Hpi Pro 4

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  • Quote: so i need both front and rear diffs???
    not really...depends on what you're racing on, track condition etc.

    the rear will always have a diff..

    the Hara Edition if perfect for outdoor asphalt racing..comes with both front one-way and front spool.
  • ok...im not to good with the tecnical stuff. so i can leave it the way it is???

    I am also looking at doing a little bit of drifting with this. so will i have to change everything?
  • ok. im new to the whole electric thing and am wondering what radio/other stuff do i need to get other than motor and speed control (i have a futuba 3pk radio). How many servos do i need, do i need a receiver or does the speed control do that... and how do i know if the speed control is compatable with the motor?


    And what tires should i go with (foam, slicks or rubbers)
  • Heres my stock carpet / foam tire set-up from yesterday. The car had smooth, but slightly aggressive steering and good rotation while transitioning very well and remaining stable. The track was small and technical w/ medium traction. Give it a try:

    Chassis / Center post: Hpi 3mm lower & 2.5mm upper w/ tweak mod. / yes.

    Front:
    Diff setting / Type: medium-tight / delrin.
    Shock oil: 70wt. Trinity.
    Shock piston: #3.
    Shock bladder: Firm (stock).
    Springs: Xray Purple - 33 lbs.
    Shock position on tower: #2 hole.
    Shock position on arm: outer hole.
    Front suspension mount: 3 deg. toe block / 1mm spacer.
    Rear suspension mount: no spacer.
    Camber mount location: #3 position on optional graphite camber plate. No spacers under inner or outer ball studs.
    Camber: -2 deg.
    Caster block: 4
    Ackerman: #1 hole on steering plate / #1 hole on steering knuckle.
    Sway Bar: 1.2mm / aluminum ball mount flush.
    Toe: out -1 deg.
    Width: 190mm
    Droop: 4mm
    Ride height: 4mm
    Tire Type / Diameter: Jaco - Orange/Purple (plaid) / 55mm (use traction compound on inner-half of tires).
    Traction compound: Paragon.

    Rear:
    Diff / Type: Medium / Delrin
    Shock oil: 70wt. Trinity.
    Shock piston: #3.
    Shock Bladder: Firm (stock).
    Springs: Xray L. Red - 35 lbs.
    Shock position on Tower: #4 hole.
    Shock position on arm: #2 hole (middle).
    Front suspension mount: no spacer.
    Rear suspension mount: 1 degree toe block / no spacer.
    Camber mount locations: inner on optional camber plate - #2 position / outer (hub) #1 position w/ 2mm spacer under ball stud.
    Camber: -2
    Sway Bar: 1.6mm / aluminum ball mount back 4mm.
    Droop: 4mm
    Wheelbase: short
    Width: 190mm
    Ride Height: 4.5mm
    Tire type / Diameter: JACO - Purple / 55mm. (traction compound full tire.)
    Traction compound: Paragon.
    Gearing: Spur 98T 64p / Pinion 31T 64p
    Final Drive Ratio: 7.70

    Body: Protoform G6
    Motor: Axxis Racing - Vitec (Monster Based)
    Batteries: Axxis Racing - Voltaxx HES IB3800
  • Quote: Heres my stock carpet / foam tire set-up from yesterday. The car had smooth, but slightly aggressive steering and good rotation while transitioning very well and remaining stable. The track was small and technical w/ medium traction. Give it a try:

    Chassis / Center post: Hpi 3mm lower & 2.5mm upper w/ tweak mod. / yes.

    Front:
    Diff setting / Type: medium-tight / delrin.
    Shock oil: 70wt. Trinity.
    Shock piston: #3.
    Shock bladder: Firm (stock).
    Springs: Xray Purple - 33 lbs.
    Shock position on tower: #2 hole.
    Shock position on arm: outer hole.
    Front suspension mount: 3 deg. toe block / 1mm spacer.
    Rear suspension mount: no spacer.
    Camber mount location: #3 position on optional graphite camber plate. No spacers under inner or outer ball studs.
    Camber: -2 deg.
    Caster block: 4
    Ackerman: #1 hole on steering plate / #1 hole on steering knuckle.
    Sway Bar: 1.2mm / aluminum ball mount flush.
    Toe: out -1 deg.
    Width: 190mm
    Droop: 4mm
    Ride height: 4mm
    Tire Type / Diameter: Jaco - Orange/Purple (plaid) / 55mm (use traction compound on inner-half of tires).
    Traction compound: Paragon.

    Rear:
    Diff / Type: Medium / Delrin
    Shock oil: 70wt. Trinity.
    Shock piston: #3.
    Shock Bladder: Firm (stock).
    Springs: Xray L. Red - 35 lbs.
    Shock position on Tower: #4 hole.
    Shock position on arm: #2 hole (middle).
    Front suspension mount: no spacer.
    Rear suspension mount: 1 degree toe block / no spacer.
    Camber mount locations: inner on optional camber plate - #2 position / outer (hub) #1 position w/ 2mm spacer under ball stud.
    Camber: -2
    Sway Bar: 1.6mm / aluminum ball mount back 4mm.
    Droop: 4mm
    Wheelbase: short
    Width: 190mm
    Ride Height: 4.5mm
    Tire type / Diameter: JACO - Purple / 55mm. (traction compound full tire.)
    Traction compound: Paragon.
    Gearing: Spur 98T 64p / Pinion 31T 64p
    Final Drive Ratio: 7.70

    Body: Protoform G6
    Motor: Axxis Racing - Vitec (Monster Based)
    Batteries: Axxis Racing - Voltaxx HES IB3800

    What's the "Tweek Mod"?
  • http://www2.towerhobbies.com/cgi-bin...?&I=LXGNY0&P=0
    Is that the one that i want??? or is it the rear one i want?

    and when i get the car i will be shure to try those settings out..but i got lost in there.
  • Quote: What's the "Tweek Mod"?
    It's been discussed at length here, but the posts are buried now and I can't find them either, so here are the best images I have of it. The part of the mod you can't see is that there are shock-seal type o-rings under the inverted purple cone washers bolted to the steering posts, and the holes that are enlarged are done so in the back and the front of the upper deck. This helps the upper deck "flex" and settle back into place without setting into a "tweaked" position.

    Hope that helps!

    Hpi Pro 4-o-ring-pro-4-mod.jpg   Hpi Pro 4-upper-deck-mod2.jpg  

  • Thanks, Cartmen34. I was dreading the thought of trying to find it, again.
  • Quote: http://www2.towerhobbies.com/cgi-bin...?&I=LXGNY0&P=0
    Is that the one that i want??? or is it the rear one i want?

    and when i get the car i will be shure to try those settings out..but i got lost in there.
    No, you want the BALL differential. here ya' go: Pro 4 Ball Differential
  • Quote: It's been discussed at length here, but the posts are buried now and I can't find them either, so here are the best images I have of it. The part of the mod you can't see is that there are shock-seal type o-rings under the inverted purple cone washers bolted to the steering posts, and the holes that are enlarged are done so in the back and the front of the upper deck. This helps the upper deck "flex" and settle back into place without setting into a "tweaked" position.

    Hope that helps!
    Note, this is now standard on the Hara edition, so take a look at the instructions for that kit for some detailed views and directions on how much to tighten things.

    Ira
  • Quote: One-ways are used in Asia, not diffs. Many tracks there are "fast" (big sweeping, flowing turns) and are better suited for one-ways or spools.
    That's a misnomer. One-ways are awesome on tight small ASPHALT tracks (9 sec laps is small) as well as big tracks. A diff will send you to the b-main here on the sunny tracks. BUT since cars.cars is new to the game he really should start with the front ball diff. Him being in PA I'm sure all the tracks are carpet any way
  • Quote: That's a misnomer. One-ways are awesome on tight small ASPHALT tracks (9 sec laps is small) as well as big tracks. A diff will send you to the b-main here on the sunny tracks. BUT since cars.cars is new to the game he really should start with the front ball diff. Him being in PA I'm sure all the tracks are carpet any way
    On carpet w/ foams, the One-way is driveable but will exhibit heavy oversteer and be inconsistent. Also, on tight, small tracks you'll have to let off the throttle way too much. Definitely not the way to go. You think 9 seconds is small... try 5 seconds!!!
  • Quote: On carpet w/ foams, the One-way is driveable but will exhibit heavy oversteer and be inconsistent. Also, on tight, small tracks you'll have to let off the throttle way too much.
    That's why I specifically mentioned asphalt. Your earlier statement reffered to all of the USA

    Quote: try 5 seconds!!!
    Woah haha That's about 3 turns and 1 straight I've raced on a track like that before... with double one-ways...and tq'd and won
  • Quote: That's why I specifically mentioned asphalt. Your earlier statement reffered to all of the USA
    On asphalt the car will still oversteer. You said it was awesome. I say - not even close. You'll have a lot more control and better handling, with a diff, on ANY small & tight track.
  • Quote: That's about 3 turns and 1 straight I've raced on a track like that before... with double one-ways...and tq'd and won
    Nah.. its, actually, about 7 turns but it's a fast layout!