World's first 2014 Sierra Denali w/ ARHeaders
Jun 12, 2014 | 08:34 AM
#22
On The Tree
Joined: Feb 2003
Posts: 101
Likes: 0
From: SC
Got mine installed: Not as easy of an installation as I was told it would be. I started at 8:30 a.m. on a Saturday morning. I have a lift and power tools. Muffler shop completed the job at 3:00 p.m. that day
But they are nice.
factoryi:
American Racing Headers:
PML deep trans pan installed at the same time:
3.5" Magnaflow resonator and 3.5" tail pipe installed at the same time:
Now everything is a full 3.5" straight thru design with no restrictive baffles or flapper valves.
But they are nice.
factoryi:
American Racing Headers:
PML deep trans pan installed at the same time:
3.5" Magnaflow resonator and 3.5" tail pipe installed at the same time:
Now everything is a full 3.5" straight thru design with no restrictive baffles or flapper valves.
Jun 12, 2014 | 08:38 AM
#23
On The Tree
Joined: Feb 2003
Posts: 101
Likes: 0
From: SC
results after headers, full 3.5" exhaust, modified stock air intake, and Diablosport In-Tune custom tune:
Here's a summary of performance changes from the original stock baseline to current set up:
0-60 mph was 6.06 sec now 5.86 sec. = 0.2 sec improvement
60 ft. time was 2.7 sec. now 2.57 sec. = 0.13 sec improvement
1/8 mile was 10.02 sec. now 9.52 = 0.5 sec improvement * I failed to record 1/8 the last time out so it may be slightly better.
1/4 mile g-tac was 14.76 sec. now !4.25 sec. = 0.51 second improvement. *old rule of thumb every 10 hp = -0.10 sec in the 1/4 would equate to approx. a 50 hp improvement. Sounds legitimate.
1/4 mile G-Tech accel. was 14.92 now 14.60 = 0.32 *I did not record G-tech on my last run so I expect it was better than this one listed. will get more later.
1/4 mile trap speed best was 100 mph, now 107 mph. * definite indicator of increased hp.
mpg was 22 average, now 23.1 at 60 mph cruise
sound level was 57 dB avg, 62 dB max, now 58 avg and 64 max with much nicer and deeper sound without being loud.
Here's a summary of performance changes from the original stock baseline to current set up:
0-60 mph was 6.06 sec now 5.86 sec. = 0.2 sec improvement
60 ft. time was 2.7 sec. now 2.57 sec. = 0.13 sec improvement
1/8 mile was 10.02 sec. now 9.52 = 0.5 sec improvement * I failed to record 1/8 the last time out so it may be slightly better.
1/4 mile g-tac was 14.76 sec. now !4.25 sec. = 0.51 second improvement. *old rule of thumb every 10 hp = -0.10 sec in the 1/4 would equate to approx. a 50 hp improvement. Sounds legitimate.
1/4 mile G-Tech accel. was 14.92 now 14.60 = 0.32 *I did not record G-tech on my last run so I expect it was better than this one listed. will get more later.
1/4 mile trap speed best was 100 mph, now 107 mph. * definite indicator of increased hp.
mpg was 22 average, now 23.1 at 60 mph cruise
sound level was 57 dB avg, 62 dB max, now 58 avg and 64 max with much nicer and deeper sound without being loud.
Jun 28, 2014 | 08:03 PM
#27
On The Tree
Joined: Feb 2003
Posts: 101
Likes: 0
From: SC
from the headers back, everything was a custom combination of parts. Two 3.5" mufflers in-line from Maganflow and the new resonator is a 3.5" Manaflow muffler also. I'll look up the part numbers. Then a 3.5" 45 degree stainless elbow and the 3.5" to 4" tail pipe.
My goals was a free flowing full system but retain the quietness. It was a success.
full description at
performance data logging : EcoTec3 6.2L V8
Super Jim's exhaust modification:
The next modification is the exhaust. I want retain the quiet ride of the 2014 Sierra but get better flow, performance and fuel economy. The factory exhaust pipe on the 2014 6.2 EcoTec is a nice 3.5" stainless pipe. It was nice bends and nice welds. That's where the good stops. The muffler must be from something else that was already in stock. It is only 3" intake and outlet. Why neck down to a 3" muffler? Of course it's the old standard reverse flow/baffle design so it's not the best flowing. Then it has this restrictive 3" flapper valve on the outlet. When I first read about the internal valve, I was visualizing a high tech electronic solenoid motor controlled valve that the ECM would open when extra flow was needed. NOT! Or maybe a vacuum controlled valve that opens up a more straight through flow like the Vette. NOT! This is the most Mickey Mouse piece of crap I have ever seen from a major auto manufacture. It is spring loaded with a huge weight on the bottom of the gate to help keep it closed. And it takes a lot of pressure to open it. Even if it were 100% open, which it will never be, it is greatly reducing the flow and causing turbulence. That's the last thing you want in an exhaust system. And I wonder in that environment, how long it will function before getting stuck in one position. I removed the factory muffler and installed Two (2) Mangaflow mufflers in series. They are both 3.5" inlet and outlet with straight through design.
I used Magnaflow part # 14909 which is 0ffset/Center inlet/outlet like the original
Inlet/Outlet Size: 3.5in./3.5in.
Body Shape: 5in.x11in. Oval
Core Size: 3.5in.
Body Length: 22in.
Then connected a Magnaflow part # 14151 which is center/center inlet/out but smaller.
The 14909 is almost a direct replacement for the stock muffler. If you just replaced the stock unit with this one, you would need a short section of 3.5" pipe to complete the connections. Most muffler shops don't stock 3.5" stainless pipe. Adding the 14151 makes a perfect fit.
3.5" resonator was installed later.
My goals was a free flowing full system but retain the quietness. It was a success.
full description at
performance data logging : EcoTec3 6.2L V8
Super Jim's exhaust modification:
The next modification is the exhaust. I want retain the quiet ride of the 2014 Sierra but get better flow, performance and fuel economy. The factory exhaust pipe on the 2014 6.2 EcoTec is a nice 3.5" stainless pipe. It was nice bends and nice welds. That's where the good stops. The muffler must be from something else that was already in stock. It is only 3" intake and outlet. Why neck down to a 3" muffler? Of course it's the old standard reverse flow/baffle design so it's not the best flowing. Then it has this restrictive 3" flapper valve on the outlet. When I first read about the internal valve, I was visualizing a high tech electronic solenoid motor controlled valve that the ECM would open when extra flow was needed. NOT! Or maybe a vacuum controlled valve that opens up a more straight through flow like the Vette. NOT! This is the most Mickey Mouse piece of crap I have ever seen from a major auto manufacture. It is spring loaded with a huge weight on the bottom of the gate to help keep it closed. And it takes a lot of pressure to open it. Even if it were 100% open, which it will never be, it is greatly reducing the flow and causing turbulence. That's the last thing you want in an exhaust system. And I wonder in that environment, how long it will function before getting stuck in one position. I removed the factory muffler and installed Two (2) Mangaflow mufflers in series. They are both 3.5" inlet and outlet with straight through design.
I used Magnaflow part # 14909 which is 0ffset/Center inlet/outlet like the original
Inlet/Outlet Size: 3.5in./3.5in.
Body Shape: 5in.x11in. Oval
Core Size: 3.5in.
Body Length: 22in.
Then connected a Magnaflow part # 14151 which is center/center inlet/out but smaller.
The 14909 is almost a direct replacement for the stock muffler. If you just replaced the stock unit with this one, you would need a short section of 3.5" pipe to complete the connections. Most muffler shops don't stock 3.5" stainless pipe. Adding the 14151 makes a perfect fit.
3.5" resonator was installed later.
Jul 1, 2014 | 06:28 AM
#30
On The Tree
Joined: Feb 2003
Posts: 101
Likes: 0
From: SC
my gear is 3.42. note my times are not official drag strip times but times taken from a G-tech accelerometer and a phone app so the accuracy is questionable. Mainly I am tracking the changes (improvement) in times.