Looking for MPG, trade offs, investments, and what you net in the end

[knkreb]

Since we've now locally crossed over the $4 mark, considerations are being made now to say "what else can I do here to increase MPG".

So, on a dwindling budget due to increased food and fuel costs, I would like to know, what the consensus amongst everyone would be for best investment made with limited budget.

Bearing in mind to, that I'm on a factory original IP at 171k miles, I don't want to back myself into such a corner that I will be dead in the water budget-wise when it goes.

So, here I weigh out my options for ECM's, software, programmers etc. I have never been a "performance" oriented person. I would like to hop in and drive without having to mark my territory with rubber stripes in the parking lot. So, I've never really investigated any of these items before.

Recently in talking with someone local, they were talking about a programmer they installed and improved their mileage from 15 to 22+ with a newer Dodge. That's a whole different animal too, but it sparked my interest to start looking into what our 6.5 options are.

As of now, all the "cheaper" stuff has been done. The soot trap is gone. The turbo master installed. Larger tires, with corrected speedo reading. Running so far as much as 16.9mpg on a good tank.

So, I come to the experienced folks here to ask what your real life experience has been with different products you've installed. To help quantify exactly what I'm looking for, is more of a before and after. I installed x-product and went from 16mpg to 21 mpg. Of course I could spend thousands upon thousands of dollars and get very high mpg, but I'm looking for the most bang for the buck at the moment.

Thanks guys!

 

[bk95td]

Get rid of any of the factory exhaust. It is very restrictive. A K47 air box will help on the intake side. I use the amsoil/donaldson nano fibre filters[no oil or washing required]. A healthy set of injectors is one of the bigger things for mpg. Better starting and better performance are a added bonus with the injectors. I personally don't go for the turbomaster. [no choice on my 92-93s]A computer is smarter than any spring. With a proper chip[or ecm for the 96+] and maintained vac system[yes, they don't work forever without replacing parts] the ecm can make adjustments to maximize mpg but still have performance when you want it. Changing gearing to 3,40 would gain some but not a good bang for the $ when you already have 3.70s. Making shure brakes aren't dragging and front alignment can help. Max tire inflation lowers rolling resistance. You right foot on the pedal is probbly the biggest factor in mpg.

 

[knkreb]

Thanks bk95td! Most of the concepts you've outlined I'm familiar with. I'm just looking at the pecking order of how to do this. Like: I upgraded my exhaust, and I averaged about 2 mpg more... or installed Heath's ECM and went from 15 to 21 mpg... stuff like that.

 

[Steve93mustanglx]

MPG improvement is hard to quantify because with more power comes more use of said power. When my sub went from being a total terd to something that surprised a few folks, my MPGs basically stayed the same. That said, it's a good thing, as it would have been less if I romped it frequently before mods.

That said, exhaust and tires. Stock exhaust is amazingly bad. I gained roughly 2mpg with this change. Tires made a major difference on my Sub. I went for a decent capability tire (AT Revo) and lost 1.5mpg average. I cant wait to buy a new set- I will go back to the semi-truck looking straight cut/rib tires. That is the ticket for MPG. However, they suck off road.

I got NOTHING with new injectors.

I am a firm believer that your right foot is one of the biggest thing you can do to help MPGs.

 

[DieselSlug]

Completely stock 3 years ago i got an average of 13 mpg's. Currently with all my mods i get in the 17's up to almost 20.

 

[Burning oil]

Went from 180* Tstats to 195* and got 3-4 mpg better.

 

[buddy]

The T-stats is probably most important, and make sure the fan is not engaging when its not needed.

Some stock programming is decent that the reprogram doesnt help as much with others. Although, in general some more advance on the timing and a light foot will help. But I dont know what you get with the Heath GLE as far as timing goes. You can request that your timing progressively increase with fueling and RPM, and Kojo's programming is a little less cost.

Put the truck in neutral when stopped at lights if you are in traffic a lot. It takes a noticeable amount more of fuel to idle in gear.

Make for sure when you are at whatever speed you cruise at, that boost is not more than 3psi. Somewhere between 2 and 3psi is all you want for economy when empty going reasonable speeds. More boost is a restriction, but if loaded or going 80mph then youre not going to be as efficient and a little more boost can help burn the additional fuel.

What size are your tires? If interested in highway mileage then I would only get 235/85/16 tires if on the stock rims. The height of the tire matters, the wider it is the more it weighs and the more surface area is more friction. If you don't travel on the interstate, then dont worry about the tall tires, as long as you are at about 1800rpm when cruising if thats 55mph. Less RPMs isnt necessarily good, as it will promote lugging. Belive me the truck doesnt like cruising at 1500rpm, doesnt save me any fuel either.

The exhaust AND air filter has been explained, its a simple one time deal, inexpensive and a huge improvement in throttle response and some efficiency. When you make more power with the same amount of fuel, and keep a light foot it helps economy. Most of use dont have a light foot.

If injectors are old they are probably not atomizing well. Precision balanced standard German nozzle injectors can help keep the engine running more efficient and prevent its destruction at the same time.

 

[knkreb]

Fishing around now for kojo tune on here..... gotta link?

 

[knkreb]

Fishing around now for kojo tune on here..... gotta link?

Dup! Was distracted, googled and found. Will post more later... Thanks!

 

[Paveltolz]

I agree 100%, Right Foot is certainly the one of the biggest factors though. I know with correct tire widths and lowering the truck to stock hight would show additional improvements.

The cost vs gains has to be figured in heavy though. 635 was pushing 23 at 62mph with his WMI and Propane set up but his motor breaths better because of the port matching and extrude honeing(sp) during the build but it drove the cost of building and installing well over the cost of a Jaspar powerplant.

Exhaust and Heath's towing tune had me up from 16 avg to the mid 17s - low 18s on summer blended fuels which should be in vogue now. I would drop to 15.5 on the winter blends though. All this on my GM-5 w/ TM at the initial spring length. ATT brought the winter blend fuel mileage up to high 16s mid 17s and that is with Heaths hotter tune too so I'm looking forward to the summer blended mileage figures.

I'm considering WMI next...the search continues.

 

[WarWagon]

Ask yourself "is it worth it?" first.

For example towing and getting 8.5 MPG:
Spend $500 for a improvement that gets you 10% better MPG at $3.00 a gal. (Exhaust)
Pays for itself in around 2 months if you are going 560 miles a work day.

Not going 560 miles a day? Do you have $1000 around just to invest in MPG to get paid back in a year? OOPS! Risk of something bad happening to where you can't get your investment back as the truck doesn't make it a year: trade in, totaled, stolen, blown engine etc.

Start with the cheap improvements first and then it turns into the quest that costs more in parts/upgrades than you save in fuel. Side benefit or justification is that some improvements improve power while the MPG stays the same. Time is money. 33 MPH up the hill towing or 43 MPH up the hill - there is a cost savings there...