OK... I am an absolute diesel newby. Maybe you guys can help me. I have a new, stock chevy 2500 duramax. I get about 14 - 15 miles/gallon around town (boy, that's disappointing). Towing my 32' fifth wheel I get about 8 or so.

I was talking with some guys this weekend about mods. I understand that a high flow intake is a must. Is there a kit to do this with? I am interested in reliability above all.

Next, I understand I need to open the exhaust. Do I need to go to a muffler shop or is there a kit for this? What about the catalytic converter?

Finally, the chip. What kind is recommended? I am not really interested in burning my tires down in a fog of white smoke, but I am very interested in some better gas milage. Also, if I get a chip (or the intake or exhaust work) how will that affect the warranty? Is there a chip that is warranty legal? I do not want to affect the warranty at all.

Any help is appreciated.

Jimbo

Welcome
Do some searches and a lot of reading, you'll get some good info to help.
FYI - High flow intake is not a must on the duramax, it's been tested, no significant gains in HP or MPG. Good idea for gasser, not needed for this diesel, won't see a cost benefit.
Exhaust is a good idea, read up on that one.
Chips, plenty out there, but don't think your going to pick up 5mpg with one, they help in the power dept, but not much in MPG.
Warranty - depends on dealers attitude, bottom line is, if it's modified, they can deny warranty and make you fight them to cover under warranty. You may win, but at expense. Remove any mods before service, and have a good relationship with your dealer. When I've taken my truck in I've had service guys tell me how nice the big tires look and ask me questions about my aftermarket tank, straightpipe, etc. with no probs, but that's not always the case for some.

There is an ongoing debate whether a high flow intake is worth it on the Dmax. Independant tests have shown the stock filter to flow as much and sometmis more than aftermarket filters. However, there are also those who swear that they can feel the difference when an intake kit is installed. There are many out there to choose from so do some reading before you buy. I suggest looking at the AFE kits with Pro-Guard 7 filter media. Great flow rates as well as filtration.

4" exhaust is an excellent upgrade for the Dmax and some have seen gains upwards of 25hp. The stock system is very restrictive due to a Catalytic converter and muffler. If you are worried about warranty, go with a cat-back system, if not, get a front-pipe to get rid of the cat. I suggest checking out the MBRP systems.

I have yet to find a chip/programmer to give a significant gain in mileage. At the most expect to see 1-2 mpg if you baby it. TONS of options out there to look into. Edge Juice/Attitude is a popular harness box that has alot of nice features. The Diablosport Predator is an excellent programmer that also has some helpful features and can be had for under $400.

Hope this info helps. Use the search option and do some reading. Plenty of info in these forums to help you make your decision. Let me know if I can help with anything.

If I an manage to keep my foot out of it, I have seen about a 10% increase in mileage with my Juice/Attitude. Goes away REAL fast when I'm goosing it, though.

Get an exhaust and a ~40-85HP tuner. At that point decide how fast you want to go.

You'll be running roughly 15.3, and you will maintain good durability and drivibility.

You wanna go faster? How much $$$ faster you want to go?

The dealers wont mess with you about the exhaust because think about all of the gassers that have dual exhaust so that shouldnt be a problem. However any "chip" whether it be a harness box or a programmer you should remove it before making a visit to the dealer.

do not do an intake