Black04SSS

What version X-Link? Did you buy it new?

I hear ya Jake99 (no pun intended)! It is literally painful at around 70mph. If I was more brave, I would try the resonator tube along the muffler body and see how that works as well. Definitely keep us posted on your results! I have one 12599 (3" DI/DO with integrated X, 22" long, oval body) and two 14419 (3" SI/SO 14" long, 4" overall width, round body) mounted in the pipes right before the muffler. The droning is only very slightly lower with the added mufflers in front of the 12599. I initially installed the 12599 by itself to replace the stock one. The thing about tubular piping and flow is one has to consider the effect of laminar flow and how it effectively reduces the volume of air that the pipe can move. This is why dual 2.5 pipes will never flow as much as a single 5" pipe. The lesser surface area of the large single tube means it will outflow the two smaller tubes. And there is almost nothing we can learn from a race application exhaust system when it comes to daily driven street vehicles. Race applications mean WOT nearly 100% of the time and zero care for loudness or drone. Scavenging is the only positive thing an exhaust system can offer to help make more power (or shape power) compared to no exhaust at all. Backpressure is never a good thing. I think when some of you say backpressure, you mean a scavenging effect. That may be due to pipe sizing and bending being tuned to create velocity in the system or by merging multiple banks (or primaries in the case of headers) together at specific distances and angles.

Based on my visual inspection of the Magnaflow before I put it in back a few years ago, it must flow more than adequately for our trucks. It is straight through with an X, 3" all the way through. I agree that an X-pipe helps flow with the scavenging effect as well. No doubt that it is a great setup for getting the best flow and power, and I do like the sound at idle and under acceleration, it is just the drone that is unacceptable for me. Others might not care. I think exhaust sound and what is acceptable for noise level and drone is very subjective. I know drone very well. I have a single 4" Flowmaster on my 87 Trans Am that makes somewhere around 450 RWHP, and with 4.33 gears, that thing drones excessively on the highway and is way loud. But it is a limited street use car so I don't care so much and I like how it sounds (first thing removed at the dragstrip is the muffler though ). My SSS is my DD and tow vehicle and for that, I want fairly quiet but with better flow than stock if possible.

I hear ya, I don't like shotgunning parts at anything and typically don't... But I did a lot of research and read a lot of reviews on the FloPro. And I talked to them directly. What they explain makes sense to me, but I will refrain from passing full judgment until I get it on the truck. An X pipe will do nothing to help with resonance - the Magnaflow muffler I have has an X-pipe built into it (the muffler is basically a perforated X-pipe wrapped in a muffler case with fiberglass packing around it). If this FloPro does not work, I will first off be calling them and calling BS, but at that point I will probably have to add resonator tubes that run along the muffler like the ones pictured on Pt.net

Well after much research and debating, I ordered a 2506 FloPro muffler. I talked to them directly and did a lot of reading on various forums and it sounds like that muffler is exactly what I am looking for. Won't break the bank, a little louder than stock, better flow than stock, but no drone. I told the guy I absolutely will not tolerate drone at cruising throttle/speeds. The guy said they have never had a call back or return for a drone problem with that muffler on a 6.0 GM truck. The reviews seem to echo that on all the forums. Seems like some people end up swapping them out because they are a bit too quiet for their taste or want all out flow and don't care about the sound, but I actually want my truck to be fairly quiet as is and then add headers with some high flow cats (or no cats) later on if I want more power/flow/sound from the exhaust. But I daily drive my SS and tow and I cannot have drone. Thanks for all the ideas and the offers for stock stuff from some of you, I do appreciate it. I will post up my opinion on the difference once I get it installed.

This makes much more sense now... Don't all the 6.0 trucks have the same muffler too? Just a different tailpipe?

1BAD2K - sent you a PM about the cat back if silveradoss0325 doesn't take it.

No worries, sorry for jumping on it late. I clearly don't come here often enough. I will be in for one next time, if/when there is one .\ EDIT: In fact, you can just keep the funds as a first payment on the next order if you are doing one for sure.

Which end is the inlet in this picture? I am thinking it is the top? If so, then the second outlet on the right hand side (of the picture) would act as the resonator function. Or am I not seeing this correctly? I don't really have the resources to do metal fab work at my house. A little welding, sure, but I can't build what you are talking about on my current system unfortunately.

I'll take one XL black hoodie.... Assuming you have one still. Black04SSS, XL BLACK HOODIE, PAYPAL SENT

Thanks for all the insight. I have felt torn over the last few years with wanting the added power and liking a little more exhaust note than stock, but hating the drone. But the drone has gotten worse as the mufflers have broken in too, so the time has come to fix it. Have you guys with Corsa done the full cat back or just swapped the muffler? Michael - I'll shoot ya a PM about your stock system. Has anybody done headers (with or without cats) but kept the stock cat back?

PM sent.

Hello folks. I have a problem with my exhaust on my AWD SSS. Here is the story (kind of long, but here goes): The truck is all stock aside from a K&N FIPK, and the modified cat back exhaust that needs to be changed. I got the truck used about 3 years ago and it had some Thrush chambered mufflers with duals straight out the back. I don't like rear exit exhaust (looks, and I tow occasionally) and I wasn't a fan of the sound, so I ditched the system in favor of a used stock cat back I just happened to stumble onto. I really wanted the side exit and the stock tailpipe look and keep it quieter since I daily drive it and then see if I was happy with the performance before doing any upgrades. There was a problem with the muffler rattling on that used system I put on, so unfortunately I had to replace the muffler. I ended up deciding on a Magnaflow because it is supposed to flow well and be a little bit louder than stock, but not drone. I ordered the dual 3" in, dual 3" out, 22" long muffler (PN 12599) and installed it in place of the stock muffler. It sounds great under acceleration, not overly loud, nice at idle with a little more rumble than stock, but at and around 70 MPH, it droned like crazy. I called Magnaflow and they said their full Cat Back system has two mufflers before the main muffler that act as resonators so I should try that. So I added two (14" long I think?) 3" round mufflers onto the pipes leading into the muffler so it pretty much mirrors the Magnaflow cat back system aside from using the stock piping and tailpipe. The additional mufflers helped a little bit, but it still resonates and drones extremely loud at and around 70 MPH. My wife hates it, I have been tolerating it. The tailpipe being on the passenger side means she gets it worse than I do, but I also get a headache after driving for any sort of extended time around 70 MPH, which is pretty much what everyone does on the highways around here. We took a longer road trip once and nearly ended up divorced. So I have to do something about this. If I could track down a stock cat back, I would swap that in, but they are hard to find (if you have one and want to get rid of it, let me know). I don't like the idea of going back to stock and losing the gain in power, and some of the slightly louder sound, but the droning on the highway is unbearable and not worth it. If I knew, without any doubt, that a different aftermarket muffler would flow decent and not drone, I would try it and just replace the main dual in/out muffler on my system. So what are your experiences? Is it possible to put a different exhaust system on these things and not have them drone at highway speeds?

Sounds perfect. I sent you a PM.

I am pretty interested in these.... like as in, if they look good in person, I will take them. I am in Ham Lake, MN. Any plugs or patches or known damage anywhere?

Great write up! I think you have me convinced to try this myself... Mine is making more and more noise and I desire to keep the down time to a minimum as well. Would it be too much trouble to ask you to make a list of what parts need to be switched if one gets a 4x4 center section, where you got it, and an approximate cost for each part? EDIT: Also, do you remember what the measure of the pinion depth shim(s) you ended up going with was in the end? I am just thinking it would save time to start with that one to see how it looks. I do have some experience in setting up ring and pinions (only done one IFS GM one though - and that was 13 years ago in school...lol) so I know they are never identical from one to another, but they also aren't usually terribly far off if the application and manufacturer of the parts are the same. Thanks!

Yeah I know. That is why I am looking for one or info on getting one here .

I don't get it...

Like the title says, I am looking for a front diff assembly. The truck is a 2004 AWD SS. The left output (stub) shaft on mine has a massive amount of play in it, and it whines a bit, and I have no idea how long it has been like this (or what else is toast in there now) since I just got the truck used a few months ago. Looking for options that don't involve rebuilding the one in my truck - like swapping in a used one if somebody has one in good shape. Or does anybody know if any company stocks remanufactured ones for our trucks or will build one upon ordering it? Last option would be to rebuild a different used one and then swap. I need to keep the down time for the truck to a minimum but I'm not totally afraid of rebuilding one as long as it saves me enough money to be worth my time. Any ideas? Thanks!

Finally got some pics. Pretty much your standard SS: I just washed it, thus the water dripping off and running down the driveway.

Here are some pics:

So my truck had some thrush chambered mufflers on it and big chrome dual outlets out the back when I got it (used) but I wasn't a big fan. Too loud and raspy for my taste and I don't like the huge chrome tips out the back. So a buddy of mine happened to have a stock cat back at his shop that I put on for free. That made the truck too quiet for my taste and the muffler had a loose baffle in it and rattled like crazy (thus why the owner of the truck it was previously on swapped it out I would guess). I did a lot of research on here and elsewhere on the internet and decided that the dual 3" in/out Magnaflow should fit my needs well and I wanted to keep the stock tailpipe and location, so no need to get a full cat back. The local muffler shop was able to modify the stock after-muffler Y-pipe and keep the tailpipe and also tucked it up closer to the body for me, which is nice, and the 3" inlets of the muffler required a short adapter piece of 3" pipe to be welded onto the stock mid-pipes so everything would fit nicely. It ended up costing me $150 for all the labor to put the muffler in, but I am satisfied with the work. Now on to the muffler itself... It is a sweet looking unit and the specs seem great for performance and it is fairly large so one would think it should muffle things well. The reviews I read said it is only slightly louder than stock until you get on it. I have to vehemently disagree with that assessment. The only time it is "only a little bit" louder than stock is at idle. Anything over that and it is easily 5X as loud as the stock muffler. Which isn't a bad thing, I'm just saying... It's definitely a lot louder than stock. I love the way it sounds at part throttle and in city driving conditions and at WOT. But I have a serious problem with the way the thing drones at highway speeds. For me, 65-75 MPH covers 90% of my highway driving. There is some sort of odd resonance at the RPMs my truck cruises at at those speeds. It is the worst right at 70MPH and then almost completely goes away at 65 and 75. It is enough to give you a headache if you drive like that for 10 minutes straight or so. I'm not really sure what I am going to do about the drone/resonance issue at this point, but just wanted to put this review out there for others. Who else out there has this muffler on their truck? Anybody else have a nasty drone at 70MPH?

Hmmm... Well I stand very corrected. The inside of the fuel door of my SS does say "Premium Unleaded Fuel Only". I really didn't see that coming from GM on a truck like this. Well then maybe the tune is still stock on mine. I will still probably play with the tune some eventually...

Well pinging and how GM ECMs and PCMs deal with it are nothing new to me, so let me share a little of what I know on this... I have tuned my own LS1 Trans Am as well as my Wife's LS1 Trans AM and I cut my teeth on tuning the old 165 MAF and 730 Speed Density Tuned Port Injection systems in the late 80s/early 90s Camaros and Trans Ams (that required modifying the Memcal and soldering on a EEPROM and manually removing and installing the "chip" each time I changed the tune!!! How archaic!). Octane is a measure of a fuel's resistence to detonation. That is it. It means nothing about how good of mileage you will get or how much power you will make. The octane rating plus the appropriate tune for that octane level in a given engine is what decides how well the engine runs and how much power it makes. GM desires engines to run forever and not cost them anything for warranty costs first and foremost and to make adequate power and decent mileage second. This means low octane fuels with rich air fuel ratios and low overall timing advance are the way to go as it reduces stress on the engine. Reducing stress also means less power and mileage than you can get if you take the time to analyze and tune what your particular engine desires. This is why having a custom tune even on a stock vehicle can often yield impressive power and mileage gains - and is a MUST when you heavily modify the engine (ie. cam swap, forced induction, etc.). But it has to be done right or messing with the tune can/will damage the engine over the long run (or short run if you F it up badly enough). So anyways... Our trucks, like nearly all fuel injected vehicles, have a knock sensor. That sensor senses when "knock" (aka ping, detonation) occurs, which the PCM recieves and then, since retarding timing lowers the cylinder pressures and temperatures during combustion, adjusts the timing downward accordingly to attempt to avoid the knock situation. Knock is recorded in the PCM and visible via a scantool as Knock Counts. There are thresholds programmed into the calibration file loaded into the PCM for each vehicle and those calibrations will decide how much knock is allowed before it triggers a timing retard routine and some systems will up the fuel trim to try to richen the air fuel ratio as lean conditions can cause or aggravate knock conditions. So your mechanic is partially correct. The PCM attempts to remedy the situation, but it has its limits - and especially when somebody messes with the tune that doesn't know what they are doing or you get a POS off the shelf "tune". If there is a massively lean condition or far too much timing advance programmed into the calibration file loaded into the PCM, it will be unable to deal with the problem and audible ping occurs - this is most likely what my truck was doing and it is likely because somebody tuned it for higher octane fuel. The end solution is to get a look at the tune and compare air fuel tables and timing tables to a stock tune to see if it was messed with. The actual knock threshold parameters and knock retard value can also be manipulated in the tune so I will be looking at that as well. Knock often occurs without a driver even knowing it. While it can be fairly audible and obvious to a trained ear, sometimes it can be inaudible or missed, so the only way to know 100% that an engine is not pinging at all is to review the knock counts from the PCM (assuming the PCM and knock sensor system is fully functional of course). But my truck was very loud, and not just a little bit here and there. WOT above about 3k RPMs equaled lots of pinging. I do not believe the cap on mine says Premium Only, but I will double check in the morning. I really cannot see GM making Silverado SS owners run premium. They almost never design vehicles to run on 92+ octane (unlike lots of other makes). Thanks for all the welcomes!

Thanks! This site has really been helpful for me. Got the muffler situation all sorted out quickly and now I am getting a set of center cap stickers to cover up my corroded stock ones! On the octane topic - if it actually has problems with 87 octane, I would suspect it either has a problem of some sort or somebody messed with the tune. GM did not tune these trucks to require 92+ octane fuel at the factory.