Taming the Beast - Making a GMC 2500HD... Less Terrible

[Plush1992]

Regular cab pickups are only good for project goers. Those interested in drag racing, my welding shop teacher owns a 90's f150 regular cab short bed that does 9's in the 1/4 miles. I would own a regular cab pickup but then again I dont have a family or anykids.

[Deezler]

Thanks for the replies all.

Originally Posted by vskid3

You're not the only crazy person here, I have the same truck in 2WD. http://ecomodder.com/forum/showthrea...0hd-32970.html

Phew! Thanks so much for the link! I didn't know anyone else was crazy enough to invest mental energy and time into what may seem a somewhat fruitless endeavor. Will definitely follow your progress/mods for inspiration.

Originally Posted by vskid3

I'm mainly doing aeromods, though parts will be replaced with more efficient ones as they fail, if available.

Yeah... it's hard to argue with the inherent reliability of these trucks. Start changing stuff... and it may not ever be the same again. And short of new heads/cams/headers (mucho $$) there's not a lot of combustion efficiency improvement to be found on these small block engines.

Originally Posted by vskid3

Stock I would get about 13MPG in mixed driving, about 14MPG doing 75MPH, and 16MPG doing about 60MPH.

Sounds like about what I am seeing in mine. 2WD vs. 4WD is probably not as big a difference in these trucks since the curb weight is so high and same poor aerodynamics & ride height.

Originally Posted by Plush1992

If you got the time, money, tools and energy, maybe you should make a truck aerocap

Eh. I know those really do the best job of getting a pickup into the proper aero profile, but they really ruin so much functionality of having the truck in the first place. Not to mention I've only seen a few that aren't totally butt-ugly. If I made one, it probably would be too.

Originally Posted by oil pan 4

That's pretty terrible because I was getting between 12 and 13 with my 454, 3 speed transmission, 4.10 gears with 1970s non aero dynamics in mixed driving.

Ha, yeah. I mean, probably similar final OD gearing, your truck may be a bit lighter, and they didn't do much with aerodynamics yet for this generation... I promise you I can beat your mpg numbers without removing my engine accessories though!

[Deezler]

Ok, so, I posted some of my mods kind of out of order here.

OBVIOUSLY, my first mod was this bad boy:



Took a few attempts to find the right x-gauge commands to add the transmission temp, air/fuel ratio, and spark-retard. But it's nice to have such diverse instrumentation available.

One of the reasons I really wanted to add the trans temp reading is that I was starting to have issues with no torque-converter lockup when it was really cold out. While I'm still not totally sure that there's nothing wrong with my TC, it did seem correlated to ambient weather temperature. I guess there is some programming logic to keep the TC unlocked to help warm up the transmission, but it was costing me some serious fuel.

The previous owner of my truck was meticulous and dedicated to maintenance, thankfully. So of course he still had the original window sticker. I didn't read it over until after taking the truck home, but much to my delight I saw he optioned the engine block heater! I dug around in the front bumper and sure enough, there was the plug.

Now, if I'm going to go to the trouble of plugging my truck in on a timer to warm the block/coolant, I realized I might as well help the transmission and oil out a little also. So I quickly ordered two of these 150W pad heaters:

Amazon.com: Kat's 24150 150 Watt 4"x 5" Universal Hot Pad Heater: Automotive



So I slapped 'em on the oil pan:



And transmission pan:


Shot of both for context:


Then I got both pad heaters wired in with stock block heater up to a marinco plug in the front bumper:



With a timer set to be on from 3 or 4am-8am I am getting anywhere from 40-60°F above ambient for the trans and coolant (no oil temp gauge yet). Whoo-hoo!

So, not quite "toasty warm", but well above the ~10 degree air we've been having lately. And I am happy to report that the T/C locks up much more readily. Probably somewhere between a 1-2mpg impact from pre-heating before my morning commute. The one time I previously tried letting the truck warm up for 10 minutes on a frigid morning before I drove to work... well, I am too embarrassed to report how bad the fuel economy was. Let's just say... single digits.

[Daox]

Good first mods. You reminded me about the pad heaters too... might have to pick one up.

[oil pan 4]

You need one of these:
http://ecomodder.com/forum/showthrea...hlight=5%2C500
If you want toasty warm.

What transmission and rear end does that truck have?
You may not need 4.1 gears.

Mine originally weighed 5600lb, I weighed it on some scales.
The alt is going back on as soon as my bracket shows up and I have electric power steering to install. I tested it so I know it works, just have to install it.
http://ecomodder.com/forum/showthrea...ion-32895.html

[Deezler]

4L80 trans and 4.10 gears.

I certainly don't need 4.10s, would rather have 3.73. But 4.10 was the only option in these 2500HDs. And with 4WD I have absolutely no desire to change both front and rear gears. Just a downside to this truck that I will have to live with I guess.

Your projects are impressive. Ambitious, too! Thanks for doing them and sharing.

[vskid3]

The 4.10 gears are really overkill in these trucks when they're empty. Over 2k RPM at 60 and creeping up on 3k at 75.

Do you plan on doing any more aeromods?

[Deezler]

Originally Posted by vskid3

Do you plan on doing any more aeromods?

Oh yeah, definitely. Will be trying to get all the low-hanging fruit taken care of, for sure. Following your work eagerly.

Kinda hard to get new mods done this time of year without a garage to work inside of though. Hoping to get my pole barn shell erected this year; might not be able to afford the concrete floor right away though....

[Deezler]

How the truck sleeps. Not surprised that my heaters can't get this thing too toasty given how much cold breeze is sweeping through the rig all night. Once I'm in a garage they should be a good bit more effective. Still helping a ton though!

Single digit mornings this week... brrrrr.

[Deezler]

And while at work. We have some construction / parking issues currently that allow me to go rogue these days, and just park up against the building. But next winter I'll probably be stuck far away from any doors that would let me run an extension cord outside.....