Performance Chips for GMC

caberto wrote:
I have a Hypertech programmer on my Duramax; had it since almost new. I know it's not a gas engine, but just wanted to share my experience.

Warranty: I never needed warranty work, so this was not an issue for me. However, the programmer is just that, it reprograms your truck's main CPU. Before it reprograms anything, it downloads your complete OEM CPU settings to the programmer unit. After it saves your OEM settings, it then proceeds to upload the new changes you choose. I can make changes to the CPU with the programmer at any time, and I can put the truck back to its original OEM settings at any time.

Mileage: I saw a slight increase in mileage when tuned with the programmer.

I have not had any components fail after 130K miles.

Now, as far as power/torque increase, in a diesel engine, programmers can make a huge difference. Hypertech is not the most powerful programmer out there, but when used at stage 3, the programmer claims 87 HP gain, and 173 Ft-Lbs torque increase, and trust me, the difference at the pedal is obvious. I don't use stage 3 while towing, due to risk of putting too much stress on the Allison transmission, but do tow at stage 2 (increase of 52 HP/108 torque) all the time and haven't had any issues. From what I've seen, I would say a good portion of diesel truck owners have some type of programmer installed, even on brand new trucks; again, reprogramming the CPU to its original state probably helps with not voiding the warranty, since no hardware changes or parts are required to program your truck, but couldn't tell you for sure.

What's funny is the reason I wanted any type of programmer in the first place was to be able to change my tire size in the CPU so the speedo would be accurate. I then researched and learned that for about $100 more I can get the unit that will add power and torque, so I did that, and am very happy that I did. The Dmax already had enough power as stock, so this has all just been gravy, but I love it!

On the older dielels like yours (2005) you could reprogam back to stock and not leave any traces of it being previously programmed. Not the case with the newer trucks (both GM and Ford, not sure about Dodge) as they log any changes. Programming a newer truck will not void your bumper-to-bumper warranty but would likely result in a denial of claim for any major powertrain work that might be needed. On any major powertain warranty claims GM now requires an ECM snapshot from the dealer so they can tell if it was tuned. With that said there are a LOT of guys out there running tuned diesels with lots of miles on them and no problems. It is also worth noting that a lot of guys that are tuning newer diesels are doing so in order to delete the emissions components (DEF, DPF, etc) as they have proven to be very problematic with a lot of owners putting the trucks into limp mode.