16 replies to this topic

[twinpotter]

Since I began playing gpl the above title concerning set ups as always made me think of it as a black art. I know some of you get it and do it while others stumble.I found the following thread/link which explains this so called black art.
Please comment and let me know your thoughts on this subject and thread.
Thanks in advance for any input.

TP.

https://groups.googl...ors/QZ0xRr1AHZc

CHOW!!

[Lee200]

Real world versus GPL differentials has always been confusing.

In a nutshell, disregard most of what you may read about real world differentials and setups as GPL is not the same; particularly when it comes to the ramp angles and number of clutches and their effect on car handling.

This has been discussed numerous times here so I won't repeat it.

Edited by Lee200, Jul 21 2014 - 04:26 PM.

[Roo]

This is my simple way of understanding diff settings.

numbers: 30/85/1 = power/coast/clutches
ie power = when applying throttle / coast = when lifting off throttle

30/85 is aggressive (alien ):
ie easy to spin the wheels when applying throttle / easy for rear to break free when lifting off throttle to begin braking

85/30 (default on 67 cars) makes the cars easier to drive by allowing you to be more aggressive (heavy footed) with the throttle pedal.

Clutches:
use them to fine tune the diff.
more clutches = makes car more stable when lifting off throttle but looser when applying throttle.

[bart]

Maybe these 2 images can help a little bit.
These are values I gathered troughout my GPL-years and still keep in my personal "GPL setup guide for dummies".
As you can see I'm a profound believer of the KISS principle

 Diff_gpl_1.png   42.94K   195 downloads  Diff_gpl_2.png   71.61K   208 downloads

[JonnyA]

That looks very useful Bart, thanks.

[john roberts]

Lee200, on Jul 21 2014 - 04:25 PM, said:

Real world versus GPL differentials has always been confusing.

In a nutshell, disregard most of what you may read about real world differentials and setups as GPL is not the same; particularly when it comes to the ramp angles and number of clutches and their effect on car handling.

This has been discussed numerous times here so I won't repeat it.

many many times ...

like this one http://srmz.net/inde...295

[John Woods]

Niels Heusinkveld authored a diff guide in German and English.
Maybe this is where Bart got the charts?
Here's English: (not sure how this will upload, think its from a webpage, so...)

Attached Files

•  LSDiffs.doc   73.5K   69 downloads

Edited by John Woods, Jul 24 2014 - 06:35 AM.

[bart]

Ah yes, that does bring back memories

[dbell84]

Once I had read Niels's doc about diffs after I became a right foot breaker and put what his ideas into practice, I never mess with the diffs in my setups.  I found it worked for me.

[Pete Gaimari]

All my PB's were set with a fairly mild diff. It still turns good if the rest of the setup is right. 60/45/1

[twinpotter]

Thanks all for the input to this thread. Been watching this and there as been some great info,advice and tips.

Many thanks TP.

[Fat Rich]

John Woods, on Jul 23 2014 - 05:53 PM, said:

Niels Heusinkveld authored a diff guide in German and English.
Maybe this is where Bart got the charts?
Here's English: (not sure how this will upload, think its from a webpage, so...)

Great stuff, many thanks for posting that. Seems my setups aren't too far off, having those locking tables will hopefully make it easier to get the car just right. Also it's interesting that Niels dismisses using the gas to stabilise the car under braking, pretty much what I always believed too.

And just to confuse things further, the Lotus 49 in Assetto Corsa has power and coast angles plus a preload setting, but no settings for clutches......

Edited by Fat Rich, Jul 24 2014 - 04:29 PM.

[John Woods]

Fat Rich, on Jul 24 2014 - 04:28 PM, said:

Also it's interesting that Niels dismisses using the gas to stabilise the car under braking...

There's also another fantasy...stay on throttle just enough to keep revs up in max power band.
LFBers can easily do that without heel/toe/rigamaroe.

Edited by John Woods, Jul 25 2014 - 09:34 AM.

[Fat Rich]

John Woods, on Jul 25 2014 - 09:22 AM, said:

There's also another fantasy...stay on throttle just enough to keep revs up in max power band.
LFBers can easily do that without heel/toe/rigamaroe.

I could maybe understand that in a turbo car to keep the boost up (like the new Lotus 98T in Assetto Corsa , what an astonishing machine!) but in a normally aspirated GPL car as long as you're in the right gear when you get on the gas I don't see how it can make much difference.

Edited by Fat Rich, Jul 25 2014 - 10:42 AM.

[John Woods]

Some may note a very distinct bogging down when trying to accelerate if revs are not in band of 90% or more max power/torque curves...correct gear means to me the highest gear that does not drag engine down below that.
Seems it can cost a few tenths.
The right gear, either up or down, keeps engine happy.

[one2fwee]

I agree keeping throttle on while braking is bad and also that you aren't using the coast side of the diff. I feel it's mostly to exploit bugs in gpl to shorten braking distances, but that's discussed in another thread.

Anyway, the part I don't really get with Niels' post is at the end.
I'm fine with all the theory but then his actual suggestions seem to go completely against it, in that he was MORE LOCKING on coast than power?

Surely you would want more locking on power so you can get the power down more effectively and less locking on coast so you can turn in better. Yet his suggested locking values are the complete opposite of this.

Btw, you can still view Niels' article online without having to download it, using the internet archive:
http://web.archive.o...guide/guide.htm

It also means you can view older versions of it too if you really wanted to (i think he shortened some parts or something but i haven't checked).

Edited by one2fwee, Jul 25 2014 - 12:36 PM.

[John Woods]

Hey thanks, one2fwee, for archive link.

Nuvolari didn't lift, btw.