Does the Duramax have reduced power till broke in?

[Big-Popper]

I bought a 2002 Duramax K2500 a couple weeks ago to replace my 1998 K3500 454. I waited till it had 650 miles on it to get into it. It does not seem to have any more power than my old vortech 454. I am wondering if the computer reduces the power for a while till it gets broke in? I know this might be a dumb question but, I knew you guys and gals would probly know. My Dad has a 2002 also. I think I will go over to his house and switch, see if they are the same. I did notice before I got my truck I rode with him and his went right up to the redline(3200) every time between shifts. Mine always shifts at or below 3000 wide open? :confused:

[Paintdude]

In my experiance so far, the Dmax is Torque and driving around 1800 rpm is the peak of the torque..

In drag racing Hp=speed..the Max HP for the Dmax is in the 3000 range..

you pull with torque and generally drive torque..Hp is the seat of the pants exceloration is what is troubling you from the Dmax as compared to a gasser..

you must just get used to it, that is the way it is or Juice it..

Hope this helps..It has me with my new Dmax..Torque is good... :D

[GMC D-Max]

I would have to agree with Big-Popper on this one. It seemed that my Duramax started shifting later, and making more power after putting about 600-700 miles on the odo.

[Paintdude]

Last week when mine had 300 miles on it..I floored it at 50mph and the thing downshifted and when almost to redline in the gears till I shut it down at 95mph..

It does seem to run better after I got 6-700 miles on it..I agree..and it gets better every day..

[RVGuy]

I am experiencing the same thing with my new DMax. Actually, mine is totally unimpressive in 1st gear, but somewhere in about mid 2nd gear, it decides to get up and go a little bit. In fact, I'm not sure I can get the rear wheels to break loose off the line right now.

I do notice that the performance improves a little with every mile.

[Maxter]

I bought mine in January and it kept getting better and better until around 10,000 km. It is now stable and running great. I have 22,000 km on it right now.

Fuel economy improved gradually and the general smoothness feeling as well. Being my first truck and my first diesel and can only compary it to my other car. It's a 5 speed mazda 626 LX-V6.

The Gtech stats are about the same for both on the 0-60 wich is around 8.4 secs stock, only K&N filters in both. The braking is better with the truck wich still amazes me for a 3 ton monster.

The trip cost is about the same considering the higher price of premium gasoline compared to diesel even if the car fuel economy is stligthly better. That's why I will sell the car... No advantage to owning one!

I heard on the board that the Dmax with the juice feels more nervous like a gasser but I don't own a juice box so I can't comment.

You have a great truck, you will lear to apreciate it in other situations than drag racing.

[walkerkd]

they seem to really run when you get around 10k on them im at 14k now and let me tell you .. these trucks will move. im in love!!! :D

[1919a4]

You've babied the truck; the transmission has "learned" this behavior and short-shifts for better economy.

By blasting full throttle a few times, it will re-learn your driving habits and will then start shifting closer to redline.

There is a way to "reprogram" the transmission, according to board lore. I've done this, so it's safe, but never have seen a factory reference to doing it.

Drive 50 MPH, pull the gear selector into "1" and let off the accelerator (don't worry, the tranny is electrically shifted and WILL NOT overrev the engine or fall out the bottom of the truck). The trans will shift progressively from 4-3-2-1 as the truck slows down. This should "zero out" the memory on the transmission.

Then, blast away and it will shift redline to redline.

SImon

[Turbo Al]

If you have access to Members Area (Member) then look at the 2002 Redezvous BD Dyno chart figures. "Maverick" showed 258 HP stock and Turbo Al showed 239 HP stock the only real difference in these trucks was that Maverick's had quite a few more miles on it. Mine pulls better every day but think the "break in" will be done somewhere around 20K. Also don't forget that there is a govenor that limits power to the trans when it is cold, it is REALLY noticeable on my truck.

[Big-Popper]

Sounds like I am not the only one wondering. My dads truck has like 12,000 miles. He totally loves it. Dont get me wrong I love mine too. Last night was the first time I got into it and I thought there would be more. I will have to look into that Juice box and re-train the trans for more agressive shifts. Maybe I should stop driving my BigBlock Hurst Olds around for a while. I think it spoiled me. Nothing seems to have that kind of power. Thanks for your thoughts.
:D Jason :D

[DURAMAN]

Big Popper - I too upgraded to the Duramax from a 00' 454. This was also my first impression of the diesel. I don't think your 454 was any quicker and certainly has less pulling power. I think a lot of it is just the different feel of the diesel vs. the gasser. They don't jump off the line as fast (for good reason) and don't run near as many rpms so it's a little different. My 454 would roll tires til I let off the pedal, but the diesel(stock) only smokes them a little. This bothers me a bit, but when I hookup the the 12,000lb skid steer and 4,000lb trailer it sits on there's no comparison at all. The Dmax would drag my old 454 from one end of town to the other. Keep in mind that the truck was made for power/torque not speed. I also agree with other posts - It will loosen up a bit and start getting better mileage and more power. I'd attempt the tranny reprogram - get speed up to 55mph, take foot off pedal and drop into 1st gear. It will downshift itself and reprogram along the way. After that stomp on it and let it run through the gears a few times. This may solve the problem with the shifting. smile.gif

[ZFMax]

What was the horsepower of the Vortech 454? And how was it geared?

As we've hashed to death elsewhere, the truck with the highest horsepower has the highest performance capability, acceleration or pulling a trailer up a hill or however you want to measure it. How that horsepower is made up, in terms of it's torque and rpm, is significant for things like longevity and efficiency but not for performance.

So if you went diesel thinking that somehow the high torque gives it more performance than a gasser of the same horsepower rating, I have some bad news for you ...

[markson]

I just sold my (2) 2001 Dmax's and I can really tell the difference with my new truck (2002 Chev Dmax)...These trucks are very tight when new and will open up around 15,000 miles...Heck, my fuel mileage started around 16 and then climbed to the low 20s by 15K...

[DmaxMaverick]

:confused: :confused:

My brother has a 2002 8.1/allison (340 HP). Pulling the same 12K trailer, it is competition, but WILL NOT out pull, out accelerate or out grunt my Dmax. Flat ground OR 6% grade (maybe downhill).
An HD with a 6.0L (same horsepower rating as the Dmax) doesn't have a chance, even with a tranny (4L80E) that has a lower power soak rating than the Allison.

Been there. Done that.


Big-Popper
My '01 Dmax did't really start to wake up until I had 15K - 20K on the clock. Even now with over 44K, it gets better every day. Cheers

[ZFMax]

"My brother has a 2002 8.1/allison (340 HP). Pulling the same 12K trailer, it is competition, but WILL NOT out pull, out accelerate or out grunt
my Dmax."

For performance, it's irrelevant whether the engine is making it's horsepower with high torque & low rpm (a diesel) or low torque and high rpm (a gasser), because gearing is used to translate whatever combination is being provided into the combination needed at the rear wheels.

And when you look at what arrives at the rear wheels, for a given rear wheel speed the engine with the most horsepower puts the most torque to those wheels. It's pure physics and easily provable. And torque at the wheels is what accelerates the truck or pulls the trailer up the hill.

We beat this absolutely to death in another thread, I have no intention of going through it again here. Find that thread ... there are detailed descriptions and examples of how engine horsepower translates into rear wheel torque and speed. Suffice to say that this notion that torque is a performance metric, and somehow the combination of horsepower and torque describes a vehicle's performance, is pure nonsense.

[ 07-23-2002: Message edited by: ZFMax ]</p>

[oneton]

Yep, I was wondering the same thing when I picked up my truck last week. It felt like it was being governed to keep the RPM's low. I drove it down from OH in one day. When I got off the interstate in Tampa the truck was totally different. I had just driven the truck 950 miles and it grew some a$$ over the course of the trip and get's better everyday.