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SC10 4x4 Thread

Old 01-11-2012, 06:39 PM
  #14686  
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Originally Posted by Chad Smith
I am running a LRP SXX V2 TC Spec and a 5.5 550 tekin and the esc is barley over 100 degree's after a 10 min main. I think the RX8 works better in the losi 4x4 just because its alot heavery. (not saying that the RX8 wont work). The factory drivers also run the TC Spec esc
Pretty sure I would use the TC too if I were paid to do so
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Old 01-11-2012, 07:00 PM
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Originally Posted by Mizchief
I have pretty much the exact same setup and also noticed a little bit of push on-power comming off center, but had a ton of off-power steering to the point of doing 180's with just a little too much brakes. However I think it will be just about perfect for me at the dirt track, might go down to 7k in the front and see if that squares it.
This is Identical to what I am experiencing.

I can however say, it is not 'perfect' for me at my track. Our 180's, I am a slug through the corner, in order to drive like a Professional. (term used for reference only) You think raising the rear up a bit and dropping the oil will help power steering? I can try that.

I tune, can tell someone what's wrong by looking at the truck drive as far as shocks, ride height, camber, motor/esc issues, Bench repairs, mods, etc. But I'm sort of at my tuning limit. example: limiting, weight dist., lowering roll center. And it's not that I don't know 'how' to change those, it's "When I should, and why." I'm more of an engineering and repair kinda guy, my tuning knowledge usually came from fixing something. Just looking for the next step to fix this issue. I don't want to hunker down into what i'm used to.

There is no 'good' place to learn the causes and reactions of tuning phsically, only environmentally.(at the track)

1. This is happening.
- This is what is 'really' happening and what changes that and why.


It's on a really feint basis or unless you've just spent so much time in it. I've even turned people down on my knowledge of the level of tuning they are trying to achieve at work being totally honest in saying "I don't know. I don't know 'how' to learn that" and they don't blame me. RC Tuning for dummies?

Anyway. I'll put 7 in the front, and lift up the rear 2-3mm.
Disclaimer: I did not just ask for a tuning class.
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Old 01-11-2012, 07:33 PM
  #14688  
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Originally Posted by Mizchief
Pretty sure I would use the TC too if I were paid to do so
Very true, but I was justing letting him know that other people use the LRP esc's as well.
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Old 01-11-2012, 07:35 PM
  #14689  
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Coyote I was running 5000 in the rear 7000 in the front and I had a on power push with the center diff I will be going to 5000 front . I also have been thinking of trying using overdrive pulley in front .
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Old 01-11-2012, 07:36 PM
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Originally Posted by Dano628
Coyote I was running 5000 in the rear 7000 in the front and I had a on power push with the center diff I will be going to 5000 front . I also have been thinking of trying using overdrive pulley in front .
I don't think running the overdrive with the balldiff is a good idea.

Mantis?
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Old 01-11-2012, 08:43 PM
  #14691  
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Originally Posted by Mizchief
I tried out my center diff and dual-stage pistons today just in the street with stock tires.

I have pretty much the exact same setup and also noticed a little bit of push on-power comming off center, but had a ton of off-power steering to the point of doing 180's with just a little too much breaks. However I think it will be just about perfect for me at the dirt track, might go down to 7k in the front and see if that squares it.

Also I forgot to reset the ride height so it was pretty much at it's lowest setting both front and rear and noticed a lot of weight transfer to the back wheels.

I did get some slip out of the center diff mostly punching from a stop or from a backwards roll after a 180. I screwed it down with the cheasy tool that comes with the kit, may be able to get it a little tighter with a socket wrench.

I also used the ACERGoo grease on the balls, may have been to thick or slick to use a ball grease and let it slip a little.

All in all I really liked the handling with those upgrades espically when you compare to stock or basket where I had to run 30k up front to keep it straight.
make sure you use "ball dif grease" it makes a huge difference, regular grease will slip no matter what you do. Dont ask me what th edifference is but if i put regular grease in , it slips with the same settings.

No reason for front overdrive but i have not tried it, technicall with the center dif the front tires expand more than the rear giving you overdrive anyway but only when you need it......down the straight!

Coyote, use my setup exactly so we have somewhere to start from. I have very slight on power push but i will take that over turn entry push anyday and its not enough to alter my driving style. You should not have to try and "rotate" your truck around the track, its very hard to drive fast and consistent not only that but with the Cdif all rotation is numbed but you will get better steering all the way through the turn. i find that if i "flick" the wheel it will rotate but most of the time it just turns wherever i want it and always seems to have more steering if i need it to pass or get off of line. Think about what is happening, you have basically seperated the front from the rear, by nature this will give you a tighter turning radius but on exit acceleration as the power plants to the rear the front will unload and give you push. for you simply using the 3-3 block may fix it all for you since it puts more pressure on the front tires you will get more on power steering.
we need a known foundation in order to help your problem and the best way is for you to copy my setup since we all know it works very well!
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Old 01-11-2012, 08:53 PM
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OK I need some help!!! I am having probs with the rear end is stepping out on me entering the corner on power. I am running the blue sway bar on rear white spring and 25 oil in shock. Should I go thicker or softer on the sway bar?
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Old 01-11-2012, 08:56 PM
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Originally Posted by buckeyeboy30
OK I need some help!!! I am having probs with the rear end is stepping out on me entering the corner on power. I am running the blue sway bar on rear white spring and 25 oil in shock. Should I go thicker or softer on the sway bar?
its not the rear that is the problem it is the front: yellow springs, yellow sway bar, 0 camber and 1* of toe in. blue sway in the rear is fine. go with either the yellow or blue rear spring.
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Old 01-11-2012, 08:58 PM
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Originally Posted by MantisWorx
Coyote, use my setup exactly so we have somewhere to start from. I have very slight on power push but i will take that over turn entry push anyday and its not enough to alter my driving style. You should not have to try and "rotate" your truck around the track, its very hard to drive fast and consistent not only that but with the Cdif all rotation is numbed but you will get better steering all the way through the turn. i find that if i "flick" the wheel it will rotate but most of the time it just turns wherever i want it and always seems to have more steering if i need it to pass or get off of line. Think about what is happening, you have basically seperated the front from the rear, by nature this will give you a tighter turning radius but on exit acceleration as the power plants to the rear the front will unload and give you push. for you simply using the 3-3 block may fix it all for you since it puts more pressure on the front tires you will get more on power steering.
we need a known foundation in order to help your problem and the best way is for you to copy my setup since we all know it works very well!
Alright. I'll redo my truck tomorrow, I have the day off and drive sunday if all goes well, and get right back to you. Thanks for taking the time, Marcus.
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Old 01-11-2012, 09:39 PM
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i only have 1mm of roll center shims if i have to much steering period what should i go to also im running 30k front diff and 7k rear
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Old 01-11-2012, 09:46 PM
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also if i got to the two stage pistons should i keep my oil weights 32.5 front 30 rear???
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Old 01-11-2012, 10:20 PM
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Originally Posted by MantisWorx
its not the rear that is the problem it is the front: yellow springs, yellow sway bar, 0 camber and 1* of toe in. blue sway in the rear is fine. go with either the yellow or blue rear spring.
Thanks, I will give that a try in the am
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Old 01-11-2012, 10:29 PM
  #14698  
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I won a new SC10 4x RTR in a raffle at the track.
I had half a mind to sell it and get a Losi SCTE as that seems to be what 90% of the racers run in Pro4 at my track. After reading over 200 pages in this thread I figured what the hell, I am up for the challenge.

I tore the truck down to get to the front/rear diffs.
Front had barely any fluid and the rear maybe 25% filled.
I filled the fronts with 30K and rear 5K.

I tore the shocks down to check the screw holding the pistons on, re-thread lock and refill.
I drained the fluid and checked the movement.
I could not believe how much drag I felt with the x-rings and shaft boot.
Per recommendations here I removed the top ring and removed the boot.
Stayed with 1.2 F/R pistons and filled the shocks 25wt F/30wt R with AE fluid.
Built with bladders and minimal rebound.
Added some rear ext. limiters so the arms don't hit the outdrives.
Unscrewed the bottom rear shock end 3 turns.
Truck came with yellow R and blue F springs.
I swapped the yellow rear for blue.
Truck is super plush...almost too soft.

I removed the stock electronics.
In their place I installed:
Savox SC1258-TG servo
MMP ESC
Airtronics receiver

I removed the receiver box and ESC tray.
Mounted the ESC where the receiver tray was and receiver in front of it.
Running stick Lipo for now but will move ESC to other side when I get saddle pack conversion done.


As for setup, I started with:
Front shock outside on arm, middle hole on tower
Front control arm outside hole on tower (0 washers) and middle on c-block.
Rear shock inside on arm, middle on tower.
Rear control arm inside hole on tower (0 washers), middle on hub.
3+2 rear toe block
Med wheelbase
1.0deg camber F/R
0 front toe
Ride height 26mm (body off)
2.0 sway bars front and rear.
20T rear pulley and 19 overdrive front.
Wheels/tires: AKA SCTE wheels with Proline Blockades in M4 compound
(I have the JC Hazard +3 offset wheels but dindn't have time to mount tires before race)

I had no practice time on this truck and jumped straight into a beginner 4x race. While my friends made fun of me for running rookie stock, I was running the stock RTR Reedy 550 3500 motor. I would have been a road block in Pro4. I just wanted to get a feel for the truck. While this motor is probably OK for a beginner or basher, it was slow on the straightaway. It had good bottom end just no top. I was running the stock 62 Spur/14 tooth pinion. Tried to go up to 15 on the pinion but hardly made a difference. I have to get a Tekin Pro4 4K motor in this thing yesterday.

As for the handling, first off this was a brand new track layout. Outdoor hardpack dirt-clay mix. The track is typically water prepped for club races and was that night. Even watered down it was very loose on that cold night. We have a long straight going into a long sweeper that wraps around going into a tight 180deg turn. I had the back end come around on me a few times in the sweeper. Once I got the feel for the truck I was able to drive in hard staying up on the bank and I could go in hot into the 180 and hook slide around the turn consistantly. The truck turns excellent and never felt too fast or twitchy and that is with a fast servo. All I did was center the servo and make my EPA adjustments.

The stock motor had just enough power to get into trouble. There was a quad jump that I was able to hit a few times in warm up but only if I backsided a table top before it. In the race I had problems getting used to the truck and hitting the jump without under or over shooting it even as a triple-single. That is where I had the biggest trouble. Everywhere else the truck handled just fine and didn't do anything strange. In the 2nd heat in warm up I came up short and stabbed the nose. The truck was spinning the pinion so I knew the motor backed off in the crash. Probably the only thing I did not check as I never removed the motor from the motor plate in dis-assembly of the truck. Why AE didn't put washers on the motor cap screws is beyond me.

In the main decided to try a 15t pinion, 20 front pulley, and 1mm washer under the front inside control arm. The pinion didn't do as much as I was hoping for. The 20 front pulley felt fine compared to the 19 overdrive but I will have to test more to make an opinion as to which is best for that outdoor track. The 1mm washer on the front inside ballstud was a loser. I noticed that the truck lost quite a bit of turn in and I was not able to dive in as tight on turns. What confuses me is that this setup is similar to Cavalieri's OCRC club setup and he runs a 5mm ballstud washer. The only thing I can think of is that the adjustment is swinging back the other way back toward increased camber rise while raising the front roll center. Something to try I guess.

Overall, I am happy with the truck but I still have some work to do. The rear end is still a little loose and wants to come around. This will only get worse when I add some power to this truck. I plan on adding a chassis brace and converting to inline saddle packs. Can't wait to get back to the track for some testing.
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Old 01-11-2012, 10:45 PM
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Originally Posted by F_ME
I won a new SC10 4x RTR in a raffle at the track.
I had half a mind to sell it and get a Losi SCTE as that seems to be what 90% of the racers run in Pro4 at my track. After reading over 200 pages in this thread I figured what the hell, I am up for the challenge.

~~~SHORTENED FOR SPACE~~~~

Overall, I am happy with the truck but I still have some work to do. The rear end is still a little loose and wants to come around. This will only get worse when I add some power to this truck. I plan on adding a chassis brace and converting to inline saddle packs. Can't wait to get back to the track for some testing.
Very cool Review, F. Thanks for taking the time.
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Old 01-11-2012, 11:07 PM
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Originally Posted by F_ME
This will only get worse when I add some power to this truck. I plan on adding a chassis brace and converting to inline saddle packs. Can't wait to get back to the track for some testing.
The biggest change I made to this truck (other than go back to a 540 motor) is to add camber shims to the inside. My last testing day I ran my 4w back to back with my 2w throughout the day, making no changes to the 2w in order to use it to reference how much grip the track had as I tested with the 4w. I wound up adding somewhere between 2-3mm in shims one mm at a time to both the front and the rear before I got the truck pretty dialed in. As I would add to the rear and get the rear more "locked in" I discovered the truck had a push so I kept going back and fourth till I got it right.

And last time I checked, washers are cheap.

Originally Posted by MantisWorx
make sure you use "ball dif grease" it makes a huge difference, regular grease will slip no matter what you do. Dont ask me what th edifference is but if i put regular grease in , it slips with the same settings.
This. I'd almost suggest you guys use some of this:

http://losi.com/Products/Features.aspx?ProdId=LOSA3012

I got some for my antique sedan to "thicken up" the front ball differential.
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