How NPP exhaust works and how AFM valves work. Why only certain exhaust tips are dirty.
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- Опубликовано: 24 дек 2022
- This is why only certain exhaust tips are dirty on cars with NPP exhaust. Also explains what exactly NPP and AFM does and provides info about making an educated decision on how to choose an exhaust you purchase.
NOTE: This is all information for a car that obviously has not had the AFM disabled by either using a Range Device or having it tuned out.
Information provided by the speaker/presenter in this video is for general information purposes only. All information is provided in good faith however no representation of warranty of any kind, expressed or implied, regarding the accuracy, adequacy, validity, reliability, availability, or completeness of this information. All actions are performed at your own risk and you assume all responsibility for any and all of your own actions.
What a legend to cut open the exhaust for explanation
You absolutely have the best videos on the C8 out there. Thank you so much for doing them. You have no idea how much they have helped me under stand my 2023 Stingray. I'd like to add one more "tell" to the Z51 enigma and that is the glass over the engine has the Z51 logo etched into the bottom.
Sensational video! Very thorough, great graphics, and the cut away exhaust was great. You have a very good knack at explaining things so I can easily understand. I have a C6 corvette with NPP exhaust and wanted to know how it all worked. This video did that and a lot more. Thanks for putting this together.
This Guy kicks butt!!!
Seeing everything cut open is a godsend!!! Can't believe he did that. Then.....good clear function descriptions. Now I know a LOT more of how things work. Give this guy an EMMY!!!
Well thank you sir, greatly appreciated 👍
Perfect, my Camaro has this, I always wondered why only my outer exhaust tips were dirty. Found out the fuse to the npp had been pulled befor I bought it so the exhaust was always open
Nice description. It is really simple to understand the way that you explain things in simple terms. Thank you!
A good explanation days before I replace the non-Z51 performance exhaust.
Sensational information. You are a very knowledgeable person, and also ... a legend!
Thank you sir
Well done! Exhaust system explained perfectly. Thank you
Very informative. I am investigating putting a npp exhaust system on my C8. On C6 I added by adding a vacuum pump to provide vacuum to the actuators, I just turn vacuum pump on or off. It looks like the npp is controlled by electric voltage.
Thank you, I am now more knowledgeable in the exhaust nomenclature and it’s functionality. Nice work.
Thank you for the simple explanation. Great work. You have my subscription!!!
This is the best explanation and discussion of exhaust systems for the Corvette I've seen. I always debate on changing my exhaust (currently running factory npp on a C7) but I just can't bring myself to chop off such a well-designed system. I love loud v8's, but the npp sounds really, really good as is. Sure I could change it out for a louder exhaust, but I like the functionality and integration with the drive modes.
Wow man…you are extremely thorough! Thank you for putting out this video and for doing the cut outs (as a visual learner, it helped alot)! Subscribed!
I thoroughly enjoyed this video!
Great content. I’ve learned a lot. Subbed.
Thanks for this video and the sacrificing your factory x pipe suitcase
Thank you. I think I'm having a problem with an AFM valve: I will hear/feel a loud sound over my right shoulder, and .5 seconds later V4 will light up on the dash. It doesn't happen every single time it goes into V4 mode, but that is def what is causing the sound. It's like hitting a paper grocery bag with a stick... so possibly something to do with whatever pressure exists when the valves flip?
Anyway bringing it to the dealership. Thank you for explaining everything - glad I'm not losing my mind :)
I drive mine in Z mode with shifting at max. This will stop that noise. Also manual mode.
@@Pharmgdb Thank you for the feedback. Track mode will also do this -- it's just preventing the car from going into v4 mode.
I brought the car in a little after posting this: they said there was a software update and I haven't had the problem to anywhere near this degree since.
You can still hear the valve clicking on once in awhile - but it that is to be expected.
Unless I'm "driving" I have it in Z mode, with everything but gearing maxed out. I figure if I'm on the highway, I'll take the couple extra MPG in v4 mode. Anything helps after seeing that 4 MPG figure when you're on it 🤣
Wow, what a detailed overview, thanks for doing it. Something I’ve never heard anyone mention is that NPP is the GM option code for the performance exhaust.
Which Is Funny Because If Anything It Just Adds Weight And Reduces Flow. The Opposite Of Performance
Great video.. I'm keeping the stock exhaust on my z51.. I'm cheap.. and sounds good to me..
I just got a 2016 Camaro SS it came with npp but the muffler been changed to a none npp factory exhaust muffler can see where pipes have been welded together. It has the wiring with plugs hanging down but no actuators or valves or any thing that would suggest it had npp except for wiring. . It has afm also but don’t remember seeing those valves. Thanks for explaining the system. Good job.
Very good video.
This video is amazing…best explanation of how it all works out there…so well done. I have a 2023 Z51 and I came to this video because of this chirping squeak I keep hearing from the exhaust at very low idle when backing up or just starting to pull forward. This is in Touring mode. Any idea what that would be? It seems like it must be something with the NPP valves? Appreciate any info man, thanks again!
Thanks for this. Now I know how my 2016-2024 Camaro NPP "suitcase" works as well. (In my case 2018).
Love the extra carbon fiber bits in the interior!
love the video! question tho, how can you tell if an aftermarket titanium exhaust has NPP/AFM valves?
Top notch video! Excellent. Thank you!! Not that I care about MPG in my Z51 but, how does the various valve opening and closing configurations affect gas mileage? 🤔 Aside from the obvious dropping to 4 cylinders improves it.
Thanks
I've been wondering about these valves since I got my C8 Z51 and so I thank you for the explanation. Question - on a C8 without the performance exhaust (not my car), what governs whether the exhaust goes out the inner or the outer tip? Is the outer tip permanently closed?
Great video bro what exhaust you recommended for the c8 is the best?
Awesome video, question does your Borla atak exhaust have multiple settings like stock exhaust? Thank you
NPP… yeah you know me 😅
Great info - so what does a non-performance C8 exhaust without NPP look like cut open???
@squirrelcagegarage, great video. Quick q. Do you see anything in the AFM exhaust valves that could produce a faint chirp/rattle noise when closed? (in V4 mode).
Great analysis! One question that I may have missed in your presentation. You speak of the huge mass of the C8 exhaust’s outer shell, which is primarily a heat shield. I am interested in either the AWE or Paragon Touring systems. How do they get away with no heat protection? They claim that the open air flow cools adequately. What about when the system is idling with no air flow? Do you agree or is heat a valid concern I have before I make my purchase? Thanks!
To be honest I have no doubt that a company like Paragon or awe did not do their research and development for a system like that when something like heat concern is an issue. Me personally I went with borla for two reasons number one the heat concern because they come with heat shields not so much for the system itself but because of everything around it that is being exposed to the heat. And number two because the borla system retained all four valves which is a separate issue. However both systems are great, me personally if I had to choose between awe and paragon I would probably choose the Paragon but that's just me.
@@squirrelcagegarage Thanks, again, for your response. I am unable to consider Borla, since my C8 is non-NPP. I, too, like the Paragon system. The welds seem to be more refined, along with the fact that there are fewer connecting joints to potentially loosen and/or leak. My primary hesitation remains to be my lack of confidence in the one dealer that i’ve found willing to do the work. He has not worked with Paragon yet. Again, great job on you Vlog. Very helpful.
El escape del C8 que no tiene válvulas en las colas el interior es igual al del que tiene válvulas gracias👍🙋
The only thing missing from your detailed explanation was the actual size of the pipes of the stock muffler?
I have a non npp exhaust on my 23, can the valves be opened to allow better flow thru the exhaust npp ? thank you, Jim
If the exhaust never flows through all four tips, where does the extra 5 hp come from with the Performance exhaust?
👍
do you still have any used of the AFM and NPP valve and its pipe. ? since you already cut it. may I buy it from You?
Freaked out when I saw the grill on the air Inlet, I was thinking my car was missing them on both sides. Why did you add the grill and where did you get it?
I have one more question, do you think a Corsa Extreme muffler delete with AFM valves Would make more power and sound louder and better than a Corvette Performance exhaust like the Z51 model with Cicio performance Sport Cats? Thanks ;)
I couldn't tell you about the sound difference, that is sort of subjective. However power difference would be negligible between all options. I can't tell you that a Corsa muffler delete would be extremely loud though.
@@squirrelcagegarage Ok Thanks Man for the reply! I'm leaning more towards the Corsa Extreme muffler delete w/ AFM valves because I Do really like to hear the exhaust in my cabin when I'm driving and the Corsa website said to go with the AFM option if you want less drone in the cabin !!! ;) Mark~
2023 c8 z51.
Irrespective of the driving mode selected, when I first start the car, it is noticeably loud. Am I correct in assuming that the NPP is always opened by the computer at start-up? And can't be user controlled.
Thx
I do not believe so. The reason that it is louder upon startup is because when it starts up, it requires a richer fuel mixture and therefore makes it louder. The rich fuel mixture is what makes it louder when it's cold not necessarily the valves being open.
@@squirrelcagegarage From the service manual:
"To provide a more aggressive exhaust note when the vehicle is started, the exhaust tailpipe valves are opened during an engine crank event during specific modes of operation if that option is available. Once the engine is running, accelerator pedal position, transmission gear and engine speed are used to determine the commanded state (open or closed) of the exhaust tailpipe valves."
This implies that in some modes, the valves are open on start-up while they are closed in other modes, but I have not found that to be the case in my C8 Z51. Also, I'm sure the high initial RPM contributes, and the quieting down coincides with the RPM dropping. Many other C8 owners have complained about this. There are statements by some that Weather is a quiet start mode, as well as quiet drive mode. Also, in my experience over 60 years rich fuel mixture affects the smell and color of the exhaust but not the sound. Also, it quiets down in 15-20 seconds, too quick for it to have warmed up enough to leave the start-up enrichment mode. No car I have ever owned or worked on had such a pronounced bark on start-up, but none of them had NPP valves. Also, all of them had identifiable mufflers except my 66 Vette which had only the mildly chambered factory side exhaust and the C8, although the change in flow with the NPP closed serves that function
If I had a stock non z51 and a friend had a z51 with the npp exhaust. Could I use it? Would it have to be open all the time? Would it throw a code? Thanks in advance.
It would bolt up and fit but you would obviously have no control over the functionality of it. And the valves would always be closed because you do not have actuators to keep those valves open.
Hi I have a 2022 Corvette Stingray and it has AFM Valves but Not NPP Valves, Can I buy a NPP Valve simulator so it Would work with a Borla Attack catback wich has both NPP Valves and AFM valves? If Not what should I do to make it work or is it Not possible? Thanks~ Mark ;)
NPP simulators are only to trick the car into thinking the valves are there if you delete them. You wouldn't even have anything to plug them into since you don't have NPP from the factory. Unfortunately if you bought a Borla ATAK exhaust, you would not be able to control it. Not unless you wired a stand alone system, which would be very involved to do so and it still wouldn't be integrated into the rest of the car really. Sorry man.
@@squirrelcagegarageThanks for the reply man I will just buy a Non valved exhaust for my vette then.
👍. Another Dead Give Away, your car is blue, 😁. Can you do a video on AFM, as i heard AFM has issues and a video on catch can. Txs
I explained AFM relatively in depth in this but are you wondering about something else? And what are you looking for as far as catch cans go? I do have a video on how to install a catch can on a c7 up.
@@squirrelcagegarage is a catch necessary for a c8 cuz i heard there's one already inside.
@@frankli9450 there is to a degree in the sense of there is baffling in the oil tank and on the valve covers. However there are still pcv lines that come straight off the valve covers into the intake as well as a like that comes of the valley cover and into the intake manifold. I ran a catch can on mine personally, some people will argue that they are pointless, I personally disagree and no one can argue that even if you run one, you certainly aren't hurting anything either, so they can only benefit.
On another note, have you installed a Catch Can? Thanks
I have actually, it is a very very easy install. I can do a video of you would like.
@@squirrelcagegarage
Actually I just finished installing one. Haven’t driven my car yet as I’m in Canada and waiting for the nice weather.
Reason I’m asking is that the “GM experts” insist that one is not needed but I’ve seen actual results of it collecting oil after driven for a period of time.
I can send pictures if you would like.
@@wazzman8760 so this technically is true that it is "not needed". The car already has a system built into it as does any engine with a dry-sump oil system. However it is not "needed" but it is still highly effective. Some people will argue that you don't need one however no one will argue that one cannot be beneficial. No one will argue that they cause harm and can be nothing but beneficial.
@@squirrelcagegarage
Thank you for the detailed explanation.
Is there any oil collected in yours? Just curious.
@@wazzman8760 Yes I changed my oil when the indicator hits about 50%. And every time it is about 1/3 full give or take.
I really hope there's nobody out there that can't figure out why certain exhaust tips are more dirty than others if they have an npp system lol. You'd think it's just common sense.
Rear Mid-Engined**
All Corvettes since 1963 have been Mid-Engined.
My 2022 SS has these and theyre sqeaking 😅 its annoying af
That is an H pipe. X pipe is actually an X.
Ummm, I don't know what you are looking at, but that could not be anymore of an X pipe. It's an X inside the cut open portion. An H pipe would be two parellel pipes that are connected by a single perpendicular pipe.