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Inferno MP9 thread

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Another TKI thread, more TKI4 Specific http://www.rctech.net/forum/nitro-of...buggy-kit.html

TKI4 Replacement Parts (Good for upgrading from TKI3) http://www.kyoshoamerica.com/Replace...ts_c_1505.html

TKI4 Optional Parts http://www.kyoshoamerica.com/Option-Parts_c_1506.html

Some notes on the new Towers/Long shocks here

Picked up a TKI3 and want to upgrade to TKI4 ? Here are all the updated parts:

Shocks

IF347-155 1.5X5 Pistons
IF471-01 Front Shock Body
IF470-01 Rear Shock Body
IF470-03BK Shock Adjust Dial
IFW154 Boots
IF346-05C Shock End Set

Wing

IF491BK Wing
IFW460B Wing Mount/Stay

Rear End

IFH006W Wheel
IF490 HUB
IF490-01 Hub Insert
IF492 Shock Pin
IF423HB Rear Arm
IF287 Hard Upper Rod Rear

Front End

IF489 Steering Rod Set
IF488 Knuckles
IF487H Front Arm
IFW458 Hard Lower Pin
IFW425 93MM CVD
IF286 Hard Upper Rod
IF486 Lower Susp Holder
IFW459 Servo Saver (Hard)
IF446B Ackerman Arm
IF426-64.5 Susp Shaft

Other

IF469B Filter
97035LW-13 Clutch Bell
IF453B Body Mount
IFW107GM Hexes
W300910 Washer
IF443B Center Diff Plate
IF444C Tank
IF479B Radio Box
96772 13x16x0.15mm Shim
IF481B Fuel Tank Stay
IFW336GM Wheelnut
IFB008 TKI4 Body
IFD403W TKI4 Decal

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Old 03-04-2015, 07:28 PM
  #18586  
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Originally Posted by aaron125
That's pretty much how I've always understood torque steer to occur. But the original post mentioning torque steer was in reply to my comment about my car getting crossed up when slowing from high speeds. How can torque steer even occur when decelerating, as there isn't any torque being applied to the wheels when braking. Is it possible for torque steer to occur while braking?

I use the ABS function on my radio, also with a delay set so it doesn't kick in instantly. And as mentioned above, brakes are not an on/off switch, just like throttle is progressive and one doesn't need to pull the trigger to WOT every time they accelerate, same goes for braking.

An interesting discussion though.
hmm the deceleration is applied at the f/r diffs I suppose. So if one wheels heavier (by mud/water or anything else), it might be resisting motion more than the lighter wheel(or freer wheel).

From this http://en.wikipedia.org/wiki/Torque_steering

Asymmetric driveshaft angles due to any combination of
Unequal driveshaft length or diameter

Torque steering effect simulated using MSC Adams.
Transient movement of the engine
Tolerances in engine mounts
Body roll
Single wheel bump
Different driveshaft torques left to right (due to wheel bearing or differential problems)
Suspension geometry tolerances
Unequal traction forces due to road surface (-Split) in combination with kingpin offset
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Old 03-04-2015, 09:38 PM
  #18587  
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The torque steer was just an idea. But from this discussion it seems the car crossing up under high speed hard breaking isn't torque steer. I thought about it and it seems that what is causing the car to cross up under breaking is the outside wheels wanting to spin backwards and the inside wheels spinning forward. Which I think is caused from the difs unloading.
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Old 03-05-2015, 01:20 AM
  #18588  
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Originally Posted by max92804
The torque steer was just an idea. But from this discussion it seems the car crossing up under high speed hard breaking isn't torque steer. I thought about it and it seems that what is causing the car to cross up under breaking is the outside wheels wanting to spin backwards and the inside wheels spinning forward. Which I think is caused from the difs unloading.
Hmmm, interesting concept, never really heard of one wheel wanting to go forward and the other backward when the car's in motion. Sure it happens with wheels off the ground and spin one, the opposite side spins the other direction but never thought of how that could happen while the car is in motion. Isn't that the whole point of the differential action, that it allows each wheel to spin at different speeds as in outside wheel has to spin faster in corners because it has a longer path to travel than the inside wheel?

I've never really understood what the phrase "diff unloads/unloading" means. Hear and read about it everywhere but what part or component of the diff is actually being unloaded? Does it refer to having the torque from the engine removed and the diff being in a freewheeling situation? What is the consequence of a diff unloading and is there anything can be done to reduce or stop this from occurring somehow? Is there anything you can suggest to alleviate this issue? When it happens, the car always gets crossed up to the right and having to countersteer to the left with the radio - does this give any indication for what to do because it always happens the same way? I kinda thought it might be coz of the extra and offset weight of the engine and fuel tank maybe? But then I've never seen it happen to Tebo or King and at the WC which King won in Pattaya, that track had huge speeds along front straightaway and quite a slow corner at the end. And, when I think about it, never happens to them on any track which I've watched their races online but, quite obviously, I sure can't drive anything like them. Maybe it is because the wheels are locking up just a little and I should back off the EPA slightly or perhaps just always use the ABS function on my radio?

Any input is appreciated. Cheers.
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Old 03-05-2015, 01:42 AM
  #18589  
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I've never had that happen with my MP9. However I was driving my e-truggy (ST-RR EVO) in front of my house the other day with really bald tires. It was stopping straight. Then I decided to crank up the brake EPA to see if I could get it to stop sooner and faster since the street had a lot of grip. Immediately it stayed doing the torque steer braking thing when I went to full brake. All I can conclude is the power of brakes of the motor transferred a lot of weight to the front (street really grippy so front tires dug in) which unweighted the rear tires, locking them up and causing them to skid to the side. Still not completely sure why they wouldn't skid straight. If you were driving a full size car and yanked the e brake would it stop straight or fish tail the rear?
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Old 03-05-2015, 05:19 AM
  #18590  
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Originally Posted by aaron125
I've never really understood what the phrase "diff unloads/unloading" means. Hear and read about it everywhere but what part or component of the diff is actually being unloaded?
Diffing out happens when you're on a high traction surface running too thin oils.
Sollution involves thicker diff oils.
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Old 03-05-2015, 09:03 AM
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In thinking of this in simpler terms, what I guess to be happening is that the good amount of flex built into the chassis is allowing it to twist under stronger braking on a rolling axis and making the car weave to the right. If the epa is set really high on cars with full plastic radio trays, you can see the whole tray twist along the roll axis. My .02 cents.
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Old 03-05-2015, 11:14 AM
  #18592  
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^^ Spads11, how do you like the MP9E? Im on the fence, I know it should be a no brainer....
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Old 03-05-2015, 03:01 PM
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Originally Posted by sn47som1
^^ Spads11, how do you like the MP9E? Im on the fence, I know it should be a no brainer....
I like it as much as I like the tki3; easy to set up and be fast with right off the bat. It does feel better with the alu front hubs for me also. I took a year off of e and recently returned and was in the top 5 with some FAST guys at my track at the first race. They have a couple of more races before I podium challenge
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Old 03-05-2015, 04:12 PM
  #18594  
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Does anyone have any experience using the ready set unmilled chassis on there spec A? I was wondering about flex and what grade of aluminum???
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Old 03-05-2015, 04:26 PM
  #18595  
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You should come out on WXE David
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Old 03-05-2015, 05:19 PM
  #18596  
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Yes, most full-sized cars will not stop straight if all 4 tires are locked up. The rear end always starts to come around if the skidding last long enough. I've always assumed it was because of inertia.

All the weight behind the locked up front wheels will still be wanting to move forward more rapidly than the front wheels, that get much more traction because of weight bias at that point, will allow. So, when the rear wheels lock up too, and since they don't have as much weight on them, the inertia will cause them and all that weight to try and go around, or to the side of the front wheels, thus skidding sideways.

I'm no engineer, and I may be way off base, but this is how I have always thought of it.

Whenever my buggy is crossing up under heavy braking, I always just take out some rear brake so the rear tires don't lock up, and the problem goes away. Because if the tires stay turning, they will always track better than if they are completely stopped. That's why people that drive in the snow alot always pump the brakes when trying to turn and slow down at the same time, a locked up tire in the front won't steer, and locked up rear tire won't follow.

Yanking the ebrake will DEFINITELY cause the car to fishtail...lol, I know that from fun experiences.

Just my thoughts...feel free to tell me I'm crazy.

Last edited by WYLDTHING; 03-05-2015 at 06:32 PM.
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Old 03-05-2015, 05:34 PM
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who needs brakes anyway ?

besides "THE JQ" anyway
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Old 03-05-2015, 05:34 PM
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Originally Posted by RockStar_199
You should come out on WXE David
I wish I was close enough that my schedule allowed it. An 18 month at home keeps all that in check!
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Old 03-05-2015, 05:44 PM
  #18599  
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Originally Posted by houston
who needs brakes anyway ?

Lol...true true...
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Old 03-05-2015, 06:30 PM
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Originally Posted by WYLDTHING
Yes, most full-sized cars will not stop straight if all 4 tires are locked up. The rear end always starts to come around if the skidding last long enough. I've always assumed it was because of inertia.

All the weight behind the locked up front wheels will still be wanting to move forward more rapidly than the front wheels, that get much more traction because of weight bias at that point, will allow. So, when the rear wheels lock up too, and since they don't have as much weight on them, the inertia will cause them and all that weight to try and go around, or to the side of the front wheels, thus skidding sideways.

I'm no engineer, and I may be way off base, but this is how I have always thought of it.

Whenever my buggy is crossing up under heavy braking, I always just take out some rear brake so the rear tires don't lock up, and the problem goes away. Because if the tires stay turning, they will always track better then if they are completely stopped. That's why people that drive in the snow alot always pump the brakes when trying to turn and slow down at the same time, a locked up tire in the front won't steer, and locked up rear tire won't follow.

Yanking the ebrake will DEFINITELY cause the car to fishtail...lol, I know that from fun experiences.

Just my thoughts...feel free to tell me I'm crazy.
Think your on to something. Recently looking at brake upgrades for my road car, almost all of them have oversized front brakes and tiny rears rotors/callipers. Never really noticed until I was in the market to buy upgrades hehe.
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