Tuning, CAI, Exhaust, I'm Lost
 

So I drive a 2005 suburban (145k miles) and have put aside some money to get some slight modifications to help with gas and such. I've been doing strict maintenance stuffs, (oil, transmission fluid, differential oil, spark plugs, fuel injector cleaning (and replaced 2 cause I broke them), scrubbed out the air intake manifold, and ran sea foam through every line that I could).
I've done spark plug foulers on the O2 sensors (after cats) to trick engine (laminar air flow, its suppose to help, and it was a cheap mod.)

With all the maintenance I get about 17mpg tooting around the city/little hwy driving. I don't have to drive like grandma, but I am also not heavy on the gas pedal. When taking off I never go above 1750~ rpm and I generally try to drive at about 5mph +/- speed limit (its the general rule here, I understand I can save gas going slower/faster so that I work in higher transmission gears, but I won't put the safety of myself/occupants to save some gas money.) When on hwy I tend to do about 65-70.

Now I am looking to actually start modding.

I've heard the first things to do is a new air intake. I've looked around and I see 4 big categories, standard CAI (like K&N), ram air, super and turbo chargers. I've heard super & turbos actually hurt mileage (they also cost 40% of the value of my car, lol). So what is the break down of ram air vs the standard K&N air intakes? I'm hesitant with the ram air because it will require me to modify the hood of the car, but what are everyones experiences? Is the ram worth it?

Regarding the exhaust, I've heard that the majority of vehicles (suburbans in particular) have a wide enough exhaust that you should save those for last. So thats what I plan on doing. Although I am curious what people have paid to have their pipes redone.

Now the meat of my questions and what I am really curious about is tuning. I've done some basic looking around and with my looking around I have learned that I know absolutely nothing about tuning. *woot* **woot*
With that said, the advantage is I am not an igneramous regarding information that people may give me for the tuning. I'm kind of used to not know what I'm doing (whether thats a good thing or not...).
I know there are hardwire modifications. I am leaning away from that because if sh*t hits the fan I want to be able to reverse the modifications I am doing (one of the reasons that I will be holding on to the old air intake boxes and such).
I've heard of "add in boxes" that are stored in the engine compartment, but I do not know much about them.
I've seen some of the OBDII systems (specifically I saw a bully dog piece) and it seems to be a rather straightforward system and the easiest to install/uninstall. This is my "worst case scenario" option.
The one that interests me most, however, is the OBDII to USB with a computer systems. I plan on installing a PC in the car (with a 10" touch screen, woot!) to run music, GPS, exterior (work related) lights, etc. The idea of being able to program the car for more fuel efficiency while on the go, along with the data that could be logged, is quite appealing.
So, how much work would it be to learn the computer based OBDII system? Price of the systems? I have not been able to find much information on these systems but they must exist.
Is there any advantage/disadvantage (economy/efficiency wise) to the computer system vs the bullydog or any other systems?
This is the part I am seriously lost on. :confused::confused::confused::confused:
What do you guys know regarding the tuning that you'd be willing to share?

It's here if you look for it.

First question is why such a big vehicle, are you towing, hauling people?

I do contract work on the side. Normally loads are around 3-4klbs but they can go up to 6klbs quite quickly and higher (tractor + concrete + trailer adds up fast). I can't afford to have multiple vehicles, insurance, depreciation, maintenance (even if you do not drive a vehicle, it has to be maintained.)

With that said, I may be oblivious, but I cannot find information on the tuning. I've read things like "tuning is good" and such, but not detail into the questions that I'm posing. Again, I may be completely missing it (I am blonde).

Edit:
I have checked the 65 mod list (actually checked it before you posted =P) but I see lots of physical modifications, and less about tuning.

Most modifications you can buy off the shelf will trade fuel economy for more power, and sometimes just hurt economy for no gain, with a few exceptions.

Start with keeping your tires pumped up near max sidewall and a partial grill block, and maybe run some ducting from the stock air box so it draws in warm air from near the exhaust manifold. I don't know much about tuning but I'm only aware of 2 factors that might help FE, and those are ignition timing (risk predetonation) and leaning out the burn (will likely cause you to fail emissions). Probably best not to touch the factory tune as you'll get small gains at best and always at a tradeoff, the engineers at GM are no dummies.

The biggest factor you can change is the nut behind the wheel. Slowing down from 70 to 60 on the highway brings me from 30 to 38mpg for instance, and learning how to drive without needing to brake will help tons in the city. I can't remember who said it, but it helps me to think that pressing the brake pedal is a great way to turn gasoline into brake dust. Some ideas: don't race ahead to that next redlight, take your foot off the gas early coast in so you arrive with some momentum when it turns green. Pick your routes carefully to avoid stop signs, as there's no way to outsmart them. Etc.

EDIT: Btw, welcome to Ecomodder!

I hope you find this useful re: exhausts and such:
http://ecomodder.com/forum/showthrea...tml#post289125

Ecky's advice is spot on. At 17 MPG you are very close to EPA highway. Don't waste your money on "tuning" your Subdivision (what Frank calls them). Sidewall max for inflation and precision driving techniques might get you another couple MPG but after that there are no miracles. Considering your driving environment and towing several tons occasionally you are pretty close to maxed out for efficiency right now.

regards
Mech

yeah, 17 for a subdivision ain't all that bad. The suggestions so far are good. Keep tires up, maybe a WAI.

You might want to start looking into what you can do about the shape of that trailer. The ideal would be to shape it into a boat tail continuation of the car, but it's ofthen not practical to go that far.

Tuning is going to cost at least $200 for a cheap unit and probably wont net you anything. I think you're pretty close to maxed out. Look into a wai