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Heads/cam 5.3. How bad will my gas mileage be?

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Old 06-20-2011, 08:28 PM
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Originally Posted by f4tal
What if the world was flat and we all fell off?!


There is no way in hell you will get 20mpg's in the city with a V8 truck, end of story.

If your looking strictly for city mpg's your best bet would be gears and a tune.


Think I could get 16? lol Give me some hope here!

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Old 06-20-2011, 08:42 PM
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Originally Posted by seh6183
My buddy just did a cam only in his ctsV and his MPG literally went to 8mpg around town. He is tuned as well. This is exactly what im afraid of and I dont want to put myself in ths situation.
It went from 17 city to 13. Dick...
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Old 06-20-2011, 08:45 PM
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Originally Posted by FRiCK
It went from 17 city to 13. Dick....
I've heard you say on more than 1 occasion that you get 8 miles to the gallon. Maybe that was pretune or something.
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Old 06-20-2011, 08:59 PM
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Originally Posted by seh6183
I've heard you say on more than 1 occasion that you get 8 miles to the gallon. Maybe that was pretune or something.
Exaggeration
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Old 06-20-2011, 09:01 PM
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Originally Posted by seh6183
Think I could get 16? lol Give me some hope here!
I NEVER saw 16mpg even when I was bone stock. My truck has all the bolt ons you can put on it besides a different intake manifold.and i havejust a decent sized cam. I got around 14mpg bone stock with a tune and 4:10 gears. I saw 13.2 mpg with current mods and a 3200 stall. I went to a much looser 3800 stall and dropped to 11.8-12mpg
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Old 06-20-2011, 09:24 PM
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Originally Posted by seh6183
In your opinion is there anyway I can do a cam, full intake, full exhaust, and a tune and get 20mpg in the city?

What if I got a 6.0 block and put 5.3 heads on it to raise the compression?

This would be possible in vette or gto but our trucks are too dam heavy....if you want the power you will pay at the pump
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Old 06-20-2011, 09:28 PM
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All depends on the angle of that right foot lol
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Old 06-20-2011, 09:34 PM
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You might be able to get 16city but not likely. Like stated above, these trucks are too damn heavy for good city gas mileage. Maybe a RCSB, with gears and a tune not ever getting over 2500rpms and locking the converter at 30mph will get 16mpgs

If you want an LS motor and good city gas mileage, Don't get a truck. Hate to kill your buzz man
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Old 06-21-2011, 01:24 AM
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It takes fuel to make power. It doesn't come from the air....

If you want more power, it takes more fuel. Of course efficiency is part of the equation, but that only goes so far. The basic rule here is power = fuel in one form or another. Power adders cram additional air into the cylinder, the PCM/tune adds the needed fuel to keep everything happy.

You could bump up your compression ratio. That adds power no matter what the combo. Even stock(who the hell would do that though).

On my combo, my gear swap from 3.73 to 4.10 took me from 19.5 hwy to 15 hwy mpg's. I don't ever measure city driving, but aftermarket torque converters typically kill that anyways.
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Old 06-21-2011, 01:32 AM
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your worried about MPG buy a honda!!
we drive 5000 pound trucks with v8s that are modded MPG is something we forget about

I average 14 and 20 cammed stalled and bolton 5.3 on stock 3.42 gears
Thats driving like paw paw...drive aggressive and you can watch the gas gauge go to E quickly
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