86LikesHpi Pro 4
07-24-2004, 02:37 AM
#6361
Thanks Erik muchly appreciated 
Originally posted by Erik Shauver
azenis: Hara's chassis just has the edge "knocked off" the battery slot contact areas to keep it from slicing the cells' shrink wrap as syntex1 points out. With the 2.0mm chassis, if you overdo the filing, your batteries will drag on the race surface, destroying your packs!! I can't stress enough, easy does it with the filing on the 2.0mm main plate. Also, a ride height of 4.5 to 5.0mm is very normal for Pro4's on asphalt (carpet will be as low as rules permit).
As a side note, when switching chassis plates (2.0, 2.5, or 3.0), don't forget to compensate by adjusting the pivot block heights by the same thickness change. If you're running a 3.0mm chassis, your blocks (and inner camber pickups to a degree) will all need to be lowered 0.5mm, for the suspension to perform the same relative to the ride height (or chassis lower plane). If you go to a 2.0mm chassis, you'll need to raise the blocks by 0.5mm. I'm pretty sure a lot of the "performance" upgrades people are seeing from aftermarket chassis is the same as if you had simply raised the blocks and camber pickups all the way around. A lot of guys will say a stiffer car is better for all conditions, but while all the other teams were trying 3.5mm or even more main chassis plates at the nats, Hara was dominating with the 2.0mm main chassis and upper deck.
Rookie Solara, kewdawg: you will need Acrobat Standard or Professional instead of Acrobat Reader to save the sheet with changes. If your screen size is large enough, you may be able to use Windows "Print Screen" and drop that info into Photoshop or similar (but with a quality loss).
azenis: Hara's chassis just has the edge "knocked off" the battery slot contact areas to keep it from slicing the cells' shrink wrap as syntex1 points out. With the 2.0mm chassis, if you overdo the filing, your batteries will drag on the race surface, destroying your packs!! I can't stress enough, easy does it with the filing on the 2.0mm main plate. Also, a ride height of 4.5 to 5.0mm is very normal for Pro4's on asphalt (carpet will be as low as rules permit).
As a side note, when switching chassis plates (2.0, 2.5, or 3.0), don't forget to compensate by adjusting the pivot block heights by the same thickness change. If you're running a 3.0mm chassis, your blocks (and inner camber pickups to a degree) will all need to be lowered 0.5mm, for the suspension to perform the same relative to the ride height (or chassis lower plane). If you go to a 2.0mm chassis, you'll need to raise the blocks by 0.5mm. I'm pretty sure a lot of the "performance" upgrades people are seeing from aftermarket chassis is the same as if you had simply raised the blocks and camber pickups all the way around. A lot of guys will say a stiffer car is better for all conditions, but while all the other teams were trying 3.5mm or even more main chassis plates at the nats, Hara was dominating with the 2.0mm main chassis and upper deck.
Rookie Solara, kewdawg: you will need Acrobat Standard or Professional instead of Acrobat Reader to save the sheet with changes. If your screen size is large enough, you may be able to use Windows "Print Screen" and drop that info into Photoshop or similar (but with a quality loss).
The pro4 is a race ready car, no hop-ups are really needed besides the 1way brace. HPI challenge here I come!
07-24-2004, 10:11 AM
#6363
Lazyboy
I usually try to get the diff where it is locked but will diff pretty freely. In other words I don't try to lock them up or anything. That being said, I still have trouble doing this consistently with the Pro4. I want to try the things the other guys have posted about reversing the diff screw. In the rear diff, a some of the Losi brown lube mixed in with the regular diff lube helps a lot.
I usually try to get the diff where it is locked but will diff pretty freely. In other words I don't try to lock them up or anything. That being said, I still have trouble doing this consistently with the Pro4. I want to try the things the other guys have posted about reversing the diff screw. In the rear diff, a some of the Losi brown lube mixed in with the regular diff lube helps a lot.
07-24-2004, 11:05 AM
#6364
thanks rob. ill have to try the mixed diff lub on my next diff rebuild.
lazyboy
lazyboy
07-24-2004, 12:23 PM
#6365
robk: Thanks for the rest of the details on your setup. It's nice to see a full setup to get a clear picture. The updated sheet is attached below. As for the 0.5mm offset steering blocks are supposed to calm down the steering a bit. We tried a lot of offset variations in testing with mixed results. I should have a couple samples from Japan soon as it is an HPI Japan part. The best thing we found on carpet was to reduce the front inboard toe (0 or 1), and then try the different steering block holes and ackerman positions. We probably won't get to try the offset blocks until Cleveland as we don't have any carpet close by to test on.
07-24-2004, 12:35 PM
#6366
jbackslash: try the linked setup, this is what all the HPI guys were using at the end of the Reedy ROC... it has very good laptime potential.
Pit-racer: Don't forget, the newest kits have our brace included from the factory. If not, just give HPI Customer Service a call (USA only).
Notes on the diff: First, make sure you compress the spring a few timew times before assembling the diff. Second, when assembling the diff, we've found that the rings seat the best when the rounded edges go towards the outdrive (look closely at the edges from being stamped and one side has a noticeably more rounded edge than the other). Third, always spin your diff parts periodically when tightening down the diff. Last, you will need to break in the parts and seat the rings. We usually hook up a 4 cell or motor run in unit to the motor, put the left side wheels down and spin up the drivetrain for a few seconds (to run in the balls and rings and thrust parts). Then do the right side down. Repeat this a few times on both sides and your parts will be seated. Readjust your diff to the deisred tightness when finished and we usually have no problems. We also make sure there is a generous amount of lube on diff and thrust balls. Over time, the rings and balls will wear out requiring more adjustment. If not seated properly in the begining, they will wear out much faster.
-E
Pit-racer: Don't forget, the newest kits have our brace included from the factory. If not, just give HPI Customer Service a call (USA only).
Notes on the diff: First, make sure you compress the spring a few timew times before assembling the diff. Second, when assembling the diff, we've found that the rings seat the best when the rounded edges go towards the outdrive (look closely at the edges from being stamped and one side has a noticeably more rounded edge than the other). Third, always spin your diff parts periodically when tightening down the diff. Last, you will need to break in the parts and seat the rings. We usually hook up a 4 cell or motor run in unit to the motor, put the left side wheels down and spin up the drivetrain for a few seconds (to run in the balls and rings and thrust parts). Then do the right side down. Repeat this a few times on both sides and your parts will be seated. Readjust your diff to the deisred tightness when finished and we usually have no problems. We also make sure there is a generous amount of lube on diff and thrust balls. Over time, the rings and balls will wear out requiring more adjustment. If not seated properly in the begining, they will wear out much faster.
-E
Last edited by Erik Shauver; 07-24-2004 at 12:44 PM.
07-24-2004, 02:36 PM
#6367
Erik:
Thanks for the information on the hubs. KevinK and myself have been running the 1* block in the front on carpet. The LHS hasn't had the 0 block, but that is the next step.
It is suprising that the offset hub calms the steering, as Kevin was telling me a guy who races with us was experimenting with an offset block on a Losi car. On carpet the car had crazy steering, but would chatter and act strange on real high speed/ high bite tracks.
Thanks for the information on the hubs. KevinK and myself have been running the 1* block in the front on carpet. The LHS hasn't had the 0 block, but that is the next step.
It is suprising that the offset hub calms the steering, as Kevin was telling me a guy who races with us was experimenting with an offset block on a Losi car. On carpet the car had crazy steering, but would chatter and act strange on real high speed/ high bite tracks.
07-24-2004, 07:00 PM
#6368
Tech Regular
Erik are you saying that all I have to do is call HPI USA to get a backer plate for the oneway.
07-25-2004, 08:00 PM
#6369
Registered User
Help
My pro4 make sharp left turn. It can turn 180 degree after full throttle straight. But the right turn cannot, it turns big curve. What cause this problem? How do I fix this?
07-25-2004, 08:42 PM
#6370
Re: Help
Originally posted by Aku-Man
My pro4 make sharp left turn. It can turn 180 degree after full throttle straight. But the right turn cannot, it turns big curve. What cause this problem? How do I fix this?
My pro4 make sharp left turn. It can turn 180 degree after full throttle straight. But the right turn cannot, it turns big curve. What cause this problem? How do I fix this?
First thing to check is tweak. Set the car on a flat surface, rescrew the uperdeck in a star pattern while pressing down on the chassis to flatten it. Then use a tweak guage balance by adjusting shock preload spacing.
Second thing I would check is the radio settings. Get hold of a hudy setup station (or something similar) that measures steering angle and set your Left/Right steering trims so that at full lock the wheels turn left/right the same amount. On my Evo3 I had to set the trims on one side like 90% and the other 100%. You can alwasy run your car in circles to make sure it's turning equally.
Last edited by Aurra Sing; 07-25-2004 at 08:49 PM.
07-26-2004, 01:09 AM
#6372
Not sure... still considering a Pro4 since it was actually designed to work with foams on carpet (I believe)... where as Evo4 i would think was designed for asphalt only.
07-26-2004, 09:35 AM
#6373
Here are some new problems.
This past weekend when I was racing, my Pro 4 all of a sudden wouldn't move any more. One of the rear wheels would spin freely. (Is that a word?) I took the rear diff apart and found out that the diff bolt head had totally broken off. I didn't have a replacement, so I replaced it with Associated's T-Nut thrust bolt, part number 6575. It went together fine and functioned properly. A few runs later I heard a spoadic clicking sound that sounded like it was coming from the rear of the car. I checked the spur and pinion gears and they were fine. I also took apart the front and rear diff and all the gears looked fine too. Does anyone know what could be causing this?
P.S. I haven't run the car since I took it apart and put it back together.
I also bent a front dog bone, but that's another story.
P.S. I haven't run the car since I took it apart and put it back together.
I also bent a front dog bone, but that's another story.
07-26-2004, 09:39 AM
#6374
Re: Here are some new problems.
Originally posted by brushless
This past weekend when I was racing, my Pro 4 all of a sudden wouldn't move any more. One of the rear wheels would spin freely. (Is that a word?) I took the rear diff apart and found out that the diff bolt head had totally broken off. I didn't have a replacement, so I replaced it with Associated's T-Nut thrust bolt, part number 6575. It went together fine and functioned properly. A few runs later I heard a spoadic clicking sound that sounded like it was coming from the rear of the car. I checked the spur and pinion gears and they were fine. I also took apart the front and rear diff and all the gears looked fine too. Does anyone know what could be causing this?
P.S. I haven't run the car since I took it apart and put it back together.
I also bent a front dog bone, but that's another story.
This past weekend when I was racing, my Pro 4 all of a sudden wouldn't move any more. One of the rear wheels would spin freely. (Is that a word?) I took the rear diff apart and found out that the diff bolt head had totally broken off. I didn't have a replacement, so I replaced it with Associated's T-Nut thrust bolt, part number 6575. It went together fine and functioned properly. A few runs later I heard a spoadic clicking sound that sounded like it was coming from the rear of the car. I checked the spur and pinion gears and they were fine. I also took apart the front and rear diff and all the gears looked fine too. Does anyone know what could be causing this?
P.S. I haven't run the car since I took it apart and put it back together.
I also bent a front dog bone, but that's another story.
Use the TC3 Shiney steel dog bones up front...very strong and durable.
07-26-2004, 09:43 AM
#6375
I don't think it's the CVDs. I got someone to hold both rear wheels when I gave it some gas, and it made the clicking noise. The only thing I can think of is that the bevel gears in the rear diff are not close enough to each other and they slip sometimes. Does that sound right?