HP cars, high flow cats will do just nice and you won't have any additional tuning or hardware requirements for your O2 sensors.

Crowley

[Bell040]

I figured that most of the benifit gained by adding the cutouts was the HP gained from bypassing the cats when the cutouts are open (decreased pressure drop)... or is it all about the sound?

I wouldn't mind the engine light being on for a minute or two, while I had the cut-outs open, as long as it disapeared when I closed them. But, I think that when the PCM throws an error code, it stays in memory until the code is reset via the OBD. - not sure about this.

[CamaroSpike23]

Originally Posted by Bell040

I figured that most of the benifit gained by adding the cutouts was the HP gained from bypassing the cats when the cutouts are open (decreased pressure drop)... or is it all about the sound?

I wouldn't mind the engine light being on for a minute or two, while I had the cut-outs open, as long as it disapeared when I closed them. But, I think that when the PCM throws an error code, it stays in memory until the code is reset via the OBD. - not sure about this.

yes and no. you may get some benefit, but with the location of the cats and the o2 sensors pre- and post-cat you will pretty much have to replace the cats with the cutouts as the location of the cats are just off the manifolds.

what power you do gain is from the exhaust not going thru the mufflers and being restricted there. its mostly sound, but there can be a gain of power, tho ive seen loss of power with a cutout open.

as for the engine light on, if anything, you will be triggering the post cat o2 sensors (if you mount the cutouts that close to them, that is) but they normally do not cause a check engine light, but they do store a code and if you have to get your vehicle emissions tested, when they hook up the scanner, they'll see that code and fail you.

but if you mount the cutouts away from the post cat o2's, you shouldnt have a problem with anything but the 5-0

[theholycow]

With how easy it is to make good quality, fully effective, inexpensive high flow cats and mufflers, should we really expect the Camaro to come with crappy restrictive stuff? What design compromise would they make that would result in restrictive cats/mufflers? I could be wrong, but I'd guess that they engineered the whole car as a system, with an exhaust that can flow everything the engine can move.

[LSxJunkie]

Originally Posted by theholycow

With how easy it is to make good quality, fully effective, inexpensive high flow cats and mufflers, should we really expect the Camaro to come with crappy restrictive stuff? What design compromise would they make that would result in restrictive cats/mufflers? I could be wrong, but I'd guess that they engineered the whole car as a system, with an exhaust that can flow everything the engine can move.

Ummmm.....did you forget that GM is in the business of building cars well within EPA/NHTSA emissions standards? How about exhaust volume laws, or the fact that they have to sell a car that will absolutely not drone at any engine load, speed, or RPM.

And exhaust that would flow everything the engine can move would just be open longtubes and a turndown after the merge. Stock manifolds and stock cats are, without fail, the two tightest bottlenecks.

[Dan]

This isnt 1979, all cats are high flow straight through designs. Removing them wont gain you shit.

[radz28]

Originally Posted by Dan

This isnt 1979, all cats are high flow straight through designs. Removing them wont gain you shit.

They're a lot better now, and unless you're adding a lot of power, I really don't think the gain is going to be too much. Even still, I'm sure there is still some left on the table because of all the hoops the manufacturer has to deal with and add for those emissions and sound requirements. I believe it is also to add (unless someone already has and I missed it ) that the further a restriction is away from the exhaust port, the less influence it will have on power. Since we have mufflers at the very end of the car, it's not likely their going to be too much of a restriction (well, to a point). If you put your cutouts a ways away from the last 02 sensor, I think you're going to get pretty good power and sound. These new cats' flow a lot better than before though

[CWI]

Originally Posted by LSxJunkie

Ummm....why don't Ford and GM stop competing and just sell the same cars?

Ummm....why don't BK and McD stop competing and just sell the same burgers?

[zebra]

Originally Posted by CWIweldace

Ummm....why don't BK and McD stop competing and just sell the same burgers?

fine with me, so long as they taste like BK. i ain't ate mcdonalds in almost 10 yrs

[theholycow]

Originally Posted by zebra

fine with me, so long as they taste like BK. i ain't ate mcdonalds in almost 10 yrs

Me too. I made a decision about 10 years ago...I'll eat from almost any grimy roadside taco truck, hole in the wall barbecue joint, pizza stand, or nasty fast food place -- except McDonalds.

Although I admit, once I was at a McDonalds with others and the food actually looked and smelled good, I probably could have made an exception that one time.