Holy smash stock exhaust Batman!

[Driver72]

So decided to look under my new 2017 Sierra with the 6.2 V8 and WTF!!!

 

Clearly I knew that this exhaust was a two into one exhaust, which is unfortunate (why not a true dual all the way?) but when I was looking at the cross over from the driver side cylinder bank exhaust to the passenger side single, they smash the 3" round exhaust down like a pancake.

 

Clearly I also know most all of you know this already, but why would they do that?

My only seemingly weak explanation for them would be for ground clearance, but it looks to me like they could of easily of ran it up higher overall in that area and NOT smashed the exhaust down.

 

With a big V8 like the 6.2, I can only imagine the power loss due to a two into one exhaust already, but smashing down the exhaust pipe on the driver's side 4 cylinders, must cut it down even more.

 

Has anybody cut this smashed section out and installed a full none smashed piece of exhaust there?

And if so, did you do dyno before and after? Results?

 

On this same note, anybody do just a catback that goes from the two into one back into two exhaust?

If so, dyno too? And results?

 

Just a guess here but I'd have to imagine you could gain 5-8 hp just by removing that smashed piece of pipe and putting in a non restricted full piece.

 

Those with experience doing this, chime in please. Thanks

[SouthernSilveradoGuy85]

Well I'm not sure if I believe in the whole back pressure thing with exhaust. But, I'm sure it plays a role since you can have too much exhaust for an engine. Think about it, would you put true dual exhaust with 4" pipe on a 4 banger (a Y pipe from 1 into 2 obviously)? A ricer might, but it would hurt performance, let alone sound like sh*t. The 6.2 may seem big, but it's still a small block so it doesn't need true duals. My '98 had true duals from the factory behind the 5.7, but the pipes were only 2", if that. Before I learned what I learned about exhaust I always thought true duals were better for performance and sound, but that's not the case with everything. I don't mind that I have a single in/dual out on my '14. It's actually louder than when I had true dual Flowmaster Super 40s on my '98. Each side had their own cat and muffler and I had an X pipe. I have a Super 44 which from what I've read is the same volume as the Super 40, it's just a different sound.

 

A smashed down pipe might not look good (shouldn't matter on a truck unless it's a show truck), but it's a reason they did it from the factory. It's most likely for clearance. I highly doubt that part being smashed in one spot does anything to the performance. I mean it's not exactly a high performance car where you try to squeeze every little bit of power out.

[kstruckcountry]

 

[MikeNH]

The overall diameter of the pipe probably doesn't change much, if at all. GM has had areas where they used oval-shaped pipes to get around obstacles for ages. You're not losing a meaningful amount of power and even gaining 5-8 HP (which you absolutely would not) wouldn't even be noticeable.

[Driver72]

Wow KStruck, that was impressive video.

Learn something new everyday. Cheers.

[powerhaulic]

Agreed

 

Thats why I did my exhaust today

 

Been looking under there for two weeks, crushed L side cross over, crushed under trans crossmember, but nice diameter to start with.......yup I'm going to reuse the cat back from the '11 yukon.

 

Muffler forward is good, so cut just forward of stock muff, check

 

pipe before muffler 3.5", inside muff.....3.0, coming out 3.0", butterfly valve 3", steps back up to 3.5", resonator 3.5, res out 3.0"

 

Installed 22" Magnaflow 3.5 in n out, 3.5 over axle, 3.5 resonator, 3.5" tail. Bit of cutting and welding, poof 3.5 catback out of spare parts.

 

not too loud, not too quiet, flows like crazy, all is well

[kstruckcountry]

I don't really like how vulnerable the crossover pipe is, it wouldn't be too hard to smash it. The stock GM exhausts do flow pretty well though. I just like a little more sound, I think many people do.

[Driver72]

I don't really like how vulnerable the crossover pipe is, it wouldn't be too hard to smash it. The stock GM exhausts do flow pretty well though. I just like a little more sound, I think many people do.

 

 

Yup this is my issue.

My Ram with the Hemi sounded darn near perfect, low growl from engine and exhaust, but quiet when cruising.

The 6.2 is near silent all the time. I don't know if I need to just change out the muffler, but I'd like a bit of growl, not annoying loud with drone, but just a bit of growl, even when idling.

Also wish GM would of put a proper dual exhaust on. Always just looks unbalanced to me to have just one exhaust pipe coming from the rear of the truck (or even most cars too).. I can live with it as it is, not a huge deal, but would be nice to have a bit of sound and balance from the exhaust.

GM could make it an option in the future, call it "performance" exhaust. Bit of growl, duals all the way, 5-10 hp increase in power or something (the 2.4 liter Honda Accord gets 4 hp increase from a sport exhaust which is meaningless since it weighs a bit more too), $695 price. Bet they'd get at least 50% take rate on that almost purely because of the sound and the looks.

[1300c]

 

 

Yup this is my issue.

My Ram with the Hemi sounded darn near perfect, low growl from engine and exhaust, but quiet when cruising.

The 6.2 is near silent all the time. I don't know if I need to just change out the muffler, but I'd like a bit of growl, not annoying loud with drone, but just a bit of growl, even when idling.

Also wish GM would of put a proper dual exhaust on. Always just looks unbalanced to me to have just one exhaust pipe coming from the rear of the truck (or even most cars too).. I can live with it as it is, not a huge deal, but would be nice to have a bit of sound and balance from the exhaust.

GM could make it an option in the future, call it "performance" exhaust. Bit of growl, duals all the way, 5-10 hp increase in power or something (the 2.4 liter Honda Accord gets 4 hp increase from a sport exhaust which is meaningless since it weighs a bit more too), $695 price. Bet they'd get at least 50% take rate on that almost purely because of the sound and the looks.

I miss how the previous generation 6.2l in the 07-13 trucks/suvs sounded. That being said I was shocked how much the airaid mit tube woke up the engine note. Much improved growl under acceleration.

[powerhaulic]

I miss how the previous generation 6.2l in the 07-13 trucks/suvs sounded. That being said I was shocked how much the airaid mit tube woke up the engine note. Much improved growl under acceleration.

Yup, wait till you do exhaust the combined tone is really nice

[1300c]

Yup, wait till you do exhaust the combined tone is really nice

I'm putting the GM borla exhaust on in the spring, and I can't wait.

[powerhaulic]

Personally like Magnaflow better, and no flapper there

[NemesisC5]

I purchased the GM Performance exhaust made by TMG aka Corsa. It is 3.5" all the way to end, sounds better than stock but could be a little louder. GM rates it +10hp on 5.3 and +6hp on 6.2. I saw the terrible pancake pipe that is barely 1" tall as it crosses under tranny pan...looks to be restrictive and the Y merge is almost a 90*, not near as smooth as my 2011 w/6.2.

 

 

[HondaHawkGT]

I don't really like how vulnerable the crossover pipe is, it wouldn't be too hard to smash it. The stock GM exhausts do flow pretty well though. I just like a little more sound, I think many people do.

Want to see vulnerable? Check out how Toyota routes their 2016+ Tacoma's exhaust. It hangs WAY below the frame. The ovaled section has enough cross-sectional area for a stock engine. The 3rd cat is probably a bigger restriction lol.