Just installed 70 series Flowmaster on 5.3

[CAtaylor]

Beautiful truck and very nice sound. I have always loved the sound of a flowmaster. I have had them on every gas burner i have owned except for the Mazda B-2500 and even that was tempting just to see how it would sound.

[Mike1220]

 

Pretty strong wheel spin from a dig with those 3:08 gears. The shifting is definitely better. My question is how did you log a best MPG of 35? Were you going downhill in neutral for a mile? My best on a normal highway here was a best of 24 mpg.

 

 

 

That was logged during my trip to NC from here in OK. I wasn't doing anything out of the ordinary as far as driving but 40 hwy does hit a few small mountains along the way. My 50 mile is 27 and my 400 mile is 22 or 23 and some change.

 

As far as wheel spin, it has tamed down a lot since I swapped my 18" wheels yesterday for 22's with 305-40's

 

 

Do you think that the high MOG rating is purely from the exhaust being so unrestrictive? Or did u tune it to be more efficient for the ride?

 

 

Sent from my iPhone using Tapatalk

[iCryWheniGoPoop]

Do you think that the high MOG rating is purely from the exhaust being so unrestrictive? Or did u tune it to be more efficient for the ride? Sent from my iPhone using Tapatalk

I just tuned the truck and installed the exhaust this week and haven't gotten a good estimate of MPG. All those MPG readings were in purely stock form, stock tune, tires and with stock exhaust. When I finalize my tune (working on the E85 side of it now) I will start reporting any gains in mileage that I see.

[cmpcpro]

I just tuned the truck and installed the exhaust this week and haven't gotten a good estimate of MPG. All those MPG readings were in purely stock form, stock tune, tires and with stock exhaust. When I finalize my tune (working on the E85 side of it now) I will start reporting any gains in mileage that I see.

I know you talked about not wanting to void your warranty by tuning.. Have you discovered that tuning won't void it or you just decided to give up the engine/trans part of warranty? Just curious, thanks.

[iCryWheniGoPoop]

I know you talked about not wanting to void your warranty by tuning.. Have you discovered that tuning won't void it or you just decided to give up the engine/trans part of warranty? Just curious, thanks.

 

You are correct, I was on the fence, mostly because it is a first year production with a new engine design. If I would have bought a 2013, I would have been plugging my laptop in while they were getting the paperwork ready for me to sign at the dealership.

Warranty issues? Well, if GM engineering requests that the dealership check the CVN Log then yes, My drivetrain warranty will be void but... I plan on some sort of a wicked build this fall and do not expect GM to eat an engine/tranny because my truck put out 200hp more than it was designed. On another note if I tapped into the ECU just to recalibrate my speedo and had my warranty voided for that, I may get a little upset.

 

I get tired of saying it and I'm sure most people are tired of hearing it, You have to pay to play and even more so now that GM is onto us. Good luck with your decision, if you have any other questions that you don't want to hear the answer to, don't hesitate to ask. LOL

 

Steve

[cmpcpro]

I see, so basically this is the first year GM can tell if it's been tuned and reset? Also curious/excited to hear your plans for this fall.

[iCryWheniGoPoop]

I see, so basically this is the first year GM can tell if it's been tuned and reset? Also curious/excited to hear your plans for this fall.

In the half tons.. Yes this is the first year but they have been busting Duramax truck tuners since 2008 and Camaros/Vettes since 2010. It was only a matter of time.

 

Build... Well... I actually have a couple 67mm .87 A/R split housing t3's sitting in my garage. They were specked for my ls6 in the cts-v but I went single on it instead. My original plan was to go NA but shit, these are some expensive ceramic ball bearing dust collectors sitting here in my garage, so I'm leaning towards that right now.

[mzodarg]

ICRY,

You ever get a pic of the third cat removal?

 

Mike

[Mike1220]

Dang it. I was considering getting mine tuned until I read through some of the new posts on this thread :-( just got the truck, don't really want to void the warranty just yet.

 

 

Sent from my iPhone using Tapatalk

[iCryWheniGoPoop]

Dang it. I was considering getting mine tuned until I read through some of the new posts on this thread :-( just got the truck, don't really want to void the warranty just yet. Sent from my iPhone using Tapatalk

 

I don't blame you a bit. The peace of mind for just having the warranty is worth quite a bit. It bothered me almost every day though, knowing that I had the means to turn this 5500 lb. slush box into something fun to drive.

[iCryWheniGoPoop]

ICRY,

You ever get a pic of the third cat removal?

 

Mike

Sorry, I did not. I was going to do it this weekend when I painted my calipers but it snowed all day Sunday where I was at in SW Missouri and the truck is covered in dirt/mud. If I can get off work before dark tonight, I will crawl my fat ass under there and snap a couple pics.

[Mike1220]

What I find odd is that they catch on to our tuning but don't catch on to the poor projectors that they are putting in these new trucks. Or at least they should catch on that most people now a days prefer HIDs over Halogens, especially for the Sierra. I mean they put a yellow light in the middle of two white LED strips. Way to go GM

[iCryWheniGoPoop]

ICRY,

You ever get a pic of the third cat removal?

 

Mike

Ok... Here it is. He cut a pipe to fit the factory connecting flange pipe and stepped it up to the big ass factory pipe at the Y-Pipe.

[mzodarg]

Sorry, I did not. I was going to do it this weekend when I painted my calipers but it snowed all day Sunday where I was at in SW Missouri and the truck is covered in dirt/mud. If I can get off work before dark tonight, I will crawl my fat ass under there and snap a couple pics.

LoL no worries...when you get a chance.

 

Mike

[mzodarg]

Oops, just aw the pic of the 3rd cat removal, I'm gonna take mine by this week sometime and get it cut out!