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ChopStix · 02-25-2016, 01:19 AM

'99 Chevy Astro Van ~ Goal 30 mpg highway

So in order to show progress from stock to aero mods I reset my van back to stock form in my "winter tires" fuel log. It shows basically the EPA mileage measured over numerous tanks of gas. Then the fuel logs progress to show ever increasing mpg ratings as mods are applied. Those fuel logs are based on the entries below. Progress steps are dated and lists the mods applied, etc. However in reading this you have to remember that I measured these first 2 fuel logs with the van loaded while using it in work conditions. This is why my best mpg is very different than my "Kumho Sense" fuel log. Empty van verses loaded van. So when I log my empty van mpg later on, the numbers will shoot way up by comparison.

02/01/16
I removed the roof rack which turned out to be worth 1 mpg towards my goal. I saw this same result using both the Winterforce tires and the Kumho tires.

02/25/2016
I picked up a couple mods towards my goal of 30 mpg highway out of my old van. I got an electric fan conversion which has been claimed to be worth a couple mpg. I also purchased a set of Jet power pulleys to slow my accessories which has also been claimed to be worth a couple mpg. But I want to test some aero mods before installing them.

03/25/2016
205/75R15 Kumho Sense tires. Which is a narrower size, low rolling resistance spec, and lighter weight tire than stock. I also picked up a set of 15x7 steel rally wheels, and a set of chrome moon hub caps. These steel wheels and tires weigh 10lbs less each over my winter tires on the factory aluminum wheels.

04/04/2016
Winter tires on stock wheels:

04/04/2016
Summer tires on lite weight wheels:

So thus far the results speak for themselves. As shown in my Kumho Sense fuel log, the wheels, tires, and roof rack removal equaled a solid 5 MPG gain from my Winterforce fuel log. However this new setup has not equaled my previous best measured MPG when empty. As remember we are comparing a loaded van mileage to an empty vans mileage in this fuel log.

On the tire subject I suppose the claimed .7 inch smaller diameter difference is a culprit of why the mileage has not been equal to my previous measurements. Well that and the fact that my old tires were worn out. But I used an online RPM calculator and it says I gained roughly 200 RPM's from the slightly shorter tire at interstate speeds. So obviously this a tiny step backwards. Well at least until these tires wear down which always helps with mileage gains.

Summary:
Specter Reusable Air Filter
Synthetic Oil
Stock Computer W/Low Altitude Program
Roof Rack Removal
Lite Weight Rally Wheels
LRR Skinny Tires
Moon Hub Caps
= 32% over EPA, or gained 5 mpg!

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'99 Chevy Astro Van build thread

02-25-2016, 01:19 AM	#1 (permalink)
ChopStix Primer is still paint! Join Date: Aug 2015 Location: box by the river Posts: 561 85 Chevy Pickup C10 - '85 Chevy C10 ‘21 Compass Latitude - '21 Jeep Compass Latitude 4x2 90 day: 33.69 mpg (US) Thanks: 100 Thanked 126 Times in 100 Posts	'99 Chevy Astro Van build thread ~ Goal 30 mpg '99 Chevy Astro Van ~ Goal 30 mpg highway So in order to show progress from stock to aero mods I reset my van back to stock form in my "winter tires" fuel log. It shows basically the EPA mileage measured over numerous tanks of gas. Then the fuel logs progress to show ever increasing mpg ratings as mods are applied. Those fuel logs are based on the entries below. Progress steps are dated and lists the mods applied, etc. However in reading this you have to remember that I measured these first 2 fuel logs with the van loaded while using it in work conditions. This is why my best mpg is very different than my "Kumho Sense" fuel log. Empty van verses loaded van. So when I log my empty van mpg later on, the numbers will shoot way up by comparison. 02/01/16 I removed the roof rack which turned out to be worth 1 mpg towards my goal. I saw this same result using both the Winterforce tires and the Kumho tires. 02/25/2016 I picked up a couple mods towards my goal of 30 mpg highway out of my old van. I got an electric fan conversion which has been claimed to be worth a couple mpg. I also purchased a set of Jet power pulleys to slow my accessories which has also been claimed to be worth a couple mpg. But I want to test some aero mods before installing them. 03/25/2016 205/75R15 Kumho Sense tires. Which is a narrower size, low rolling resistance spec, and lighter weight tire than stock. I also picked up a set of 15x7 steel rally wheels, and a set of chrome moon hub caps. These steel wheels and tires weigh 10lbs less each over my winter tires on the factory aluminum wheels. 04/04/2016 Winter tires on stock wheels: 04/04/2016 Summer tires on lite weight wheels: So thus far the results speak for themselves. As shown in my Kumho Sense fuel log, the wheels, tires, and roof rack removal equaled a solid 5 MPG gain from my Winterforce fuel log. However this new setup has not equaled my previous best measured MPG when empty. As remember we are comparing a loaded van mileage to an empty vans mileage in this fuel log. On the tire subject I suppose the claimed .7 inch smaller diameter difference is a culprit of why the mileage has not been equal to my previous measurements. Well that and the fact that my old tires were worn out. But I used an online RPM calculator and it says I gained roughly 200 RPM's from the slightly shorter tire at interstate speeds. So obviously this a tiny step backwards. Well at least until these tires wear down which always helps with mileage gains. Summary: Specter Reusable Air Filter Synthetic Oil Stock Computer W/Low Altitude Program Roof Rack Removal Lite Weight Rally Wheels LRR Skinny Tires Moon Hub Caps = 32% over EPA, or gained 5 mpg! From To '99 Chevy Astro Van build thread Last edited by ChopStix; 04-21-2017 at 03:16 AM..