4.10s, 3.73s, or 3.55s?

JCart · Nov 29, 2015

thatsmokinobs said:
If I'm getting approximately 20ish+ on the high way with 265/75s, 4.10s and that POS e4od, what kind of increase would 3.73s and a zf5 swap gain me? Just curious

With all due respect that sounds a little optimistic especially if it's US gallons, for 4:10s and such short tires, are you sure you have those gears? I'd think you'd pick up 2-3 miles per US gallon with a ZF 5 swap. Not sure with 3:73's.

Why not first try some 285 or 305 tires? Each truck is a little different and having owned three best mileage on a consistant basis was my '96 F350 cc 4x4 with ZF5 285 tires, 150/146 injectors with IC DP and 3:55 gears, electric fuel, 1.0 exhaust housing and T Wildman tunes. I would get 20-22mpg (80/20 hiway/city) and get as high as 24 mpg (road trips empty) now these are imperial gallons though. When the truck was completely stock I'd get best 18 mpg.

Not really worth the dollars to swap to ZF for mileage (pay back wise) I don't think, but to rid yourself of the E4OD (if not close to BTS) then it makes total sense IMO.

jrc

lincolnlocker · Nov 29, 2015

brain fart, not a superduty thread..

morefuel · Nov 30, 2015

With 4.10 and a zf it seemed like i got a high of about 16.5. Then i had 3.55 on the highway was about 19.5 or so and with the 3.73 i get about 18.5. I found it pretty interesting that the fuel mileage was just about exactly inbetween the 3.55 and 4.10.

thatsmokinobs · Nov 30, 2015

I haven't seen another obs with 4.10s get the mileage I can get either, but I drive a little over 200 miles to school and use half or just over half of my 19 gallon tank. And I'm driving 70-80 the whole time

powerjoke4life · Nov 30, 2015

I get about 19.5-20.5 on the highway with an intake exhaust and tune with 3.73. Unloaded, bed cover on and cruise set.

smokinobs I bet if you topped off, drove and topped off again your mileage would look a little less. If you go by 1/2 a tank its not really accurate. Especially cause I have never seen an OBS where the needle moved at the same rate on the second half of the tank. I feel they stick up top until they hit half a tank and then drop like a rock.

thatsmokinobs · Nov 30, 2015

Lol that is true, soon as you hit half you might as well make your way to the pump. But seems like every car/truck i get to drive that long is like that. I don't know if I'll bring it back to school till the spring, if we get a warm streak when there no salt on the roads, then I'll bring it back up and see how much it takes to refill it after the drive.

Obsstroked · Jan 28, 2016

thatsmokinobs said:
I haven't seen another obs with 4.10s get the mileage I can get either, but I drive a little over 200 miles to school and use half or just over half of my 19 gallon tank. And I'm driving 70-80 the whole time

What are your rpms at that speed cause I have a cclb zf5 and 4.10s and best I can get cty is 17.6 and that's babying it my rpms at 70 are almost 3k but I recently put a 295/70R17

Sent from my XT1254 using Tapatalk

Obsstroked · Jan 28, 2016

powerjoke4life said:
I get about 19.5-20.5 on the highway with an intake exhaust and tune with 3.73. Unloaded, bed cover on and cruise set.

smokinobs I bet if you topped off, drove and topped off again your mileage would look a little less. If you go by 1/2 a tank its not really accurate. Especially cause I have never seen an OBS where the needle moved at the same rate on the second half of the tank. I feel they stick up top until they hit half a tank and then drop like a rock.

Man that's the truth

Sent from my XT1254 using Tapatalk

Wes Lewis · Jan 28, 2016

Did the same swap on my truck at the end of this summer. 4:10s to 3:55s on a 35" tire. One of the best things that i have done. It's like having an extra gear.

Mpg stayed about the same. 12-14 range. That's with an e4od, 238/100s, intake, exhaust, swamps idm and ts. Not tuned for the injectors is what's killing it.

old man dave · Jan 31, 2016

JCart said:
With all due respect that sounds a little optimistic especially if it's US gallons, for 4:10s and such short tires, are you sure you have those gears? I'd think you'd pick up 2-3 miles per US gallon with a ZF 5 swap. Not sure with 3:73's.

Why not first try some 285 or 305 tires? Each truck is a little different and having owned three best mileage on a consistant basis was my '96 F350 cc 4x4 with ZF5 285 tires, 150/146 injectors with IC DP and 3:55 gears, electric fuel, 1.0 exhaust housing and T Wildman tunes. I would get 20-22mpg (80/20 hiway/city) and get as high as 24 mpg (road trips empty) now these are imperial gallons though. When the truck was completely stock I'd get best 18 mpg.

Not really worth the dollars to swap to ZF for mileage (pay back wise) I don't think, but to rid yourself of the E4OD (if not close to BTS) then it makes total sense IMO.

jrc

My buddy did the auto to ZF-5 swap. While towing his small 5'ver the ZF-5 got 1.5 more mpg and better downhill coasting control than the auto did over the same 400 mile trip.

My rockstock truck with 4.10s best was 19.3 mpg with the stock 235s pussyfooting it on my 105 mile daily commute. With stage IIs, BTS and 285s milage dropped to 16.5 highway cruising only.

thatsmokinobs · Feb 1, 2016

Obsstroked I'm at 2500+ at 70 ish. Haven't had it on the road for a few months so I can't recall exact numbers.

Wes how's the take off on your truck? Mine will launch really hard but dies off after that. How much slower does it start off now?