Ways to increase the efficiency of a GM 5.3L

[Solarpowered]

Hi all, I wanted to stop by and ask about ways to increase the fuel efficiency of a GM 5.3L v8. My old 5.7L 350 is worn out, and I want to replace it with a more modern, better engine. It will be going in a 1987 Chevy Silverado.

I don't really trust junkyard engines, so I'm going to have a reputable engine builder put the 5.3L together for me. So why not have him use parts that increase efficiency? Here's my rough list of things that may increase the fuel economy of the 5.3L engine.


1. Lighter connecting rods
2. Better roller rockers Aluminum
3. Lighter crankshaft? Aluminum
4. Good oil cooler with thermostat
5. Good trans cooler too, also with thermostat
6. Electric water pump
7. Electric fans
8. Electric power steering?
9. More efficient alternator
10. High flow oil pump with bigger better filtration system
11. Canceled - Bad idea.
12. Lighter better flywheel?
13. Aluminum or carbon fiber driveshaft
14. Long tube headers and good exhaust system
15. Floating pin pistons
16. Internally balanced. The crank itself is balanced, and does not need a harmonic balancer or balanced flywheel? Seems like less rotating mass if no harmonic balancer
17. Cancelled - bad idea
18. Better pistons and rings somehow?
19. The usual heads, cam, and intake upgrade - if this can increase efficiency
20. A "tune" for fuel economy
21. E3 spark plugs
22. Upgraded ignition system?

I tried posting this earlier, but I think it glitched and didn't post my thread. Hopefully two threads don't appear.

[freebeard]

Windage tray, else dry sump.

[Solarpowered]

Thanks! Wasn't sure if they came with that from the factory or not. I'll add it to my master list. I'm hoping I can manage to squeeze out 5 more MPG just from modding the engine itself.

Also the ones with question marks are things I'm not sure of. In case anyone wants to chime in with info on whether or not that item could increase fuel economy. For instance, I'm not sure if there are any lighter pistons that would increase efficiency. One would think that forged pistons pack more material into a smaller package. Thus increasing the density, and increasing the weight.

[freebeard]

How do we know what #11 and #17 are?

Also ported and polished heads with three-angle valve grind.

[Solarpowered]

Originally Posted by freebeard

How do we know what #11 and #17 are?

Also ported and polished heads with three-angle valve grind.

Those two were just bad ideas and stuff I don't want to do, like over inflating the tires in an attempt to squeeze out more. Stuff I'm really not all that comfortable with.

As for the cylinder head thing, that's something I haven't really been able to work out well. You can port and polish, but where is the stopping point? There must be a sweet spot somewhere, and if you go over that, now you have to spray more fuel.

But there comes a point where you increased power by doing that, and thus you might have increased efficiency somewhat.

[cRiPpLe_rOoStEr]

I don't remember having ever seen aluminium crankshafts. Since it's way softer than both forged steel or cast iron, most likely it won't be up to the task.

[jakobnev]

Those two were just bad ideas and stuff I don't want to do, like over inflating the tires in an attempt to squeeze out more.

That would outperform anything else on that list.

[Isaac Zachary]

1. 2. 3. and 12.

Aluminum parts that are under high stress will not last long. I'd forget about aluminum cranks, connecting rods and rockers unless you're ok with replacing that sort of stuff every year or so.

You could do titanium rods, but not worth it in my opinion. Those need to be very well designed and treated so as to prevent galling.

In the end, I don't think 1. 2. or 3. would be worth lightening unless you're trying to make a high revving racing engine. But for fuel mileage you won't notice a difference IMO.

You're best bet is a lighter flywheel, which is what you'd want to do before trying to lighten anything else of the rotating assembly. But whether a lighter flywheel will help or not depends on one thing: are you going to be accelerating and decelrating a lot? A heavy flywheel won't noticeably hurt fuel mileage if you're just going to get on the highway and cruise. But around town a heavier flywheel takes more energy to spin up and then releases more energy spinning back down.

4. 5. 6. 7.

These are great ideas!

8.

Have you seen the thread where someone took an A/C pump clutch and put it on his power steering pump? That way the power steering could be turned on and off as needed.

9.

Nice idea.

10.

How is this going to help fuel mileage? I'd say just change your oil regularly (every 3,000 miles or 3 months for your engine) and use a good filter and good oil.

14.

I saw an interesting idea for unequal length headers for a crossplane V8. There are also 2 into 2 headers that accomplish a similar idea. I wonder if you could make them long enough (depending on your RPM goal) to connect the two end cylinders of one bank with the two middle cylinders of the other bank to create 180° firing order manifolds...

The problem with a crossplane is you have firing interavals of 270° 180° 90° 180° on each side. That 90° space between the two cylinders means you have one cylinder starting it's exhaust cycle while another is still in it's exhaust cycle on the same exhaust manifold. That means more back pressure for those cylinders.

Or you could try to convert to a flatplane crank and have all 180° firings on one side, but then you'd have a secondary imbalance.

16.

This is a great idea. Dynamically ballancing with the pistons and rods is best. A crossplane crank cancels out primary imbalance of the pistons by means of counterweights.

18.

Hypereutectic pistons hands down! These are lightweight and expand less than any other aluminum piston letting you build with tighter piston to cylinder tolerances, so less blowby and less friction. They are also less conductive to heat so they keep more of your heat in the engine, kind of like with ceramic coatings.

I'd go with good cast iron rings too for best wear.

20.

Man! There is so much you can do tuning, I'm going to have to get back to you on that! Tuning is where it's at!

[Piotrsko]

Dont forget a block girdle when doing boring. I slao prefer perfect circle or no gap rings and spending time matching fits to mating parts.

[freebeard]

As for the cylinder head thing, that's something I haven't really been able to work out well. You can port and polish, but where is the stopping point?

Three angle valve grind is pretty straightforward. Porting and polishing is a black art, at least it was in the mid-1950s.. Rough finish in some areas prefered.

Today we have extrude honing.

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Automotive - Extrude Hone AFM
This makes Extrude Hone AFM's contribution complete: better performance, better fuel efficiency, and cleaner exhaust emissions. Bring Us Your Components Today If you are interested in using the AFM process to improve combustion and efficiency, we recommend starting with the intake manifold.

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Extrude Hone Porting in Charlotte NC - Extrude Hone AFM
Extrude hone porting in Charlotte NC can deliver many benefits for any passage that gas or liquid will be flowing through. The most commonly ported parts are intake and exhaust manifolds, but we can also port engine heads, turbo impellers, housings and pumps, and 2 or 4 stroke cylinders.

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Extrude Honed Intake Manifolds - Don Terrill's Speed-Talk
The problem is greatly exacerbated in a dual plane intake with it's sharp 90* turns. Next intake, you'd be well advised to follow joes advice. Even if you hand port it yourself, you stand to gain far more than the extrudehone. You'll have the ability to direct the air where you want it. Extrudehone was just an easy money fad back in the day.