Hello everyone, I just purchased my first first diesel a few days ago, its a 05 GMC 2500HD crew cab and so far I am loving it, but for the last 4 years I have been driving a 2500HD with the 8.1 vortec and allison and I was really pleased with the 8.1 but the gas mileage was killing me. I guess the only thing that I miss about the 8.1 is the quickness or should I say the get up and go, don't get me wrong the Duramax has plenty of it also, but my question to you is what does it take to make the duramax even quicker then the 8.1. Like I said this is my first Diesel ever and I know nothing about the performance upgrades to them, so could someone clue me in to which products are the best and what they do.
The first thing I would like to do is get rid of the 95 MPH limit and then go from there. When I was doing upgrades to my 8.1 I could adjust the rev limiter and the top speed and so on are the diesel's the same way. Please shine some light on this for me.

2 questions, how much money are you willing to spend and how fast do you want to go?

Possibilites are endless and hopefully your pocketbook is too.. Welcome, happy reading and good luck...

Stop NOW!!!! RUN!!!!

Damn, too late. :(

OK, first you need a simple 40HP tuner...




:D

Like I said I know nothing about Diesel upgrades or the cost. I have been use to doing upgrades to the gassers, but I know thats like night and day compared to the Diesel's, so what would be a good starting point for a newbe. I would like to be able to make it quicker then my old 8.1 and get rid of the top speed limiter thats the first things on my list, but I really don't won't to tear into the allison right now.

All you need to do is buy the predator from any of the vendors here, upload the 40hp or 65 hp tune and it will blow the doors off of your 8.1L. If you are brave you can run the 85hp tune but that is definitely pushing the limits of the Allison. There is also 100hp tune that will limp the Allison every time. The Predator will be around $350-$400 It will also allow you to raise your speed limiter to 120mph and correct your speedo for different tire sizes. Be carefull there are 2 different products using the predator name. You want the downloadable tuner but diablo.

If you want to take it to the next level you can upgrade your transmission but that starts about $2000 minimum with average cost being probably around $4000 or so.

Hello Kyle and welcome here. I'm one of the few that will advise you to just leave your new truck stock, maintain her well, drive her nicely and enjoy the reliability. Leave the speed limit stuff alone. There's not a road in the U.S. that is safe at 95 mph especially considering that you're out there with a bunch of numnuts involved with their damn cell phones, driving in the wrong lanes, not using rear view mirrors, only the vanity ones and in general paying attention to everything but driving. Our interstate highways in most areas are a series of patchwork that makes safety at even the legal speed limits questionable and even the truck itself is not engineered to be a high speed item. Save yourself some bucks, some headaches and use the truck for pulling or hauling as designed. I might get a little heckeling from some forum members for writing this but what the hell, that's what makes this place fun.

I agree, driving faster than 95 is too dangerous!!!

(for YOU guys!) :D

Seriously, if you expect to upgrade the trans in the future at some time, you might want the PPE instead. Yes, it does have lower power levels, remove the limiter, reset codes, adjust tires, but it also has the most powerful high performance tune when you set it on "kill".

With the PPE on Kill and a VA box, you won't even fear 8.1's with superchargers.

I took a trip to florida recently and I agree the roads there SUCK!!! You guys actually pay TOLLS for 2 lane blacktop roads. That blew me away!

Here in Texas we have great roads, we know what concrete is, and around Houston and out on the open interstate doing 80-85 is called "just keeping up". Under those terms you hit the limiter just trying to make a pass on someone doing 75mph.

I am with McRat, a small tuner will get you easily where you want to be. I have been running 110+rwhp over stock for over 13,000 hard driven miles and have never limped the tranny. Results may vary of course, and a smaller tune sounds better for you, but I can tell you one thing for sure:

No way can any stock 8.1 even dream of beginning to keep up with my truck. Most sports cars have their hands full trying a modded dmax, much less any other pickup out there (barring the lightning and srt-10)

I would advise the quad at 70hp or the pred at 65, both will do you fine on the power you want while giving you the options on the tires and limiter.

Congrats on the new truck, and good luck!

.

Hello Kyle and welcome here. I'm one of the few that will advise you to just leave your new truck stock, maintain her well, drive her nicely and enjoy the reliability. Leave the speed limit stuff alone. There's not a road in the U.S. that is safe at 95 mph especially considering that you're out there with a bunch of numnuts involved with their damn cell phones, driving in the wrong lanes, not using rear view mirrors, only the vanity ones and in general paying attention to everything but driving. Our interstate highways in most areas are a series of patchwork that makes safety at even the legal speed limits questionable and even the truck itself is not engineered to be a high speed item. Save yourself some bucks, some headaches and use the truck for pulling or hauling as designed. I might get a little heckeling from some forum members for writing this but what the hell, that's what makes this place fun.


:funnypost I guess a lot of us would agree with this if we were also 108 :lol:

kidding aside, if your into a rig just for trans from A to B , then do what the 108 old guy says. If your rig is a hobby; 'surf' this dieselplace and you will have a lot of fun and get more info (and lies) than your head can hold :grd:

Thanks everyone for the suggestions, but I have a question about the predator you are talking about. When you say downloading diff levels are you talking about downloading a program from their web site or what and if so do you have to do it everytime you change to a diff setting.

What "downloading" means is that you change the performance levels. No, you don't get these from their website. They are built in and work the same way a Hypertech programmer works.