i personally am active with my 92 in the 1st gen forums and my dad is looking to step up the performance in his stock 04. its not the 04.5, and only mod is an MBRP 4 inch exhaust kit without the downpipe because we bought the kit for an 04.5 on accident. what are the basic mods to wake this truck up? from my reading i have established: an aftermarket intake horn and air box, gauges (obviously), and a programmer. ive seen a lot of happy customers with the smarty jr. am i going on the right path here? and any other suggestions?


04 2500 4x4 QCLB HO 5.9 Cummins 4 inch MBRP exhaust 153k miles TROUBLE FREE

 

Sav the money on the intake and put it toward the full Smarty.
Intake will not make much difference until over 500HP.
Many are running stock intake well above that.
EGT gauge is important.

 

Smarty Jr is a good buy and a good tool, the Sr is a better buy given the enhancements.

Leave your stock air box and either add a cold air inlet from the wheel well or just drill 4-5 holes in the bottom of it. Use the newer Fleetguard filter with the 4" pleats. Hard to beat for efficacy and efficiency.

For just a small step up in performance the air horn is bling. The GDP offering is about the best all around. The IAT drop is noticeable but hard to quantify the cost.

A much better choice would be address the LP and better filtration. That will pay you much better dividends than exhaust, air box, or intake.

The biggest impedence will be the turbo. It is close to maxxed out stock and there is not a lot of wiggle room to add soilid performance.

Gauges are a given with performace. At a mnimum boost, LP, rail pressure, and EGT.

 

how big of an improvement is the smarty?

 

I used the GDP Walbro kit to replace the lift pump and made my own 2 micron filter, right after buying the truck used with 25k miles. Then I put on a 4" muffler, then turbo and the turbo alone improved the power band and driveability a lot even with no fuel change - got rid of the flat spots and really helped the top end . Too bad they put such a marginal turbo on the 03-04.4. It was the most expensive mod but now it will take all I want out of the diablo pred/puck stack. Craig

 

no-6 gave good advice, you can build your own 2 micron filter for $60. consider buying a he351cw off a 04.5 up. they run about $350 and replace the he341 on there now. just stay with the jr, you are going to spend to much money for upgrades to need the senior.