6.2L (L9H) Owners - Get all your questions answered here

[Jsdirt]

Usually when it fails, it'll stay disengaged when you turn the key .. but anything's possible. When that happens the starter won't spin or click at all - sometimes clicking the ignition key to start a bunch of times will get it to engage ... but at that stage, it's not long before your stuck at the last place you stop.

Edited December 28, 2015 by Jsdirt

[Brendan Cosworth]

Usually when it fails, it'll stay disengaged when you turn the key .. but anything's possible. When that happens the starter won't spin or click at all - sometimes clicking the ignition key to start a bunch of times will get it to engage ... but at that stage, it's not long before your stuck at the last place you stop.

 

Fair enough, it is an assumption on an assumption as well so not the end of the world. Thanks for the info. I'll have to figure out a way to test it.

[CarbonDenali]

Anyone know what a stock 6.2 ( truck) is doing the quarter in?..I'm hearing 14.9 to 15.9. Thought the hemis were running high 15's already..before they bumped the horsepower up in the ram.

[CarbonDenali]

I've got a 2013 Sierra Denali, pretty much all stock, muffler delete, and a CAI but no tune yet... I'll have to post the pic later when I get back to the shop, but I ran a 15.5 at Tulsa Raceway Park. I'm hoping with a tune I'll drop into the high 14's but we'll see. Does anybody on here have a preference on a tuner? I'm leaning more towards a custom tune from XP Racing in OKC, but they don't have an AWD Dyno...

[CarbonDenali]

Hey,

 

Any resources on this website for exhaust systems or muffler swaps for the the 6.2L? I have an '13 CC with the 6.2L and want to make it a little louder then stock. Looking for ideas.

 

I was thinking of just doing a swap for a straight through muffler and keeping the rear resonator or thinking of deleting the muffler altogether and keeping the stock resonator but that may be too loud for me.

 

Seems cheaper then a full system to basically achieve the same thing... Magnaflow has a straight through 3.5'' in/out muffler for about $100 that seems would work well.

[CarbonDenali]

I wanted the same thing, the truck sounds great stock but my imagination ran wild with how awesome it would sound if it were uncorked a little. I just deleted the muffler (which was the size of a small bath tub) left the resonator after the axle and I'm pretty happy with it. I could probably go back and re-weld the pipe that the muffler shop put in to seal up any small leaks that may be present. But over all I can set off near by car alarms with cold starts in the morning haha

[NemesisC5]

The resonator is basically straight through and will not restrict flow at all, it does its job to help control drone without hurting performance at all. The huge muffler is not a problem in my opinion, it sits under the truck and I never see it. Flo-Pro makes a muffler that is made for the 6.2 trucks with correct offsets and 3.5" single in/out that flows a little better than factory and slightly louder than factory. They make another that is 3 chamber design with 4" in/out that flows even better (and louder) than their 3.5". If the muffler was going into a much lighter vehicle the size and weight would influence me to look for something else but then I would be more concerned about the power lost by my GM 22's compared to factory 20's. Reciprocating mass will slow down your rate of acceleration because of extra weight but more so because the extra weight is farther from the center line of your axle.

 

To keep it smog legal I'm planning to install C6 ZO6 or ZR! 3" cats on a Kooks y-pipe and eliminate my 3rd cat. Downstream I may install a Flo-Pro muffler if the cats and y don't give me enough exhaust note.

[NemesisC5]

So had a chance to start it this morning. Luckily it doesnt sound like a metallic noise like I thought, it more sounds like a snuff noise. Almost like a valve cover breather. Kind of strange. Thoughts?

 

 

 

Mine was making a slight ticking noise so I brought it into dealer to check under 100k powertrain warranty. They found a broken motor mount and a cracked exhaust manifold. Replaced them both free of charge and sent me on my way with a smile of relief.

[Phillip123]

When did this happen and how come I never got a call?

[RyanbabZ71]

This topic is for 2009-2013 L9H trucks not 2014

 

 

Ryan

Edited January 6, 2016 by RyanbabZ71

[sledog]

So I guess its time to add to the group. I have a GMC reg cab SWB 4X4 that is now sporting the guts and drivetrain from a 2013 Silverado L9H, NHT truck. This is the truck that GM should have built. Its been a bit of a project and not quite done as I'm having a few CEL/Airbag lights but I have good friends with the right equipment to address those issues. Just waiting for the weather to get better. Was able to utilize all of the factory exhaust from the L9H minus the muffler, was a bit too long so I had a local shop put in a Dynomax bullet. Sounds pretty good and not too much louder than stock.

Edited January 27, 2016 by sledog

[Daryl Z71]

So I guess its time to add to the group. I have a GMC reg cab SWB 4X4 that is now sporting the guts and drivetrain from a 2013 Silverado L9H, NHT truck. This is the truck that GM should have built. Its been a bit of a project and not quite done as I'm having a few CEL/Airbag lights but I have good friends with the right equipment to address those issues. Just waiting for the weather to get better. Was able to utilize all of the factory exhaust from the L9H minus the muffler, was a bit too long so I had a local shop put in a Dynomax bullet. Sounds pretty good and not too much louder than stock.

 

 

 

Definitely badass! Where'd you find the donor truck at?

[sledog]

Salvage yard. The frame had damage at the rear so I was able to use the front clip and cab for another project.

[Zebrafive]

So I guess its time to add to the group. I have a GMC reg cab SWB 4X4 that is now sporting the guts and drivetrain from a 2013 Silverado L9H, NHT truck. This is the truck that GM should have built. Its been a bit of a project and not quite done as I'm having a few CEL/Airbag lights but I have good friends with the right equipment to address those issues. Just waiting for the weather to get better. Was able to utilize all of the factory exhaust from the L9H minus the muffler, was a bit too long so I had a local shop put in a Dynomax bullet. Sounds pretty good and not too much louder than stock.

Yes, GM should have built this! I see you have the high end interior too. I like it!

[sledog]

The only thing that will not look correct is the drivers door switches as they never made the switch panel for only 2 windows. It will be nice to have the cooled seats for the summer.