Ways to increase the efficiency of a GM 5.3L

[Isaac Zachary]

Originally Posted by freebeard

I tried a CB Performance Magnaspark ignition. Now the Magnaspark II

After a year It was corroded from ozone or something, sent back to the factory for a refurb ($$$) and it didn't help it. Went back to 009 with Hall effect sensor.

I had a digital Magnaspark. I'm not sure they still sell it, but they still sell the Black Box that does basically the same. I wish now I would have stuck with a 009 and just added the box somewhere. I could get a stock fuel pump on with that wide Magnaspark distributor, nor did it look stock with the rest of the engine (like the Oil Bath air filter).

I wonder if it would be possible for someone to design a "Rolex" precision vacuum/mechanical distributor that's just as accurate as anything digital (with the exception of knock detection).

[cRiPpLe_rOoStEr]

Originally Posted by Isaac Zachary

I wonder if it would be possible for someone to design a "Rolex" precision vacuum/mechanical distributor that's just as accurate as anything digital (with the exception of knock detection).

Not a distributor properly said, but some guys in Argentina did some makeshift capacitive-discharge ignitions which worked like that. Plus side is it was better than a distributor when it comes to weatherproofing.

[Piotrsko]

If you do waste spark on an aircooled, you need 2 crank triggers and use the distributor to steer the spark or you could use 2 systems and get that style of precision sans the distributor

[Isaac Zachary]

One thing worth mentioning as it could (???) pertain to any old two overhead valve engine would be adding a second sparkplug per cylinder. I don't know if or how you would do that on a small block Chevy, but it would increase flame speed and therefore efficiency.

This is something that has been done on Type 1 VW engines with good success.

[Ecky]

Reading through this thread, I'm largely in agreement with Isaac Zachary - reducing rotating mass is going to have a negligible effect on economy. As long as you manage that inertia productively, it isn't a loss.

The areas where you'll see gains are in reducing parasitic losses, and to some extent, things that increase thermal efficiency. Some tricks modern engines use, in no particular order:
-Elimination of belt drive items (e.g. fan), electric power steering
-Variable displacement oil pumps
-Variable displacement water pumps
-Higher compression
-Low friction coatings
-Low tension piston rings
-Atkinson cycle
-Reduced displacement

Maybe you can get away with a highly efficient V6 that makes similar torque/power to an older V8?

[Isaac Zachary]

Originally Posted by Ecky

Maybe you can get away with a highly efficient V6 that makes similar torque/power to an older V8?

Isn't there also an inline 4 cylinder that would work? (or you could take all the pistons out of one bank on a V8?)

[Ecky]

Originally Posted by Isaac Zachary

Isn't there also an inline 4 cylinder that would work? (or you could take all the pistons out of one bank on a V8?)

I'd be concerned about the 4's torque - it would require a different rear-end, and likely there isn't a 4 that bolts up to the existing transmission. A modern 6 can out-torque an older V8. But, it's certainly worth considering. A 4 is far more efficient than a V6.

I'd be concerned that a V8 with a bank removed (or even just two cylinders at the end) would have terrible balance and would vibrate a lot.

[Solarpowered]

Originally Posted by freebeard

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.

I actually have some experience with extrude honing, and it's got nothing on plain old hand porting. Extrude honing is a very expensive service and the process doesn't remove a lot of material. Forcing a media thru a port/runner is not going to re-shape the port/runner for better average flow as if you were hand porting it. The media removes more material in areas of high flow better than areas of low flow which is not effective when compared to hand porting. At best, extrude honing can save a bit of time for the hand porter. But he's still going to have to go back in and get everything that extrude honing missed, which will be quite a lot.

[Isaac Zachary]

Originally Posted by Ecky

I'd be concerned about the 4's torque - it would require a different rear-end, and likely there isn't a 4 that bolts up to the existing transmission. A modern 6 can out-torque an older V8. But, it's certainly worth considering. A 4 is far more efficient than a V6.

I'd be concerned that a V8 with a bank removed (or even just two cylinders at the end) would have terrible balance and would vibrate a lot.

I think there are two things to consider.

1. What is the intended purpose of the vehicle (not everything needs a lot of power and torque)
2. What is possible with a 4 cylinder? There are 3 cylinder engines now with over 300hp (I think there's one with 600hp IIRC). I'm sure getting 150 or 200hp out of a 4 cylinder is perfectly possible. But could you get that and better fuel mileage and not cost a lot?

The V8 to 4 cylinder idea would require a lot of work, that's for sure. For one you couldn't use a crossplane crank, you'd have to use a flatplane crank. And yes, even then the thing would not be balanced for only 4 cylinders.

Originally Posted by Solarpowered

I actually have some experience with extrude honing, and it's got nothing on plain old hand porting. Extrude honing is a very expensive service and the process doesn't remove a lot of material. Forcing a media thru a port/runner is not going to re-shape the port/runner for better average flow as if you were hand porting it. The media removes more material in areas of high flow better than areas of low flow which is not effective when compared to hand porting. At best, extrude honing can save a bit of time for the hand porter. But he's still going to have to go back in and get everything that extrude honing missed, which will be quite a lot.

And there's no need to port. Just as was said that you want small (but long) exhaust primaries, you want small (but long, if possible) intake runners. The same with exhaust and intake ports.

Intakes and exhausts are not an "open it up and you get better flow" type system, although the majority of people seem to think so. Air, fuel and exhaust are constantly speeding up and then being forced to stop. This creates pressure waves (harmonics) that bounce back down the runners to the plenum and then come back. If things are way off, including too big, you actually get less flow in and out of the engine. The lower the RPM target, the longer and narrower the intake and exhaust should be.

Nice smooth intake ports can also lead to more fuel condensating and accumulating on the port walls. A rough surface should, in theory, help keep more fuel in the air.

[Isaac Zachary]

Originally Posted by cRiPpLe_rOoStEr

A guy from Bahia who used to own a buggy told me 14.0 was the limit for a VW air-cooled block.

It seems a lot of folks think even the classic 7.3:1 is too much, and will lower the CR down to 6.5:1 or around there. Then they also enrich the snot out of the carburetor and run very low advancing distributors like the 009 (no load advance) as if they're trying to keep the engine from blowing up or melting down.