Sc00by

I'm currently getting around 16-17mpg. I still have the DOD system up and running. Probably will until my warranty runs out at 60,000. It runs in and out of v4 mode only on flat roads when maintaining speed. If I baby it I can probably get 20mpg on these flat Florida roads. I do wish to have a slightly louder exhaust system.

Thanks man for the complement. When I first seen the combo online I knew that was the truck I wanted. I love it, just having some typical vibration issues at 75-80mph and it vibrates at idle which I think is because it idles too low (right at 500rpm). Plus im dealing a little with the torque converter issue that happens with the 8l90e.

JRoyPDX

I've been running mine pretty long without tune after the muffler and flapper delete. It doesn't like 87 octane as much anymore, but I always run 92.

So did you delete the resonator too? Hows the sound/volume?

00pooterSS

iTrader: (40)

I bet removing the flap won't hurt the warranty. I doubt they would even notice. But I understand worrying about losing warranty.

When I first got my truck it idled a bit rough, I did a top end cleaner on it and it got smoother. They do idle normally around 500, I think it's actually 550 so I don't think you have low idle, and if you did you should have a check engine light on for idle speed issues. Does your truck vibrate at light throttle at those speeds or under throttle? Mine vibrates from 50-60 but only under heavy throttle.

Interesting it doesn't like 87 anymore, the flapper stops up a lot of the pipe so IMO it's worth taking a look at the tune once removed.

I kept the resonator when I did the flap delete and magnaflow. It was perfect if you like it quiet. I could hear it fire up in the house and there was a very nice deep tone to it but in the truck you can only hear it at the lightest amounts of throttle, once you actually accelerate you don't hear it really. Not enough to even get close to having a drone situation at cruise. I loved it. If you want to see how loud it is with the resonator out and you have a muffler swap done, start it up before they weld the rear section of the pipe back on. I considered doing that but didn't.

00pooterSS

iTrader: (40)

I would recommend taking a look at the tune on these trucks with exhaust changes. I was really surprised in the difference before and after the tune when I did headers. My truck was already tuned and I slapped headers on it. At my test spot it did the same MPH untuned with headers as it did before the headers, and it feel kinda lazy too. After the tune was adjusted for the headers it picked up 3 MPH on average. I've hit that spot a few times. One day it was around 4 MPH higher another 2-3 so I'll call it 3. Surprisingly the tuner said it was a bit rich with the headers.. Not what I expected at all.

JRoyPDX

These trucks are pretty rich out of the box, I logged WOT air/fuel in the mid 10:1 range so no addition of exhaust or intake is really going to change that enough to be a danger. I did lean it out some with HP Tuners, nothing drastic. WOT fuel is now around 11.8-12:1. I never added timing or played with cam timing at all, those are still stock numbers.

I actually have no muffler at all. I have just the resonator and I often think I'd like it to be a little louder.

00pooterSS

iTrader: (40)

Not surprised. I fired mine up at the shop with the catback disconnected and just the stock manifolds and y pipe on it and it wasn't that loud at all. I wan't mine louder but I don't want it to drone on the highway or when pulling the boat. So I'm torn on what I want to do next. Right now I have stock 6.2 exhaust on it with the flap cut out and I can hear the exhaust going through the thin *** Y pipe/tiny amount of leaks I still have louder than the cat back. It's super annoying.

The 3 cats quieten down the exhaust a lot. I fired it up open headers and of course it's loud as hell. I figured the catback would be louder than it is since I now have long tubes and no cats, but still super quiet considering the setup.

JRoyPDX

I considered deleting the 3rd CA emissions cat.

I also have a set of Pacesetter long tube headers. I cleaned up the ports (horrible welding and construction at the flanges) and removed the collector flanges, then replaced them with marman flanges, now they're waiting to go to the ceramic coaters. Out of the box those things are kinda junk, but they should be pretty good with my added work to them. I got them dirt cheap with an off-road y-pipe (that looks like complete trash) as well. I'll likely have a new y-pipe custom made when I do the headers and exhaust someday.

arthursc2

iTrader: (5)

Sounds typical of pacesetter honestly

JRoyPDX

So I've heard... only reason I have them is because I got em for very little $

00pooterSS

iTrader: (40)

Speaking of welds etc. The speed engineering headers were far beyond expected. All the welds etc were flawless.

I hear ya on the Y pipe and cutting out the cat. But hell if you're just gonna replace it might as well leave it. I have to come up with something for flanges, I haven't looked into them enough yet. I have eliminated 99% of my leaks but I don't think there's a way to have a 100% leak free slip fit.