HPI Sprint

Discussion in 'RC Drifting and Setup' started by imported_Denzo, Oct 8, 2005.

  1. Hi, ive got a Sprint that i really want to drift, but im having stupid diff issues, which in the first place was the reason for getting the Sprint, since my Yok SD got diff issues... Enough about that.

    The sprint is beautifully balanced, no torque steer, 17t LRP engine, Yok ECU, well oiled and so on, but the diff's been bothering the crap outta me! no matter how gently i start a drift, if i counter steer more than 20 - 30 % from neutral position, the car spins out, no matter the speed, angle, direction, surface, tyres, nothing matters, the car spins out EVERY time! (i can do donuts from 10cm diameter to 20 meter diameter and all sizes in betwen, aslong as i do not counter steer, cause then i spin out)

    Watching the car have its weird behaviour, i can see that if i drift through a right hand turn, countersteer left, the left wheel stops, just long enough for the eye to catch that it has stopped, then the car spins out (same happens the other way aswell, only the opposite wheel spins)

    My Yokomo SD4 has the same issues, but those are self inflicted. I buildt the kit from scratch, left it 100% standard, only to find out the Yok shocks suck ass, so i got some aftermarket ones, the car was gorgeous to drive, 100% control, but then a friend of mine said "lock the rear diff, come on, its going to be soo much better" and i was dumb enough to do so. Opened diff, locked with glue gun, closed, tested, and spun out, so i removed the glue from the rear diff, but that was too late. diff ruined, and getting spare parts for a Yokomo in Norway, is not possible, so i got a HPI Sprint RTR...

    Never even touched a nut on that car, just put in the motor, ecs and rec.so i dont know whats wrong...


  2. sam101

    sam101 Guest

    hi George
    I run a sprint 2 and this is probably one of the best places to find info on the sprint that I know of, helpful and very up-to-date.


    It sounds like the diff needs thicker oil/grease in the front, maybe a 40000wt.(this is a guess as i run a front one-way)
    From your post you have had bad experiences locking diffs but in this case i am going to have to suggest it for the back, but before you get worried this will not harm the diff in ANY way, you will be able reverse this and the diff will run exactly the same as it does now.
    Remove the diff from the chassis, unscrew the 4 little screws that hold the diff together, crack the diff open. Careful there will be two gears that can fall out. Simply take out the two small gears that can be removed, fold a small piece of fabric up and wedge it into the gears, put the two gears back, add another small piece of fabric, screw the diff back together and your done. Check that both out-drives want to turn together, dont worry if there is a small amount of slop as there is not that much resistance when using drift tyres and it will jam up while your running the car.
    I can prob do some photos if you need.

  3. Hey, that diff locking there sounded pretty smart... if you could supply some pictures, i would be really happy, since ive never touched the sprint when it comes to that, it was a rtr, and the diffs on the Yokomo that i have, are very different from that...