David Lampkins

What is going to end up happening is the gas truck market will hold its value after you cannot buy them anymore.

Pretty soon these gas engines will be a thing of the past. 14-16 weeks to get a whipple supercharger directly from them. $7,200 plus Install and supporting accessories… roughly $10k. If the performance is what you say it is it is worth it!

What kind of MPG are you averaging after the S/C?

I did notice Whipple has an option to purchase a three-year 36,000 mile warranty for $650. It looks like it keeps the original three-year 36,000 mile warranty intact for the drivetrain. But in doing these mods I know the risk that I’m taking in voiding warranty past that. Still curious what some real world performance numbers are.

When I did the TRD S/C on my Tundra it was installed by the dealership and the only supporting mods were intake and exhaust and tune. I’m assuming it’s the same with the Sierra… However, I would love to do some internals but it might require transmission upgrades. If it is 650 ish at the crank that is respectable. I saw that Hennessey has a Goliath 700 and 800 kit but I don’t want to drop $30k into that.

That’s good to hear! Did you have them install it and what supporting mods did you do? I know tune is a must and intake and exhaust but anything else? What were you final dyno numbers and 0-60/ quarter mile times if you did it. I am about an hour and 20 minutes north of Fresno so I might be taking a trip down there tomorrow

I have a 2021 6.2 Denali and am seriously interested in boosting it. I live in Northern California and want to know some relatively close and very reputable shops to get this done. I’m willing to travel out of state too but don’t want to drive 3 days to get there… any recommendations and if possible some feedback from someone who has done the S/C mod? I did a TRD S/C on my 2014 tundra back in the day and that was the best bang for the buck hands down. Hoping the same for this truck…

I have found out why it does it. It has to do with OUTSIDE electrical interference. I can pass by the same area and know when Apple CarPlay will cut out. This tends to happen when driving next to a lot of electricity pole lines and areas where there might be lots of electrical interference (transformers, etc.). No matter what app I have up or if I’m using my phone or not it will disconnect and reconnect after I am out of that area. I drive by the same power poles 5 days a week and it does it predictably at certain spots. This gets particularly annoying when I am on a phone call. I have learned to put the phone in my hand and turn the speaker on because I know it will disconnect.

I am not trying to pry on how much this setup cost just for the heck of it but I am seriously considering a supercharger and supporting mods for my 2021 Denali. Did you only do the supercharger and tune or did you also install a CAI, exhaust, and change the headers? Also, you don’t have to give an exact cost but about how much out the door is it to achieve what you achieved on your truck? Thanks.

Thanks I will check it out. I did the rear two resonator deletes and a Rotofab CAI. Not sure if I really noticed a difference since I installed it within the first 500 miles of the truck being new. Truck has about 8k miles on it now and more than anything it feels to have woken up a little after the first oil change… I was thinking of going with a true exhaust system to get rid of the drone I have now. It’s not terrible but definitely not quiet like stock. I’m a guy that wants better sound, as much performance as possible, and little to no drone. By the way it is a 2021 6.2 Denali.

What are the dyno numbers for a fairly stock 6.2 with just intake and exhaust? What is drivability like and if anyone has them what are before and after 0-60 and 1/4 mile times?

My 2021 Denali starts to blow warm air after about 5-10 minutes of driving it then goes back to cold air. This normally happy on 90+ degree days. I have an appointment next Friday on this. The weather is starting to get cooler which probably means it’s hard to reproduce… it is noticeable for at least a few minutes. I had a 2020 SLT 5.3 and never had this issue. I don’t want this turning into a bigger problem later as I have seen the entire inside ripped apart on other posts to fix this problem. Anyone else having the inconsistent A/C issue?

That is my exact experience as well. Sounds like a loose spare tire. Not a metal clunk but almost like a tire hitting the chassis. Please let me know what you find.

I am having the same issues. I brought it in the dealership and they tightened bolts, however it was to no real avail. Let's get more people to chime in and maybe GMC will actually do something about this in a TSB...