Tuner for 6.2L 8 speed 2015 GMC Sierra Denali

midwestdave33 · December 8, 2015

You will wish you didn't do that when the driveshaft exits the truck. I am all for going fast but the driveshafts in these trucks are known for flying out, good way to get killed. YouTube is your friend if you don't believe me. Not busting your balls for speeding at all, I love to rip, I just know the limits of the driveshaft on these trucks and you don't want to have the rear end of the truck catapult 6ft in the air when doing 120mph, it will kill you

AGREED! so who makes aftermarket driveshafts for us to solve this problem??

crushNchowda · December 8, 2015

Youtube is your friend...i have seen videos of many many gm trucks doing well over 130+ for extended periods of time. I have been over my 98 speed limiter twice, ever. Once to make sure it was turned off, hit 104 and then last weekend. The new 6.2 is so fast it hits these speeds far quicker then you would think. I hit that passing 2 spaced out cars downhill. There isn't a doubt in my mind the 8 speed 6.2 can do 140+ but I wont do those speeds that long.

While these trucks are plenty powerful enough to hit the speeds you mention, they for sure aren't designed for it. I never understood the need to make a truck super fast, sure it can be done, sure I guess its cool if you wanna rip 4wd 1/4 miles and destroy your truck over time in the process - but unless you want to REALLY set the thing up to do those speeds "safely" on the street - and that would entail more downforce/spoiler, dropping it, big brake kit (like new pistons, cylinder, lines, pads, rotors THE WORKS) sticky Z rated tires, suspension overhaul including new coil over shocks, sway bars, etc. - then it is just pure lunacy taking a 1/2 ton truck past 95mph for any extended period of time.

Good luck swerving even @ 80-85mph to try and avoid something in a panic situation.

I think alot of guys have always been truck buyers and just get amped up at the power/tq these things produce and want to explot it, but I believe the majority probably have minimal experience w/ ACTUAL high performance vehicles that are MEANT to go fast like that and don't realize what it takes to do so in a controlled/"safe" (again quotations on safe - its all relative) manner.

I'm sure my truck would have no issue hauling down the freeway @ 120+ mph just like my Z06, problem occurs when you have to make a manuever or come to a complete stop - essentially you will not stop in any reasonable distance in these trucks from those speeds (if you stop at all more than likely the pads will cook and you'll rear end someone or worse) let alone swerve evasively.