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Speed Discussion For Earthlings


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#1 wreckah

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Posted Jun 28 2011 - 05:22 AM

Hi guys,

i got a couple of questions regarding setups and driving style for earthlings ( normal people who do not push the throttle while braking etc...)in order to get the best out of our moderate talent. I have read many setup guides, and there is quite some contradictory info out there.

- What kind of GPLrank can one more or less reach without using the trailing throttle/unrealistic brake bias?

- what kind of brake bias gives best stopping performance (lotus) in a straight line...and related: does the car stop better when you hear the squeal or when you do NOT hear the squeal?

- Is it better to rely on brakes only, and not use engine braking? so is it better to downshift not too agressively?

- I know diff settings are personal, but let's say you can adapt to a more agressive diff, can you drop laptimes accordingly? Or is it better to keep using whichever feels comfortable and concentrate on your racing line? Are some diff settings inherently slower than others? Or is the difference marginal?

- what is the optimum tire temp or pressure which gives the best inherent grip? Which is the more important: optimum tire pressure when hot, or optimal tire temps inside-middle-out

- Is it important to have tire pressures/temps more or less the same for inside and outside wheels?


I will post more questions whenever i feel confused.
I am at GPLrank -25 now, which is nowhere near extraordinary, but i feel i am reaching a peak, and i need to adjust my driving style to become quicker. I think i am driving too much on/off style, too 'digital' for these old cars. I also think i have the wrong ideas about setups caused by years and years of hearing about aero cars setups.

GPL with all its mods is such a rewarding game to play, everytime i sit behind the wheel i learn something new. GPL makes you try out new driving styles and really lets you feel the difference. It is simply amazing to see the sim react to your inputs...i have the best time ever when im racing: it is challenging you all the time and a real joy when you get it right!

I am a returning GPL player after 10 years, and slowly but surely i am adapting a more realistic way of playing: i threw F10 overboard just two weeks ago ( shame on me i know :D ) and i will be trying out clutch and H-shifter soon.

Thanks for your input :)
cheers
Jan

#2 brr

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Posted Jun 28 2011 - 05:56 AM

View Postwreckah, on Jun 28 2011 - 05:22 AM, said:

- What kind of GPLrank can one more or less reach without using the trailing throttle/unrealistic brake bias?


I think Joosa Riekkinen did his laptimes with right foot braking, and his setups usually seem to have 54 percent brake bias (if I remember correctly). So -90 is possible. I would not place too much blame on the setup unless you are getting close to alien laptimes.

#3 Dark - guest

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Posted Jun 28 2011 - 07:02 AM

I right foot brake and i'm knocking on the door of -70 (i should pull my finger out and get that done soon)

Carsten Thiele has gone past -80 using a shifter and clutch so its possible to achieve a really nice rank.

I think i got to about -50 using really stable setups with an 85/30 diff and i peaked there for a bit until i went to a slightly more aggressive diff and clutch setting and i think i could get to the mid -70's if i put the time in and thats using a shifter and clutch with heal and toe.

My brake bias is 54% i think and i tend to use as much engine braking as possible to help me slow the car down but also to help turn in when i can. I seem to remember that i'm squealing the tires on the brakes a fair bit

I've tried higher brake biases but i just end up locking the fronts and lower i end up loosing it more often than not when really pushing.

Hope that helps Jan

#4 Lee200

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Posted Jun 28 2011 - 07:19 AM

View Postwreckah, on Jun 28 2011 - 05:22 AM, said:


- what is the optimum tire temp or pressure which gives the best inherent grip? Which is the more important: optimum tire pressure when hot, or optimal tire temps inside-middle-out

- Is it important to have tire pressures/temps more or less the same for inside and outside wheels?


Faster drivers than I can answer more of your questions, but here are the answers about the tires.

The optimum temp and press for the various mods:

'67--261 F, 24 psi ft, 26 rear
'65--187 F, 24, 26
'69--261 F, 24, 26
'Sports Cars--261 F, 32, 32.  P910--261 F, 28, 28

Ideally, you'd have both temp and pressure at optimum although this can be difficult to achieve depending on your driving style.  As a rule of thumb, either a 6 psi or 90 degrees F difference from optimum results in a 2.5% loss of grip.

Ideally, all four tires would be at optimum pressure and temperature.  This is also difficult to achieve as the outside tires will typically be hotter than the inside.  About the only way to adjust this is by increasing the roll bar setting which takes load off the outside tire and adds it to the inside.

Edited by Lee200, Jun 28 2011 - 07:32 AM.


#5 Rudy Dingemans

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Posted Jun 28 2011 - 10:42 AM

View Postwreckah, on Jun 28 2011 - 05:22 AM, said:

- What kind of GPLrank can one more or less reach without using the trailing throttle/unrealistic brake bias?

- what kind of brake bias gives best stopping performance (lotus) in a straight line...and related: does the car stop better when you hear the squeal or when you do NOT hear the squeal?

- Is it better to rely on brakes only, and not use engine braking? so is it better to downshift not too agressively?

- I know diff settings are personal, but let's say you can adapt to a more agressive diff, can you drop laptimes accordingly? Or is it better to keep using whichever feels comfortable and concentrate on your racing line? Are some diff settings inherently slower than others? Or is the difference marginal?

- what is the optimum tire temp or pressure which gives the best inherent grip? Which is the more important: optimum tire pressure when hot, or optimal tire temps inside-middle-out

- Is it important to have tire pressures/temps more or less the same for inside and outside wheels?


I am at GPLrank -25 now, which is nowhere near extraordinary, but i feel i am reaching a peak, and i need to adjust my driving style

My take on some of these issues:
You can get quite high with 'realistic' inputs, it just depends on your talent. Some aliens reach deeply negative values with a keyboard...

Personally, in my brake settings I rarely went for maximum braking power but more for stability (usually, that meant moving it forward so the front wheels would lock up first). It's little use braking as hard as possible if it means you're swerving all over the place. To that end I also adjusted my brake pedal by putting some stuff underneath it, so that the pedal ended up *just* short of locking up the brakes at maximum foot pressure.

Secondly, having a bit of throttle on during braking *does* help for that... in my view it doesn't mean that much speedwise but just makes the car easier to control on the limit. And that helps.

Similarly, you *do* need to use engine braking. Again, it's not so much in the braking power but it helps to make the car more stable during braking. Distinctly remember learning this on approach to Crowthorne Corner a lot, and figuring out how not to fly off...   :P

Tyre pressures: need to be fairly even, but it doesn't matter that much in terms of outright speed and handling if there differences are not too big.

In terms of diffs, yes, especially in GPL, more aggressive (30/85 style) diffs help in terms of speed. Imho, it only starts to really matter once you pass -20 in Rank. Then it'd be harder to gain mucho speed if you'r still on 85/30 diffs. Some aliens can do fine without such diffs, but for regular drivers like me it did make a difference for sure.
Once I wanted to go faster on that level, I first learned to drive the 65 Mod cars, which have 'torque-yourself-into-the-corner' diffs by default but have a much more mellow response, making them easier to learn. Once I got the hang of that, I gradually applied those diffs and my adapted driving style to the 67 cars. Did help, in the end I went from somewhere around -25 to -40 (took a looong while though since I ain't no alien).

:2c:

Regards, Rudy
(GPLRank: -40)

Edited by Rudy Dingemans, Jun 28 2011 - 10:43 AM.


#6 FlaviusManlius

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Posted Jun 28 2011 - 11:01 AM

It seems to me like there is a 'light' squeal == good and full-on squeal == bad

#7 tooncheesef1

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Posted Jun 28 2011 - 11:11 AM

For tyres temps, pridibula shows them in green, so you can glance down and see your 12 tyre temps.

I think inside and outside differences are OK unless the gap is quite big.

Squealing I tend to brake hard, hear the squeal then back off 'till I no longer hear it.

85/30 is the most aggressive diff I believe.

Two tips I know that are good for laptimes are using camber effectively and trail braking. I hate using camber and unsettling the car, and I'm rubbish at trail braking. I also have a high rank. Jim Pearson put up a big guide when he did his training course: http://jrpearson.hom...nstruction.html

#8 John Woods

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Posted Jun 28 2011 - 12:26 PM

Whew! Too many questions better answered by personal experience trial and error I think.
Nonetheless...
Pretty sure the most aggressive rear is 30/30/6, which is maybe good for Monza, Spa, etc., (courses with long straights and wide sweepers).. I now use 45/60/6 at the Ring. Then all other setup variables are tuned after tuning diff, so there is no absolute...for me it depends on shape of intended projected racing line (trajectory) when exiting turns typical of specific track.
After reading about analog racing clutches and diffs, I think the goal is to set things up as "quick/hard/stiff" as possible.

#9 FlaviusManlius

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Posted Jun 28 2011 - 01:29 PM

Here's the guidelines I've used
http://www.intothere...ing/setups.html

I don't know where to find the links to each car directly, but if you google "into the red" + the name of the car you want they have setups for each '67 car.

They seem to say that the middle tire temp should be hotter than the inside and outside.

I notice sometimes the outside of my tires get hotter than the middle.  Should I adjust camber to counteract?  I'm usually at -.25, would -.5 or 0.0 be the way to go to reduce outside temps?

Edited by FlaviusManlius, Jun 28 2011 - 01:30 PM.


#10 MECH

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Posted Jun 28 2011 - 01:58 PM

View PostFlaviusManlius, on Jun 28 2011 - 01:29 PM, said:

They seem to say that the middle tire temp should be hotter than the inside and outside.

That's a simple way of telling that your tires have a flat contact patch with the tarmac.
I could be wrong but that's a basic guideline for a flat track like monza.

I believe this phrase was also in the setup guide that was in the original box and as a pdf on the cd :)
Have you read that book yet?

#11 FloP

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Posted Jun 28 2011 - 02:13 PM

View PostJohn Woods, on Jun 28 2011 - 12:26 PM, said:

Pretty sure the most aggressive rear is 30/30/6, which is maybe good for Monza, Spa, etc., (courses with long straights and wide sweepers)..

This setting will give you massive oversteer on throttle and massive understeer off throttle. 30/85/6 gives you lots of oversteer in all situations, although you'd have to choose XX/85/1 for maximum off throttle oversteer. :)

#12 Lee200

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Posted Jun 28 2011 - 03:34 PM

View PostMECH, on Jun 28 2011 - 01:58 PM, said:

View PostFlaviusManlius, on Jun 28 2011 - 01:29 PM, said:

They seem to say that the middle tire temp should be hotter than the inside and outside.

That's a simple way of telling that your tires have a flat contact patch with the tarmac.
I could be wrong but that's a basic guideline for a flat track like monza.

I believe this phrase was also in the setup guide that was in the original box and as a pdf on the cd :)
Have you read that book yet?

Yes, Martin is correct.  As a good rule of thumb, all three temps on the same tire should be the same and at optimum temperature.

GPL uses the average of the three temps to compute the tire pressure and resulting effect on grip.  It uses the maximum of the three temps to compute the temperature effect on grip.  It apparently makes no difference which tire section is the hottest.

#13 wreckah

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Posted Jun 30 2011 - 03:17 AM

thanks for the input guys, been a bit busy the last couple of days, but planning a GPL weekend to further learn and understand how these cars should be driven :) (this is too much fun ;) )

View Postbrr, on Jun 28 2011 - 05:56 AM, said:

I would not place too much blame on the setup unless you are getting close to alien laptimes.

you are absolutely right. :) The 'slowness' lies with me, and i need to find out where i loose all this time. Studying alien replays and trying to use the whole track has helped a bit, but i think i need some fundamental altering of the driving in order to gain more speed. I've done a million testlaps on Kyalami, trying out different setups and lines, and it is quite frustrating to be many seconds away from proper good laptimes on such a small track and you can't really see where you are going wrong.

Is there a replay analyser which lets you compare two different replays next to eachother frame by frame?

#14 wreckah

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Posted Jun 30 2011 - 03:33 AM

i just discovered that pribluda thing, very very interesting! thanks for the tip :)

#15 MECH

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Posted Jun 30 2011 - 04:47 AM

View Postwreckah, on Jun 30 2011 - 03:17 AM, said:

Is there a replay analyser which lets you compare two different replays next to eachother frame by frame?

Yep, and it's called GPLReplayanalyzer, go figure  :lol:

You have several ways to check what's different if you load 2 replays (or even more)
It can even merge replays so you can see both cars in the same replay.
Try it, i'm sure you'll like it :)

#16 Art-J

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Posted Jun 30 2011 - 09:25 AM

Hear! Hear! In the first of my days with GPL I though Outer Loop at Watkins Glen was the most important turn on the track. Then, I installed Replay Analyzer, compared quite a few laps and... was quite surprised to see that most of the other turns over there were much more important and these were the places where I actually was loosing ridiculous amounts of laptime (ehm... those damn Esses!). GPLRA is a really handy tool!

Cheers - Art

#17 Frenchy

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Posted Jul 01 2011 - 04:57 AM

View PostLee200, on Jun 28 2011 - 07:19 AM, said:



The optimum temp and press for the various mods:

'67--261 F, 24 psi ft, 26 rear
'65--187 F, 24, 26
'69--261 F, 24, 26
'Sports Cars--261 F, 32, 32.  P910--261 F, 28, 28



Thank you very much for this Lee. Since you explained this to me after the release of the SportsCar mod, I've changed the way I do setups and (I think) benefited. Probably the main thing that I've changed is keeping away from extreme pressure variations. For instance, in the 65 mod, I always start with cold tyre pressures at 21psi. If a tyre is getting a bit hot from working hard, I'll drop the pressure to 20psi but no further. If temps are still going out of range, I can try a change to setup or, better, change driving style in one or two critical corners, but that cold starting pressure out of this range are counter-productive. (With the exception of over-inflating for higher max speed which is a hot-lapping thing anyway.) Also, I don't pay any attention to to the middle tyre temp any more. I use the inside/outside temps to adjust the camber but use the hot press reading in setup to adjust my cold starting pressure.

I was going to start a thread to try and see if we could work out these figures but you've done it for me thanks.  ... except the 66 mod which I think uses very different optimum tyre temp to 67's at least. Also, I assume the 69extra mod is the same as for the orig 69s? Oh, and any info for ThunderCars or Stratos mod?

Another question that perhaps you can help me with: To what degree is patch temp used to calculate optimum grip? I starting to think its quite a lot. I find most of the times I start to have oversteer problems I can have the 'core' temps in the green but patch temps are going in to the red.

Thanks again
David

Edited by Frenchy, Jul 01 2011 - 05:06 AM.


#18 brr

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Posted Jul 01 2011 - 05:07 AM

View PostFrenchy, on Jul 01 2011 - 04:57 AM, said:

but that cold starting pressure out of this range are counter-productive. (With the exception of over-inflating for higher max speed which is a hot-lapping thing anyway.)

I haven't noticed it being counterproductive. My race setups usually have somewhat low tyre pressures because I want the pressure to be close to optimal for most of the race (i.e. when tyres are as hot as they are going to get). Only problem is trying to keep position during the first couple of minutes of the race when there is noticeably less grip due to low tyre pressure, but in a long race the slight grip advantage achieved later seems worth it.

#19 Frenchy

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Posted Jul 01 2011 - 07:30 AM

View Postbrr, on Jul 01 2011 - 05:07 AM, said:

View PostFrenchy, on Jul 01 2011 - 04:57 AM, said:

but that cold starting pressure out of this range are counter-productive. (With the exception of over-inflating for higher max speed which is a hot-lapping thing anyway.)

I haven't noticed it being counterproductive. My race setups usually have somewhat low tyre pressures because I want the pressure to be close to optimal for most of the race (i.e. when tyres are as hot as they are going to get). Only problem is trying to keep position during the first couple of minutes of the race when there is noticeably less grip due to low tyre pressure, but in a long race the slight grip advantage achieved later seems worth it.

I meant counter-productive in trying to find the best combination of temp and press. In particular, with the 65 mod, if I find my outside rear tyre overheating I used to reduce the starting pressure down to 19psi which helps to keep the temp down but stops the pressure from reaching optimum. My theory is that its better to adjust the setup and/or driving technique to avoid the extremes. ie due to the fact that temp and pressure are related, optimum grip will never be reached unless you start with 20psi for a tyre that is working hard and 21psi for a tyre that is not working so hard (or at the very least that the range for optimal grip will be impractically small). I haven't driven the 67s for a while to test it out but most of my 67 sets have the outside rear at 19psi.

Actually where I've really changed my setup technique is over-inflating the inside front trying to get it to warm up. Now I adjust it so that I attain optimum pressure and if its a little down on temp, that seems to lose less grip than being way too high in pressure. Of course this is also influenced by the fact I didn't realise that optimum pressure for the fronts is less than the rears anyway.

#20 Lee200

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Posted Jul 01 2011 - 07:37 AM

View PostFrenchy, on Jul 01 2011 - 04:57 AM, said:

I was going to start a thread to try and see if we could work out these figures but you've done it for me thanks.  ... except the 66 mod which I think uses very different optimum tyre temp to 67's at least. Also, I assume the 69extra mod is the same as for the orig 69s? Oh, and any info for ThunderCars or Stratos mod?

Another question that perhaps you can help me with: To what degree is patch temp used to calculate optimum grip? I starting to think its quite a lot. I find most of the times I start to have oversteer problems I can have the 'core' temps in the green but patch temps are going in to the red.

Hi David,

Glad to help.

The '66 mod tires all use an optimum pressure of 26 psi and 207 degrees F.

The '69 and '69 Extra tires use the same optimum pressure and temps.

As you know, GPL keeps track of 6 temps for each tire; 3 inside or core temps and 3 outside or tread temps.  It uses the average of the core temps to compute the actual pressure which in turn is used for the pressure correction on grip. It uses the maximum of the tread temps to compute the temperature correction on grip.

The tread temps are more volatile than the core temps so it's very common to see the treads spike at higher (or lower temps when cooled) than the cores.

The actual pressure is based on the general gas laws (I always forget which one) which state that pressure increases in direct proportion to the temperature.  So GPL simply increases the setup menu pressure in proportion to the average core temp increase from ambient temp.

I'm not an expert on Pribluda, but I understand that you can modify the temperatures where it changes colors.  Assuming it changes into the red color at the correct point, then having the cores temps in the green while the tread temps are in the red is not unusual.  This condition indicates that the optimum core temps are achieved, but the tread temps are higher than optimum and grip is appropriately decreased.  The optimum pressure may not be reached either depending on the setup menu pressure.

I'm an incredibly slow driver, but my suggestion is to disregard any Pribluda core temps and adjust the setup menu pressure to achieve optimum pressure once the tires are heated up.  Then use Pribluda to monitor the tread temps and make any setup adjustments necessary so that the maximum of the three tread temps is at optimum.

Hope this makes sense.

Lee

Edited by Lee200, Jul 01 2011 - 07:54 AM.





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