Just lurking...

[Randy_the_Hack]

Originally Posted by RH77

Economy tune -- cool stuff. It's seems like theres a pretty big aftermarket for Diesel tech -- is this the case?

There's just something about a finely tuned turbo-D (and the sound)
I saw on a Dodge yesterday "Smoke Doesn't mean it's Broke"

Not sure if you had a chance to see the PINKS episode with the 10-second Ram 4x4. What a machine.

RH77

Yeah, there's a HUGE after market for diesel engines. And it gets about as techy as you can imagine. Starts with programmers, and goes to CAI, various exhausts, propane injection, water/meth injection (my next step ), nitrous, and then you get into the twin turbos, etc. There's a guy out in SoCal that is putting more than a thousand rear wheel horsepower down... and getting 32+ mpg's. I got into this last July, and I tell ya, it's addictive.

Just added a 4" exhaust the other day (cat delete)... and now the turbo whine never ends... the truck sounds like a jet helicopter engine spooling up.

Didn't see the PINKS episode... but there are lots of YouTube movies of quick diesel trucks - look for one called the world's fastest Duramax. Simply amazing.

[Randy_the_Hack]

Originally Posted by igo

22mpg! I assume you are crushing the epa. Good job!

Yep.

EGR blocked/unplugged, PCV rerouted, cat delete... just to name a few. Needless to say, when I romp on it, it blocks out the sun momentarily... and then I'm just not there!

Repeated accelerations like that and my 22 mpg drops like a dying man's blood pressure.

[cfg83]

Randy_the_Hack -

Welcome to EM! I looked at the EPA website but I couldn't find your car. I did find a CNG version that get's a little over 10 MPG combined :

2004 Chevrolet Silverado 2500 HD 2WD (CNG)
http://www.fueleconomy.gov/feg/calcu...D%202WD%20(CNG)

CarloSW2

[Randy_the_Hack]

Originally Posted by cfg83

Randy_the_Hack -

Welcome to EM! I looked at the EPA website but I couldn't find your car. I did find a CNG version that get's a little over 10 MPG combined :

2004 Chevrolet Silverado 2500 HD 2WD (CNG)
http://www.fueleconomy.gov/feg/calcu...D%202WD%20(CNG)

CarloSW2

Yeah... the EPA doesn't rate diesel trucks. Go figure...

BTW, for those interested in a peek, I have some pics of my truck in my garage.

[Lazarus]

Originally Posted by Randy_the_Hack

Yep.

EGR blocked/unplugged, PCV rerouted, cat delete... just to name a few. Needless to say, when I romp on it, it blocks out the sun momentarily... and then I'm just not there!

Repeated accelerations like that and my 22 mpg drops like a dying man's blood pressure.

Welcome to the site. Really nice job with the truck. But why unplug and remove all the emissions control? Does it really help that much and at what cost?

[Randy_the_Hack]

Originally Posted by Lazarus

Welcome to the site. Really nice job with the truck. But why unplug and remove all the emissions control? Does it really help that much and at what cost?

The '04.5 LLY was the first year for emissions equipment on GM's diesel trucks. It may or may not have been the first year for that type of equipment on any diesel engines; I just don't know. The rationale is as follows:

1. The cat reduces exhaust airflow, which increases exhaust gas temps, which in turn threatens the turbo when the truck is under load, e.g. towing a trailer in the summer up a long hill. By increasing the exhaust diameter, ditching the cat, and replacing the muffler with a flow-through (sort of like a Flowmaster or Cherry Bomb on a gasser), you increase horsepower by 15-35 hp (depends on the system, phase of the moon, alignment of the planets), and decrease EGT's significantly. Bottom line - much more efficient use of the fuel.
2. The PCV, as routed by GM, feeds direclty into the suction side of the turbo, pre-intercooler. As a result, when you're running under boost, the engine is actually having the engine oil mist being positively sucked out of the valve covers, and then pressurized into the intercooler. The net result is that the intercooler gets coated with this oily mess which can result in the intercooler boots being blown off, leaking, etc. Amazingly enough, if you reroute the PCV and cap off the intake to the turbo, almost nobody ever sees any oily discharge from the rerouted hose. I know I haven't. And... the intercooler is cleaner and you don't run the risk of blowing the boots off under heavy use, which leaves you with no power.
3. The EGR takes exhaust soot and blows it right back into your intake. Even a few thousand miles of this can and does literally cake the intake tubes with thick layers of soot. Worst case is that you end up with clogged equipment, which is extremely expensive to replace... plus it again works against you as it increases overall exhaust gas temps. By blocking the EGR, you run cooler and more efficiently; most people see quicker response and better fuel economy. You will notice that the newest diesel engines use a DPF to deal with accumulated soot in an enterly different method. The EGR was a good idea gone amok on this particular diesel engine.
4. The resonator is another good idea in theory gone amok. Supposedly it makes the engine quieter, but by blocking it you avoid unfiltered air getting into the intake if the sucker ever develops a leak (and they do), and by blocking it you increase hp a little.

There is a method to the madness. My truck now smokes less than it did when it was stock... and runs way more efficiently (16-17 mpg v/s 21-22+ mpg) while putting down an extra 150+ RWHP and 100-200 extra ft-lbs of torque.