Victory14red

Mine has a power steering sounding whine when I start it, and if it's really cold out it sounds that way till it's warmed up. I can only assume it's either the vacuum pump or high pressure fuel pump. I wouldn't worry about it too much unless it really concerns you.

I have the metal mulisha exhaust which has no valve and is arguably the loudest cat back available (although it's deeper than it is loud I think). No flapper valve in there, it's not "louder" when in v4 per say, it's just different. It doesn't sound terrible to me, at low rpm sounds like a Subaru, higher rpm sounds more like a Harley. If the flapper does anything I think it's just to eliminate the sound it makes. Cause it almost seems to stay in v4 more now that I have the exhaust.

Interesting info. What about the fact that the y-pipe would still be 3" but after the second cat it increases in size? Still detrimental? I would think it would act as a restriction and cause the "hot and tight" situation you speak of up to that point. I'm just trying to figure out gibsons logic using 4".

I'm a professional mechanic. I don't know what it would adjust to (other than possible Leanness due to increased airflow)? Maybe it has to relearn stft and ltft. Not sure. But just going based on the science above and logic it seems to me that shortening an exhaust would be better for low end torque......therefore adding a bigger pipe after a smaller one effectively shortens it. It makes sense in my head lol.

Here's my question. Which I have been trying to figure out on my own to no avail. On the 5.3 if you get the metal mulisha exhaust it's 4" however the piping that it connects to is 3" so because it's a thru flowing exhaust you're essentially "ending" the exhaust at the point where it becomes 4" correct? So you'll still have a 3" exhaust for the scavenging effect but it's "shortened" which should be good for low end torque? Is my logic sound there?

The following is copied from http://www.dsmtuners.com/threads/exhaust-the-straight-scoop-on-backpressure.168578/ Granted this is a completely generalized answer not in any way specific to our trucks bit the science makes sense. The copied text follows: There is a common misconception that engines need backpressure in order to run properly, generate low end torque, etc. That is simply untrue. Backpressure is a bad thing. Always. Take a look at a top fuel dragster...how much backpressure do you think those zoomie headers make? Very little, and those engines produce 6500 hp. So, what is backpressure? Any fluid flowing through a pipe experiences drag on the walls of the pipe. This depends on a number of factors, including the diameter of the pipe, the smoothness of the inside of the pipe, the viscosity of the fluid, and the velocity of the fluid. This drag results in a pressure drop through the pipe. In order for the fluid to flow at all, the pressure on one end of the pipe must be higher than at the other. In an exhaust system, that pressure drop is what we refer to as backpressure. It's pretty obvious that the engine has to produce this pressure differential, so the less power it has to spend making pressure to push the exhaust out, the more power it can send to the wheels. Given that exhaust pipes are pretty smooth, and that we can't change the viscosity (thickness) of the waste gas being forced through the pipes, we are left with basically 2 parameters we can have any control over: The pipe diameter and the gas velocity. Unfortunately, the pipe diameter controls the gas velocity since the volume of gas is prescribed by the engine. So, we really only have one thing we can change. So, bigger pipes allow less pressure drop for a given volume of gas because the velocity is lower. The pressure drop (backpressure increase) is proportional the gas velocity squared, so if I double the gas velocity (by reducing the cross sectional area of the exhaust pipe by half) then I quadruple the pressure drop. Well, there's an easy solution for that: Just make the exhaust pipe bigger. Bigger pipe, lower gas velocity, less pressure drop, so less backpressure. Wow, that was easy. After all, this is the way it's done for basically any type of commercial plumbing system. Need less pressure drop on a chilled water pipe or a natural gas line? Just make the pipe bigger. But wait, there's a problem....Having a huge exhaust pipe has killed my low end torque!!! What's different? Oh, there's no backpressure!! Therefore backpressure makes torque! Wrong. An exhaust system is different than just about any other plumbing situation. How? Because the flow is pulsed, and this turns out to be a big deal. Every time a pulse of exhaust gas runs through the pipe, a strange thing happens: it as it passes, it has a little area of vacuum behind it. Just like a NASCAR stocker running around the track, the pulse generates a little bit of a vacuum behind it. In NASCAR, a driver can take advantage of another driver's vacuum by getting right behind him and driving in it. The wind resistance is drastically reduced. This is called drafting. Well, how big the vacuum behind each pules is depends on the gas velocity. The higher the velocity, the bigger the vacuum the pulse has behind it. Now, this means that I can "draft" the next pulse, just like in NASCAR. In NASCAR, it's called drafting, in an exhaust system, it's called scavenging. You've probably seen this term used when talking about headers, but the same concept applies in the pipe. I get the maximum scavenging effect if the gas velocity is high, so the pipe needs to be small. By maximizing the scavenging effect, I help to pull pulses out of the combustion chamber, which means the engine doesn't have to work as hard to do that. This has the most effect when there's a bunch of time between pulses...in other words, at low rpm. As the revs rise, the pulsed flow becomes more and more like constant flow, and the scavenging effect is diminished. So, at low rpm I need a small pipe to maximize scavenging, and at high rpm I need a big pipe to minimize pressure drop. My exhaust pipe can only be one size, so it's a compromise. For a given engine, one pipe diameter will make the most overall power (i.e., have the largest area under the curve on a dyno chart). So, the loss of torque has nothing to do with backpressure, and everything to do with gas velocity. So you need exhaust components that are not restricive (manifolds/headers, mufflers) and that are sized correctly for your application. To further dispel the "backpressure is necessary" theory, try this if you want. If you have access to a vehicle with open headers, make a block off plate that will bolt to the collector. This plate should have only a 1" hole in it for the exhaust to flow through. That will give you PLENTY of backpressure, and zero scavenging. Then you can report back on how much low end power it has. The one exception to sizing an exhaust is for turbo cars. Since the turbo is in the exaust stream, the gas flow spinning the impeller tends to come out of the turbo with the pulses greatly diminished. In this case, you can get away with running a larger pipe than on an equivalent HP N/A engine because you can't take as much advantage of the scavenging effect.

Interesting. Good to know

Mine were installed before I got the truck. Don't mind the dirt.

The openings in the little nubbies inside the muffler should be facing the rear of the truck. If you look through it in the direction of flow you should see the bumps but no openings. According to MBRP having it on backwards can cause more cabin noise but otherwise will work. I just found that info by googling it, since I'm looking at that same exhaust.

I just got mine installed yesterday. Seems built well. I have no info on how well it will seal out moisture yet but it should do a fair job.

http://www.gmpartsdirect.com/chevrolet/silverado-1500/20922755/2014-year/lt-trim/5-3l-v8-flex-engine/body-cat/frame-and-components-scat/?part_name=skid-plate This is the transfer case slid plate

Mexico

Not that it seems like this is a real,hot topic right now but I just got my truck back. They found the leak and replaced the radiator. The bulletin is PI1513 and for the non max tow 5.3 the updated parts are 23378655 radiator 12671393 outlet with thermostat

Hi there, first time post here. I just picked up my 14 in 12/17 and have noticed since I got it the coolant is down about an inch in the resovoir and my driver side is cracked. Just dropped it off at the dealer this morning and was immediately told there is no tsb and they've never had to replace a radiator in one of these yet. I showed the service advisor the,crack and he said that it's just a mounting tab and that it has nothing to do with coolant loss but they would check into it. I told him that the coolant must be going somewhere. Now, I am a professional mechanic,by trade (heavy equipment/ buses) so I'm not going to let them pull anything over on me. Btw, 25k on the truck.