Mileage Maker

[1972RedNeck]

With gas prices where they are, I would like to build a 4X4 that gets decent economy. I have been toying with the idea of a turbocharged 292.

From what I have read, Turbocharging a 6.2 diesel causes the mileage to drop. Would turbocharging a 292 lower the fuel economy?

[Dingfodgy]

I'd look into a Cummins or Isuzu diesel swap before I slapped a turbo on an old inliner that gets pretty crummy mileage to begin with. Just sayin'!

[1972RedNeck]

A 292 may get worse mileage, but gas is also cheaper. You only have to get 16.5 MPG to be at the same cost as a cummins at 20 MPG.

[hugger6933]

You have some flaws in your idea. 4x4's even the new ones with ls type power are not known for the economy. First we need to find out what is the target MPG good is a relative term. Good compared to trucks now then or what. Turbocharging will give you power and torque to get that brick moving but you will also get to likeing the power so much that it will be hard to "drive right". That brings another issue to light your driving habits, everyones is differentand some lean more towards better MPG than others.A masor increase in mileage will come from gearing ,either in the rearend or in the trans with a overdrive and in the case of 4x4 it will be twice as expensive to raise the gear ratio cause you have to do it twice. The best hope for econmy short of a diesel or ls/overdrive swap is like I said in another post recently tune up to the max. Carb, dist vac and mech advances timing perfect adjust the valves for better efficentcy tire pressures front end alginment and so forth. I'm not trying to discourage you or pee on your cheerios. I would hate to see anyone spend gobs of money and it not live up to expectations. Good luck in your quest.

[rsavage]

A stock LS swap might gain you some mileage but lots of variables such as differential gearing, tire size etc. Don't really see turbo charging as being a mpg increaser. You can buy a lot of gas for what it will cost for an engine swap, turbo charger, gears, transmission etc. Figure out what you want to do, add up the cost of parts and labor if you can't do it yourself, double it because it is always much more than originally figured. Compare the costs against cost of gas at your present mileage and see what the cost benefit will be. I would bet it would take years to recoup the investment.

[biggestjohn]

For the cost involved, you can buy ALOT of gas!!

If you want added HP turbos are great, but if your goal is only mileage, spend it somewhere else.

One great feature of a turbo system is that a factory stock, mileage cam is ideal, but you will always lose some mileage due to exhaust back pressure. And you WILL have to use premium gas.

But if you want some of the two worlds, they can't be beat.....and when those turbos kick in...................

[msgross]

why do you need mpg's? daily commute? If so then park the truck and buy a TDI like I did... I went from 13-15mpg's to 35-45mpg's for about $4500...

Now if you need the truck for work and drive a lot then a small 2WD beater would be a better option...

[1972RedNeck]

The only problem with cars/2WD's is mud, snow, ice, (etc).

I would like to get 15 - 16 mpg at 70. I also like horsepower. This would be a ranch truck. Occasional trips to town, light trailer towing, dirt roads (etc). I was thinking 4.10's and a .73:1 overdrive would be about right at 2.99:1 overall.

I have always liked 292's and a turbo would add the cool factor.

They made fuel injected 292's for UPS trucks, didn't they? I would get one of those to use.

[sbc10guy]

If it doesnt have to be an old truck I get 20 mpg highway, and 17 city with my 4wd 98 gmc truck. Has a 350 and can do anything i want it to, they are very nice trucks.

[msgross]

700r4 and higher gears might work then

[1972RedNeck]

I plan to use a NV4500. I have the truck ($100 1972 K20). I want to do something different. I prefer old trucks to new.

[Dingfodgy]

Originally Posted by 1972RedNeck

I plan to use a NV4500. I have the truck ($100 1972 K20). I want to do something different. I prefer old trucks to new.

I can relate to your preference to an "old truck", but the reality is that if you are going to insist on rollin' around in 45 year old iron with 45 year old technology- it's going to cost you. If you need to get 16-18 mpg and still have hauling capabilities and 4wd.....a late model truck is by far the best and cheapest route. You could still have the classic to play around with and a inliner on boost would be kick-ass for sure, just not very practical for a DD or work truck.

[MARKDTN]

My '83 K20 gets about 17 city and 21 highway. It has 3.42 gears, 700R4, and a stock 350 Tuned-Port from a '91 Corvette. The only flaw is that it has to have premium fuel or it knocks. If I did it again, I would use the same short block with Vortec heads and hopefully base fuel.

[1972RedNeck]

Originally Posted by Dingfodgy

I can relate to your preference to an "old truck", but the reality is that if you are going to insist on rollin' around in 45 year old iron with 45 year old technology- it's going to cost you. If you need to get 16-18 mpg and still have hauling capabilities and 4wd.....a late model truck is by far the best and cheapest route.

I don't need to get more than 10 MPG. It just gravels my a$$ giving the oil company's that much money. I am just wondering if a L6, SBC, or BBC will get decent mileage and horsepower. If a turbo and a 292 can get good mileage, that is a plus. As long as it gets better than 12 I'll be happy.

[406 Q-ship]

If your set on using the early truck. Then an overdrive trans with reasonable gears, tires not too tall or wide (rolling resistance and inertia), weight reduction, and Fuel inject the 292.

[1972RedNeck]

The NV4500 has a .73:1 overdrive. Would 4.10 or 3.73:1 rear end gears be better. The 292 has a lot of low end torque as it is.

What would the max safe boost be? 7 Lbs.?

[Indyuke]

Originally Posted by 1972RedNeck

The NV4500 has a .73:1 overdrive. Would 4.10 or 3.73:1 rear end gears be better. The 292 has a lot of low end torque as it is.

What would the max safe boost be? 7 Lbs.?

A 292 isn't going to give you much by way of fuel economy. I believe they are on par with the average SBC. If you went with a 250, your fuel economy would be noticeably better. Turbo or supercharging any motor will actually give you worse fuel economy overall. The only reason Ford does it with their new ecoboost motor is so they can get away with putting a dinky V6 in a full-sized truck while still tapping into the power of a V8 when you want to. But when that turbo kicks in, fuel economy goes down the drain.

If you want fuel economy, a 250 I6, NV4500 and 3.73 rear gearing would give you the best options. Good fuel economy overall, but still able to haul around a full load without too much hassle. I imagine you'd see high teens mixed city and highway driving with that setup.