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best rpm to shift zf5?

Discussion in '6.9L IH & 7.3L IDI Diesels' started by BlackNoma, Nov 20, 2019.

  1. BlackNoma

    BlackNoma Full Access Member

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    I recently did a zf5 swap and love it.

    I'm just wondering what rpm yall usually shift at on the daily cruise?

    I have been shifting around 2100 and am very easy on the throttle. i drive like a grandpa. flat roads where i live. trying to see what is the best for MPG.
     
  2. hesutton

    hesutton The Anti-Anderson Supporting Member

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    ZF5 or T19 - I usually shift around 2000-2500 depending on the situation. Merging into traffic... rev's will be higher. Same when hauling.... usually kiss 3000+ when pulling the camper.

    Heath
     
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  3. Oldiron

    Oldiron Full Access Member

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    Ive been shifting between 2k and 2.5k also, but ive been "gittin it" ever sense the new ip, electric lp, and inj. Now that I'm trying to see what I get for mileage, I'm trying to shift around 2 depending on the situation.
     
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  4. Rusgo

    Rusgo Full Access Member

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    Grandpa shift on flat ground @ 1500rpm

    Keeping up with accelerating traffic or moderate hills @ 2000rpm

    Pulling hard or passing fast, and steep slow hills @ 2500rpm

    Anything more is purely liesure!

    1500 to 1700 rpm shift definitely maxed mileage...unless it makes you blow smoke out the tailpipe. Then something else is going on.

    Sent from my SM-G975U using Tapatalk
     
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  5. Clb

    Clb Another old truck Supporting Member

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    Down, at 2600 up at 3300 towing is all I do with mine.
    Mpg...tween 2000-2600 seems best for mine, no power and empty...
     
  6. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    4500! E7729FC9-975D-4158-BAC8-315513757EA9.png
     
  7. Clb

    Clb Another old truck Supporting Member

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    Didja follow thru with the drag truck?
     
  8. 79jasper

    79jasper Chickenhawk

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  9. Macrobb

    Macrobb Full Access Member

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    Around town, I'll upshift as soon as 1800; rarely under that unless I'm just on a flat road not accelerating anymore.
    When accelerating(stop to 45MPH road or 60MPH road), I pretty much start in 2nd, get it up to about 2500-3K and then shift. When it's still cold I take it easy, once she's warmed up I usually get on it and wind her out getting up to speed.

    I've realized that driving it like a grandpa just soots everything up; driving it hard like this... she runs as good as she ever did, after a year+ of doing this.

    Of course, towing (heavy), it's pretty much wind it up to the governor and then shift.
     
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  10. Mulochico

    Mulochico Supporting Member Supporting Member

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    My owners manual says:
    1-2 15 mph
    2-3 25 mph
    3-4 35 mph
    4-5 45 mph

    When I 1st got the truck I did that and the mileage wasn't bad (15-17 in town, with an old IP). New Baby Moose, Injectors, etc. (no turbo yet). my foot is a little heavier now as at those speeds it is a bit more likely to smoke. Now I shift between 2000 and 2500.
     
  11. chillman88

    chillman88 Supporting Member Supporting Member

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    I typically shift around the 2k mark empty, my old girl is just too doggy if I shift any earlier than that, and my wife says I typically drive like a grandpa too lol! I've found if I'm gentle to it and on flat ground I can run 30mph in 5th to keep the RPMs down. I do have 4.10 gears though, don't think I could get away with that if I had 3.55s.

    If I have a big load on the trailer it's shift by feel but typically around 3k.
     
  12. mexicanjoe

    mexicanjoe Full Access Member

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    with 4.10 gears I take off in 2nd and wind it up to 1500 rpms. out on the highway i usually run 2100 / 60 mph. Never have wound it up past 2600
     
  13. BlackNoma

    BlackNoma Full Access Member

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    I have 3.55's and a 460 zf5, I never use 1st, always second. shift @ 2,000 ish and don't bog it. I have my pump turned up and I don't let it smoke at all.

    With my GV on (double overdrive), I ran 84mph @ 2,000rpm and got 18mpg going on i10 to SA for the CDD IDI meet. I had to drop the GV a couple of times for large overpasses to keep speed without smoking.
     
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  14. saburai

    saburai Supporting Member Supporting Member

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    I know that this is a zf5 thread, but FWIW, Towing my 10K trailer with Raylan - e4od & 4.10 gears it's happiest cruising at about 2500 and above. Much below 2500 egts, coolent and to a lesser extent tranny temps climb. Also, if I let it drop below 2500, when I put my foot in it for a hill, I don't build boost fast enough to keep egts sub 1k...
     
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  15. pelky350

    pelky350 Full Access Member

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    2000 in town, highway usually 2500-3500 or so depends on how much turbo noises I want to here really lol cruising is basically as low of rpms as it will go above idle
     
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