part time vs full time

Discussion in '80-Series Tech' started by bugsnbikes, Jan 2, 2019.

  1. Will Van

    Will Van

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    How do you like running the extra caster? Any drawbacks to a little extra caster?

    I’m still getting some mild vibration at highway speeds after PTing the case, so I’m not sure what that’s from. Maybe needs more caster? Maybe rear panhard? Maybe rear driveshaft?
     
    Last edited: Jan 4, 2019
  2. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    I like lots of caster ran 7° on my 40 and you could run at 100mph with comfort. My long term plan is to go up to 5° on the 80 series.

    Rear panhard will not change any vibs but a needed part with many benefits on a lifted 80. I would not think more caster would make a difference either unless you are extreme negative now.
    Have you balanced your rear drive line? I have the driveline balanced with the slip yoke is the ride height position for best results.
     
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  3. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    Very cool to see the results of a ~4300lbs 80 you will be in uncharted area. Im guessing a split case for even lower gears?
     
  4. Will Van

    Will Van

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    Great intel. Thank you.

    I was vascilating between the DVS 2 inch radius arms and the 4 inch (I have a 2.5” OME lift). It sounds like there is no downside to running the extra 4” radius arms.

    I have not balanced my rear driveline, but I didn’t know that was necessary.

    You need to balance the driveline after a lift? How do you balance with the slip yoke “in the ride height position”? Mark it on the truck before you take the driveshaft to be balanced?
     
  5. Heckraiser

    Heckraiser

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    Be aware the Delta radius arms are designed to be at the top of the caster spec for the given lift heght. I.e., if you have a 2" lift and run the 2" radius arms, you will be close to +4* caster. This is a good thing, but there is a potential to overdo it, so definitely talk to them before ordering.
     
  6. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    Talk to @Delta VS they can recommend the correct arms to get 4° caster. The difference in driving an 80 between 2° - 4° caster is huge.

    Ride height of a 2.5" OME lift changes with weight so saying I have a 2.5" is a variable. I run OME 850Jw/spacer & 863J rear and measure ~2.5 of lift due to gross weight.

    You do not 'need' balance your rear drive line after a lift but you are trying to eliminate a vib and a drive line could be it.:meh: When the position of the slip yoke changes on a used drive line its not uncommon for the balance to change.
     
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  7. incogrhino

    incogrhino

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    I love pt. Way better than awd. Did it to my 95' and already bought the parts to do it to the lx. Spring time.
     
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  8. bugsnbikes

    bugsnbikes SILVER Star

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    My Fzj55 (80) is 4300lbs on completely stock height suspension with 35's full time......handling is much more planted and maintains 265/stock tire handlings nimble feel. alot less body roll than stock mainly due to weight and im running no sway bars front or rear and its alot more planted than a stock cruiser. this 80 is going to be on 3in. Frankies lift- so it should be slightly more tippy/ higher cog.......i may need to toss on a rear sway bar, but we will see how the Progressive Frankies do with 4300lbs 3" higher up. My old 80 that ran the same springs 37s at 5300lbs was fine with just the rear swaybar only.

    The split case will be stock gearing for starters--as the h55f first gear is a notch lower than the 1fz/auto. I will see how the stock split case gears work before jumping to the weaker and noisier 3:1marks gears. the om606 will be putting out a bunch more torque than the 1fz.......and the 25% drivetrain loss of the auto trans is going bye-bye which should move a 4300lb unloaded 80 nicely.
    the goal is to be loaded for trips at stockish 80 weight- 4800-4900stock w/ 35s p/4.11's with 25% more torque and hp than a stock 1fz auto. The om606 guys are running 40psi+/500ish + hp and torque fairly safely...... Im only going to be running a 1.5bar actuator -22psi roughly-with a 150cc pump (hopefully spending most time in the 110-130cc fueling-1/4-1/2throttle) which should put me in the 250-260hp at the wheels. And maybe 330tq. WIll see what the dyno says.
     
    Last edited: Jan 4, 2019
  9. ThundererZeuS

    ThundererZeuS

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    a slightly off-topic question, those of us with factory part time and H4 button, at what speed can we still engage H4, is it on the fly, or has to be stopped and in "N"?
    no hi-jack is intended
     
  10. ryan greathouse

    ryan greathouse

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    In summary, please correct/add/subtract where neccessary (isnt that what forums are for? lol). Assuming the rig has not been heavily modified and is at or close to stock specs the following is true for the part time 4wd mod (with manual locking hubs):

    positives:
    less wear and tear on front end
    reduced vibration and road noise
    possible fuel consumption gains
    more versatiliy in regards to auto-locking front diffs
    more versatility on the trail in certain situations
    more responsive throttle and or more torque to rear (not 100% split, 100% rear)
    all wheel drive (previous, stock condition) can still be achieved with hubs free and CDL off

    negatives:
    will not corner as well
    steering is different
    have to get out and manually adjust hubs when engaging 4x
    more complexity/components means more can go out (CDL, hubs)
    further mods are neccessary to correct/minimize handling issues and/or castor needs adjustment if lifting or heavily modified
    responsiveness and agility/handling is worse *safety*


    I seem to remember reading a thread on this topic where someone stated that South American 80s came stock with Aisin hubs/part-time for a while and they were sought after and preferred by drivers in that region (which had me sold). I have to say that IMO for a stock or near stock rig the positives out weigh the negatives and probably more so for a 3fe. But...hard to put a value on the last negative bullet point: handling. That one just about cancels out all of the positives because of safety.

    In my case, the 92' is quite loud and viby as well as very sluggish. I dont corner fast anyway, and I dont plan on heavily modding it any time soon. As far as MPGs go the incentive is strong to go for PT even though this varies on a case by case basis. It would seem that this particular mod is well-suited for some, but not others. Strong consideration should be weighed based on road conditoins, cargo, mods, $$ (does wear and tear and mpg matter to you), driving style, miles driven, on and on

    Still on the fence, saving for gears...
     
  11. sunrk

    sunrk

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    I have a factory part-time 80. I've never driven a factory full-time 80 to compare against mine. The fact that under normal circumstances there is no 'drive' to the front wheels could well make for quite different handling on-road compared to full-time 4wd 80's.

    One good thing with part-time is that the front diff gets nearly zero wear. The rear one is bigger and beefier for a reason. ;)

    There is much less to break with part-time 4wd in the factory config. I can't comment on the Marks and similar full-time to part-time conversion kits.

    HF1a transfer case has no CDL like on factory full-time 4wd. It also has a lot less parts, is lighter weight, and using real Aisin hubs (not junk AVM ones) makes for a very reliable rugged package.

    I do not see how having full-time 4wd makes something 'safer'. The same argument probably gets used to justify having an auto gearbox instead of a manual one... lol
     
    Last edited: Jan 10, 2019
  12. mudgudgeon

    mudgudgeon

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    Why are there so many AWD sedans and family cars?
    Every major manufacturer makes multiple AWD cars for good reasons. Safety is the number one reason.
     
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  13. cody c

    cody c

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    So, I assume your from a warmer climate, maybe Australia, but for colder climates, or specifically winter snowy and icy roads AWD is better than 4WD for highway driving, with the centre diff AWD can be left on and is much nicer here where you are doing tight turns in a dry parking lot and then cruising winding icy backcountry roads not long after.

    You can put a vehicle in 4WD for the windy icy roads, but 4WD will break traction easier than AWD and a few club members have mentioned they noticed a significant difference, if your not familiar with the logic, your front axle will travel in a smaller circle than the rear axle, this will cause the rear wheels to drag the slightest bit with the CDL engaged ((4WD) whereas an AWD vehicle has a centre diff to alleviate the difference.

    Also, engaging and disengaging 2WD/4WD as you are continually transitioning from dry pavement to snow and ice is not user friendly, and driving a 4WD on pavement is much harder on components than AWD is, as there are more binding forces without a centre diff
     
    Last edited: Jan 11, 2019
  14. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    Im one of the strongest cheerleader for part time and if I lived anywhere there was snow I would never have done it. Common sense should tell one that without question AWD will make travel MUCH safer in a low traction situation.
     
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  15. 80t0ylc

    80t0ylc Hill & Gully Rider

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    Question for PT kits....when you put center diff or transfer case lever in neutral, are the drive shafts locked together or are they independant?
     
  16. baldilocks

    baldilocks Battle Ground, WA GOLD Star

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    Will still be independent until low range is selected or the center diff switch is pushed into the “on” detent.
     
  17. thatcabledude

    thatcabledude SILVER Star

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    Front ain't doing anything until the button is pushed. You'll just be in low 2WD
     
  18. baldilocks

    baldilocks Battle Ground, WA GOLD Star

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    This applies only if the pin 7 mod is in affect right???
     
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  19. thatcabledude

    thatcabledude SILVER Star

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    Haha yeah, you’re right. I forgot that’s even a thing.
     
  20. baldilocks

    baldilocks Battle Ground, WA GOLD Star

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    For some, it’s a very significant thing, for me, not so much.....
     
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