I want to buy a catback today, but I don't want the car to be loud.

Also I should probably buy a header and test pipe with it.

Which catback is the most quiet while still providing excellent performance.

And which header/test-pipe setup for a complete new exhaust to matchup to the catback that is the most quiet.

So what is the most quiet complete exhaust setup? I'm ready to do this today.

...

One final question, I was going to get a K&N Intake but my local Jegs store only has a BBN? (something like that) brand in stock. Will that provide as high of performance?

thanks.

 

Corsa Sport cat back. I'm not sure what you mean about a header/ test pipe. Random Tech makes a high flow cat, but it only gains about 8 HP. If you go with a full header system, it's gonna be loud.
You might want to get the headers first with the stock exhaust and see if you like the sound.

The BBK should perform as good as the K&N.

 

The Corsa Sport muffler system is the nicest out there. It will be louder than stock when you step on the throttle, but decently quiet the rest of the time. It will not drone at low RPM up hills or under load.

All header systems are going to be louder than the foactory cast iron exhaust manifolds, especially without catalytic converters. You will also experience gas fumes without catalytic converters. I would recommend an American Racing 1 3/4" primary header with high flow catalytic converters in the X pipe. It will be slightly louder than stock, but deeper and in my opinion, more like a muscle car. Remember, the X pipe must be matched to your header system in order to mate up properly.

 

[quote=TommyV;1574170274] If you go with a full header system, it's gonna be loud.
You might want to get the headers first with the stock exhaust and see if you like the sound.quote]

I added headers after my cat back and it was too loud. I went back to stock mufflers and love how they sound with the headers. You can always keep adding but don't waste your money if you're satisfied after the headers.
Jeff

 

Why not go for NPPs? Then you can switch between quiet and loud. I just added LG Street Series headers/cats/X pipe to my stock NPPs, and I gotta say, it's farking loud with the butterflies open. I can't imagine what an aftermarket muffler system (which can't be put into "stealth" mode) would be like.

 

So would i get more performance upgrading the header than upgrading the catback? So I'd I have a loudness issue but want performance should I do one or the other?

Corsa sport catback is what I'm going to go with. Now I'm a little confused by how they sell cutbacks and a headers... It seems some headers come with xpipes and some cutbacks come with xpipes. Also I thought a full header replaces the cat with nothing? I guess in my original question i was unsure whether to get a short or long header for most quiet and then what goes from there.

Cars i have to compare sound to.. 2.4l 4cyl turbo header, down pipe, nvidia exhaust (mendral pipe and a race muffler) is a car i have which is louder than what I want out of the vette. Ive heard a camaro iroc with a header and a catalytic conveyer and straight pipes and it wasn't too loud.

So with the exhaust upgrade a lot of the sound increase comes from the cat removal? Correct me if I'm wrong.

How much of a difference in hp is there between cat less and catted setups?

I'm thinking a header with a catalytic converter and a corsa sport may not be too loud but im only getting. But if I do keep a converter am i wasting a lot of potential in the upgrade?

One last thought is if qtec or another company electronic has headers with an electronic opening cutout for a c6 ls2. That would be perfect. I'd have the header performance upgrade with a catalytic converter and possibly a stock exhaust, so it would be quiet, but then full race straight pipes when opened. I think this is how it works i could be wrong.

So what about electronic cutouts?

 

Just do the headers and keep the stock exhaust if you don't want loud. The catback exhausts are pretty much just for noise, the performance gain is negligible. If you do headers you'll have to go with their catted x-pipe or off-road x-pipe, don't get the catback x-pipe.

 

How much louder would a corsa street exhaust catback be with a header with a catalytic converter instead of a testpipe. Would the converter be doing most of the sound dampening and the corsa just give it a better tone. As long as cruising and a idle are quiet i would be happy. Wot can be as loud as it gets I just want to be able to be stealthy if needed.

Could I put electric cutouts on a header or do they make one with cutouts, that cutout the exhaust before the catalytic converter? Cause that would be best with a stock exhaust.

I've heard videos of the Qtp and npp electric cutout cutback system, the screamer, and it sounds awfully loud in quiet mode. But it is just a video. It put the cutouts at the mufflers and switches between mufflers and a straight pipe, which is much different than putting the cutout before the conveter on the header. Unless i misunderstand the screamers design, the quiet mode doesnt appear to be anywhere near stock.

 

This is what i want to do if it can be done. I wanna run full long tube headers.... Then somewhere between the start of the x pipe and the rear eshaust section install y pipes with an electric cutout. Then have the rest of the exhaust have a magna flow resonator and a muffler so it is quiet. The y pipe then will dump out to hopefully the rear of the car or side pipes with flat tubing if it can be done.

I saw a nice custom cutout exhaust on another thread. But the only difference is i want to install a resonator in between the y pipe and the muffler which there wouldn't really be much room with the setup I saw.

One last question. What is the performance and sound difference between a catalytic conveter and a resonator?

I ask this because magaflow has a catback with either a muffler or a resonator so a muffer and a resonator have the Same performance loss and similar sound qualities. Im trying to determine if a catalytic conveter or an extra resonator would be best since they both dampen the sound but one obviously is better for the environment.

One more but really last question is if i did install full headers and a axle back muffler system, how much loss would I have by using a resonator xpipe? (again with what the resonator does for the sound would that be better accomplished with a catlytic converter? Or does a high flow cat have a higher loss than a resonator?

Thanks for all the input I'll get it figured out what I want.

 

Hi flow aftermarket catalytic converters are only down about 3hp from an off road pipe and that loss is up near redline.
Most resonators will reduce power more than the hi flow cats.

Here is the problem: Long tube headers extend back under the floor boards. They then connect to an X pipe made by the header company to fit their headers and extend back to just in front of the rear axle where they mate with either the factory muffler system or an after market cat back muffler system, your choice.

A cat back with resonators adds the resonators to a special X pipe made by the cat back manaufacturer. Their X pipe is made to connect to the factory catalytic converters up next to the oil pan and extend back to just in front of the rear axle where it connects to their cat back.

The Cat back X pipe and the header manufacturer X pipe are not interchangable. You would have to find an exhaust shop willing to cut and modify the header X pipe to add the resonators.

Why not just run the hi flow cats that come with the header X pipe!! They are less restrictive and will also quiet the car.

I would avoid a C6 Magnaflow system if you are concerned about noise. I would also avoid a cutout system if you are concerned about noise.

I agree with the the person above, start with a quality set of long tube headers and their X pipe and then decide if you want more noise.

 

Exactly.

As I asked above, why not just go with NPPs? You really don't get much of a performance gain with just aftermarket mufflers vs. NPPs, and with the NPPs, you have the option of opening and closing them to make them louder or quieter at will. It seems to me like you're trying to add an exponential amount of complexity to a system that already exists in pre-manufactured form.

Keep in mind that space under the car is very, very tight.

 

That's a "no brainer"....and I'm brain challenged. NPP's fit OEM...they are stock like quiet when asked.... and they're as badass loud as anyone would want on command. Just remember this. Any exhaust system gets louder as the mods go up. What may sound good today might be too loud as you upgrade the engine and/or exhaust.

 

What are NPPs? If they are the same as the qtec screamer system the electric cutout changes between a muffler and a straight pipe.

The electric cutout system didn't sound very good to me in the videos.

Is the aftermarket muffler they use as quiet as stock? If so it seems Ike the best solution would be a header with a high flow cat and one of those systems. With an as quiet as stock muffler a header and high flow cat wont be too much louder.

If I change the exhaust system and upgrade the intake will I need a tune? That may sound like a silly question but it does change the back pressure to the head. Though having a cat will be more pressure than straight pipes so it may not be much of a change. Can the stock computer even be tuned?

 

When you get behind a C6 and see a bunch of clutter in 2 tips and around the cans....that's NPP.

 

The stock exhaust with the electronically controlled butterfly valves in the tips. Standard on ZO6 and ZR1 cars (thicker piping), optional on base cars. Valve closed = stock quiet. Valve opened = pretty loud, especially with headers.

Do a search here on NPP and/or "NPP in a box", and you'll learn all you need to. With an Exhaust Commander, you can switch between open and closed at will via remote. Way better than the system you're talking about, which sounds like it'd be perfect for leaks and malfunctions and, since it's a stock part, you know it'll fit.

 

Would a z06 npp have thicker piping and bolt up to an aftrmarketnheqaadeqr header and high flow cat? If so I think thats the way I'm gonna go.

 

Just making sure I get the right part list before I go through with this... Here is the tentative list.

Z06 oem stock 'npp' axle back muffler set
Aftermarket header
High flow cats and x-pipe

I'm trying to find the best header and x-pipe set that has high flow catalytic converters that will bolt up to a z06 npp system. My other question is there a performance difference between a z06 and a zr1 npp system. Also is it just an axle back system? So going with aftermarket headers and a high flow cat qre the right way to go with everything?

So what parts will i need (header, cat, and x-pipe set) to go with the npp system to reach my goals? Still confused on header length and whether I need a shooter x-pipe that fit the header and has catalytic converters built in.

Thanks for all the help. I'm confident that I'm gonna be happy and not wasting my money.

One last minor consideration... Do I need any o2 sensor extension wire sets or anything: additional gaskets, hangers, bolts, etc.... Or anything special to make the npp system work such as switches, wires, oem buttons or parts?

Thanks. I'm excited.

 

Which is the quiestet npp system available... Oem, or one of the aftermarket brands... Besides whatever the factory gm one is... I see a borla and a b&b system... I'm asking about the quiet mode. Which system is gonna be the mow quiet quiet mode? I wanna be able to be near silent like a stock standard c6. And since i wanna do a header and higher flow cat... Would a z06 exhaust manifold and cats along with a z06 npp system.. They should fit together well, but would a z06 manifold and cat provide much of a gain in power?

 

Pretty sure the OEM NPP is the quietest dual mode. I don't know of a Borla one, just the B&B. The Z06 exhaust manifolds and cats get around 10-15 hp, it seems.

 

Other than headers (with high flow cats) nothing else you do to the exhaust will make any noticeable HP. Cutouts on factory exhaust or headers make barely 5 RWHP. Headers on the other hand with a tune can make 20 RWHP or more. People change the exhaust more for noise, not some huge performance gain. If you want quiet, put some headers and high flow cats on and leave the rest factory. Your not giving up much.