[Camaro 79]

Originally Posted by KingLT1

Just an update...Holley performance group is sending me a brand new axle back exhaust. It's been a slow process but nonetheless they are taking care of me.

Are you happy with the sound and quality otherwise? I'm still debating between this and the Borla S-type. I want to keep NPP functionality

[KingLT1]

Yes it sounds excellent and there is a significant different in volume between valves closed/open.

[70chevelleSS]

Originally Posted by Camaro 79

Are you happy with the sound and quality otherwise? I'm still debating between this and the Borla S-type. I want to keep NPP functionality

Two pretty different sounding exhausts. The flowmaster will be deeper sounding and probably a little louder with the valves open


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[Camaro 79]

Originally Posted by 70chevelleSS

Two pretty different sounding exhausts. The flowmaster will be deeper sounding and probably a little louder with the valves open


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I was looking for something deeper. I'm getting ready to pull the trigger, but the NPP and 6th gen's aren't easy to find a good exhaust for! Every other car I owned there were 2 or 3 clear winners, but this seems to be a whole other beast.

[KingLT1]

Installed the new exhaust, same issue.


Edit*

After driving the car and logging some miles, I can say it is actually better then the other exhaust. It no longer has the same leaky sound after I have been driving it for a while. It does still have a slight hiss with the valves closed in park at idle that you can only hear when standing behind the car. I can live with that so case closed.

[VegasZ]

A couple question for the Flowmaster guys / gals or anyone that already has one of these on their ZL1.

Does the exhaust valve closing during off throttle bother the sound at all? Can you tell that it's switching between the two muffler types instead of using a single one all the time? From the sound in your videos it doesn't seem to bother it but theres a spot around 3 - 4k RPMs that sounds different than the rest of the RPM range, is this stupid valve the cause or is it something else in the motor that just sounds different in that range?

Thanks so much for any help! I'm getting ready to order an exhaust for it but it's so hard to tell what they really sound like on the internet esp when most people use shit microphones to capture the sound. Your recording is one of the best I have heard not only in how the car sounds but the quality of the capture. Did you use a real Mic to capture it?

I have removed the fuse for the NPP and it def made a difference although its still not loud enough esp when off throttle but you can tell that it's louder than it was with the fuse in so it's deff closing the exhaust valve under a certian throttle amount or whatever they use to base the valve operation off of instead of just relying on the settings we can manipulate to force them to be "open all the time" since they are overriding that setting for cruising throttle for example.

I could keep the fuse out but it seems kinda silly to buy an NPP aftermarket exhaust and pay extra for it if you can't actually use it because of the other BS the car is deciding to do with that valve instead of leaving it alone for us to set as we want.

If you can't tell I hate how quiet the exhaust is inside the car, I have a 6m and have always driven sticks off of the sound of the engine more than looking at gauges and to know if I put the right amount of throttle to take off without having either to much or not enough. If I have music on at even a moderate level the exhaust is basically un audible inside the car with the fuse in unless you give it a good jab of throttle. Removing the fuse made a small difference in the RPM ranges that it was closing on but not enough for me to not need something aftermarket.

I had a 93 mustang GT back in 96 when I was 18 that had flowmasters and I LOVED the way it sounded. I know Camaros and Mustangs sound different but it had that nice old school muscle car sound that I can't come up with a word to describe other than old school muscle car. I assume you have an idea of what im talking about since it was your company that made them. The American thunder seems to sound the closest to the sound im looking for at least when the valve is open. The closer I can get to how the GT sounded inside the happier I will be. I'm totally fine with the tone / sound being different from a GT but that is the level of in car volume I am searching for. You could always hear the exhaust inside of the car even at very low RPM. People today would probably call it drone in the lower RMP range but to me that was the best part of the sound and I ended up driving around in that RPM range more than I should of or short shifting so I could stay in it

Last question, is it even possible to get the exhaust loud enough to make it sound anything like a 80something to 93 Mustang GT inside the car?

Thanks again!

[SmurfMaf1a]

Originally Posted by VegasZ

A couple question for the Flowmaster guys / gals or anyone that already has one of these on their ZL1.

Does the exhaust valve closing during off throttle bother the sound at all? Can you tell that it's switching between the two muffler types instead of using a single one all the time? From the sound in your videos it doesn't seem to bother it but theres a spot around 3 - 4k RPMs that sounds different than the rest of the RPM range, is this stupid valve the cause or is it something else in the motor that just sounds different in that range?

Thanks so much for any help! I'm getting ready to order an exhaust for it but it's so hard to tell what they really sound like on the internet esp when most people use shit microphones to capture the sound. Your recording is one of the best I have heard not only in how the car sounds but the quality of the capture. Did you use a real Mic to capture it?

I have removed the fuse for the NPP and it def made a difference although its still not loud enough esp when off throttle but you can tell that it's louder than it was with the fuse in so it's deff closing the exhaust valve under a certian throttle amount or whatever they use to base the valve operation off of instead of just relying on the settings we can manipulate to force them to be "open all the time" since they are overriding that setting for cruising throttle for example.

I could keep the fuse out but it seems kinda silly to buy an NPP aftermarket exhaust and pay extra for it if you can't actually use it because of the other BS the car is deciding to do with that valve instead of leaving it alone for us to set as we want.

If you can't tell I hate how quiet the exhaust is inside the car, I have a 6m and have always driven sticks off of the sound of the engine more than looking at gauges and to know if I put the right amount of throttle to take off without having either to much or not enough. If I have music on at even a moderate level the exhaust is basically un audible inside the car with the fuse in unless you give it a good jab of throttle. Removing the fuse made a small difference in the RPM ranges that it was closing on but not enough for me to not need something aftermarket.

I had a 93 mustang GT back in 96 when I was 18 that had flowmasters and I LOVED the way it sounded. I know Camaros and Mustangs sound different but it had that nice old school muscle car sound that I can't come up with a word to describe other than old school muscle car. I assume you have an idea of what im talking about since it was your company that made them. The American thunder seems to sound the closest to the sound im looking for at least when the valve is open. The closer I can get to how the GT sounded inside the happier I will be. I'm totally fine with the tone / sound being different from a GT but that is the level of in car volume I am searching for. You could always hear the exhaust inside of the car even at very low RPM. People today would probably call it drone in the lower RMP range but to me that was the best part of the sound and I ended up driving around in that RPM range more than I should of or short shifting so I could stay in it

Last question, is it even possible to get the exhaust loud enough to make it sound anything like a 80something to 93 Mustang GT inside the car?

Thanks again!

They sound amazing. Far better than stock npp. Very loud and deep with my secondary cat delete with the valves open. Quiet with the valves closed, but they are rattling like crazy for me. I am kind of disappointed at that. I am trying to see if i can fix it.

[VegasZ]

Originally Posted by SmurfMaf1a

They sound amazing. Far better than stock npp. Very loud and deep with my secondary cat delete with the valves open. Quiet with the valves closed, but they are rattling like crazy for me. I am kind of disappointed at that. I am trying to see if i can fix it.

Thanks for the info! Let us know if you can get the rattle fixed. I had a heavily modded car in my past that needed a custom created exhaust. It was kinda to big for the room around the back axels and it rattled every time I started from a stop. It drove me nuts, 10 years later now that i'm thinking about it I can still hear the sound in my head

GL

[KingLT1]

It's a decent exhaust...has some quirks but it sounds pretty good. A lot of it is going to depend on what other mods are done to the exhaust setup.

With headers and no cats it's going to sound super loud with no refinement when the valves are open because the Outlaw mufflers basically do nothing. Closed it will sound really good through the 40 series.

With stock headers and cats, open will sound good being you have cats to control sound and drone similar to stock NPP. Closed will be really tame...Almost quiet as stock NPP just deeper.

[SmurfMaf1a]

Originally Posted by KingLT1

It's a decent exhaust...has some quirks but it sounds pretty good. A lot of it is going to depend on what other mods are done to the exhaust setup.

With headers and no cats it's going to sound super loud with no refinement when the valves are open because the Outlaw mufflers basically do nothing. Closed it will sound really good through the 40 series.

With stock headers and cats, open will sound good being you have cats to control sound and drone similar to stock NPP. Closed will be really tame...Almost quiet as stock NPP just deeper.

I agree with you. After driving it for 2 weeks its alittle too loud for a daily driver with my secondary cats cut out. I am going to take it back to the exhuast shop on monday to weld them back in the same spot. Hopefully it does not look like shit lol. That should make it about 20% quieter and calm down the cold starts that scare my daughter every morning.

[SmurfMaf1a]

Originally Posted by VegasZ

Thanks for the info! Let us know if you can get the rattle fixed. I had a heavily modded car in my past that needed a custom created exhaust. It was kinda to big for the room around the back axels and it rattled every time I started from a stop. It drove me nuts, 10 years later now that i'm thinking about it I can still hear the sound in my head

GL

I could not get the rattle and leaks fixed. I called flowmaster and they want me to pay the shop to take it off and ship it back to them and then I have to pay the shop again to install the new exhuast they send me that could also possibly rattle and leak. It would just be cheaper to weld my secondary cats back in and always drive in sport mode with a more tame exhaust.

[Abubaca]

I've followed this thread a little bit over the past few weeks. That rattling and potential rust I think is enough to push me away from this system. -And for all the high dollar options, I really like the way the FM sounds too.

[SmurfMaf1a]

Originally Posted by Abubaca

I've followed this thread a little bit over the past few weeks. That rattling and potential rust I think is enough to push me away from this system. -And for all the high dollar options, I really like the way the FM sounds too.

flowmaster honestly sounds way better than corsa and borla imo. I've heard both in person and they get very raspy when you go wot. These LT1 engines are raspy in general so they pair very well with the flowmaster deep tone. However your right the flowmaster does have drawbacks. I havnt noticed any rust but they do rattle and leak. So if you do go flowmaster i would just leave the valves open all the time since its a gamble with the npp functioning like it should.

[OB0001]

just got mine installed sounds awesome! no rattle or drone and no rust stainless steel don't rust