Muffler delete

[HopnDude]

Since I did the muffler delete, I can definitely tell the difference between L9 and Drive. L9 all the gears go up and down as they should. Drive u can hear when cylinders shut down and when they kick in. L9 is all I do now

Just get a AFM disabler.

 

[Blueicebob]

I’ll save the $500 and the headache of problems they have with it

 

[DylanVK]

Noticed a significant drop in MPG once I cut the muffler off of my 6.2... but probably almost exclusively due to the fact I can't keep my foot out of it b/c it sounds so good LOL!

 

[Blueicebob]

When cruising 60ish and let the truck coast, it goes much farther with the muffler gone

 

[Zl127]

Does any company make a muffler delete that includes removing the flapper valve? Magnaflows design is something I'm looking for.

 

[HopnDude]

Does any company make a muffler delete that includes removing the flapper valve? Magnaflows design is something I'm looking for.

They should have two options. There's two different part numbers.

 

[Zl127]

In the pictures of the install it shows pipe being cut identically. Before the valve.

 

[GETGONE]

I cut mine as close to the front of the muffler as I could. I cut the flapper out of the pipe. I cut the ends off and pulled it out so there was enough pipe to make it work. There is some play in the rear of the exhaust to pull forward and make it fit.

I should note this is on a 6.2L which only has one flapper after the muffler. 5.3's have 2 for some reason. One in front and one after the muffler.

 

[Zl127]

I cut mine as close to the front of the muffler as I could. I cut the flapper out of the pipe. I cut the ends off and pulled it out so there was enough pipe to make it work. There is some play in the rear of the exhaust to pull forward and make it fit.

I should note this is on a 6.2L which only has one flapper after the muffler. 5.3's have 2 for some reason. One in front and one after the muffler.

Mind taking some pics?

 

[Zl127]

I cut mine as close to the front of the muffler as I could. I cut the flapper out of the pipe. I cut the ends off and pulled it out so there was enough pipe to make it work. There is some play in the rear of the exhaust to pull forward and make it fit.

I should note this is on a 6.2L which only has one flapper after the muffler. 5.3's have 2 for some reason. One in front and one after the muffler.

And what exhaust did you end up going with?

 

[GETGONE]

Magnaflow 19491 Sound video on the Dyno LINK

 

[bsjeep99]

So, I want to do the muffler/flap valve delete to a Vibrant 3" in/out muffler, but here's the issue that's holding me back;

Ever since I got into cars, I first started learning how people from my dads' car group would modify Chevy 350's. From stock block with decked heads to raise compression, to higher compression pistons, to head pocket porting jobs, and how to clearance a block for a larger stroke crank, etc. Depending on the desired outcome, they'd take a certain path on the build.

This get's me to the exhaust backpressure. The flapper valve is in part to restrict sound and exhaust from escaping. At the same time it creates more back pressure in the exhaust. So if you ask anyone who builds engines professionally that knows HOW they work, they'll tell you, the second you open the exhaust valve, you're letting precious torque out the window.

That being said, for better MPG at low RPM in a high gear, you want torque more than horsepower. This way the engine wont buck under light load or need to downshift. So, if I open up the exhaust, I may notice more downshifts to comp for the loss of exhaust backpressure, resulting in decreased fuel economy on long road trips.

If anyone has already went straight pipe or muffler system minus the flapper valve, please let me know if you're fuel economy stayed the same.

I was getting 19-20 around town stock I added a cat- back MBRP exhaust now I'm at the best 17 highway.

 

[HopnDude]

I was getting 19-20 around town stock I added a cat- back MBRP exhaust now I'm at the best 17 highway.

Sadly, mine didn't stay stock for long. I did my intake, OCC and cat-back exhaust about the same time. I went from 50 mile best of 24 mpg to 26.3 mpg during a road trip that ranged 55-65 mph for long stents.

There was only 1 flapper on my stock exhaust, so not as bad on the back pressure. I haven't towed anything either so unsure if I lost much low end torque, but mid throttle it starts to scoot.

 

[Zl127]

Magnaflow 19491 Sound video on the Dyno LINK

View attachment 4219View attachment 4220

That rear clamp looks a little ehhh. No leaks? Is it a real stretch deleting the front flapper too or?

 

[GETGONE]

The rear clamp is a lap joint one I had laying around that I had tried to use elsewhere before. The Magnaflow clamp it came with wouldn't tighten down enough. The 6.2's only have the rear flapper.