Gear ratio for better fuel econo. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

swampbuck · 02-25-2010, 03:50 PM

I have a 2000 suburban 2500 with a 6.0L. It has 4:10s, narrow 35 inch tires, a K&N intake and a true duel exhaust. No matter how easy I drive it (70-75mph down the e-way for long distances) all I get is 10 mpg.

I don't plan on towing anything heavy and I have a 3:73? front end (but will need to find a matching rear) I could put in but would that help? Btw I'm turning about 2000rpm at 55-60 mph. Is there a chip that would really help? I drive almost no city, 99% back country roads (55) and highway (70-75). Any help would be great.

msgross · 02-25-2010, 04:02 PM

what are you going to max out with 13-14 MPG max? The 35's don't help...

swampbuck · 02-25-2010, 04:17 PM

But if I drive 20k to 30k a year it will add up. It was sucking just as much gas when I had the 265's on it. It seems to run almost rich at low rpm 700 to 1200 rpm. I never expected 17 or 18, hoped for 13 to 14 since my 06 hd with a 6.0 got 15 to 16, but 10 is just crazy. My fault for buying it I guess.

02-25-2010, 03:50 PM	#1
swampbuck Registered User Join Date: Apr 2004 Location: carleton,mi Posts: 45	Gear ratio for better fuel econo. I have a 2000 suburban 2500 with a 6.0L. It has 4:10s, narrow 35 inch tires, a K&N intake and a true duel exhaust. No matter how easy I drive it (70-75mph down the e-way for long distances) all I get is 10 mpg. I don't plan on towing anything heavy and I have a 3:73? front end (but will need to find a matching rear) I could put in but would that help? Btw I'm turning about 2000rpm at 55-60 mph. Is there a chip that would really help? I drive almost no city, 99% back country roads (55) and highway (70-75). Any help would be great.

02-25-2010, 04:02 PM	#2
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Gear ratio for better fuel econo. what are you going to max out with 13-14 MPG max? The 35's don't help... __________________ The Garage: 1968 K-10 SWB - "Project Money Pit" 1996 Z-71 - "huntin rig" 1969 C-10 LWB (SOLD) "Project flip that truck or else" 1993 Passport, F@rd 1-ton (SOLD)"Project Cousin Eddie" My Garage Build "The 1,000 footer"

02-25-2010, 04:17 PM	#3
swampbuck Registered User Join Date: Apr 2004 Location: carleton,mi Posts: 45	Re: Gear ratio for better fuel econo. But if I drive 20k to 30k a year it will add up. It was sucking just as much gas when I had the 265's on it. It seems to run almost rich at low rpm 700 to 1200 rpm. I never expected 17 or 18, hoped for 13 to 14 since my 06 hd with a 6.0 got 15 to 16, but 10 is just crazy. My fault for buying it I guess.



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