Observations on suspension settings

[TT3AZ]

Yes, drag affects the top speed aswell, more downforce = lower top speed, i drag race alot in straight lines, and without a wing i catch slightly higher top speed.

 

[No_OBsT33R]

Problem is nobody is doing controlled tests which means setting up a car as neutral as possible and testing one variable at a time and delivering specific observations about changes in handling. So far all I have seen is arbitrary setups with highly conjectured reviews as concrete evidence.

You can also have differences in cold lap best times and hot lap best times. Setting a car up with certain characteristics such as com > ext or com = ext usually results in slower cold laps with gradual lap time increases. A car with ext > com on the other hand will post faster cold lap times with gradual decreases in lap time as tires warm. I don't see any elimination of other factors in any of your arguments either.

Read my post, the test it will show concrete results for effect at least on acceleration.

Then with the same car we do the same adjustments and check Top Spped as a controlled test for top speed (that shouldn't be hard) then we have direct effect on acceleration and top speed.

I think we can examine the results and take it further based on them.

I'm thinking PD modeled drag and air effects but under exaggerated the effects (or dint factor in at all) of the air flowing under the car.

 

[budious]

Air? What's that? No, but seriously, downforce is probably handled much like SRF as an adhesion bandaid; that is why the cars handle like slot cars but the moment they go airborne they go all slow motion matrix and bobble around like moon men. If PD was modeling actual air then they could have just as easily added wind speed and direction changes onto the courses and events that were weather related.

 

[Z1-AV69]

Regarding straight line speed: I believe it was already in gt4 that high negative rake did make the downforce pull the car forward, resulting in higher top speed. Downforce seems to be applied 90° to the "reference plate", which is obviously wrong. I didn't test if this is still true in gt5, but a test about straight line speed seems not be the best for the question here.

Over-/understeer is not a good measurement either, because it 1). is very unspecific and 2). is the result of many factors.

 

[The Outlaw]

Haven't tried it like that, but if drag was modelled correctly you'd lose top speed proportionally to how much downforce you used... and top speed remains the same no matter what you set downforce to.
.

Well that depends on what is the limiting factor (drag limited or rev limited) regarding the top speed of the car.

Btw, I could have sworn in my testing with the GT500 GT-R that max DF did have a slight impact (less than I expected) on top speed....so maybe this is something that should be tested more thoroughly. But Regardless, DF should play a much bigger part in terms of introducing drag to the car than it does currently.

 

[No_OBsT33R]

Why waist time debating the possibilities when a quick test will show direct result, this is testable, and a controlled test has been suggested.

Regardless as to how PD decided to implement aero effects, the result of them is testable, and all I care about. No matter how they did do it, it's still Aero Effects...

I just need to brain storm a bit to think of a good controlled test for under car aero effects. I think the jump at Eigar might do.

I tested it in GT4 and got concrete results showing it reducing acceleration and top speed, but the amount of grip that was generated in the corner was off the scale in comparison. We seem to have the same effect but MUCH lower available DF adjustments. Still no under car aero effect as of yet, but that needs testing

Also we should test if it's a steady amount or progressive with speed.

 

[Joey975]

I've just been doing some more testing with different cars and it now seems to me that it is only the ride height that is reversed. At first when I tested it with a super gt I thought it was all of the settings that were reversed but after a bit more testing with different cars I noticed that it is definitely only the ride height.
Try this with the Cappuccino race modded at 133bhp with sports soft tyres.

 

[No_OBsT33R]

I've just been doing some more testing with different cars and it now seems to me that it is only the ride height that is reversed. At first when I tested it with a super gt I thought it was all of the settings that were reversed but after a bit more testing with different cars I noticed that it is definitely only the ride height.
Try this with the Cappuccino race modded at 133bhp with sports soft tyres.

How did you test it? What were the results that lead to your conclusion?

 

[No_OBsT33R]

I ran the test at home and I'm going over the data. It shows a progressively smaller rolling radius (indicative of a reduced amount of drag as speed increases????) not sure what to make of it, a lil tired, I'm going to grab a bite and go over the data. I thought the result would be a higher value not a lower one indicative of an increased resistance as speed increases. Ill figure it out when I start adjusting, it's one way or the other, lol.

This is pre adjusting testing

BMW M3 CSL

I'm establishing a testing environment.

 

[nomis3613]

Haven't tried it like that, but if drag was modelled correctly you'd lose top speed proportionally to how much downforce you used... and top speed remains the same no matter what you set downforce to.

Could be up to an extent, maybe keeping top speed but loosing rate of acceleration.

It is as simple as running the test and seeing for sure, it wouldn't surprise me as PD seems to do things a lil odd from time to time.

Anybody in front of their system with GT5 running have 5 min to spare?

I do! Right, hopefully this will sort out this top speed distraction stuff (I've also heard the "top speed might not change but acceleration will" argument somewhere else. Hoping to kill two birds with one stone here).

Integra RM on Sports Soft at SSR7 Test
(other settings available on request, but I don't think they're relevant)
Downforce setting: top speed (I tested the min and max downforce settings)
5 / 5: 295 km/h
15 / 35: 288 km/h

As for acceleration vs top speed, I lined up with my ghost each time. The minimum downforce setting started pulling away from the the max ghost above 260 km/h. Myth: busted!

The same test can be used on ride height, adjusting one side (raise or lower) and see variation on result for effect.

Good idea.
Rake vs top speed (using maximum downforce)
-25 / -25: 288 km/h (baseline)

-25 / +40: 284 km/h
+40 / -25: 295 km/h

Hmmm... so nose-up (according to the settings screen) appears to reduce drag.

I ran the test at home and I'm going over the data. It shows a progressively smaller rolling radius (indicative of a reduced amount of drag as speed increases????) not sure what to make of it, a lil tired, I'm going to grab a bite and go over the data

Sorry, but I don't understand how any road speed vs engine speed test is useful. For starters, the results could be affected by clutch slip if that was modeled.



Anyways, hopefully we can now put the top speed stuff behind us and return to the task of trying to figure out if nose-up tuning reduces understeer because
a) the front/rear ride height adjustment is the wrong way around
b) downforce is modelled as a vector perpendicular to the car's surface- this means nose-up is putting more downforce on the front tyres and actually the downforce is accelerating the car forward
c) spring rates are affected by ride height change- 40% higher front height means 40% stiffer front springs (even though the value in the spring adjustment hasn't changed)
d) something else!

 

[budious]

So if you had negative rake wouldn't that in effect create a high pressure zone under the car and create lift thereby counter-acting downforce on long straight accelerations?

Did you also do an acceleration test at +40/+40?

 

[Casper06]

Is PD aware of this bug?

 

[No_OBsT33R]

So if you had negative rake wouldn't that in effect create a high pressure zone under the car and create lift thereby counter-acting downforce on long straight accelerations?

Did you also do an acceleration test at +40/+40?

This is where I think they failed, still testing.

The calculation will display first off if the effect is linear or progressive. Second it will show a definitive result for effect on acceleration.

Try the same test you did but with a fully jacked up car, then dropping a side.

 

[oppositelock]

Anyways, hopefully we can now put the top speed stuff behind us and return to the task of trying to figure out if nose-up tuning reduces understeer because
a) the front/rear ride height adjustment is the wrong way around
b) downforce is modelled as a vector perpendicular to the car's surface- this means nose-up is putting more downforce on the front tyres and actually the downforce is accelerating the car forward
c) spring rates are affected by ride height change- 40% higher front height means 40% stiffer front springs (even though the value in the spring adjustment hasn't changed)
d) something else!

I'm going with D. Personally I think it has to do with the way the physics model factors body roll. If you think about it, handling balance is primarily a function of front roll resistance versus rear roll resistance, right? By raising a car you're decreasing roll resistance by increasing the leverage of the center of gravity, which is why a lifted 4x4 will lean more than a sports car with the same spring rates and sway bars. By raising the front and lowering the rear you're effectively decreasing front roll resistance and increasing it in the rear, same as if you softened the front spring and stiffened the rear.

Now, it probably doesn't work that way in real life, I don't know because I've never known anyone to race a car that sits three inches higher in front. That added front body roll should theoretically also have a negative effect on front grip by increasing lateral weight transfer and overloading the outside front tire. My theory is that the effects of ride height on roll resistance is greatly exaggerated by the model and therefore overrides these effects. It wouldn't surprise me if PD thought the effects of ride height with a realistic model weren't noticeable enough to an end user so therefore purposely exaggerated the effect on vehicle handling. You also have to realize PD probably doesn't have info on CG height, roll axis, etc. for all these cars, so the whole thing is likely based on a somewhat crude formula which might explain such goofy results.

Another thing to remember is that this nose up attitude may transfer weight to the rear, which would also increase oversteer. Whatever the explanation, I find it highly improbable that the menu itself is reversed, or that the ride height info is being inputed into the physics engine backwards while remaining visually correct.

 

[nomis3613]

So if you had negative rake wouldn't that in effect create a high pressure zone under the car and create lift thereby counter-acting downforce on long straight accelerations?

Yeah, but IRL the far greater effect would be the air under the car creating masses of extra drag.

Did you also do an acceleration test at +40/+40?

Nope. If you test +40 / +40 and it reveals something earth shattering, I'll eat my hat! But I don't believe that GT5 models ground effect, so I didn't see the point of testing +40 / +40.

 

[budious]

Yeah, but IRL the far greater effect would be the air under the car creating masses of extra drag.


Nope. If you test +40 / +40 and it reveals something earth shattering, I'll eat my hat! But I don't believe that GT5 models ground effect, so I didn't see the point of testing +40 / +40.

Point is not speculating what you might observe or what conclusions you might draw from them. The point is do control testing because why expect it to match expected behavior profile when you are measuring for test cases for an effect outside of an expected behavior profile. You assume it works without testing it but are flabbergasted at the thought that rake effect might be reversed...

 

[nomis3613]

^ Sorry, re-reading my previous post (eg "eat my hat..."), it could be interpreted as being hostile. It was meant to be tongue-in-cheek. Sorry.

 

[Stotty]

I'm still not 100% sure if other suspension settings are reversed (or have the reverse effect of what they should have), but I'm convinced ride height is, as are others with a similar experience with GT games.

However, I was thinking about this whole thing last night and I've come to the conclusion that I'm really not that bothered why the ride height thing works, but I'm bloody glad it does!

Using the ride height setting/bug/glitch/trick/expolit (call it what you will) has completely rekindled my enjoyment of the game. Before this, I'd take a car I fancied driving and spend hours trying (and failing) to get the car to handle how I wanted it too. Everything just understeered horribly, and most required stupid amounts of toe to try and fix this. I wasn't really enjoying the driving experience as I had expected to.

Yesterday, I tried a few cars I had driven previously and not enjoyed. Sticking the front max, rear min ride height on them immediately made them feel so much better to drive. A few other changes to cancel out previously high toe or camber settings and they started to feel wonderful. Now, instead of just plowing on under turn in, they will carve to the apex... they will still understeer if pushed too hard, but that's how it should be.

For whatever reason, the cars 'feel' much more like they should IMO with this setting applied so I will continue to use it and enjoy the game so muhc more as a result

 

[Z1-AV69]

Anyways, hopefully we can now put the top speed stuff behind us and return to the task of trying to figure out if nose-up tuning reduces understeer because
a) the front/rear ride height adjustment is the wrong way around
b) downforce is modelled as a vector perpendicular to the car's surface- this means nose-up is putting more downforce on the front tyres and actually the downforce is accelerating the car forward
c) spring rates are affected by ride height change- 40% higher front height means 40% stiffer front springs (even though the value in the spring adjustment hasn't changed)
d) something else!

Theory "b" should be fairly easy to test: Just take stottys MP4-12C tune from here:

Ride +15 -35
Spring 12.5 14.3
Rebound 8 6
Bound 6 4
ARB 4 6
Camber 3.0 2.0
Toe -0.10 -0.15

Brakes 3 2

LSD stock

Now test the top speed both with min aero and max aero. If max aero is faster, theory "b" is probably right.

I'm at work now and can do it only in a few hours. Maybe someone else has the time...

 

[praiano63]

I'm still not 100% sure if other suspension settings are reversed (or have the reverse effect of what they should have), but I'm convinced ride height is, as are others with a similar experience with GT games.

However, I was thinking about this whole thing last night and I've come to the conclusion that I'm really not that bothered why the ride height thing works, but I'm bloody glad it does!

Using the ride height setting/bug/glitch/trick/expolit (call it what you will) has completely rekindled my enjoyment of the game. Before this, I'd take a car I fancied driving and spend hours trying (and failing) to get the car to handle how I wanted it too. Everything just understeered horribly, and most required stupid amounts of toe to try and fix this. I wasn't really enjoying the driving experience as I had expected to.

Yesterday, I tried a few cars I had driven previously and not enjoyed. Sticking the front max, rear min ride height on them immediately made them feel so much better to drive. A few other changes to cancel out previously high toe or camber settings and they started to feel wonderful. Now, instead of just plowing on under turn in, they will carve to the apex... they will still understeer if pushed too hard, but that's how it should be.

For whatever reason, the cars 'feel' much more like they should IMO with this setting applied so I will continue to use it and enjoy the game so muhc more as a result

Exactly the same for me, i'm working on 2 cars and i use more the ride height to correct the car .Don't use more toe than necessary.
For example, i've done a speed 12 with ride heigh -25 / 0 and no toe. After i just put a little toe +0.08 /-0,08 to make it more sharp, and it stay perfect now, another car.
Same for my esprit sport 350 with ride height -20/0 to correct the oversteer and after that don't need any toe at all 0/0. perfectly equilibrate,now one of my best cars.
I publish a 111R on my tunes like this also.

It will take time to rewiew all my tunes ,but now i've the feeling that when i do something on the car, it react logicaly, no more crazy toe on it . That is good very good...

 

[Sm0k3:D]

I noticed there was something wrong with all this stuff... I was confused with the setups of my cars...
After reading this thread: I tested a few laps with the Minolta 88C-V at Fuji with two diferents radical setups: (all the others parameters set the same front and rear, toe and camber set all to 0)
Ride heigh 15 / -30: Oversteering a LOT.
Ride heigh -30 / 15: Not ideal setup but much better than other.
My conclussion: Wrong: In ride heigh rear is front and front is rear.

Then I did the same test with spring rates: (all other parametres set the same front and rear, toe and camber set all to 0)
Spring rate: 20 / 11,1: Oversteering
Spring rate 10,4 / 20: Not ideal, but much better than other.
My conclussion: Spring rates is OK.

 

[Johnnypenso]

Err, my settings in the NASCAR are in the 1st post in this thread (I'm happy to share gearbox and LSD settings if wanted too, though if you leave these stock you shouod still be able to feel the effects of suspension changes)... go test them against the reverse... car is any NASCAR on race mediums, track is Indy Road.

That's close Stotty but not what I'd call empirical testing. What Nomis did with the top speed test is what I'd call empirical. Gave us the car, the aero settings (all other tuning specifics remain the same I assume), the location for the test and the exact test results. Anyone can repeat that test quite quickly and easily to confirm results. Good job by the Nomis, funny how that "myth" has floated around for months and was basically gospel and was blown away with a little bit of testing...lol.

For the ride height adjustment, it would be posting an exact tune for a vehicle (I'd prefer a common street racing vehicle with zero front downforce so as to concentrate on the suspension effects..a Nascar road race is an oddity to me on GT5) along with posting some lap times as in best 3 out of 10 or something like that. Then run 10 more laps with the ride heights changed to whatever the theory proposes and post those results. To me, 4 sets of results would be good:

1. Car completely lowered.
2. Car raised in front, lowered in rear.
3 Car lowered in front, raised in rear, same degree as #2.
4. Car raised to the max.

Again, anyone willing to do this type of testing I'll be more than happy to repeat it. Until then it's just a theory...

 

[nomis3613]

Hi Johnny, thanks for kudos. I agree there might be some useful results in comparing the effect on high and low downforce cars. I was mucking around with a FF hatch today and noticed... (sorry, no empirical test data this time!)
- nose-up had far less benefit than the Ferrari I'd previously tested with (agree that there are sooo many differences between the cars that assuming it's downforce-related is foolish at this stage)
- effect was greater at reducing mid and exit understeer. Turn-in was actually less accurate. Since the oval tracks don't need much turn-in and are all about exit front grip, this might explain why nose-up has such a dramatic effect for Nascar.

Theory "b" should be fairly easy to test: Just take stottys MP4-12C tune from here:


Now test the top speed both with min aero and max aero. If max aero is faster, theory "b" is probably right.

I'm at work now and can do it only in a few hours. Maybe someone else has the time...

I'm out for perhaps a day, would be great if you could test it though. If max downforce front+rear doesn't increase top speed, try leaving front downforce at minimum and only test the rear- this might give different results.

 

[No_OBsT33R]

If you can't tune it, Glitch it.

 

[chuyler1]

Ride heigh 15 / -30: Oversteering a LOT.
Ride heigh -30 / 15: Not ideal setup but much better than other.
My conclussion: Wrong: In ride heigh rear is front and front is rear.

I've always been told that spring rates and ride height go together. If you drop the ride height but don't stiffen the springs, you will bottom out and break traction. I personally would expect 15/-30 to oversteer because the rear would run out of suspension travel before the front and break loose at the next bump in the road. With -30/15, I would expect some understeer for the same reason. I know the raked stance will give you some front downforce, but the extremely low ride height is going to mess with traction.

 

[No_OBsT33R]

I've always been told that spring rates and ride height go together. If you drop the ride height but don't stiffen the springs, you will bottom out and break traction. I personally would expect 15/-30 to oversteer because the rear would run out of suspension travel before the front and break loose at the next bump in the road. With -30/15, I would expect some understeer for the same reason. I know the raked stance will give you some front downforce, but the extremely low ride height is going to mess with traction.

Run some test

Run ONLY default spring rates for baseline.

Then run the rear dropped with stiffened rear springs, then soft springs. Then Do the same with a raised rear.

 

[Sm0k3:D]

I've always been told that spring rates and ride height go together. If you drop the ride height but don't stiffen the springs, you will bottom out and break traction. I personally would expect 15/-30 to oversteer because the rear would run out of suspension travel before the front and break loose at the next bump in the road. With -30/15, I would expect some understeer for the same reason. I know the raked stance will give you some front downforce, but the extremely low ride height is going to mess with traction.

👍

I think this can be true. I will repeat my test with other parameters, and then I will share my conclusion.

 

[Rotary Junkie]

I'm half tempted to think it's not F/R ride heights being backwards but the height itself.

So "raising" one end effectively drops it and vice-versa. Amazing how much of a change I've seen from 2-3mm rake though.

 

[No_OBsT33R]

I agree this needs be factored in to testing (stiffer for lower). I also can't believe I didn't draw the connection, it screams at me since brought to light. A real face palm moment, regardless if it's the case or not.


I think the worst thing to do is just assume it's a way based on arbitrary observations. Especially if your assumptions are it's glitched. (backwards would be a glitch) if you make this claim without tangible test data to confirm, all your theories come in question since you make assumptions off arbitrary observations.

The data is only as good as the test, it's been brought to light making ride height drops without accommodating the spring rate is a potential killer of the previous under/oversteer test results (those who state the observed effect) that were not really as controlled a test ass they could be.

Then we factor in the visual effect, downforce effect, it's looking more and more legit, but with the lack of under car aero effects (get the benefits from up top, with none of the draw backs from underneath. ). I've yet to see what I would consider a controlled test that the data would suggest a reversed ride height.

Rather I see a way of glitching higher speed taking advantage of PD not factoring in the negative effects of under car air flow. Sort of a cheap trick for speed that masks a lack of tuning ability.

 

[eclipsee]

Again, anyone willing to do this type of testing I'll be more than happy to repeat it. Until then it's just a theory...

Go ahead and try by yourself your empirical testing, if you need feedback from others this means you can't feel what the car is doing, therefore you can't tune your car properly, it's a simple syllogism.