Possible sticky section for mpg improvement

[Tileman2003]

Tire make a big difference, I just went from 295's to 315's and my mileage sucks now. Looking to go 285's. I'm kinda stuck with big tires because I bought the truck with a 4'' lift, when fuel was below $ 3.00...

 

[94K30]

remove fwd facing hood scoops that create drag mite make the list, but loss of mpg compensated by coolness factor , 94K that a add a scoop or a Goodmark hood, looks good tho

It is the goodmark steel hood, the forward facing scoop is non funtional, but the cowl induction part works just fine....

 

[JiFaire]

Burning your used motor oil is a great way to dispose of a gallon and a half of used waste oil and to keep form having to buy a few gallons of diesel.

ACK! Bad idea, my friend! In your 6.2, this might be sort of acceptable with a DB-2 IP, but this is the 6.5 section, and this should DEFINITELY not be attempted with a DS-4 Electronic IP.

There are lots of reasons, but here's 2 of the best:

- Used motor oil (especially used diesel oil) has small, hard, sharp particles in it that can really eat an IP up. You need to filter the used oil down to at least the 3 micron level to make it remotely safe in a DS-4.

- contaminants in the oil (largely soot) can dye the optic sensor, rendering your IP useless.

I know, I know, I've heard all the old farmer stories about how Grandpa ran used oil in his International Harvester for 30 years , but I gotta tell you, every single GM 1994-2000 6.5 guy I've had this discussion with has started out claiming he was smarter than the conventional wisdom, and ended up asking where to buy a new IP.

For some reason, most of them get pissed at me for doubting this practice, like it's MY fault their IP got broke... but...

Please don't take this as a slam against you... it isn't. It's just a warning to people who might not know better, and think that because they read it on here, it's something all of us do.

This is a public forum. I personally support your right to do whatever you want with your truck, including burning your waste oil.. However, as a Moderator, I need to make it very clear that this is NOT a recommended practice, that it IS almost certain to cause you grief with a DS-4 Injection pump, and that I CANNOT recommend this practice to anybody.

 

[94K30]

replaced the injectors last week, in NH with a buddy, on way home i managed 19.3 MPG

 

[GM Guy]

ACK! Bad idea, my friend! In your 6.2, this might be sort of acceptable with a DB-2 IP, but this is the 6.5 section, and this should DEFINITELY not be attempted with a DS-4 Electronic IP.

There are lots of reasons, but here's 2 of the best:

- Used motor oil (especially used diesel oil) has small, hard, sharp particles in it that can really eat an IP up. You need to filter the used oil down to at least the 3 micron level to make it remotely safe in a DS-4.

- contaminants in the oil (largely soot) can dye the optic sensor, rendering your IP useless.

I know, I know, I've heard all the old farmer stories about how Grandpa ran used oil in his International Harvester for 30 years , but I gotta tell you, every single GM 1994-2000 6.5 guy I've had this discussion with has started out claiming he was smarter than the conventional wisdom, and ended up asking where to buy a new IP.

For some reason, most of them get pissed at me for doubting this practice, like it's MY fault their IP got broke... but...

Please don't take this as a slam against you... it isn't. It's just a warning to people who might not know better, and think that because they read it on here, it's something all of us do.

This is a public forum. I personally support your right to do whatever you want with your truck, including burning your waste oil.. However, as a Moderator, I need to make it very clear that this is NOT a recommended practice, that it IS almost certain to cause you grief with a DS-4 Injection pump, and that I CANNOT recommend this practice to anybody.

x2,
Also, doesn't synthetic give off dangerous fumes and toxins? Sniffin diesel exhaust just got more dangerous!:crazy:

Actually, i heard about the synthetic thing from the local Case IH dealer, they have a waste oil heater and tell everyone to keep it separate (syn/dino) I doubt they even take the syn.

 

[GM Guy]

Air dams..? Any feedback on them?

They seem to be pretty inexpensive on gar-bay, not sure if they are stock GM items though.

How about tire suggestions 235/85R16s? or some Commercial tread tire? The next tires I buy will not be A/Ts like now as they are not the most efficient on fuel.

I personally like air dams, but i like 2wd and Handshakers so take it as my opinion!:crazy:

quandts (quandtsonline.com) looks (I never dealt with) to be a good outfit with a good story, new take off stuff (mainly wheels and tires), (plus some obvious replacement stuff, door, tailgate skins, fenders, etc.) they have 20 dollar 4wd air dams, and 18 dollar 2wd ones.

I heard somewhere that air dams divert the air around instead of under the vehicle, and that eliminates most airflow under vehicle, which supposedly allows for better airflow through engine compartment (and the radiator), as the air isn't fighting to merge with the under-vehicle air stream.

On the tire subject, i personally like stock size, as on a gasser (dads 98) it actually got sub tens when we went to 235/85, back up to regular mileage when back to 225/75 (but we never re-programmed for the 235s), so idk how it affects diesel.

On tread, i do feel that highway only tread would yield better mileage (dura grappler, all other brands HT tread)

 

[jmiller]

Tire make a big difference, I just went from 295's to 315's and my mileage sucks now. Looking to go 285's. I'm kinda stuck with big tires because I bought the truck with a 4'' lift, when fuel was below $ 3.00...

Was the speedometer recalibrated when you changed the tire sizes??

if not odometer isn't accurate and throws off your mileage. ( just a thought )

To a point, bigger the tire, lower the effective gear ratio. Motor should be turning slower, better mileage.

 

[jmiller]

Hypermiler technique - Urban driving

Turn of engine at stoplights:
Started to turn off the engine at stop lights. Estimate 20 minutes or more of idle time saved per tank. Last tank gained a little over 1 MPG around town.

Make sure ignition is full off, managed to set the SES last night from bouncing the ignition switch.

 

[radrick]

Let off the throttle early for stops and be smooth with the throttle on accelerations. You can do more with these two then anything else as far as driver input goes. Smooth on acceleration doesn't necessarily mean slow though. I haven't figured out what my truck likes for acceleration for best mileage but my wifes caddy gets better mileage if you accelerate fast from stops. When I drive it and accelerate nice and easy the average mileage goes down. I have tried everything to figure out what to do to have it not do that and it turns out the right answer is quicker accelerations from a stop. Unfortunately this meant that the wife won that argument:yikes:. I hate it when that happens. It is much harder to figure this out without a computer giving you average mileage thou.

As far as changes to the truck, in addition to the others list hear I would add remove visors. Also any change that lowers the overall profile of the truck, I have been wondering how much we could save by lower the front end a half inch or so?

 

[Turbine Doc]

Burning your used motor oil is a great way to dispose of a gallon and a half of used waste oil and to keep form having to buy a few gallons of diesel.

.

Also a good way to muck up a good IP, used oil, as fuel additive not a good idea, yes many do it, Dad did it, Grandpa did it, but they didn't have "intelligent" fuel management systems, and tight tolerance IPs/injectors that will get scored if any solids are in the oil that make it past fuel filter Then there is possibility of high acidity and other contaminants in used motor oil, more potential negative to burning used motor oil than the minor mpg difference/benefit it might add.

 

[Turbine Doc]

Dang Jim you beat me to it, guess I should have read to bottom before posting, not ganging up on you OP4, I didn't see that Jim had posted what I was gonna add

 

[gonnasellit]

Speaking of additives, does anyone have any accurate data on mileage improvement using additives/cetane boosters? I have read where many say 1-2 mpg increase. I haven't driven the 6.5 enough to get any real numbers, but using PS silver cetane booster in my Ford (when it runs!) actually seems to decrease mileage slightly. Anyone else experience this? I would think since a higher cetane number decreases the temperature at which the fuel ignites that it would have a similar effect of advancing IP timing and hence better fuel mileage. It should also aid in cold starts with less fuel wasted on startup. Am I completely off base with my logic here? I don't really understand how increased cetane number could adversely affect mileage.