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Old 10-22-2019, 09:06 PM   #9
71chevswb
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Join Date: Oct 2011
Location: NorthWest
Posts: 129
Re: How to optimize a RCSB for gas mileage

Quote:
Originally Posted by Ziegelsteinfaust View Post
If you really want mpg. Take a look at the 14+ Silverados with the V6.

I have a 18 crew cab with a 2/4 drop, and usually average right around 26 highway at 66-70 mph. Goes slower doesn't help, and faster it drops quick. Trailing a semi helps alot, but I rarely get to cruise behind one.

If I cruise from LA to Lancater, and back. Ac on or off doesn't matter much. Even with the hill going there I get right around 25 round trip. I have hauled a 7500 trailer over the mountains around lake tahoe, and it did amazing.

As for the early model your looking at. I liked my 4.8 in the new 07 model. 21-22 highway at 70-75. It had 3.23's when I got it, and I swapped to 4.33's. The hwy mpg stayed the same, but the city mpg went up alot. It used to get something like 13/22, and after the gear swap it got like 17/22.

Tonneo covers help alot of you have a tool box or keep stuff in the bed. As this messes up air flow. So if you keep the bed clean they do effectively nothing. Also consider a roll up soft tonneau as they as very flexible since it they roll up.

When I got my 07 I put in a tool box and my mpg went from 21 to 17 hwy. I got a tool box soft tonneau, and it went back to 22. Not enough to justify it by itself.

I wish a 5.3/6l80e combo was in budget. Especially those new ecotec 5.3s... but that is beyond my budget for a daily!
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