First Truck
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New User
Joined: Apr 2011
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Ok. Im not pulling anything though. This is just highway commuting. Im trying to find out why others with the same size truck V10 and tires are getting 13 on the freeway. My buddy has a lifted Excursion V10 and hes getting 13-14 on the freeway. Some guys in here are saying gear swap. Will that make the engine rev lower on the freeway? I thought I would have to go higher in gear to get lower revs on the freeway.
Junior User
Joined: Apr 2005
Posts: 82
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From: Castle Rock, CO
For finding your axle ratio, you can also look at the driver door label. On the lower doorpost behind the driver's door is a Federal Certification Label, that includes VIN, month/year of assembly, tire size and PSI, and some codes, including the axle code. Here are those codes:
Code:
Axle Type 31 - 3.31 non-limited slip 35 - 3.55 non-limited slip 37 - 3.73 non-limited slip 3H - 3.31 limited slip 3J - 3.55 limited slip 3L - 3.73 limited slip 41 - 4.10 non-limited slip 43 - 4.30 non-limited slip 48 - 4.88 non-limited slip 4L - 4.30 limited slip 4N - 4.10 limited slip 4W - 4.10 limited slip (ambulance package) 53 - 5.38 non-limited slip 5L - 5.38 limited slip 8L - 4.88 limited slip
Modular motor junkie
Joined: May 2009
Posts: 6,190
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From: Texas
Normal.
Mine always does that cold.
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Joined: Apr 2011
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Ok does anyone else have this goin on? When my gas needle gets below half it starts dropping FAST. And when it gets to 1/4 tank it really starts moving. It went from 1/4 to almost empty in just 16 miles.
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New User
Joined: Apr 2011
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For finding your axle ratio, you can also look at the driver door label. On the lower doorpost behind the driver's door is a Federal Certification Label, that includes VIN, month/year of assembly, tire size and PSI, and some codes, including the axle code. Here are those codes:
Code:
Axle Type 31 - 3.31 non-limited slip 35 - 3.55 non-limited slip 37 - 3.73 non-limited slip 3H - 3.31 limited slip 3J - 3.55 limited slip 3L - 3.73 limited slip 41 - 4.10 non-limited slip 43 - 4.30 non-limited slip 48 - 4.88 non-limited slip 4L - 4.30 limited slip 4N - 4.10 limited slip 4W - 4.10 limited slip (ambulance package) 53 - 5.38 non-limited slip 5L - 5.38 limited slip 8L - 4.88 limited slip
Thank you!!!
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Cargo Master
Joined: Sep 2007
Posts: 2,624
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From: OR and UT
My truck has 4.30 gears, 5 speed manual transmission and 34" tires. 55 MPH = 2,000 RPM and about 14 MPG.
Are you hand calculating your MPG and factoring in the oversize tires?
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Example: 4.30 gears will have higher RPM at a given speed than 3.73 gears. The V10 has a "sweet spot" where it makes good power and is most economical. Mine is right about 2,000 RPM. If you change gears to lower your RPM, you may get out of the "sweet spot" and start lugging the engine, which means more throttle to maintain speed. That means less MPG.
My truck has 4.30 gears, 5 speed manual transmission and 34" tires. 55 MPH = 2,000 RPM and about 14 MPG.
Are you hand calculating your MPG and factoring in the oversize tires?
My truck has 4.30 gears, 5 speed manual transmission and 34" tires. 55 MPH = 2,000 RPM and about 14 MPG.
Are you hand calculating your MPG and factoring in the oversize tires?
Cargo Master
Joined: Sep 2007
Posts: 2,624
Likes: 7
From: OR and UT
If you are 2000 RPM at 75 MPH (assuming your speedometer is correct) you probably have 3.73 gears, which means you are using more throttle to push your truck. Your lifted truck is pushing a lot more wind at 75 MPH than my non-lifted truck is pushing at 55 MPH, so your MPG will be down compared to mine.
I see you have a tuner on order, but have you done the tune-up things yet?
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OK! Just got back to Vegas from Solvang California. Before heading out to Cali I did a tune. Changed paper FRAM air filter to a K&N washable, cleaned MAF sensor with MAF spray cleaner, new fuel filter, tire air pressure filled with Nitro 7 psi below tire rating, and here are my results.
Before the trip:
Ave Highway MPG-11
Ave in town MPG- 8-9
Ave MPG -10
After the tune/ during the trip:
Highway MPG -15
In Town MPG -12-13
Ave MPG -14
This is incredible! After the K&N install and the MAF wash, the truck had a noticeable difference in throttle response and power. The only negative thing I have to note is that my engine "pinged" around 3,000 rpms during hill climbs. My average MPH was 75-80mph at 2,000 rpms. Tried filling up on premium and still pinged and got worse MPG. 87 treated the engine best.
Before the trip:
Ave Highway MPG-11
Ave in town MPG- 8-9
Ave MPG -10
After the tune/ during the trip:
Highway MPG -15
In Town MPG -12-13
Ave MPG -14
This is incredible! After the K&N install and the MAF wash, the truck had a noticeable difference in throttle response and power. The only negative thing I have to note is that my engine "pinged" around 3,000 rpms during hill climbs. My average MPH was 75-80mph at 2,000 rpms. Tried filling up on premium and still pinged and got worse MPG. 87 treated the engine best.
Junior User
Joined: Dec 2010
Posts: 90
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Pulling my 5ver two weeks ago through the WV turnpike I got 9. I am pulling 10K camper. In town 11-12 with hitch and generator in the bed. Highway at 65 cruise on same load I have hit 15 max. Check your brakes mine were dragging-needed cleaned up and slides lubed. Cleaned MAF also. Full syn Mobil1 and new air cleaner. My foot is not heavy. 4.10 gears. Keep us posted on your project-good luck.
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Joined: Apr 2011
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Well this past 10 days back home in Vegas my trucks mpg went down again. I found by the Code chart that I have 3.31 gears. In town driving is obviously the problem so what do y'all suggest in gears? I don't pull anything and don't plan to. 4-6 " lift with snug top shell, 35" tires. I plan on traveling every couple of months to Cali and lock the cruise at 65-70.
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