[ZLRob]

Originally Posted by IneedAZ

i have to look at it again, but i think i didnt use stealth cause it may have closed it beyond the 3k rpm threshold i desired.

I will say in Track mode my exhaust gets really deep! I will try to get some audio soon. Not sure how well my cell phone will pick up the differences.

I will also say i think the tuning of the valves was made more complicated then needed. Why do we need a table for Open and a separate for Closed? Seems like the possibility of causing a tuning conflict increases if not paying attention. With one table if set to close 70% lets say at 1k rpm, then we know 30% is left open. Why the second table?

Originally Posted by KingLT1

Stealth keeps the valves closed under all conditions even Wot.

I setup touring so it keeps the valves closed under all conditions below 4k rpm. That way you never need to use stealth and if you happen to go wot the valves will still open and not put any strain on the system.

I set sport to not close until 10th gear below 3k rpm. That way when you are highway cruising the valves are closed and you can crank the tunes up without fighting the exhaust note.

Track I set to never close under any conditions.

This is actually really good info to move forward with as I'm probably going to pick up the credits to tune the FSCM (not the CCM, that was my screw up in previous post) here this next month.

I don't know why they would allow the valves to be open 30% in stealth, but I do notice that mine doesn't fully close up and allows some exhaust to escape out of the "loud" side.

If you have an aftermarket exhaust it almost seems like tuning of the NPP valves is almost mandatory in order to really make the most out of your setup and to have complete control over the way the valves behave which seems to me that GM tuned with sort of funky.

[Z OH 6]

Originally Posted by Camaro1973

Bringing this back alive... I just removed my cats, its loud .


My Setup


2" Kooks Headers
3" Borla Cat back w/Stype Mufflers


My question is, what kind of fabrication is needed to fit the magnaflow in place of the 2x pipes that come with the borla kit for each bank? Almost seems like by looking at the lenth of the magnaflow and the straight pipes it might be a simple swap?


If anyone has similiar setup let me know. Thanks.. I have the magnaflow in the garage.

Was this still loud even in touring or stealth mode? I thought that was the point of having the exhaust valves to control the sound level.

[Camaro1973]

Originally Posted by Z OH 6

Was this still loud even in touring or stealth mode? I thought that was the point of having the exhaust valves to control the sound level.

If you compare having cats and removing them the decibel increase was across the board. When valves closed it was still substantially louder then when I had cats on it, same when valves were open.

There’s quite a bit of decibel difference between open and closed in both cases. The problem wasn’t with the valves, Just removing the cats it was just too loud.

High pitched and raspy too. I would say on stealth it was tolerable, but any throttle when valves are open you can hear me a mile away.

It’s just too much with headers no cats, full 3” exhaust and an aggressive muffler.

Some guys like it obnoxious like that, I’m Over that. My car is still loud but at lower rpm’s and throttle it’s much more tolerable.

Honestly having the cats is pretty much like adding decent resonators like the mbrp ones, changes the tone and lowers decibels a bit.

I actually added them when I had no choice after blowing 3 cats but removed them after adding the gen 2’s because I thought it got too quiet

[Z OH 6]

Originally Posted by Camaro1973

If you compare having cats and removing them the decibel increase was across the board. When valves closed it was still substantially louder then when I had cats on it, same when valves were open.

There’s quite a bit of decibel difference between open and closed in both cases. The problem wasn’t with the valves, Just removing the cats it was just too loud.

High pitched and raspy too. I would say on stealth it was tolerable, but any throttle when valves are open you can hear me a mile away.

It’s just too much with headers no cats, full 3” exhaust and an aggressive muffler.

Some guys like it obnoxious like that, I’m Over that. My car is still loud but at lower rpm’s and throttle it’s much more tolerable.

Honestly having the cats is pretty much like adding decent resonators like the mbrp ones, changes the tone and lowers decibels a bit.

I actually added them when I had no choice after blowing 3 cats but removed them after adding the gen 2’s because I thought it got too quiet

Interesting. Thanks for the feedback.

[WillyZ83]

25 pages and finally got an idea of what route to go with, I'll be going with the JonesMF2469, using Amazon as Zoh6 did. My exhaust option is probably different than most around... Stock headers, New Era Cat delete (all4), Speed engineering X pipe into a Corsa sport axle back. The speed engineering Xpipe has the x right in the middle so I'm guessing the MF will take the place of the current X. Will get it welded in hopefully before too long.

After the cats were deleted and SE xpipe installed....First start up and it barked loud and very aggressive. On the first drive it was somewhat enjoyable scaring the shit out of people but I got in the car the second time and I found myself barely touching the gas so it wasn't obnoxiously loud.

I'll try and get a before and after video of the difference in sound. Good thread and lots of useful info in here.

[grampa_ss]

In case you missed this...search Amazon for "Jones Exhaust 5X8OVAL18 MUF24 OVRALL"
then select more buying choices (62.34). Be sure to select the one from Verocious Motorsports. According to the prior posts, these guys have the correct one.

[WillyZ83]

I used the link you posted as a matter of fact. I then asked around some more and found some Kooks Green cats that I'm picking up. Thanks Grampa

[1badtie]

Please post up sounds clips and videos planning on going with some headers and intake in December

[WillyZ83]

Originally Posted by 1badtie

Please post up sounds clips and videos planning on going with some headers and intake in December

Will do, if you check my Instagram, you’ll see a few videos of startup videos of the current Catless setup. I should have the kooks installed by Thursday and will update the thread

[Z OH 6]

Originally Posted by WillyZ83

Will do, if you check my Instagram, you’ll see a few videos of startup videos of the current Catless setup. I should have the kooks installed by Thursday and will update the thread

You will still have a deep throaty tone with the Kooks cats, but it won't have any of the nasty resonance that you get with a catless setup and of course no more stink.

[SHE'Z 18]

Originally Posted by Z OH 6

I currently have the Magnaflow muffler, I can do a before sound clip and then an after sound clip when I get the Jones muffler installed. It might be a week or two though, my exhaust guy is also a baseball coach and heavily into the season traveling around the southeast right

Hi ZOH6,
Did you ever get a chance to do some before and after sound clips? If so, would you mind throwing them up so we can hear what that Jones system sounds like compared to the magna flow? Thanks brother

[Z OH 6]

Originally Posted by SHE'Z 18

Hi ZOH6,
Did you ever get a chance to do some before and after sound clips? If so, would you mind throwing them up so we can hear what that Jones system sounds like compared to the magna flow? Thanks brother

I did not do a before and after but I can tell you I was not happy with the sound after the Jones muffler install. I was actually happier with the previous Magnaflow muffler even though it was probably more restrictive. It still sounded raspy and "sloppy" is the best description I can give you with the Jones muffler installed. I really really hated it. I've come to the conclusion that these cars just don't sound that good with cats removed so I went back to a high flow cat setup. High flow cats really clean up the exhaust tone, remove the raspyness and obviously get rid of the obnoxious fumes. I will not pursue running this car without the cats anymore unless it was a 100% drag car. It costs more to use a high flow cat setup but the benefits are worth it to me. My exhaust guy teases me because I tried so many different combinations of mufflers and resonators trying to make it sound right without the cats. I gave up.

[SHE'Z 18]

S*#T!!!! I just ordered the Jones X today. But, after reading through your post, it’s got me thinking that I need to cancel it. In any case, did you end up keeping the Jones muffler after adding the high flow cats back to your set up? If so, would you mind throwing a sound clip up of how it sounds now? Thanks bro

[Z OH 6]

Originally Posted by SHE'Z 18

S*#T!!!! I just ordered the Jones X today. But, after reading through your post, it’s got me thinking that I need to cancel it. In any case, did you end up keeping the Jones muffler after adding the high flow cats back to your set up? If so, would you mind throwing a sound clip up of how it sounds now? Thanks bro

Nope, I ditched the Jones muffler and went back to my original setup of Kooks headers, Kooks high flow cats, and AWE resonated touring catback exhaust. Very happy with it again.