Originally Posted by Goatboy
Im most likely wishing more then anything on the 35/5. A few things I have read about are much easier and some what cheaper.
Cold air intake said to be good for a few extra horses
Full synthetic oil for a hp or two
Throttle body and spacer? (am the most unsure to this one. Would guess more hp but equally less mpg.
And like you suggested, a bigger exhaust.
New chip (same as new ECM?) Again, dont know much about this one either.
To be realistic, if I could get 20/2 Id still be happy. And as you said its the aerodynamics thats the killer and I have no intention of flatting out the front end
ill just have to settle with some stuff I can do... To bad that tornado air thing and the 75hp chips are bogus. Its amazing what kinda crap you can come across looking for better mpg
Flatting out the front of the truck would actually hurt the aerodynamics, there isn't a whole lot that can be done to improve the aerodynamics of the truck, it isn't even the drag coefficient it's the frontal area, the drag coefficient ties into the frontal area directly but the larger the frontal area the more power is required to do the work.
Anyways little things added up can get you that 20 more hp, getting 2 more mpg in addition to the 20 more hp cannot be done cheaply no matter what, if you increase HP you almost have to increase the fuel injector sizing but let me clarify this, larger fuel injector if you are making a LOT more hp. These engines have a thermal efficiency of around 22-25% which for it's time isn't all that bad but compared to today it sucks. In order to get the best of both worlds (power and mpg) you need to basically re-engineer the engine in just about every possible aspect (which is what I'm doing currently).
Well to answer your questions.
1. Cold air intake, these trucks already have a cold air intake, you could probably get another 5-10HP by ram air, but this cost money to cut a hole in the hood to do such.
2. Synthetic won't do much for HP, synthetic is good because it has a better cold start protection. If you use a thinner oil it helps with friction reduction but these motors don't permit a thin oil.
3. Ok the throttle body spacer! It will do jack crap, only thing it will do is increase your plenum volume (very little) which will improve low end torque (minimally) and will slow down the throttle response.
4. Changing to small tube full length headers or just about any header system will only show a benefit with the proper cam shaft, intake manifold, in/ex valve diameter. In those cases the ECM would come into this mix. The exhaust system on every production vehicle is tuned perfectly for the entire engine, some exceptions out there but for our engines it's just about perfect, these engines because they are emissions controlled rely on back pressure to operate properly and efficiently (if you can believe efficiently). But you can rarely get more hp and mpg together without laying down big bucks, you would literally have to change the entire dynamics of the engine.
I could get you a crap load more HP I mean a crap load but I don't think you are going to get better mpgs.
As for tuner chips and such, some of the real good ones the tuners that actually reprogram your ECM can help you get one or the other only, but not both. Sadly just changing the ecm or just changing the exhaust or just changing the intake isn't going to do anything you kindof have to change everything to increase hp and mpgs.
One thing you can do to help decrease engine wear if to use a good quality oil or a synthetic, personally I don't like synthetics I prefer old fashion valvoline I been using it forever and well things keep working. But get a synthetic fiber air filter, they are much less restrictive then paper filter elements. You aren't going to notice a HP increase but it helps a little with mpgs and I mean very very little like for our engines maybe 1/8th more mpg. But the fact it puts less wear on the engine should be good enough that and you can clean and reuse synthetic fiber filters (tada!).
There is just very little that can be done without spending decent money, I've tried.
You could if you haven't already get rid of the viscous fan and get a electric fan, that will remove a majority of the load on the water pump shaft bearing so the pump lasts longer, but you also remove that direct mechanical load and since the pulley system is a under drive system the load the fan makes is great. The e-fan will help free up aprox 2-4 HP and you may get another 1/8th mpg so you are up to 1/4 mpg not bad for say 200 bucks!
Drive with the pickup tailgate closed not open, the roof of the truck is designed to deflect the wind over the top of the tailgate. The open tailgate increase the drag period. I cannot tell you if you will notice gains in hp or mpg, there will always be a change but it's goes un-noticed.