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Discussion Starter #1
I have a 1997 f350 f350 Long Bed, Crew Cab, Automatic, 2wd
Have an Edge Evolution programer
4.10 gears and 5.8 mpg :(

I was wondering what kind of speed and milage differences I would see if i put in 3.73 or 3.55 gearing. What would yall sugest. Thank you
 

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You have more problems than just gearing if your getting 5.8 mpg.

What mileage are you at?
 

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Make sure your ebpv is open all the way. Make sure you don't have brake drag. Check for leaks in your up pipes. Boost leaks.
 

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yeah, something is fked up there. i would check the brakes like sbluke says. thats waaay bad fuel mileage. my ccsb 4wd with 35 inch tires gets 13-14 mpg
 

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Discussion Starter #8
I unplugged my ebpv and got maybe a .5 increase. My brakes aren't dragin and if there was a leak in the up pipes or a boost leak, wouldn't it be pretty loud cause the truck sounds normal to me. Any other ideas? 😂
 

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Boost leaks and up pipes won't make a lot of noise.

The ebpv maybe stuck shut and unplugging it won't do anything.

What are you using to track your mileage? You might want to try comparing your odometer to a GPS.
 

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Also check for a fuel leak.
 

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Discussion Starter #11
I bought the Edge Evo CS2 and it comes with a monitor so thats where i get my mph reading and they are exactly the same as when you do the math yourself. This weekend im gonna gut the ebpv cause fk it lol. And i have already fixed all of the fuel leaks. Whats the best way to see if there is a boost or up pipe leak?
 

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EA - Eggfarts Anonymous!
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you can build a boost leak tester pretty easy evidently, i'll see if i can find a linky for it...

edit: here's a quote from a post i started a while back. hook something like this up to you turbo inlet, pressurize, and then look for leaks! now for exhaust leaks, look for soot, and maybe stick you hand back there while its running to see if you can feel nor them (i recommend starting it up cold & then feeling around so you don't get burned lol).

 

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Boost leak tester

Look for soot on the up pipes at the collector.
Also check your icp for oil in the connector.
Those numbers don't seem right, I would definitely check your odometer vs a GPS.
 

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i usually dont tell people this, but take it somewhere and get it looked at. if you are using that much fuel, it wouldnt take long at all to recoupe the cost of a decent diesel tech. besides, sbluke already stole all my answers. but first, i would check that math again. seems like something would be noticeably off with that truck if its using that much fuel.
 

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Re-gearing is he strongest thing you can do to improve MPG. That is, beyond moderating your driving style.
 

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Can't say that I've ever heard "strongest" used as an adjective to describe how gearing can effect MPG.

As has been said many times, this thing has more than a gearing problem. Even if it was gearing related, you'd have to save a LOT of fuel or drive non-stop to recoup the cost of a gearing change, especially with a 4x4 which requires two gearsets to be swapped.
 

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EA - Eggfarts Anonymous!
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alrighty, time to nerd it up a bit! your going from a reduction of 4.1 to a reduction of 3.73, so you'll be going a little bit faster, just enough to get a speeding ticket if you go by your speedo :eek:

simple way:
your ratio looks like this now ( 1 / 4.10 ), but you are going to this ( 1 / 3.73 )...

to take a ratio of the ratios: desired rat/current rat = (1/3.73) / (1/4.10)

so basically after some math:
4.10 / 3.73 = ~1.1, so you'll be going about 10% faster than before per engine rpm, or 110% (multiply by 1.1) of your speedo readout. [or take a 10th of your current speed and add back to it]

sound about right? our 6.0 with 3.73 goes about 70mph at 2000rpm; our 6.0 with 4.10 goes about 70mph at 2400 rpms (both stock 245/75/17s)

ok i'm done, i just wanted to ramble a bit lol
 
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