Wanted: reliable horsepower for my '03

[B.O.B.]

Here's my recommendation list followed with a lot of rambling you may or may not take the time to read:
-CAI
-MAF (BA2600)
-Ported TB
-Ported upper plenum
-Ported SC
-6# pulley
-Plugs
-Exhaust (cat-back or full system) - Bassani, Cannon or ARH come highly recommended
-Wideband AFR gauge
-Fuel pressure gauge
-AeroForce Interceptor digital scan gauge
-Valve body
-Traction bars
-5/8" IC lines
-Oil separator or catch can
-Handheld tuner and a tune from a reputable Lightning/HD tuner

Presumably your truck is in sound mechanical condition since its been in your hands for the last 12 years. Regardless its worth mentioning to ensure all preventative maintenance is taken care of before modding:
-Clean air filter
-Clean MAF
-No vacuum leaks
-Fresh fuel filter
-TPS adjusted to .99 volts
-Fresh plugs in the proper heat range for your mods
-Clean IC, plugged turkey pan is recommended



Gauges become increasingly important as you push the envelope but they are often overlooked. A wideband AFR and fuel pressure gauge are most critical. I'm also a huge advocate of the AeroForce Interceptor to monitor all of the parameters monitored by the ECU to include battery voltage, IAT1 (at the air filter), IAT2, post-SC, tranny temp, and engine coolant temp.

In your case a fuel pressure gauge can be a valuable diagnostic tool to ensure your have adequate fuel delivery before you begin modding. Inside the fuel tank there is a plastic y-fitting that merges the fuel delivered from the two pumps into one line. Unfortunately this y-fitting cracks and causes improper fueling. The in-tank fuel line may also deteriorate and crack causing fueling issues. A FP gauge can help identify these issues, or other fuel delivery issues such as weak pump(s) before you begin modding.

Once you have verified all preventative maintenance is complete and the truck is mechanically sound, let the modding begin. The weak link of the factory motor is the sintered-powder rods. Just like brittle bones any excessive load exerted onto the rods has the potential to result in catastrophic engine failure. Excessive load comes in many forms to include:
-the insane cylinder pressures caused by detonation as result of poor tuning, poor fuel quality, or fuel delivery issues
-too much power
-WOT tranny kickdowns (not an issue in stock trim or when mildly modded but increasingly risky as power output increases)



Boost is merely a measure of resistance and is far from an accurate measure of performance since it is effected by numerous variables such as ambient temperature, exhaust restriction, porting, etc. More boost does NOT equate to more power or a better power curve. For example, free-flowing exhaust typically increase power but decreases boost due to the improved efficiency of the exhaust. Generally speaking anything done to improve efficiency pre-SC (i.e. CAI, porting the inlet side of the SC) will increase boost, anything done post-SC (heads, cams, exhaust, porting of the heads, etc.) will decrease boost.

Pulley ratio is the best yardstick and is very easy to determine. Pulley ratio refers to the number of revolutions the SC pulley makes for every one revolution of the crank pulley. In order to determine the ratio of any given pulley combination all you do is divide the diameter of the crank pulley (in inches) by the diameter of the SC pulley in inches. For example, the factory HD pulleys measure 3.16" (SC) and 7.5" (crank). Crunching the numbers you get:

7.5 / 3.16 = 2.37 --> 2.37:1 (when written as a ratio)

What that number tells you is that the SC is making 2.37 revolutions for every one revolution of the crank pulley.

To go on step further, once you determine the pulley ratio you can determine the SC speed by multiplying the pulley ratio by any given engine RPM. For example:

2.37 x 1,000 RPM = 2,370 SC RPM
2.37 x 2,500 RPM = 5,925 SC RPM
2.37 x 5,000 RPM = 11,850 SC RPM
2.37 x 5.500 RPM = 13,035 SC RPM



Porting the SC is beneficial of various fronts. An unported Eaton makes great low-end torque, hits peak power output, then power falls of quite drastically due to its inefficiency. Excessive heat further adds to the power loss in the upper RPMs due to the need to tune more conservatively (decreased timing, richer AFR) in order to stave of detonation which can lead to catastrophic engine failure. Porting improves the efficiency of the Eaton and when done properly it will retain all of the low-end grunt while improving peak power output and significantly reducing power loss after peak power.



As I mentioned previously the factory crank pulley measures 7.5". Aftermarket pulleys vary slightly depending on the brand, but its generally accepted that:
2# = 8.0"
4# = 8.5"
6# = 9.0"
8# = 9.5"
10# = 10.0"

With an HD most guys opt for either a 6# (9.0") or 8# (9.5") pulley which produce 2.84:1 and 3.01:1 pulley ratios respectively when used with the factory HD SC pulley. Although either can be done safely I recommend sticking with the 6# lower for added safety margin. With either a 6# or 8# pulley you will need to swap to a cooler range spark plug. NGK TR-6 come highly recommended since they are inexpensive and durable.

Upgrading the MAF is good insurance and doing this mod now might save the expense of retuning for it should you decide to upgrade the MAF down the road.

Tuning is critical, do NOT:
-install a pulley without a tune revision
-port the Eaton without a tune revision
-install a MAF upgrade or MAF extender without a tune revision
-install injectors without a tune revision

A valve body is also highly recommended. A VB increases performance, increases the fun factor, and improves transmission life.

What he said. Lol awesome info if that's not a sticky it should be!

[SLOWBRA]

Agree with Bob. Also, My truck has every mod and suggestion in that post. Love it.

[Merlin]

As throttle jockey stated..."Oil separator" is not a performance mod but IMHO it's a must do.
While you're doing the Pulley, Plugs and Tune it is a very good idea to clean the intercooler.
After it is cleaned you will want to keep it clean. This is where an oil separator comes in.
Most folks on here go with the L&S oil separator. It's a set it & forget it, do it once, oil sep.

For a fuel filter I went with the The Navigator Fuel Filter Upgrade. I feel it is worth doing.

For a short list to start I'd do: PP&T, Clean I/C, oil sep, clean/filters and tranny valve body.

[cayman150]

Thanks for all the response, Alien, excellent stuff.....I have a better understanding of actions to take. I guess the 425 horse i want is probably too high of a goal? I will proceed with caution, because I do not want to ventilate this block. Who is the "go to" for canned tuning. I am not sure of anyone near by that does dyno work, but I at least need a baseline tune that will support the mods and can be changed as I go....ideas for that will be greatly appreciated.

For those in East Tennessee, a big shout out, if yall know a good live tuner in our area, contact me!

If you can't get it to a dyno for a proper tune then JLP, JDM, WMS all will do email tunes. If you go that route it is better to do some data logging with your hand held tuner of normal city driving, normal highway driving and a couple of 1/4 mile WOT runs each saved to a separate file to send them which helps them dial in your tune. If you also have a wide band gauge that can data log then do that one as well and it should be spot on when you get it back.