S-10 trying to have it both ways!
 

howdy folks, I've got a few questions for the hive-mind, and I believe ecomodders is the place to get answers.

I drive a 99 s-10 2.2 5spd, std. cab short bed as my daily driver, getting 26mpg avg., depending on fuel quality.
my daily driving is rather minimal, 4 miles to work, and then back again. light traffic, minimal hills, the usual. around 150k miles on the clock.

on weekends, I make a 150 mile round trip to visit my girlfriend. The drive is 70% interstate highway, and 20% steep, twisty, but paved mountain roads, and about 10% dirt and gravel mountain roads.

I've got plenty of top-end power at 70+mph, keeps up with traffic just fine...but is sorely lacking bottom end torque. I'm often loaded down with a canoe, or mountain bikes, camping gear etc. and the poor little thing struggles when the going gets steep, and is generally slow around town.

I see 3 ways around this without totally trashing my fuel economy

I could do the usual N/A mods...intake, exhaust, underdrive pulleys, e-fan etc. and probably gain a small amount of economy, pick up a small amount of power, but spend relatively little money. the motor could probably use a rebuild sooner or later, so this would be an ok stop-gap.

I could rebuild the 2.2 and add a small turbo...they make a manifold with a t-3 flange...maybe run 5-8lbs of boost, and pick up more power than the above option, spend a lot more money, and possibly gain some amount of economy. In this situation, I'd likely go all out...forged pistons, camshaft, gapless rings, injectors, megasquirt PCM, increased compression, and water/methanol injection, as well as the supporting mods in option#1.

my third option is to pull the 5.7 vortec L31 motor out of my rusted out '99 express 2500, detune it a bit...or a lot, considering it makes 3x the torque of my 2.2, mate it to a t-56, and have all the power I need, minimal expense (full swap kit is under $600), and again, probably lose a bit of economy...or not? I've never done a v-8 economy build, just mo'power builds in the past.
I'd be able to pull some pretty tall gears, but I'd be adding 200+ lbs to the front of the truck.
For perspective, a fullsize station wagon like a Buick Roadmaster pulls down the same highway mileage as my s-10 with a 5.7 v8 and a 4-speed auto.

what does everyone think?
I'm no stranger to engine swaps and rebuilds, and I've got a budget of a few thousand dollars.

I'd like to keep fuel economy as good or better, and will explore aero-mods at a later date.

Any chance a hybrid addaption would work?

What about a hefty alternator that you turn on when braking to charge a battery to run an electric supercharger?

I'm starting with a 5spd v6 s10 with a blown motor. Im probably just going to rebuild the v6 for reliability and simplicity.
I was considering a v8 or even diesel swap but i have done swaps before and the cost, mantinence and all the unknowns that go with a swap would probably negate any potential savings in gained fuel economy. Same problem with a turbo, turbo ing an engine is always less reliable and the cost of the parts and need for premium fuel would make the savings from potential mpg gains less significant.
I've had a few s10s.
I've learned that these trucks get their best economy around 55-60mph any more and it starts to drop.
Maybe start with a tune up using quality parts and swap all the fluids for synthetic. Skinnier tires may help when the time to replace them comes.
If the truck goes good at 70 but the engine is lugging around town, swapping the rear end to a deeper gear will hurt mpg on the highway but may help in town.
A free flowing exhaust with a lighter/ smaller muffler may be worth trying too

If you do a lot of highway driving almost all your gains to be had will be had with aero mods.

Thanks for the quick replies! Please keep in mind, the existing motor is in need of a rebuild within the next year or two, and I'm looking for some more bottom end torque.
I've already done the synthetic fluids, tune up, and low rolling resistance tires...but that doesn't get my oil pressure back...or make my lifters any quieter...or fix my leaking rear main seal.

So the choice comes down to rebuild an already somewhat inadequate motor for my purposes, and still struggle on hills, or try to make an improvement.

I know modifications cost money, but fuel economy is only half the equation here. What makes the 5.7 swap so attractive is that I already have a good running motor and the complete donor vehicle of the same make and year.
That old 3/4 ton van got 19mpg average pushing 3.73 gears, with an extra 1000lbs of body and frame, and the aerodynamics of a brick.

Obviously, it'll be more work than my other options, but I do have a well equipped shop and plenty of extra hands to help.

Does anyone have any real world experience with this combination?
I've found a few threads with folks proposing a similar project, and plenty speculation and bench-racing, but not too much in the way of results.

I briefly considered using a large truck alternator with the rectifier and voltage regulator removed as a sort of hybrid drive experiment. it could, with appropriate switching, be utilized as both a 3-phase generator, as well as a motor, but the battery, charge controller, and variable frequency drive would cost as much as an engine rebuild.

I do really like the idea though. I think i could make an adapter plate to bolt one down in place of my a/c compressor, and allow it to apply torque to the drivetrain through the crank pulley.

I'd probably torch off more than a few serp belts before I got all the bugs worked out!

I feel that realistically fuel economy with a v8 would probably be the same as the 2.2 simply due to the extra 3.5 liters of combustion chamber needed to fill with fuel/air.
That being said I had an auto 4.3 v6 4x4 truck and an auto 5.3 v8 4x4 truck that both got the same mileage
I suppose an economy tuned or flashed ecu could net some gains.
The 5.7 probably makes the same power at 2000 rpm as a 2.2 at 5000 so with tall gears in the rear you may see improvement.
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Gasguzzler, that was exactly my line of thinking. It would net me the low end torque I want without losing much if any fuel economy, as well as being a reliable, long lasting engine that I already have.

Then I started poking around the shop, and kicking ideas around...seems I've got quite a few motors lying around.

there's a subaru 2.2...probably gonna be the same low torque problem as my chevy 2.2, but they do love forced induction! plus it could be built while I drive around with my leaky chevy 2.2...hmmm. clutch and adapter plate could be interesting to source.

then there's a pile of jeep 4.0 and 4.2 inline sixes...boy i wish there was room for one of those under my little hood! lots of low end torque, reasonable displacement, good aftermarket support, and some real low lift/duration cams available...again, not pushing a 4500lb brick around would probably wake one of those up nicely.

a guy can dream I suppose.

back to reality...assuming I do the 5.7, I'll need to source a transmission, and it'll be a manual for sure.
the most expensive route is a t-56, but I could retain my axle gear ratio because of the double-overdrive.

I could go 5-speed, like a t-5 or nv3500, or an ax-15(that I have lying around already). cheaper, but I'm in for a re-gear if I want to see any real MPG gains.

I've also heard that a 4-speed has less parasitic loss than a 5 or 6 speed because of the lack of an intermediate shaft and one less gear cluster, but I'd be going crazy tall with my axle ratio, and I'd have pretty wide ratio changes between gears...seems like it wouldn't drive as well.
my feeling is that the 5 or 6 speed will be the way.

Have you seen this?
https://ecomodder.com/forum/showthre...mpg-33961.html

yeah, I ran into that thread before. It's rather impressive what can be done with gearing! I don't have any plans to take things that far, because I'm also interested in my ability to climb rather steep grades while loaded, and drive on the interstate for an hour with a canoe on top, but if I could eek out 30 mpg from a daily drivable 350 powered s10, I'll have exceeded my goals.

what I like about this approach is that I can build a drivetrain, and amass the parts needed to complete the swap while I'm still driving the truck, and then just borrow a car for a week, take off work, and complete the install without a major life disruption.