How to best improve fuel economy with '76 Pickup?

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Originally Posted By: Steve S
Originally Posted By: Big O Dave
Originally Posted By: Steve S
Wrong engine ,trans,diff,vehicle setup for gas mileage.


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So helpful!
It is the absolute truth!!!
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What is the cost of any of the mods to increase the mpgs and what will you gain? You could do an engine ,trans, diff,low rolling resistance tires etc and get 2 or 3 mpg max if you are lucky . Some Amsoil users seem to get an increase of 5 mpgs
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Of course, you're right, it is certainly NOT a high mpg vehicle; my goal is not to get 20 or 30 mpg, but to simply get the best mileage I can with this vehicle.

The reason I posted here was not to accomplish some unrealistic goal, but to get some ideas and thoughts from the BITOG readership, which on the whole tends to be more cerebral than many other forums. For example, I am curious just how much of a difference gearing makes. I know that with my Explorer, every time it locks up in overdrive the fuel economy increases several mpg, per the onboard computer (depending upon throttle usage).

I have a free-flowing intake and exhaust, I am pretty gentle on the throttle (although I DO have a vacuum gauge I need to install to do an even better job with this) and my truck is in an excellent state of tune (it produces lower emissions than the Explorer or my wife's Camry, despite not having a catalytic converter). I am using P-metric tires which are inflated for optimal fuel economy.

That's why I'm exploring overdrives and gearing changes, but I hadn't thought of going with an Edelbrock or Holley fuel injection system; that's a good idea.

Just as an FYI: the short block for this engine is a 2000 model year Vortec 350 for a 1-ton pickup, and it has 4-bolt main bearings. The hydraulic roller cam is the cam that cam with this short block. I bought this crate engine new, removed the Vortec heads and installed the AFR 190's, which really widened the power-band, retaining good low-end, but allowing a stupendous upper end (for a truck engine). It has turned out to be a pretty efficient setup, and the fuel economy I'm achieving now is pretty good for a 3/4-ton pickup without an overdrive.

Anyway, I truly appreciate all of the input - you guys are great!
 
What about a TPI setup and the 700R4 swap? A good friend of mine has a 700R4 in an S10 with a nice strong (~425HP) 355 in front of it and the OD does help.
 
Actually, I don't think 20 MPG on the highway is out of the question. My 97 Chevy pickup with the Vortec 350 you described, fuel injection and 4L60E trans has gotten twenty and a half on the highway. I don't remember the gearing offhand, but it is turning around 1800-2000 RPM at 70 MPH.

I also have experience (positive) with adding fuel injection in place of a Q-Jet on one of the trucks I described earlier. I saw a measurable savings in stop and go traffic, where you said you do much of your driving. I didn't see much improvement on the highway, but the overall improvement in drivability was significant. This was not even a sophisticated system, just the first generation Holley Pro-jection.
 
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The port systems from Holley and Edelbrock are a bit pricey, but they do have 2 and 4 barrel TBI setups for much much less.

I remember on Horsepower TV they put a 4 bbl TBI on a 350 and it made like 20 more hp and fuel consumption dropped by like 15% or so. Totally plug in and forget as it uses a MAP sensor and an 02 sensor to adjust things.

That in combination with a top notch electronic distributor would give some serious fuel economy gains.
 
Well for cost and durability changing to a 3.10 ring and pinion from someone like DTS would be the way to go. Now if I was going to to change my drive train I would get a 4L80 with standalone transmission controller from GM PErformance Parts. You can get one for about what you are looking at for the OverDrive unit. It does not get much better then a 4L80 for a high volume production transmission. This thing is used behind the 572 crate motors and such. You know if you change your ATF at the very least at 10,000 miles then every30,000- 50,000 miles with high quality stuff like amsoil,Redline or the latest Dex formula that that 4L80 will easily last 200,000 miles.
 
If you do not already have a small 4 barrel that helps too. I would limit the secondaries so that you really can not open them much. I am assumeing you mechanical secondaries since no one likes vaccum secondaries. You might consider useing E85 since a carberator can not richen the mixture the way fuel injection does you can get and extra 1-2 mile pergallon out of e85 where with a fuel injected engine you will get worse fuel milage since the computer just lengthens the injector pulse to make up for the E85 being used.Useing synthetic fluids of the lowest viscosity that will work in your application also helps. So if your 350 will build decent pressure with 5W20 say greater then 8psi at idle and forward swing of say 30 or more psi at cruiseing RPM's that wold help!
 
Originally Posted By: JohnBrowning
If you do not already have a small 4 barrel that helps too. I would limit the secondaries so that you really can not open them much. I am assumeing you mechanical secondaries since no one likes vaccum secondaries.

The Q-Jet has all that covered already and really isnt a bad carb if everything is kept up and working right.
 
Originally Posted By: Drew99GT

That in combination with a top notch electronic distributor would give some serious fuel economy gains.


Drew, I have a MSD HEI with a MSD coil and module, plus MSD ignition wires (I like MSD, I guess
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). Is this what you're talking about?

(JB, I was wondering when you were gonna show up!
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)
 
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Originally Posted By: Papa Bear
Put a 250 Kawasaki in the box and everytime you have to go somewhere ... take the bike.
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When I first glanced at your post, I thought you were recommending that I swap out the SBC and put in a Kawasaki 250, instead. Not only would the truck barely move (and then only with REALLY low gearing), but the fuel economy would be even worse!
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Pulse and glide when on the highway. Open the throttle wide, accelerate, then put in neutral and close throttle, shutting down the engine. You'll need a throttle that closes 100% with no room for idling, and a speed activated idle solenoid that activates when you're below maybe 20mph. An extra few cubic feet of vacuum storage can be made from high temperature plastic piping so you'll still have power brakes, or maybe an electric vacuum pump for good safety factor. Insulate the engine with a heat resistant foil so it stays warm enough. Electric power steering might be good, too, and a larger alternator since the engine will only be running about 10% of the time. This should get you well above 30mpg.

This is the technique used by the super mileage contest winners who get in the thousands of MPG with their microcars.

This is actually a parallel hybrid system, with inertial storage instead of battery storage. Inertial storage is 100% efficient, while batteries and regen braking might be 80%.
 
Originally Posted By: oilyriser
Pulse and glide when on the highway. Open the throttle wide, accelerate, then put in neutral and close throttle, shutting down the engine. You'll need a throttle that closes 100% with no room for idling, and a speed activated idle solenoid that activates when you're below maybe 20mph. An extra few cubic feet of vacuum storage can be made from high temperature plastic piping so you'll still have power brakes, or maybe an electric vacuum pump for good safety factor. Insulate the engine with a heat resistant foil so it stays warm enough. Electric power steering might be good, too, and a larger alternator since the engine will only be running about 10% of the time. This should get you well above 30mpg.

This is the technique used by the super mileage contest winners who get in the thousands of MPG with their microcars.

This is actually a parallel hybrid system, with inertial storage instead of battery storage. Inertial storage is 100% efficient, while batteries and regen braking might be 80%.


I have a feeling that in order for this strategy to work, the vehicle in question has to have low rolling resistance and low aerodynamic drag, both of which would enable the vehicle to minimize loss of speed with the engine off.

Unfortunately, this truck has neither.
 
in order of greatest effectiveness to least

1. 4 spd trans with lockup converter
2. 3.x gearing
3. consider slimmer tires
4. syn fluids in driveline
5. EFI
6. (dreaming) Throttle-based/load based cutoff to 4 injectors to allow cylinder deac during cruise to allow more open throttle/reduce pumping losses/greater efficency
 
Originally Posted By: meep
in order of greatest effectiveness to least

1. 4 spd trans with lockup converter
2. 3.x gearing
3. consider slimmer tires
4. syn fluids in driveline
5. EFI
6. (dreaming) Throttle-based/load based cutoff to 4 injectors to allow cylinder deac during cruise to allow more open throttle/reduce pumping losses/greater efficency


Thanks, Meep! This is the kind of stuff I've been looking for. Do you think with the OD trans w/lockup converter there would be an additional advantage to change to 3.x gearing?
 
Originally Posted By: meep

6. (dreaming) Throttle-based/load based cutoff to 4 injectors to allow cylinder deac during cruise to allow more open throttle/reduce pumping losses/greater efficency

There is a lot more going on with cyclinder deactivation than just turning off injectors. It actually doesnt open the valves, not a DIY project.
 
Originally Posted By: Big O Dave
Originally Posted By: meep
in order of greatest effectiveness to least

1. 4 spd trans with lockup converter
2. 3.x gearing
3. consider slimmer tires
4. syn fluids in driveline
5. EFI
6. (dreaming) Throttle-based/load based cutoff to 4 injectors to allow cylinder deac during cruise to allow more open throttle/reduce pumping losses/greater efficency


Thanks, Meep! This is the kind of stuff I've been looking for. Do you think with the OD trans w/lockup converter there would be an additional advantage to change to 3.x gearing?


Not worth the cost to do both due to diminishing returns IMO. New trucks with 3.73s and overdrives turn pretty reasonable RPM. 4.10s are not very far away from 3.73.
 
Originally Posted By: Duffman77
Originally Posted By: meep

6. (dreaming) Throttle-based/load based cutoff to 4 injectors to allow cylinder deac during cruise to allow more open throttle/reduce pumping losses/greater efficency

There is a lot more going on with cyclinder deactivation than just turning off injectors. It actually doesnt open the valves, not a DIY project.


True if you're designing one from scratch. It doesn't mean that you're at a total dysfunctional system without that feature. What would be nice is to have a synchronized rotation of the cut injectors so that cylinder temp is uniform. Unfortunately, without some adaptive software, you're going to be leaning your exhaust a good bit with 2X the O2 (or more) ..richening the active cylinders (or so I reason).
 
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