V8 Lover looking for better MPG's

[blade]

welcome to em
appears to me your more of a gearhead then a modder (your not alone )
the best think i can recommend is slow down a bit set your cruz speed at 60 i think you will have more money to put in the old cutlass

[Nonhog]

Yes I am a gearhead 1st! No issues there. However I drive smoothly and calmly. I do try (and with a fair amount of effort) to get the best mpg I can.
I've been a slacker about doing anything to my truck.
Many other projects. Been using Mobile 1 oil 0w-30 and it seemed to make no difference. No surprise. I'm torn between leveling the truck(lowering the back 2-3" or complete lower. Thats another item that won't upset me if it shows no big gain. Getting too old to jump off the tailgate of this thing, it sits so high. From what I've researched its probably not a good engine to supercharge due to the limited EFI system. I swear the V8's got a mile or two better than the six but maybe I was wrong?
Either way Its been almost 3 years as a daily driver and I'm getting about 18
avg. Yet to see a 20mpg tank and boy have I tried.
Now its winter and I just installed winter tires and my mileage has dropped to high 17's Had a few high 19's. Was hopping for a 20 before any mods but what the hey.
Thanks for the reply's

[blade]

maybe a new air filter and air inlet like those little riceburners run

[bhazard]

Wow they still used the 4.3 in 2008? That has to be close to 25 years or so for that engine.

Definitely slow down. If you stayed at 55-60 no doubt you would have 20 mpg. Lowering would help a lot too, that thing is all jacked up.

[rmay635703]

I've gotten 22mpg with an Auto 5.2 v8 dodge 1500, trust me, If I can do it in that thing you can definately do it in your infinately better GM.

If its a 2wd put small tires on the front end (I did with my dodge and it really helped, I think the loss of height was the reason that and they were LRR)

Things I have been considering are
1. Aero topper
2. Plenum gasket (shouldn't apply to you)
3. MT swap

I would estimate the best thing you could do would be an MT swap, it takes patience but remember the 700r4 and NV3500 were the same dimensions and XMBR wise, I would estimate with a bit of visual inspection you would find your XMSN and a MT counterpart might be drop in replacements.

I am right now waiting on getting me 89 diesel sub converted to double overdrive MT. I will actually need grandma gear to take off.

Something else you can do but everybody here hates is to reprogram the ECU the hard way using some of the freeware ECM utilities and move your maps past stoich in your highway cruise region (if you cruise on the highway a fair amount) thats good for about 2-4mpg in of itself. You need a good bit of tuning knowledge and patience to pull it off properly though.

Just make sure you can flop back and forth.

Good Luck
Ryan

[darcane]

Originally Posted by rmay635703

Something else you can do but everybody here hates is to reprogram the ECU the hard way using some of the freeware ECM utilities and move your maps past stoich in your highway cruise region (if you cruise on the highway a fair amount) thats good for about 2-4mpg in of itself. You need a good bit of tuning knowledge and patience to pull it off properly though.

Just make sure you can flop back and forth.

Good Luck
Ryan

What's the scoop on this freeware ECU tuning?

I've looked at a service to reprogram the ECU for my '03 Silverado. One that caught my eye claims 1-3mpg improvement (Not much on a Prius, huge on a full size truck). The thing that has stopped me is cost. $200+ for a mod that may or may not improve efficiency. A free utility to play with sounds interesting, but you still need a ECU -> PC interface of some sort...

Mike

[rmay635703]

Originally Posted by darcane

What's the scoop on this freeware ECU tuning?

I've looked at a service to reprogram the ECU for my '03 Silverado. One that caught my eye claims 1-3mpg improvement (Not much on a Prius, huge on a full size truck). The thing that has stopped me is cost. $200+ for a mod that may or may not improve efficiency. A free utility to play with sounds interesting, but you still need a ECU -> PC interface of some sort...

Mike

You are more or less completely and utterly on your own is the scoop.

Those services may or may not work and the price is obviously not very good.

The megasquirt and other options that are controlled by you are also not real cheap.

If you do it yourself completely you need to understand the binary portion of the rom, how to make it into a human readable thing, how to identify its parts and how to modify it.

Generally you will also need a computer, a soldering/desoldering iron, nerves of steel *******izing and putting a socket in your ECM and a ROM reader for the PC.

I failed when I tried that route so I am little help, also remember each vehicle and motor varient has its own club and potential utilities, a google search might help.

Oh and if you do it yourself it voids any warranty you may have.

Cheers
Ryan

[Everett]

Originally Posted by Nonhog

Yes I am a gearhead 1st! No issues there. However I drive smoothly and calmly. I do try (and with a fair amount of effort) to get the best mpg I can.
I've been a slacker about doing anything to my truck.
Many other projects. Been using Mobile 1 oil 0w-30 and it seemed to make no difference. No surprise. I'm torn between leveling the truck(lowering the back 2-3" or complete lower. Thats another item that won't upset me if it shows no big gain. Getting too old to jump off the tailgate of this thing, it sits so high. From what I've researched its probably not a good engine to supercharge due to the limited EFI system. I swear the V8's got a mile or two better than the six but maybe I was wrong?
Either way Its been almost 3 years as a daily driver and I'm getting about 18
avg. Yet to see a 20mpg tank and boy have I tried.
Now its winter and I just installed winter tires and my mileage has dropped to high 17's Had a few high 19's. Was hopping for a 20 before any mods but what the hey.
Thanks for the reply's

if you are gonna spend the money on a synthetic oil go with amsoil....dollar for dollar the best oil out there

[ECONORAM]

Here is a site I used for some of my initial ideas for FE improvement:
A Truck That Drinks Less Than a Car? | Popular Science
Just doing the panels outlined in this article will benefit you. I am, and can get 20 mpg nearly at will once the truck hits 4th gear. My truck is rated 14/19.
Make sure your front end alignment is correct. I discovered mine has been out of whack for a year?! Boy is that frustrating.
Lowering your truck will also help, but not dramatically. It does reduce the drag coefficient. Synthetics also help, but the kicker is reducing your truck's Cd. Speed (velocity) is the enemy, as drag increases with speed squared, not just directly with speed. See the drag equation, rearranged to solve for your Cd:
The Drag Coefficient
Drag = (1/2)*Rho*Cd*A*V*V where Rho (I don't have the greek letter key) is air density, Cd is your drag coefficient, A is your frontal area, and V is your speed (or velocity).
The factors you can really change are your speed/velocity and Cd.
As you can see, the faster we go the drag increases dramatically. My truck has a 0.52 Cd, and with 32 sq ft of frontal area (A), I am in a world of hurt for drag. I suspect your truck isn't that much better than mine.
Here's another page to look at: Drag Force Calculation and Equations. Drag Coefficients.

[edit] rmay, when my alignment was on track I hit 24 mpg driving across northern Utah on I-80, so I agree, GMs are typically better on aero than Dodges, especially my Gen3. GM has an aeronautical engineer working high in their company, so I am sure he is influencing things...

[Frank Lee]

Re: that Pop Sci bit: Wow. Just... wow. Aside from the pickup aero info (good), their "test" and their premise is complete crap.