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Differential Settings At Each Track?


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#1 mcmirande

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Posted Feb 04 2019 - 11:17 AM

Hello everybody.

There are several interesting threads about GPL differentials, which I already have read, but I prefer to open this question here.

Which track features affect your selection of diff settings and in which manner?  Until I understand, the "quickest" diff would be as tight as possible in power and as looser as possible in coast (something like a 30/85), but looking some alien's setups I noted that many of them use(d) other configurations (from a "more relaxed" 45/60) to many other combinations including multiple clutches.

I know that much of GPL setting result from multiple tests... but "a priori", which track features do you think would justify a different diff than 30/85?  I mean, only considering speed, not easiness to handle.

Open and fast corners?  bumps on track?

Well, thanks for any comments.

Marcos.

#2 Millennium

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Posted Feb 04 2019 - 01:00 PM

I would say tracks with long / high speeds corners could benefit from a more closed diff (like 45/60) so you'll scrub off less speed when you are rotating.

But I'm not an alien, so I don't know if that's a hard fact in GPL.

#3 Cookie

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Posted Feb 04 2019 - 03:03 PM

The more acceleration is needed the more locking is usefull. Monza
The more corners the less locking. Clermont

Please forget ramp angles without clutches! 30/x can be less locked as 60/x by using more clutches!!!

Lee has explained very good to use the "locking percentage" -> 30/x/1 = 8% but 60/x/3 = 10%

#4 mcmirande

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Posted Feb 04 2019 - 03:31 PM

View PostCookie, on Feb 04 2019 - 03:03 PM, said:

The more acceleration is needed the more locking is usefull. Monza
The more corners the less locking. Clermont

Please forget ramp angles without clutches! 30/x can be less locked as 60/x by using more clutches!!!

Lee has explained very good to use the "locking percentage" -> 30/x/1 = 8% but 60/x/3 = 10%

Thanks Cookie!
yes. I know very well how are the calculations about the clutches but as most alienish setups I saw use a very loose rear I was thinking always in 1 clutch.

When you compare locking in Monza vs Clermont, refer only to power or power and coast? I drive with three pedals doing heel and toe, so coast value IS important to me too...

Marcos

#5 Robert Fleurke

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Posted Feb 05 2019 - 07:39 AM

For me it depends on the track, and car, and mod. I have no real guidelines for track characteristics, but for example at Kyalami with BT24 I use 45/60/1. At Surfer's Paradise 60/60/1, and at Tucuman 45/45/1.

I agree with Axel the faster the track, the looser diff you can get away with. At more twisty tracks most of the time I like a more stable diff. You can also tune the diff for achieving lesser offset between front and rear tire temps.

Some ppl drive always with the same diff BTW. Again, no right or wrong, just try out what you like the best for a track and car. For most mods I standard use 30/85/1 or even 30/85/x (for example SCX).

#6 Pete Gaimari

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Posted Feb 05 2019 - 09:29 AM

A lot of it can be braking zones and high-speed sweepers that need to be taking off throttle with no braking. There's other variables too.

Usually, different diff settings are tried and the one picked is comfortable to drive while still being fast. There's no sense picking the fastest setting if you're out of control driving it.

#7 mcmirande

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Posted Feb 05 2019 - 09:57 AM

Ok, thanks to all. I agree that every track and every driver have their optimal settings.

My question was focused in "theory". That is, before driving, which diff settings would you choice just looking the map and length of the track.

If you had to chose (for simplicity only with 1 clutch) a setting for Monza and one for Clermont, in which track is "logical" to select a looser diff on either power and coast?

Cheers. Marcos

#8 Pete Gaimari

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Posted Feb 05 2019 - 10:08 AM

Monza would be a tighter power side and looser coast side compared to Clermont. Monza is a very easy track to drive and can handle a faster diff. It has two fast sweepers that can take advantage of a fast diff.

With that said. Greger did a 1.26 lap at Monza with an 85/45/1 diff. So, if you're fast you're fast with any diff.

Edited by Pete Gaimari, Feb 05 2019 - 10:11 AM.


#9 John Woods

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Posted Feb 05 2019 - 11:12 AM

Think it can be track specific if that is the solution to special case.
For instance if starting with xx/xx/1 and add clutches to help at a specific corner.


:D

Edited by John Woods, Feb 05 2019 - 11:22 AM.


#10 mcmirande

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Posted Feb 05 2019 - 11:58 AM

OK, thanks!

Pete, so I was thinking within the logical way...

Maybe power diff could be tightest with "flatter" tracks (I noted that bumps turns the car very unstable with tight diffs) and the predominance of medium to high speed corners.
And coast diff should be looser in tracks with tight corners.

Also... I think that power and coasts shouldn't be necessarily correlated, isn't it?  I guess some tracks would need tight power diff and relatively tight coast too.  And maybe an overall loose diff could be fast at Clermont, for example...

As said, I'm just trying to think it in logical terms.  I know that Greger will be always faster than me and also that if experience contradicts these rough "logical terms", I always would select the diff with which I'm more comfortable.

Thanks to all again!

Marcos.

#11 Pete Gaimari

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Posted Feb 05 2019 - 12:44 PM

I never take bumps into a diff setting but I will work on the suspension for bumpy tracks.

Yes, Greger will always be fast but he does show us that the setup may not be as important as precise driving. He did get faster when he went to more aggressive diffs but not as much as you might think. On some tracks it might be less than 1/2 second. You also have to consider he was getting faster and would have gone faster with the 85/45/1 diff had he stayed with it.

In my own case I started with a 45/85/1 diff and sett all my PB times with that diff. A few years later I decided to go to RF braking and went with a 85/45/1 diff for all tracks because it was comfortable with RF braking. My times got slower but over the years I got faster and caught up to all my 45/85/1 diff times with the 85/45/1 diff.

Sometimes not worrying about the setup and putting all your focus on driving perfect laps will be all you need to get faster. As a bonus you're trying so hard to drive perfect laps that you're always in complete control and never spin off. You don't even come close to spin anymore. Compared to trying to go faster with the setup it's like night and day in consistency.

A hot lapper will used the fastest setup and every now and then get a fast lap in. Mostly his laps will be inconsistent. All he wants is that one fast lap that he can hardly ever repeat.

A racer will use a fast comfortable setup and never think about it when driving. All his focus is his driving and on the track. Hitting his spots every lap. Never out of control.

Never drive over your head and never use a setup you can't control.

None of this applies to aliens. They can be consistent with the fastest setups. Are you an alien? If not, why are you using their setups?

Drive smart and make believe your real life is on the line. You only get to die once.

#12 mcmirande

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Posted Feb 05 2019 - 01:24 PM

Yes, Pete. I race gpl online since 2011 and I'm aware and agree with all that you say.

I also changed to strict RFB using mandatory clutch and prefer realism and consistency over "doin' the lap".

But I was just thinking about setups and wanted to know if I was doing it in the right way.

Thanks! Marcos

Edited by mcmirande, Feb 05 2019 - 01:24 PM.


#13 Pete Gaimari

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Posted Feb 05 2019 - 01:51 PM

Marcos nobody can tell what feel is. Try all the different diff settings on the track and see what you like. I'm not sure there is a right or wrong way. If it works for you who can say it's wrong?

#14 JonnyA

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Posted Feb 05 2019 - 02:05 PM

One thing I only just learned for bumpy tracks is to reduce Bump and then if necessary increase Rebound.

#15 Arturo Pereira

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Posted Feb 05 2019 - 02:51 PM

Also consider if you are tweaking a setup for a long race or for a hot lap. In the first case you should priorize stability and control. In the second case, speed everywhere if it´s possible, though setups usually means a compromise between speed and stability/control.

#16 mcmirande

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Posted Feb 05 2019 - 03:35 PM

View PostArturo Pereira, on Feb 05 2019 - 02:51 PM, said:

Also consider if you are tweaking a setup for a long race or for a hot lap. In the first case you should priorize stability and control. In the second case, speed everywhere if it´s possible, though setups usually means a compromise between speed and stability/control.

Yes, for sure. At the end I always race with stable setups, but I was trying to know if there were some obvious correlation between tracks and diffs.

Cheers

#17 Pete Gaimari

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Posted Feb 05 2019 - 04:03 PM

Not sure it helps but like I said, I use 85/45/1 at all tracks and it works ok. The only time i'd change it is if I went back to LF braking and that's not going to happen. I just ordered some Fanatec Clubsport V3 pedals. I wore out my Clubsport V2 pedals. I'm thinking of a direct drive wheel but good grief those are expensive. So, maybe not. The pedals I needed, the wheel I don't.

Anyway, I use the same diff for everything. Others don't, so it's your choice.

#18 John Woods

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Posted Feb 05 2019 - 04:26 PM

If there is a lot of track camber on turns there is less need for diff rotation, because the track will turn the car?
On flatter tracks, the only way to get grip is if the rear of the car rolls and rotates at the same time?

In either case, just a guess, as a driver skill improves the preference is a looser diff because of being more expert at control of the range of motion?

This is not the same as the loosest diff possible because the expert driver would tune-in the least rotation needed to turn the car.
Which, still a guess, would result in faster times thru a turn?


:D

#19 Pete Gaimari

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Posted Feb 05 2019 - 04:39 PM

How do we measure the camber on the track John?

#20 Warren Hall Jr.

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Posted Feb 05 2019 - 05:50 PM

The more diff locking you use the harder it will be to get the car to turn naturally. You will have to use tricks to get it to turn. Track camber is another story.
When you use your normal negative camber and the inside tire temps are much higher than normal it's a sign of a convex curvature of the track.
Try Bridgehampton to feel this to full effect.  It happens when a race track is using regular roadways or is built that way. You have to adjust the camber and stay to the inside of curves. If you end up on the outside of a curve you just fall off the road. Just like on any real country toad. At Bridgehampton start with .o negative camber just to see how little negative camber you can get away with.

Warren

Edited by Warren Hall Jr., Feb 05 2019 - 05:51 PM.





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