Exhaust for 5.3 liter 2002 Silverado

[Tommo]

I just got a new Silverado and I have no idea what kind of exhaust to get.. I want a really low rumbly sound. I was wondering if I could get some suggestions.

[Altimat]

http://www.gibsonperformance.com/index2.html

[XOTech]

I have a 1999 GMC Sierra (see the GMC Sierra Thread for pics) that I designed a true dual exhaust for. Flowmaster 50 series. There are more details in the thread with the pics.

The system is wonderful. It sounds perfect. Not too loud to be annoying, but just right. When you get on it hard, it pipes up a bit. Sounds very aggressive.

If cost is a concern, and a true dual system is out of the question, I cannot recommend anything else. My research on the Gibson or JBA system didn't give me what I wanted. I would not have been happy with anything less than the dual system I have on there now. As you will read in the other thread, I have plans for a Wipple charger when my 1959 Elky is done in a few months so the duals are a must for the additional breathing the engine will do.

[BRANDO]

I ALSO JUST GOT MY LT Z71 AND I PUT A CUSTOM EXHAUST ON IT. THE MUFFLERS THAT WERE USED ARE CALLED TURBO TUBES AND IT IS A TRUE DUAL SYSTEM. I HAD THE PIPES COME OUT AT EACH END OF THE BUMPER WITH 4" CHROME TIPS. I HAD THIS DONE AT A CUSTOM MUFFLER SHOP. I AM VERY PLEASED WITH THE SOUND OF THEM, THEY MAKE A NICE RUMBLING SOUND WHEN TAKING OFF AND WHEN YOU REALLY STEP ON THE GAS THE COME TO LIFE. HOPE THIS HELPS.

[prod78chevy]

:bandit: :bandit: I got a single outlet, dual outlet 40 series flowmaster on my 2000 GMC Sierra with a 4.8 V-8 and it rumbles pretty good. A dual outlet flowmaster is good if you'd like to keep some of your back pressure.

[Silverado1500]

Originally posted by XOTech
I have a 1999 GMC Sierra (see the GMC Sierra Thread for pics) that I designed a true dual exhaust for. Flowmaster 50 series. There are more details in the thread with the pics.

The system is wonderful. It sounds perfect. Not too loud to be annoying, but just right. When you get on it hard, it pipes up a bit. Sounds very aggressive.

If cost is a concern, and a true dual system is out of the question, I cannot recommend anything else. My research on the Gibson or JBA system didn't give me what I wanted. I would not have been happy with anything less than the dual system I have on there now. As you will read in the other thread, I have plans for a Wipple charger when my 1959 Elky is done in a few months so the duals are a must for the additional breathing the engine will do.

This is what I have, and I love it. Not sure what series, but it sounds great!

[lilwrestler]

Might as well get some fart pipes!!!!!!!!!!!!!!!


Everyone else is! :finger: :frog:

[XOTech]

No Fart Cans for me.

A pair of Flow Masters and a specifically designed exhaust Dual system.

I am not too fond of the Import Rage and the use of Fart Cans.

BTW, my '99 is a Sierra 1500.

I have posted pictures of my truck somewhere in this Forum. I don't remember where.

[slopjoc]

I've got a 99 Z71, and went a pretty cheap route for what I think is a great sound. My local shop cut the muffelr and til pipe off, and put Y in it, 2.5 inch pipes back until the last 18-24 inches, depending on how loud you want it, and then put chrome 3.5 tips. some local guys go through a semi dealer and get 5 inch heavy chrome pipes, and it will raise the roof if you get on it . I live in the middle of no where, and at about 3500 rpms a person can hear it fro abotu a miel and a quarter. Just driving, or in town it has a low deep tone, that will draw attention. a few hundred is all it ran me.

[Dihappy]

Take care not to get too much of a free flowing exhaust on the new trucks.

The new vortecs seem to work best with a little backpressure, you could lose some low end torque opening it up too much.

[Scott 02]

If looking for loud noise.....Flowmaster 2 chamber 40 series or Dynomax Ultra Flow Welded Mufflers.

A nice rumble tone......Flowmaster 50 series or Thrush Turbo's

[flylwsi]

fyi>>> backpressure is bad.

you don't want it. people are using the terminology incorrectly... but the idea is right, you don't want restriction at all, you do want a little, not completely open on a street vehicle.

also...

no one here has a true dual setup unless you are running straight off the header/manifold into a separate cat and out into a separate muffler, which is hard to do on today's vehicles... i've been under those trucks, and it doesn't make sense to put two mufflers on it...

also...

www.corsaperf.com... nice kit there... expensive but sounds as good as the flowmaster setup if not better...

backpressure explanation, if you want to read it...

this isn't necessary to read, but will open some eyes...
not my post, but found from texan who used to post here...

A lot of people have different thoughts on backpressure, and often confuse it with Velocity and Delta Pressure...
I will now post a colaboration of posts from Purehonda.com

"THE MYTH OF BACKPRESSURE"

…is probably the most widely misunderstood concept in engine tuning. IMO, the reason this concept is so hard to get around lies in the engineering terms surrounding gas flow. Here's the most impotant ones you need to be aware of to understand the things I'm about to say:

BACKPRESSURE: Resistance to air flow; usually stated in inches H2O or PSI.
DELTA PRESSURE (aka delta P): Describes the pressure drop through a component and is the difference in pressure between two points.

One other concept needs to be covered too, and that's the idea of air pressure vs. velocity. When a moving air column picks up speed, one of the weird things that happens is it’s pressure drops. So remember through all this that the higher the air velocity for a given volume of gas, the lower it's internal pressure becomes. And remember throughout all of this that I’m no mechanical engineer, simply an enthusiast who done all the reading he can. I don’t claim that this information is the absolute truth, just that it makes sense in my eyes.

Ok, so as you can see, backpressure is actually defined as the resistance to flow. So how can backpressure help power production at any RPM? IT CAN'T. I think the reason people began to think that pressure was in important thing to have at low RPM is because of the term delta pressure. Delta pressure is what you need to produce good power at any RPM, which means that you need to have a pressure DROP when measuring pressures from the cylinder to the exhaust tract (the term "pressure" is what I think continually confuses things). The larger the delta P measurement is, the higher this pressure drop becomes. And as earlier stated, you can understand that this pressure drop means the exhaust gas velocity is increasing as it travels from the cylinder to the exhaust system. Put simply, the higher the delta P value, the faster the exhaust gasses end up traveling. So what does all this mean? It means that it's important to have gas velocity reach a certain point in order to have good power production at any RPM (traditional engine techs sited 240 ft/sec as the magic number, but this is likely outdated by now).

The effect of having larger exhaust pipe diameters (in the primary, secondary, collector and cat-back exhaust tubes) has a direct effect on gas velocity and therefore delta P (as well as backpressure levels). The larger the exhaust diameter, the slower the exhaust gasses end up going for a given amount of airflow. Now the ***** of all this tech is that one exhaust size will not work over a large RPM range, so we are left with trying to find the best compromise in sizing for good low RPM velocity without hindering higher RPM flow ability. It doesn't take a rocket scientist to understand that an engine flows a whole lot more air at 6000 RPM than at 1000 RPM, and so it also makes sense that one single pipe diameter isn't going to acheive optiaml gas velocity and pressure at both these RPM points, given the need to flow such varying volumes.

These concepts are why larger exhaust piping works well for high RPM power but hurts low RPM power; becuase is hurts gas velocity and therefore delta P at low RPM. At higher RPM however, the larger piping lets the engine breath well without having the exhuast gasses get bundled up in the system, which would produce high levels of backpressure and therefore hurt flow. Remember, managing airflow in engines is mainly about three things; maintaining laminar flow and good charge velocity, and doing both of those with varying volumes of air. Ok, so now that all this has been explained, let's cover one last concept (sorry this is getting so long, but it takes time to explain things in straight text!).

This last concept is why low velocity gas flow and backpressure hurt power production. Understand that during the exhaust stroke of a 4 stroke engine, it's not only important to get as much of the spent air/fuel mixture out of the chamber (to make room for the unburnt mixture in the intake system), it's also important that these exhaust gasses never turn around and start flowing back into the cylinder. Why would this happen? Because of valve overlap, that's why. At the end of the exhaust stroke, not only does the piston start moving back down the bore to ingest the fresh mixture, but the intake valve also opens to expose the fresh air charge to this event. In modern automotive 4 stroke engines valve overlap occurs at all RPM, so for a short period of time the exhaust system is open to these low pressure influences which can suck things back towards the cylinder. if the exhaust gas velocity is low and pressure is high in the system, this will make everything turn around and go the opposite direction it's supposed to. If these gasses reach the cylinder they will dilute the incoming mixture with unburnable gasses and take up valuable space within the combustion chamber, thus lowering power output (and potentially pushing the intake charge temp beyond the fuel’s knock resistance). So having good velocity and therefore low pressure in the system is absolutely imperative to good power production at any RPM, you just have to remember that these concepts are also dependent on total flow volume. The overall volume of flow is important because it is entirely possible to have both high velocity and high pressure in the system, if there is simply not enough exhaust piping to handle the needed airflow.

It’s all about finding a compromise to work at both high and low RPM on most cars, but that’s a bit beyond the scope of this post. All I am trying to show here is how the term backpressure is in reference to a bad exhaust system, not one that creates good low RPM torque. You can just as easily have backpressure at low RPM too, which would also hurt low RPM cylinder scavenging and increase the potential for gas reversion. And understand that these tuning concepts will also affect cam timing, though that is again probably beyond the scope of this post. At any rate, hope this helps, peace. "

-here's a reply to the above post-

"I've been seeing a resurgence of the backpressure misnomer, but didn't have the time or inclination to write it up. So, again, thanks.

There is one thing I'd like to add to texan's work:
Exhaust Scavenging
In essence, this is the opposite of the exhaust reversion that texan describes.

Reversion: at the beginning of the intake stroke during cam overlap, exaust gas in the header is under high pressure (negative delta P) and is pushed back into the cylinder, diluting the new air/fuel charge.

Scavenging: at the beginning of the intake stroke during cam overlap, the momentum of the exiting exhaust gasses creates a brief vacuum (positive delta P) in the header, pulling out the remaining exhaust gases from the combustion chamber, and allowing the new air/fuel charge to be full-strength.

Scavenging is also the reason for differently shaped headers (4-2-1, 4-1) and collectors. We use the momentum of exiting exhaust from one cylinder to scavenge exhaust from another that is next in the firing order! The different shapes allow for this to happen at different airflow velocities thus at different RPM bands.

Scavenging takes advantage of the momentum of the exiting gasses. In essence, the fast moving exhaust pulse pulls a vacuum behind it. Momentum is mass times velocity. So not only do we need to keep the velocity high to prevent reversion - but it greatly improves the scavenging effect.

Thus we have a balancing act (as others have pointed out). We want to minimize friction to lower the backpressure as much as possible - larger pipes have less friction because they have less surface area per unit volume. But we want to increase the delta P as much as possible to prevent reversion and increase scavenging effects - smaller pipes increase delta P because they increase velocity.

There are lots of tricks to try to widen the useful RPM band (stepped headers) or to increase the overall effiency (ceramic coated exhausts), but it's still subject to this basic tradeoff:
Friction vs. Velocity
AKA: Backpressure vs. Delta Pressure
You want low friction and high velocity.
You want low backpressure and high positive delta pressure.

[Scott 02]

I can't believe you posted that long ass thread on backpressure.

[flylwsi]

it's worth posting...

alot of people have an idea of what they're talking about, but don't know what the words mean...

that's why i like to clarify

sorry...

[prod78chevy]

The lack of backpressure does have some effect on torque during your lower to mid-range rpm's. At least that is what some professionals have told me.:bandit: