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Clutch In Gpl Setups

GPL clutch

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#16 FJBH10

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Posted Nov 29 2017 - 04:07 PM

I found I'm fastest and happiest with 30/85, I got my best ever qualifying result with that (But blew up in the race) and it feels so much better than the stock setup. I like having the car really twitchy normally and was struggling to get that in GPL, especially in the '65 cars with their low power but thanks to you guys I am now about a second quicker on most of the tracks I've tried so far.

#17 John Woods

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Posted Nov 30 2017 - 09:29 AM

View PostJonnyA, on Nov 29 2017 - 03:41 PM, said:

it's about how the car rotates into the corner as I come off the brakes and onto the power.

Have been wondering a long time about how to deal with "not right in the middle" because there is no setup adjustment for pre-load, (as Vari-loc guide recommends).

Now see it must be clutches alone that tune how the car behaves in transition.
(Takes awhile).
Also, another guess based on experience of really having no idea, it also depends some on load balance, brake bias, and rear camber?

So, x-ing everything else out, for a given setup:

1. Tune coast ramp for entry.
2. Tune power ramp for exit.
3. Adjust clutches to tune for the middle?

Or, as some with no respect for reality might want to try, just set it for the quickest possible digital effect and run 15/85 and adjust clutches to maybe work best for a particular track?

More clutches > big tracks, long straights, fast sweepers?
Less clutches > twisty circuits?

:)

#18 Pete Gaimari

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Posted Nov 30 2017 - 09:51 AM

Use the ramp adjustments to set how you want to balance the car. Use clutches to set how hard and fast you want those ramp settings to lock.

#19 Michkov

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Posted Nov 30 2017 - 04:46 PM

Posted Image
This here diagram should help illustrate what the ramps do. The yellow peg transmits power from the engine towards the driveshafts to the left and right of the white block. If you stomp gas the peg moves forward and puts pressure on the block pushing it apart. Depending on the peg/block angle (this is your ramp angle) a certain amount of the peg force is transferred from the forward peg motion to sideways motion pushing the block apart.
Same goes for the deceleration case where the block is moving into the "stationary" peg which then pushes the block apart.
As you can see the closer the ramps are to 90° the less force is produced to push the block apart.

Now for where are the clutches? They sit at the end of the blocks. They function like a clutch you find on a gearbox, just in reverse. IE they're natural state is disengaged, allowing the shafts to rotate independently. The force pushing apart the blocks engages the clutch, locking the axle, or at least stick it together a bit more.

What adding more clutches does, is decrease the force necessary to achieve locking. Because there is more friction surface to work with. Below is an exploded LSD, clutches are the dark grey parts.
Posted Image

The TLDR:
Increasing clutch count has the same effect as decreasing ramp angle.
They effect both coast and power side equally
Consult the sheet mentioned above for on how big the effect is but my usual guideline is ramps for rough balance and clutches for fine tuning. So similar to the Springs/ARB to damper relationship.

View PostJohn Woods, on Nov 30 2017 - 09:29 AM, said:

View PostJonnyA, on Nov 29 2017 - 03:41 PM, said:

it's about how the car rotates into the corner as I come off the brakes and onto the power.
So, x-ing everything else out, for a given setup:

1. Tune coast ramp for entry.
2. Tune power ramp for exit.
3. Adjust clutches to tune for the middle?

Or, as some with no respect for reality might want to try, just set it for the quickest possible digital effect and run 15/85 and adjust clutches to maybe work best for a particular track?

More clutches > big tracks, long straights, fast sweepers?
Less clutches > twisty circuits?

:)

I use coast for braking stability after everything else doesn't work
Power for cornering, as I'm steering with the throttle more than the wheel if I have my car set up to my liking
Clutches for fine tuning.
There isn't really a steady state variable to tune, I'm not sure what GPL does in that case. Intuition says you got an open if no there is no preload build into the mechanism to force the clutches together at least a little bit. But I am not in the know how exactly GPL diffs are set up internally.

#20 Pete Gaimari

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Posted Dec 01 2017 - 12:47 PM

The problem is.......just like the suspension settings. The real car settings don't transfer to GPL like we'd like them to. I think that holds true for the diff too.

#21 John Woods

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Posted Dec 02 2017 - 10:47 AM

Agreeing with Pete, the effect is more important than the setting.

Ease or let off throttle while turning and the sprung weight of the car seems to rotate to the inside as the rear suspension relaxes and weight on the rear makes a line that is different and outside the line the front is on. That is a good thing.

Happy on-purpose coast induced minimum necessary rotation is the goal.
The entire setup has to be balanced and centered to achieve that effect.



:D

Edited by John Woods, Dec 02 2017 - 10:47 AM.


#22 Michkov

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Posted Dec 02 2017 - 03:29 PM

I've never been one that like the "because that's the way it is" answer. So I go looking for how the mechanisms work. Not there is anything wrong with the the higher the number the less nervous the car is approach either. Doesn't help with the interplay between the tunable components I find.

#23 Pete Gaimari

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Posted Dec 02 2017 - 05:03 PM

Nothing wrong with that to understand how the real car worked. It's only helpful in GPL if it's modeled 100% like the real car. I don't believe any of the settings for suspension or diff is accurate in GPL to the real car.

Papy said the diff in  GPL should be 45/85/1 to match the real car. If you RF brake it will be a real struggle to tame the car under braking. You could then match the suspension settings and it will become stable, but will have so much understeer it will be nothing like the real car which leaned towards oversteer.

So, forget what settings the real car had and setup the GPL car to feel good for you. There's no such thing as a realistic setup in GPL. You can make the car drive close to what the real car drove like, but the settings won't be close to what the real car had.




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