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Clutch In Gpl Setups

GPL clutch

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#1 FJBH10

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Posted Nov 27 2017 - 06:18 AM

Hello all,

I've recently been on a mission to learn how to properly set up a car, I'm using GPL and Assetto Corsa as my main platforms. I have been making some good progress but one aspect of the car setup that I have never came across before and cannot find any proper resources for is the clutch. I'm guessing that the GPL setting relates to the clutch plates but I don't know what effect it has on the car, would more clutch plates give better acceleration but less reliability due to friction? I would be thankful if someone with a bit more knowledge than me could enlighten me on the subject.

#2 Millennium

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Posted Nov 27 2017 - 06:59 AM

More clutches means tighter diff, less clutches means looser. It should also be adjusted to the weight/amount of torque of a car.

I recently made a video about it, although it just covers the basics and is not very in depth.
https://youtu.be/awLhSsy5IqY?t=3m1s

Here's an excellent guide by Charlie Williscroft:
http://srmz.net/inde...?showtopic=1140

Edited by Millennium, Nov 27 2017 - 07:04 AM.


#3 mcmirande

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Posted Nov 27 2017 - 07:12 AM

They're clutches of the differential. Nothing to do with gearbox.

The more clutches (in combination with slower angles), the hard differential.

Cheers, Marcos.

#4 Cookie

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Posted Nov 27 2017 - 07:40 AM

My way to handle the differential is to look at Lee's Setup Manager wich displays the locking percentage,
so you get an absolute value of the differential locking ;)

#5 John Woods

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Posted Nov 27 2017 - 09:31 AM

There's a t-t-t-ton of info about this.

One idiot's theory:
There are only two differential conditions.
1. Power on accelerating, (99.9 percent of the time).
2. Coasting with power off, (momentary condition only to set sprung weight on rear of car for acceleration thru a turn).

Also note, as I understand, springs and anti-roll bars define the extent of sprung weight travel. Shocks and the diff effect the speed of travel.

The standard operating condition is power on accelerating.
The only time and reason to lift throttle and go into coast is to rotate the rear of the car to set it up for acceleration thru a turn.

So the diff setup priority is dependent on driver style and technique as well as the car's capability.

Refer to gpllinks tech section for some links to diff technology.

Here's one that is simple and easy enough to apply to GPL setups: Vari-loc

Plus this link to some setup secrets:http://srmz.net/inde.... skid fun&st=0

And a great place to test setups and effect of changes: Skid Fun

:D

Edited by John Woods, Nov 27 2017 - 09:43 AM.


#6 FJBH10

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Posted Nov 27 2017 - 10:05 AM

Thanks guys, a great example of the fantastic community we have here! I never thought that it could be referring to the diff... good job me! Gonna read through all the links and watch Millenium's videos and hopefully I can get an understanding of how to set up a diff. Thanks again... in less than 4 hours you guys gave me more info than I expected I would have after a fortnight. (Also Millenium you are a god to be able to drive at all with a pad, never mind as competently as you do!)

Edited by FJBH10, Nov 27 2017 - 10:11 AM.


#7 Stefan Roess

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Posted Nov 27 2017 - 10:28 AM

GPL Setup Sheets (Setup Basics) [English]

http://www.gplworld....ps-replays.html


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#8 FJBH10

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Posted Nov 27 2017 - 10:41 AM

Thanks a ton Stefan, those are really useful.

#9 Michkov

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Posted Nov 28 2017 - 09:11 AM

It's clutches in the differential. GPL cars have a limited slip diff which is between solid axle and an open diff. The clutches are the locking parts in this case, with more clutches offering more area to grip hence a harsher locking.
The ramp angles control how much of force the accleration of the tyres/driveshaft puts on the clutchs. With the power angle(first value) in use when the engine is driving the wheels and the coast angle for the other case.

#10 JonnyA

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Posted Nov 28 2017 - 01:33 PM

My rule of thumb is, if the car feels otherwise balanced but reluctant to turn (not just because of understeer), I add clutches. And if too twitchy, take some out. Other than that, I never touch the diff settings.

Not rocket science (but then I'm only an average driver) but it works for me.

#11 Millennium

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Posted Nov 28 2017 - 02:34 PM

It's interesting to see the different approaches here on determining the amount of clutches. I am by no means an expert on this subject, personally I just start with the default settings to find out how that drives.

1. If I want more rotation under power, I lower the first ramp angle number. (power)

2. If I want more rotation while braking/steering into a corner, I raise the second ramp angle number. (coast)  

3. Based on how loose or tight the diff feels with the ramp angles I've chosen, I raise or lower the amount of clutches.

In that way I sort of use the amount of clutches as a way to fine tune my diff settings, not as a base to build up from. I don't know if that's the right way to look at it, but it works for me.

#12 leon_90

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Posted Nov 28 2017 - 02:44 PM

View PostJonnyA, on Nov 28 2017 - 01:33 PM, said:

My rule of thumb is, if the car feels otherwise balanced but reluctant to turn (not just because of understeer), I add clutches. And if too twitchy, take some out.

Its the exact opposite

#13 JonnyA

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Posted Nov 29 2017 - 12:41 AM

View Postleon_90, on Nov 28 2017 - 02:44 PM, said:

View PostJonnyA, on Nov 28 2017 - 01:33 PM, said:

My rule of thumb is, if the car feels otherwise balanced but reluctant to turn (not just because of understeer), I add clutches. And if too twitchy, take some out.

Its the exact opposite

Well it works for me!

#14 John Woods

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Posted Nov 29 2017 - 10:12 AM

View PostJonnyA, on Nov 29 2017 - 12:41 AM, said:

View Postleon_90, on Nov 28 2017 - 02:44 PM, said:

View PostJonnyA, on Nov 28 2017 - 01:33 PM, said:

My rule of thumb is, if the car feels otherwise balanced but reluctant to turn (not just because of understeer), I add clutches. And if too twitchy, take some out.

Its the exact opposite

Well it works for me!

:)

Say...what?

Small part of what Vari-loc says about tuning ramp angles:
"Differential locking action creates drag between the tires that in turn produces push. In general, the greater the locking action, the more push that is created."
"Corner entry and exit are controlled by the ramp angles, and neutral throttle by preloading the clutch pack."
"Locking rate of both sides of the ramp can be lowered by reducing preload, or by rearranging the clutches to reduce the number of active surfaces."

Pretty certainly, more locking causes more push. So Leon is correct in noting that increasing clutches will not correct push but actually does the opposite.

Maybe JonnyA is also correct, when steering car using throttle, as the effect of stiffer diff could be an advantage in precisely turning (rotating) the car?

Just a guess...plus if a typical morning post probably exactly wrong somewhere.


:D

Edited by John Woods, Nov 29 2017 - 10:40 AM.


#15 JonnyA

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Posted Nov 29 2017 - 03:41 PM

John, your guess is right. It's nothing to do with correcting understeer, it's about how the car rotates into the corner as I come off the brakes and onto the power.




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