[CaptainChad]

Hey guys,


So if I decide I want to buy an aftermarket axle back exhaust, lets say for example the MBRP dual Axle back black coated exhaust, I heard that I lose control for opening and closing the valves and people suggest to just keep them open.


So how exactly does that work? Is it because there is some kind of configuration with the stock exhaust that controls opening and closing the valves? And if you put an aftermarket you lose the ability to have that configuration?


Appreciate any knowledge on this.

[enzia35]

https://www.borla.com/products/chevr...t-system-11925

Look at the outside set of tips. A set of valves is removed from NPP exhaust and installed onto that plate. If the exhaust you're looking for (say the MBRP) doesn't have that place to install the valves, then the functionality of NPP is lost.

I wonder if people are talking about the fuse pull when you mention keeping them open. That also works only on NPP cars as removing the fuse cuts power to the valves.

[SnowWhiteSS]

Our cars continue to close the valves under around 2k RPM no matter what mode the exhaust is in to eliminate drone in the cabin. Some people don’t like that and would rather the exhaust stay wide open so they pull the fuse for the valves to force them to stay open. I believe it’s 51? Could be wrong. Now as far as MBRP, they aren’t valved exhausts. They are pretty much just pipes to replace a muffler delete. They do however have a place to mount the valve motor in order to avoid a CEL but there is no actual valve inside the pipe. stock set up? They are fine. As soon as you do headers? They get pretty loud and very drony since there is no muffler at all. I see a lot of people end up selling them used on here and Facebook because they say they are too loud. A lot of tune shops I know hate cars that come in with them too. The tips look pretty good though. It’s all about preference. If you plan on doing headers later? Pay the money and get valved pipes. I have them and love them. Payed a pretty penny for them but the fact that I can blow the car next to me’s ear drums out and be quiet as a mouse when I pass a state boy? Is worth it

[CaptainChad]

Originally Posted by SnowWhiteSS

Our cars continue to close the valves under around 2k RPM no matter what mode the exhaust is in to eliminate drone in the cabin. Some people don’t like that and would rather the exhaust stay wide open so they pull the fuse for the valves to force them to stay open. I believe it’s 51? Could be wrong. Now as far as MBRP, they aren’t valved exhausts. They are pretty much just pipes to replace a muffler delete. They do however have a place to mount the valve motor in order to avoid a CEL but there is no actual valve inside the pipe. stock set up? They are fine. As soon as you do headers? They get pretty loud and very drony since there is no muffler at all. I see a lot of people end up selling them used on here and Facebook because they say they are too loud. A lot of tune shops I know hate cars that come in with them too. The tips look pretty good though. It’s all about preference. If you plan on doing headers later? Pay the money and get valved pipes. I have them and love them. Payed a pretty penny for them but the fact that I can blow the car next to me’s ear drums out and be quiet as a mouse when I pass a state boy? Is worth it

Hey thanks for the advice, I think it would be wise to save a little more just to get pipes with valves, I might as well use a feature of the car that I paid for. As far as being loud, honestly I don't want my tinnitus to get a lot worse hahaha so being able to switch from being a bit loud to being quieter is always a good thing.



You've given me some wisdom to hold on to.


EDIT: I know that Borla actually makes the valve NPP variant of their exhausts with the valves, so when the time comes to do my long tube headers I can pay the 2k or so and get those (they are a little pricey, but like you said they are worth it).

[SnowWhiteSS]

Not a problem. that’s exactly how I looked at it. NPP is a cool feature that can keep you out of a lot of trouble. Get a ticket for obsessive noise? (Which I’ve gotten before). Close the valves and take it to the police station and it will pass the decibel test no problem. Also another bit of advise. Not trying to knock on borla. But I’ve seen from sound clips that they don’t sound much quieter when the valves are closed. If your stuck on borla, look at their S-line mufflers. Also look at stainlessworks legend series. That’s what I have an I love it. 1200 bucks instead of 2k. Also look at corsa. Just do your research is all I’m tryna say. They are all good brands. All about preference. Glad we could help.

[MMC(SW) Retired]

I have the Borla S-Type NPP compatible exhaust on my LT1, and it is fairly quiet when cruising; no drone. It sounds very good when getting on the go pedal!

[Ventmaster]

Originally Posted by SnowWhiteSS

Our cars continue to close the valves under around 2k RPM no matter what mode the exhaust is in to eliminate drone in the cabin. Some people don’t like that and would rather the exhaust stay wide open so they pull the fuse for the valves to force them to stay open. I believe it’s 51? Could be wrong. Now as far as MBRP, they aren’t valved exhausts. They are pretty much just pipes to replace a muffler delete. They do however have a place to mount the valve motor in order to avoid a CEL but there is no actual valve inside the pipe. stock set up? They are fine. As soon as you do headers? They get pretty loud and very drony since there is no muffler at all. I see a lot of people end up selling them used on here and Facebook because they say they are too loud. A lot of tune shops I know hate cars that come in with them too. The tips look pretty good though. It’s all about preference. If you plan on doing headers later? Pay the money and get valved pipes. I have them and love them. Payed a pretty penny for them but the fact that I can blow the car next to me’s ear drums out and be quiet as a mouse when I pass a state boy? Is worth it

+1, I really enjoy keeping my NPP intact and calmly sliding up in Track mode on someone I've been trying to get around and when the time is right- nailing the throttle and, opening the valves, waking them up as I blow by. My Borla 60606 (2nd cat delete) kinda adds to the effect. But its loud enuff for me when I want to be loud, and quiet when I need to be quiet.

[lubeman1969]

It’s worth the extra to get the valved exhaust, after all you pay a lot for the option. I have the stainless works with npp. Love it

[arpad_m]

Another option is Corsa, their NPP exhausts ain't cheap, but oh, do they deliver the goods, plus I strongly prefer their angled, aggressive tips to Borla's soft looking rolled ones.

[CreeperRS]

Originally Posted by arpad_m

Another option is Corsa, their NPP exhausts ain't cheap, but oh, do they deliver the goods, plus I strongly prefer their angled, aggressive tips to Borla's soft looking rolled ones.

[Crushin_LT1]

Originally Posted by arpad_m

Another option is Corsa, their NPP exhausts ain't cheap, but oh, do they deliver the goods, plus I strongly prefer their angled, aggressive tips to Borla's soft looking rolled ones.

I have the Corsa NPP and it is amazing.

[ste6000]

Originally Posted by arpad_m

Another option is Corsa, their NPP exhausts ain't cheap, but oh, do they deliver the goods, plus I strongly prefer their angled, aggressive tips to Borla's soft looking rolled ones.

depends on what tips you get. the carbon ones are not rolled.