alexchen86

iTrader: (45)

For the issue of not being able to hit 70mph stock out of the box they should have at least given the correct pinion gear to bump it up lol. Even the Slash 4x4 VXL throws in the high speed pinion haha!

Honestly I don't care about performance or parking lot racing. Been on-road racing for a couple of years...just not that exciting at least in Houston for 1/10 TC.

Plus with my limited weekend free time I just either grab my OFNA GTP2e for high speed runs, work on my several custom scale crawler abs plastic bodies work for proper hidden chassis fitting, or bash with my Slash 4x4 MMP/2400kv 4s beast upgraded to handle all the insanity.

This one is just a toy to tinker with....doubt the build would have been any fun if it came in kit form being so ridiculously simple. Sort of like building a Tt-01 haha.

Normajean

iTrader: (5)

I got The "updated" dog bones in from hpi and with one 1 o ring on the diff side they were still loose, but put 2 in and it was perfect but still want to the spec r or hpi cvd, which ever one's come available first.

Also I installed my savox SC1258TG from one of my old buggies and my steering goes back to straight every time! I was so excited about it to because I use the sport 3 for drifting and having it wonder every time I turned it was annoying plus I only had to set the steering trim once! Lol

I wish I could post pictures but I am new.

alexchen86

iTrader: (45)

Yup Savox servos are definitely awesome. Faster and more torque than similar Hitec variations especially important in racing and bashing. For my crawler rigs requiring at least 400-600 oz/in torque I only opt for Hitec though.

Anything else is either Savox or Protek.

Endaar

Well I don't know what to make of that. I just installed the same servo and while it's better, the steering still noticeably wanders. I have been through the steering linkage probably five times now. There is nothing binding. There's nothing loose. Everything seems fine, yet the car won't track straight and won't return to straight.

The problem just seems to be too much slop in the steering linkage, combined with a bellcrank that gives the servo very little leverage over the front wheels. There is significantly more slop in the steering of the Sport 3 than my RS4 Nitro Pro 3, and you can see the front wheels subtly shift left and right when under throttle. This is apparently enough to cause the wandering.

I'm fairly certain I've figured out the refusal to re-center as well. Full lock on the Nitro has the linkage physically stopped by the drive shaft tunnel, so there is no way any feedback from the wheels can force the wheels to turn any further. On the Sport 3, there's a point between where you want full lock to be so as to keep the wheels from rubbing the suspension and the point where the linkage itself is physically prevented from moving any further.

There's enough slop in the assembly that the wheels can move from the artificial full lock set by the servo EPA to the full lock caused by the limits of the steering rack travel; this can happen without the servo moving at all, so when the servo goes to re-center, IT re-centers, but since the wheels are not where the servo left them so to speak, they are not centered.

I don't see any way to fix this, and I'm about done with the Sport 3. If anyone is interested in buying it as a rolling chassis, shoot me a PM.

Endaar

Bri

I did find this information in regards to another brand of touring car that might be a contributing factor to the car wandering issue –

“Well I swapped out the front end regular diff with the rear end locked diff and holy crap what a difference! It handles way better and tracks straight under power! Thanks for all the advice guys.”

Then this was added by another poster –
“With an open diff, one tire is very likely getting more power than the other side, so even if the car would roll straight, it’s going to pull. Swapping this around locked the front which pulls the car straight.”

The bottom line is you want thicker diff fluid in the front diff in relation to the rear diff.

Best regards,
Brian

fyrstormer

iTrader: (1)

Generally speaking, yes, the front diff should resist diffing-out more than the rear diff. However, a lot also depends on the weight balance of the car. My Nitro RS4 has raised and softened suspension so I could drive it rally-style, and I knew it would need swaybars -- but I incorrectly assumed a softer swaybar in the rear was the right way to go. That car has a rear weight bias, so it actually needed the same swaybars front-and-rear to keep it from tilting randomly and veering off-course during hard acceleration. I never had to touch the diffs to improve its handling, I just had to make the rear suspension resist tilting a bit more than it was previously.

SagadSetup

iTrader: (38)

Try using 500K, 1M, or 2.5M.

Normajean

iTrader: (5)

My rs4 sport 3 is set up for drifting where I have my rear suspension softer then the front, softer springs and lighter shock oil, also have 8mm offset wheels instead of the factory 6mm (I have the e30 m3), so increased track width and narrow tread width hard drift tires so less resistance on the servo, might be why my car tracks straight.

fyrstormer

iTrader: (1)

Why do you have lighter shock oil if you're running softer springs? You need more damping to keep the chassis from bottoming-out with softer springs.

Normajean

iTrader: (5)

The car will never bottom out while drifting and with so many dynamics to suspension setups, I'm going to try a variety and see what the best result Will be. Shock positions, droop, ride height, it's fun to try different setups.

alexchen86

iTrader: (45)

Endaar,

I just ran my Sport 3 Flux for the first time completely stock configuration except for adding much needed preload to balance out my hardcase 2s lipo with the electronics side and to keep the low Porsche body from bottoming out running on the street.

Before I even ran the car I read through most of this Sport 3 thread to get an understanding of known problems from first hand users.

My stock setup does not have wandering problems as you describe, and I did not adjust the servo saver or change it nor did I even switch radio systems yet. The only thing I did was add 2 additional O-rings with Associated black grease to all my dog bones. The driver side front dog bone had so much play it was ridiculous! I already saw 2 orange O-rings HPI put in on the front differential output side but I needed 2 more on the hub side to have just the right amount of movement.

I already have 3Racing CVD's on the way, but this is ridiculous for a MSRP $315 brushless RTR car. The Sprint 2 had dog bone issues as well but not this bad!

Thank goodness I only paid $250 for it new off eBay for a never ran just taken out of the box Sport 3 Flux version.

Maybe I am not experiencing the wobble you describe as the Flux version runs on 26mm front racing slicks and 31mm rear racing slicks?

Could it be the rattling of the dog bones due to the extreme amount of excess play at WOT causing the car to wander as well? Looking at the steering rack setup and the overall front end in general is all new HPI plastics which is super flexible I guess for durability at the expense of precision.

I have an HPI Bullet ST Flux I bought totally wrecked, and rebuilt it with a lot of new eBay rc junkyard stock spare parts along with a ton of GPM upgrades trying to combat this stadium rig's steering issues as well. Even going full CVD's front and rear, aluminum c hub's, aluminum hex hubs, aluminum knuckles, and aluminum steering rack....the play in the steering will cause the rig to be undriveable even with a Savox SW-0231MG at 208 oz/in. with just a GPM aluminum servo horn...no servo saver. The torque of that Savox servo should be just enough for a little rig like that.

I figure that because HPI's newer kits come with snap on plastic camber and steering links tons of wandering comes into play due to the flexing of the car or truck under WOT. Even if you were to upgrade to a stronger servo it won't combat the fact that the links, arms, c hubs, knuckles are flexing while the dog bones are literally bashing side to side causing more abnormal movement.

The last 4 HPI kits I've had all have this new plastic: Mini Trophy Desert Truck brushless conversion, WR8 Flux, Apache C1 Flux, and the Sport 3 Flux

jacobe82

I do have a HPI rolling chassis for sale on ebay with adjustable tie-rods and graphite front brace , current high bid is $189 , and would be a great deal for anybody looking to pay less on a used system that has little runtime. Will come with original box and manuals . shoot me a message on here if you can beat the $189 high bid + $30 shipping fee. and we can continue the transaction through paypal. I also have a 60c 2 cell 6500mah lipo and quick charger that I would be willing to sell for another $100. Want somebody to get a great deal on a slightly used system at a great price.

Endaar

I really appreciate the comments. The thing is I've already got CVDs and have run the car both with the stock Flux slicks as well as standard 26mm TC tires. The same problem exists either way.

Unfortunately I think you're right that the flexibility of the plastic suspension is hurting precision and there doesn't seem to be a way to fix that. I have no idea why it's working OK for some of you and not for others. (I'm not the only one here complaining about wandering.)

Ironically the car hasn't been particularly durable for me either, as I've now had the lower screw strip out of four knuckle arms and also broken two hub carriers. My Nitro RS4 - which has taken a lot more abuse - hasn't needed a single part replaced.

I finally broke down and ordered a TC4 club chassis yesterday, with the intent of stripping the electrics out of the Flux. I like working on my cars but this has gotten excessive and I'd actually like to use the darn thing once in a while.

I think I may put a cheapie brushed ESC / motor in the Sport 3, slow it way down, and give it to my 4 year old to abuse. The accuracy of the steering won't affect his propensity to crash it, lol.

Thanks,
Endaar

fyrstormer

iTrader: (1)

Duh. Right. Drifting happens on smooth surfaces. I keep forgetting that.

Normajean

iTrader: (5)

https://m.youtube.com/watch?v=DupQy1FJJgw

Here's my sport 3 "sliding around".