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Somewhat theoretical MPG question

tanman_2006

tanman_2006

Just a farm kid...
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Seiling, Oklahoma
I am looking at a 82 C3500 6.2L 4speed dually. http://wichita.craigslist.org/grd/3879962835.html

I have a 82 c1500 that got 25mpg ran hard and 32mpg highway but it is pretty rusted and needs alot of attention to be ok again. I want to replace it and have a soft spot for big bottom girls.

So if I got the 82 single cab dually what would be optimum gear ratio for a truck that doesnt have O/D but will hopefully end up with a NV 4500 when funds manifest. Would 3.42's give me a decent cruise rpm w/ 30-32" tires? I know I could look it up easy and I figure that would put me ~2-2200 @65 but would that combo give me decent mpg in a N/A 6.2?

Thanks for any help, feel free to throw out any random MPG/ N/A Power related ideas.
 
Been playing with the #'s here and looks like 3.42's and 235/85's will get me to 23-2400 which isnt great but better than 3K

Precision gear has 3.73 gears for a 83-87 C30's and 81-87 c20's. What differences are there in the axles? I could find a 90's 14 bolt and and swap it in if i had to but changing spring perches isnt on the top of my to-do list. Still searching for info on gear ratios.
 
Don't think getting 3.42 R&P for that dually 14 bolt/10.5 is a problem. There are 2 carrier sizes - catalogs list the ratio break - if it happened to originally have 4.56:1, that carrier won't fit the 3.42 or 3.73 ring gears - think the break is 4.10, 3.73, & 3.42 is the smaller carrier, then 4.56 up is the larger carrier.

There was a bearing size change/upgrade through the years on the 14 bolt (also some seal improvements & later housings have more ribbing in the center housing casting. Believe the 3rd bearing on the pinion was upsized (maybe also carrier bearings, can't recall for certain), but not a problem, just buy the correct carrier & pinion bearings for the year 14 bolt you've got.

I moved the spring perches (and you typically also need to move the jounce bumper pad) on my GMT800 14 bolt for my truck. Not a super big deal, but consumes time.

Relating to your plan down the road, you might gain some mileage in the naturally aspirated state (but couldn't tow a lot very fast), then turbo & fuel it accordingly later, & give up the fuel economy gained earlier?
 
The plan is not to have a heavy tow rig or I would keep the 4.10's. I want something that can pull a stock trailer and use as a parts runner (my 95's current job) and I like the looks of the 80's duallies.

IF I turbo it the goal will be to keep most of the economy and do a remote or center mount. I dont want a race truck either and being a 2wd I dont think 20-25mpg is out of the question with a little work.

I have plenty of workhorses, I want a cruiser.
 
Go single rear wheel for MPG. 2 more tires on the ground generate heat and wear eating fuel.
 
I know, but I like the look of duals. I'm sure a 2wd 2500 would do better on fuel but I want to ride in style while I'm at it.

I COULD fix my 82 c1500 but it needs alot of work. Can see through the floor and doors are swiss cheese for starters. Needs a whole new bed and front clip, tranny leaks bad and didn't shift right last I tried it and I parted out most of the interior and accessory drive when I needed cash.

Sent from my Milestone X2 using Tapatalk 2
 
tanman_2006 said:
I know, but I like the look of duals. I'm sure a 2wd 2500 would do better on fuel but I want to ride in style while I'm at it.

I COULD fix my 82 c1500 but it needs alot of work. Can see through the floor and doors are swiss cheese for starters. Needs a whole new bed and front clip, tranny leaks bad and didn't shift right last I tried it and I parted out most of the interior and accessory drive when I needed cash.

Sent from my Milestone X2 using Tapatalk 2
Click to expand...

Sometimes you have to put one out of it's misery. This sounds like one of those times before it becomes a black hole for cash...
 
Since you like the looks of duals, could you fake duals and still have just the four wheels? What I'm thinking about is take the inner wheel of the duals off and just put the outer wheel back on. This would still look like duals, without having six wheels creating extra road friction. I'm not real familiar with duals, but I saw this done many years ago when the guy wanted traction in snow (only about 6") and claimed that the outer wheel setting outside the front wheel track and running in fresh untracked snow gave him better traction.

Or, would this create too much offset for the wheel bearings and wear them out faster?

Don
 
Just got some news that might put this project on hold but I am still interested in doing this. It just might not be the right time to spend extra money.
 
handcannon said:
Since you like the looks of duals, could you fake duals and still have just the four wheels? What I'm thinking about is take the inner wheel of the duals off and just put the outer wheel back on. This would still look like duals, without having six wheels creating extra road friction. I'm not real familiar with duals, but I saw this done many years ago when the guy wanted traction in snow (only about 6") and claimed that the outer wheel setting outside the front wheel track and running in fresh untracked snow gave him better traction.

Or, would this create too much offset for the wheel bearings and wear them out faster?

Don
Click to expand...


A few only run single wheels in the winter as a dually in the snow is brutally bad and sometimes downright scary.

It won't hurt the bearings, they are very big and designed for work.
 
I like the wide hipped girls too, 3.42 in a 14bolt Full Floater aren't that hard to find. Yukon gear makes a set, I've bought that exact set for my 1995 suburban thinking of going from 3.73 to 3.42 (was originally 4.10) and got the 3.42 front diff to go with.

I think 3.42 is the perfect Diesel gear ratio personally.

The 235/85 R16's would be the ticket.

Bet you'll see 18-19 driving it easy and empty and around 65mph.
 
I put 3.42 in my one ton srw. It tows anything I need still witch isint much. It went from 4.11 and is so much quieter now.
 
Yeah, I am holding off on the extra dually and going to put my efforts into my 95z71 it already gets 19mpg unloaded but lately has been running around with 100 gal of diesel, extra oil, and 3 tool boxes.

I have all of Ol Blues original axles from when I started on the sas. So I am thinking of converting to 8 lug k3500 parts w/ 3.5" drums, 3.42s, and a wh1c hybrid turbo. Not going for a race truck but I have the wh1c on hand. I also have a set of 20" rockstars w/ 33x12.5 r20s, those won't help the mpg but I have them lol.

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