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Old 09-29-2018, 02:30 PM   #1
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How to optimize a RCSB for gas mileage

In the market for a 99-07 chevy/gmc single cab short bed (rcsb) 2wd..... I'm looking for one with a 5.3l .... I've always wanted one. It will be a commuter vehicle for me. Driving 55-70 mph about 80-90 miles a day for 3 or 4 days a week.

My question is, what kind of gas mileage can I expect? I would ideally like to push it to 22 mpg. I know this is a bit of a stretch. What speed, air dams, tonneau cover, etc... can I add to achieve this? Will a 4/6 drop help at all? I plan to add a 4/6 drop either way. What wheel/tire size will work best? Will a 4.3 or 4.8 be any better? My thought process is that a bigger motor wont have to work as hard.

Any thoughts or suggestions are appreciated. I know this is not the best "commuter" vehicle but I'm currently driving a v6 tacoma 4x4 getting 16-18 mpg.
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Old 10-02-2018, 06:02 PM   #2
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Re: How to optimize a RCSB for gas mileage

Doesn't matter if it isn't working as hard, your still turning a certain number of RPM's and moving air threw the engine that needs fuel added. The 4.8 vs 5.3 seems to work out like your thinking, but the v6 will get better mileage.
As for mods to help, everything you listed helps. Bed cover, lower the truck, keep small rims on it [the lighter weight the better]. Make sure the factory air dam under the front bumper is there.
-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle.
-98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes.
-02 Suburban 4x4: stock
-CBR600F4i, CBR600RR, CBR1000RR, and standup skis
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Old 10-02-2018, 08:24 PM   #3
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Re: How to optimize a RCSB for gas mileage

4.3L/5 speed manual is your huckleberry if you can find one. It has plenty of power and is efficient in the right package. Custom tune, smaller/lighter wheels and low rolling resistance tires. Synthetic fluids throughout. You could expect about 18mpg combined, 19 tops if you drive like an old lady. 22 combined is probably not going to happen.
'19 Silverado Trail Boss ~ '15 Challenger R/T Scat Pack 392 ~ '11 Escalade ESV ~ '87 Silverado swb 4x4 ~ '71 Cheyenne swb ~ '55 Pontiac Safari ~'50 3100 bagged ~ '80 Wife ~ Late model kids

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Old 10-11-2018, 06:38 PM   #4
Matt Man
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Re: How to optimize a RCSB for gas mileage

My 06 rcsb had the 4.3/Auto and when it had the 17" steel wheels it got 17mpg. The truck was lowered 5/7 K&N cold air intake and magnaflow cat back exhaust. I would get the 5.3 like you mentioned.

Here is a picture:
86 c30 crew cab dually 454/400 4/6 drop SOLD 1-8-11
1981 chevy K10 shorty 350/350C 12bolt, 10bolt, NP208
4" lift 35's
4.10's Detroit locker/Truetrac
Vintage Air
67 GMC Stepside Straight six/3 on the tree "The Peach"

K10 build

The Peach build

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