How can I improve fuel economy? - Page 3 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chris mc bride · 07-24-2014, 09:08 PM

expensive way to do it but ceramic bearings will help a lot. They are hot ticket in racing world. A car that runs 7 second 1/4 mile times can pickup.02 and 1 to 2 mph just from the reduction in drag. A guy I know in Kansas said his tow ropes retractor would actually move his car on level ground since he went to full ceramic bearings in car. Now front bearings alone run 200 to 300 bucks,but are good for million miles or so. How long to regain 300 if you pick up 1.5 to 2 mpg? Just throwing it out there.

**Jurassic-1** · 07-28-2014, 10:53 AM

I have a 1972 K5 Blazer with 32" tires and 373 gears. I previously could not go too far out of town at 70 miles an hour. I get 8 MPG . I replaced the engine with a rebuilt Napa short block and a set of 194 double hump heads. It now has around 100K on it. I installed a 700R4 in it about 16 years ago and it improved drive ability but the mileage was un changed. I can now cruise at about 2600 RPM at 70 and drop that another 250 RPM when I lock the converter. I also have a 1970 C-10 that gets 10 MPG with a rebuilt 350 using vortec heads and a mild cam. Both trucks have a Q-jet style edelbrock on them.

Cumminpwr11 · 08-02-2014, 11:51 PM

I went the diesel option. First gen Cummins diesel ve fuel pump, built 47rh transmission 4x4 with 33 all terrains. My best hand calculated was driving 70 from Phoenix to Las Vegas. Averaged 24.7 mpg.

I ran the truck hard and I would get 15. Now she is getting stripped to become a pretty pig!

Chris

highwinger · 09-22-2014, 05:01 PM

I've been doing a lot of work on the burb lately some of which addresses the efficiency. I added the O2 sensor, changed the tranny shift points, changed the vacuum advance port on the eddy... I'm still playing with the timing, mixture and idle to get rid of the dieseling. Last mpg was 11.8, but I was still playing with it. I hope to get to 12 once I make some more eddy tweaks.

highwinger · 10-06-2014, 09:10 AM

I got up to 12.7mpg on my last fill up. About 3/4 was highway miles doing 65-75 (no A/C). I did another tuning adjustment since and will see how that works. The A/F seems to be pretty good. I would have expected the plug to be a bit cleaner (tan) though.

I'm curious how many folks here use ported vs. manifold vacuum for timing advance.

07-24-2014, 09:08 PM	#1
chris mc bride Registered User Join Date: Aug 2008 Location: greensboro nc Posts: 686	Re: How can I improve fuel economy? expensive way to do it but ceramic bearings will help a lot. They are hot ticket in racing world. A car that runs 7 second 1/4 mile times can pickup.02 and 1 to 2 mph just from the reduction in drag. A guy I know in Kansas said his tow ropes retractor would actually move his car on level ground since he went to full ceramic bearings in car. Now front bearings alone run 200 to 300 bucks,but are good for million miles or so. How long to regain 300 if you pick up 1.5 to 2 mpg? Just throwing it out there. __________________ Only the stupid know too much to learn something new.

07-28-2014, 10:53 AM	#2
Jurassic-1 Registered User Join Date: Jul 2007 Location: New River Arizona Posts: 1,180	Re: How can I improve fuel economy? I have a 1972 K5 Blazer with 32" tires and 373 gears. I previously could not go too far out of town at 70 miles an hour. I get 8 MPG . I replaced the engine with a rebuilt Napa short block and a set of 194 double hump heads. It now has around 100K on it. I installed a 700R4 in it about 16 years ago and it improved drive ability but the mileage was un changed. I can now cruise at about 2600 RPM at 70 and drop that another 250 RPM when I lock the converter. I also have a 1970 C-10 that gets 10 MPG with a rebuilt 350 using vortec heads and a mild cam. Both trucks have a Q-jet style edelbrock on them.

08-02-2014, 11:51 PM	#3
Cumminpwr11 Southern Nevada Coal Roller Join Date: Oct 2008 Location: Las Vegas NV Posts: 191	Re: How can I improve fuel economy? I went the diesel option. First gen Cummins diesel ve fuel pump, built 47rh transmission 4x4 with 33 all terrains. My best hand calculated was driving 70 from Phoenix to Las Vegas. Averaged 24.7 mpg. I ran the truck hard and I would get 15. Now she is getting stripped to become a pretty pig! Chris __________________ Chris 72 Suburban, 1 ton dodge chassis 4wd cummins, DTT 47rh 89%, PDR VE 3200 spring, PODS, Piers Turbo. 36 Chevy P/U rat rod project. 4bta cummins

09-22-2014, 05:01 PM	#4
highwinger Registered User Join Date: May 2014 Location: Melbourne, FL Posts: 298	Re: How can I improve fuel economy? I've been doing a lot of work on the burb lately some of which addresses the efficiency. I added the O2 sensor, changed the tranny shift points, changed the vacuum advance port on the eddy... I'm still playing with the timing, mixture and idle to get rid of the dieseling. Last mpg was 11.8, but I was still playing with it. I hope to get to 12 once I make some more eddy tweaks.

10-06-2014, 09:10 AM	#5
highwinger Registered User Join Date: May 2014 Location: Melbourne, FL Posts: 298	Re: How can I improve fuel economy? I got up to 12.7mpg on my last fill up. About 3/4 was highway miles doing 65-75 (no A/C). I did another tuning adjustment since and will see how that works. The A/F seems to be pretty good. I would have expected the plug to be a bit cleaner (tan) though. I'm curious how many folks here use ported vs. manifold vacuum for timing advance.

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