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Old 04-29-2009, 11:24 AM   #16
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I think that works for you guys in the US where you race foams on carpet. Everyone I know who ever tried one here in oz with rubber on carpet said it was absolutely horrendous
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Old 04-29-2009, 07:24 PM   #17
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Made some research and a 1.5 way LSD is what race cars use generally.
Kinda like it acts like a normal diff but under torque it tightens automatically,
something like that, I think it's adjustable as to when it tightens. Also,
LSDs cure torque steers from rear wheel drive cars.

Im not into RC drifting because I dont like the idea of using plastic tyres
so I dont lock my rear diff. Street racing is what I do so traction and
stability in the straights is important plus good handling for dog fights.
But I also drift when needed. So I just want to apply some race car technology to my rc cars for better performance.

The surface we race on is typical flat street concrete with some slippery
spots because of dust or sand build-up so the condition is loose to medium
traction. When I first got my RTR TC4, its front diff is fully tightened like
a spool and after months of running, it began to have straight line issues,
it would wander left and sometimes right. But when I loosen the front diff,
it tracks straighter than ever before. Surprisingly, my TT01D with stock
gear diff runs the best on straight line, I mean you can point it to the
direction that you want and just let go of the steering wheel.

So basically, an LSD gives you grip on corners? Which will be beneficial
in quick launches, loose, tight or mildly tightened diff?
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Old 04-29-2009, 11:48 PM   #18
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1.5 way LSDs are open off-throttle and limit slip on acceleration.
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Old 04-30-2009, 12:27 AM   #19
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Spool is NEVER used with foam on carpet. On the other hand, Europeans are doing fine wit spools on carpet rubber.

Quote:
Originally Posted by niznai View Post
I think that works for you guys in the US where you race foams on carpet. Everyone I know who ever tried one here in oz with rubber on carpet said it was absolutely horrendous
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Old 04-30-2009, 02:16 AM   #20
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LSD is a acid
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Old 04-30-2009, 03:57 AM   #21
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Quote:
Originally Posted by kschu View Post
if loose, i think d tyre wont spin but the diff is slipping tremendously rite?...
well, when i said loose.. it's not "loose" as in the diff would be slipping, but "loose" as in the diff can have/execute differential action easily.

settings diffs for races is more than just "loose for low grip surfaces and tight for high grip tracks". in my case, it has always been just try to drive your car around the track then adjust your diffs according to what you want. i just use the quoted statement above for a good starting point for my diffs.


@Airflow

yes, generally, a looser diff would have much more grip but at the price of speed. the looser you set your diffs, the more it will be prone to slippage, and thus loss of speed. so if you want to have quick launches, then have it "tighter", but again, compromising maneuverability.
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Old 04-30-2009, 05:23 AM   #22
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Quote:
Originally Posted by Airflow View Post
Made some research and a 1.5 way LSD is what race cars use generally.
Kinda like it acts like a normal diff but under torque it tightens automatically,
something like that, I think it's adjustable as to when it tightens. Also,
LSDs cure torque steers from rear wheel drive cars.

Im not into RC drifting because I dont like the idea of using plastic tyres
so I dont lock my rear diff. Street racing is what I do so traction and
stability in the straights is important plus good handling for dog fights.
But I also drift when needed. So I just want to apply some race car technology to my rc cars for better performance.

The surface we race on is typical flat street concrete with some slippery
spots because of dust or sand build-up so the condition is loose to medium
traction. When I first got my RTR TC4, its front diff is fully tightened like
a spool and after months of running, it began to have straight line issues,
it would wander left and sometimes right. But when I loosen the front diff,
it tracks straighter than ever before. Surprisingly, my TT01D with stock
gear diff runs the best on straight line, I mean you can point it to the
direction that you want and just let go of the steering wheel.

So basically, an LSD gives you grip on corners? Which will be beneficial
in quick launches, loose, tight or mildly tightened diff?
I think you're a bit confuse. RWD cars don't suffer from torque steering.

A FWD car needs an LSD on the front to sure understeer not torque steering. The torque steering is somewhat tamed by an LSD but that's not its first purpose. The reason it does cure torque steering to some extent is because LSDs typically induce more drag between gears.

Historically LSDs were used to transfer power to the loaded wheel in street racing when under hard cornering inside wheels tend to lift and unload therefore all torque was transferred to the unloaded wheel making little use of the engine's power.

These days there's a number of LSD and torque biasing diffs used in cars such as Quaife or Torsen. Look them up on the web and you'll see their function and applications. Most FWD cars really benefit from Quaife diffs (such as Peugeot 205 GTIs with hotted up engines and so on). RWD cars also benefit form torque biasing action but that's because in hard racing they tend to lift rear wheels so in such situations a Quaife is the solution (such as on BMW 2002). There are also a number of production cars that come equipped with Quaife diffs from factory such as Celica GT-Four (rear diff).

In the world of R/C there is an italian company that makes Torsen diffs but not for electric 1/10 cars.

Also, as long as you have all wheels on the ground you don't rally need limiting action. In R/C you need some limiting action because you want to correct under/oversteering effects induced by other components in the transmission train, such as more powerful motors, tires, etc.
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Old 04-30-2009, 12:26 PM   #23
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Tight diff in a FWD RC works best IMO.
when you stear left your right tire wouldn't slip as much as if it was loose. when your stear right your left tire won't slip as much.

4WD cars I would think a loose rear diff would give you more stearing and a more stable feel.

I think a spool runs good on outdoor low grip tracks.
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