Is Suspension Tuning Backwards? - A Test with RX-8

[Maturin]

post

That's fine, I can see your point. Why don't you post your OWN test, proving your case, and then myself and OTHERS can test it.

All I see from the "it's OK, PD didn't screw up" side is a bunch of theory, but NO tests, etc.

Post your settings, do three tests, like I did, and we'll give it a go.

 

[tuff240]

Why do I bother.

Posted several pages ago...

Ok here are my observations from an hour or so of tinkering last night.
Brace yourself it's going to be a long one

Now I didn't do super scientific testing, I just did a whole lot of hot laps and looked at the handling of the car from a racers point of view.

Controller - Dual Shock 2
Track - Grand Valley East section
Car - M Coupe
I have all stability control & TC off always
Shocks for all setups - F/R - 7-8/8-7 ( bound and rebound)

First with R1 tyres-

My race setup (well the parts that matter to this discussion)
Springs - F/R - 9.5/9.0

I did half a dozen laps with this setup for a start to get settled in
-----
Changed set up
Springs - 9.5/8.5 (softer rear)

Now with the slightly softer rear tyres I was immediately slower, I could not carry as much speed into the corner I had to slow it down more or use more lock (which automatically scrubs speed) to get it to turn in the same and could not get on the power as early as before ie. it had less corner exit steering

Conclusion - the car had less steering everywhere, which means the rear had more grip, which was predictable
-----
Changed setup
Springs - 9.5/9.5 (rear springs harder than original setup)

I went faster than my original time 2nd lap! I could carry speed way deeper into a corner than my original setup and get on the gas earlier, the car just rotated better in the corners.

Conclusion - the car had more steering everywhere, which means the rear had less grip, again predictable
-----
Changed setup
Springs - 9.5/15 (full hard in rear)

Was slower again, the car had a lot more corner exit steering, I could light the rear tyres up relatively easily, but surprisingly it developed some understeer on corner entry in the mid to highspeed corners.
Overall the car seemed very unbalanced and would switch from oversteer to understeer seemingly at will

Conclusion - car had less rear grip everywhere except for where I highlighted, it seemed like the settings were so out of whack that the physics engine got confused.
-----
Changed setup
Springs - 9.5/12.5 (rears inbetween full hard and my normal setting)

Was still slower, now this setup behaved more like I thought it would, not much rear traction on corner exit which meant that I had to go easy on the gas coming out of corners, on corner entry the rear was a little bit more skittish than my normal setup but not dramatically so, the only exception was on the very highest speed corner it still under steered a tad.

Conclusion - car had less rear grip, but the car felt more balanced and consistant than the full hard rear spring setup, it didn't switch from over to understeer at will
-----
Changed setup
Springs - 9.5/4 (fullsoft rear)

Was still slower, now the car had heaps of turn-in off power steering, infact violently so but as soon as I touched the brakes and slowed down into the middle of the corner it switched to massive understeer also with massive understeer on corner exit.
Now I could get the car into a nice drift if I was violent with the steering and brake/throttle so as to keep the rear of the car unstuck from the initial violent oversteer, but if I let the rear settle down the understeer reared it's head again.

Conclusion - car had way more corner exit rear grip, but less high and midspeed rear grip - same sort of comment as the full hard rear spring setup but reversed, again I'm not sure how to explain the oversteer, but it seems to correlate wit hmy real-world findings
-----
Changed setup
Springs - 9.5/7.5 (rear in between full soft and my normal setup)

Was still slower, the car had a little less corner exit rear grip than the full soft settings and but still had the oversteer in the highspeed corner throttle liftoff case

Conclusion - see my middle stiffness rear spring conclusion but just reverse it

Now with N3 tyres

The same observations apply as for the above cases although I was 5 sec a lap slower and the differnces in handling where increased with the less grip available, I was however more easily able to control the attitude of the car with the throttle, being able to make it wheelspin almost at will in any corner.

-----
At the end I went back to my new slightly altered race setup (changed the back springs to 9.5 from 9.0) and went almost 1sec quicker than I had 3/4 of an hr ago with the same setup.

-----
So the conclusion that I take from all of that is that possibly the physics engine in GT4 is very lifelike, it is alot more consistant to the engine in GPL which I play a lot and is widely recognised as a very good sim, the problem that I think we may be seeing is that because it is so real not many people would have run a real car with such hugely different spring rates and so they would not know that it is not a strictly linear thing, if you go to soft the you will get some oversteer, and so setup changes made in GT3-2-1 may not apply for the full adjustment range

This is just my opinion from what I have observed myself

 

[Maturin]

Uh...yeah, I'm aware of that "test". As you'll see by mine and others comments.

"has more grip everywhere, I was much faster this lap". Mmmmkkkaaayyyy.

 

[sukerkin]

Maturin, you've had, to misquote Monte Python, several 'last chances'.

Either rein in your vitriol or methinks that you'll be re-registering with a new username sometime in your future as personal remarks and unfriendly sarcasm have no place in a discourse that is largely technical in nature.

As it happens, there are a number of intelligent posts in this thread that have attempted an objective look at this and there is by no means a consensus as yet. That doesn't mean you're not right but neither does it mean you're not wrong - time and a broader testing base will tell.

I've had a dabble with tuning myself between attempting to 'gold' licences (gosh) and have not found the evidence of huge effects that you promulgate. Some corners favour stonger front rates and some favour stronger rear rates ... well, that's not exactly a surprise.

Driving style has a much more noteable impact than spring rates and I'm fully expecting to find that, as has always been the case in GT games, the spring rates are not a particularly subtle or effective way of balancing the car for cornering as we don't actually know where the CoG of a given car lies. You'll have much more luck trying to use the dampers in that regard.

Off-topic a little, welcome to Tuff240. It's good to get another experienced drivers point of view in these matters and I suspect that, once you get a bit more settled, you'll find that there are a number here who you'll fit in with just fine (Bad760 and M-Spec amongst them I'm sure).

EDIT: Noted Tuffs 'status' and OLR ranking and revised view of how familiar with the Planet he was .

 

[Bad760]

Uh...yeah, I'm aware of that "test". As you'll see by mine and others comments.

"has more grip everywhere, I was much faster this lap". Mmmmkkkaaayyyy.

As i said in the post it is not a super scientific test, but it quite effectively showed how spring rate changes effected the car, I did it in an unbiased manner and was ready to accept the results either way.

If you are going to quote me please make sure that you quote something I actually said in the post

I think it is quite clear from my original post that tuff240 kindly reposted that i did 12 separate tests on spring rate, 6 with sport tyres and 6 with N3 tyres.

I went back and read the following posts to my original testing post and it appears that you were the only one making negative comments about it.

 

[Bad760]

I almost thought I had proved Maturin right the other night when doing some hot laps on the El Capitan track.

I had been running a car fully worked with the exception of any power adders using a substantially raised rear spring rate to get the steering that I wanted

I then put all the power adders onto the car a switched over to the suspension setting B page so I could keep my stock setup.
Now I started doing laps getting used to the car again and found to my dismay that it was understeering badly when cornering in a steady state situation whereas it hadn't been before.

I went to change check all my settings and found that i had inadvertently forgotten to reset the spring rates to the ones that I had been using.

The settings that i had been using with the car stock power wise had the rear springs at a higher rate than the front, but I found that the standard settings for the race suspension (that i had forgotten to change to my prefered rates) had the rear spring rate softer than the front rate.

Now I think that is a very subjective test, although totally by accident, and every bit as good a test as letting someone else change a setting and then testing it blind, only I didn't need a friend

Well off to give my RUF another thrashing

 

[Kiljoy]

Just been rereading the results from Bad760's tests, I will admit I haven't tried these, so you can take my assessment as either that from someone who may know a little or is just a complete idiot (I’ll leave that to you to decide).

Firstly lets get off topic a little and talk a about oversteer and understeer. My view of this (and it is only an opinion) is that what we are trying to achieve when we set up spring balance is to achieve a steady state cornering attitude for the car, this state whether oversteer, understeer or neutral is adjusted by the use of spring rates and roll stiffness, spring rates also help define our wheel rate, but we wont go into that, as its only balance where interested in.

Why did I consider telling you what you already know? Well it gives you a perspective as to where I’m coming from and braking into a hairpin and accelerating out of it is hardly steady state cornering. Why is this important, because these transitions are effected by diff settings, in its ability to rotate the vehicle and damper settings which (as well as the spring) affect the speed at which weight can be transferred. Ultimately too much bound in a damper will transmit the weight directly to the tyre essentially removing the spring from the initial weight transfer. Whether the game models the damper correctly is I think still up for debate, as I haven't really come to terms with this yet, maybe others have a better handle on this and can share their findings. But so far I think it is very easy to over damp the springs and have been wondering whether this is causing some of the confusion and varying results people are having.

Now for my assessment on Bad760's set up, I'll restate this is only my opinion, I haven't tried this set up and I expect others may not agree. The description you give as to how the car reacts says to me that you may need to pay closer attention to the damper setting of your vehicle as a lot of what you talk about is entry and exit increase/decrease of grip, (hence the rant above) and less about its steady state cornering ability. If I miss interpreted this I am sorry but would like to here more about what you felt it was doing in some of the longer bends rather than its transitional response.

 

[Kiljoy]

Sorry bad didn't see that you had made a couple of extra posts while I was writing the above, but would still like to here the assement for the M Coupe on the longer corners.

Cheers

Don't want to upset a fellow Kiwi

 

[Bad760]

Sorry bad didn't see that you had made a couple of extra posts while I was writing the above, but would still like to here the assement for the M Coupe on the longer corners.

Cheers

Don't want to upset a fellow Kiwi

No worries it happens to all of us.

And I don't mind people questioning my findings as long as the questions are constructive and your's most certainly are

I would just like to say that as I have played the game more I have come to like turning the damping down 1 click from the seems to be standard setting of 8 all round, the cars just react better to my inputs with the less damping.

It has been a long time since I did those test on the M Coupe so my memory is quite hazy.
When in the middle of turn 1 at Grand Valley East where I did the testing, in the small stage between letting off the brakes and applying the power, (steady state) although it is a very brief moment I could not carry as much corner speed when the rear springs were set 0.5 softer than my base setup, i think I said in my write up that it didn't rotate as well, (or maybe i said it rotated better with the slightly harder rear springs) that was just how i expressed that.

Now talking about my experience at the El Capitan circuit, on the first corner which is a long left, I definitely found that I had to use more steering lock and/or less throttle to keep the same line when I used by accident the standard spring settings which have the rear softer than the front, whereas my prefered settings for the car have the rears being harder than the fronts.

I have to stress that I used the stock spring rates totally by accident so i was not blinded by my normal thinking about how springs should work.

 

[tuff240]

Okay, I was feeling like a bit of an ass for throwing my thoughts in w/o actually trying what this thread was originally asking us to do, so I went out and bought a brand new RX-8 Type S, installed only the racing suspension and headed straight to Trial Mountain. Checked all the settings to make sure they matched what he posted and turned off all of the ASM/TCS stuff.

Not knowing exactly what corner Maturin was referring to and thinking we, as a group of concerned GT4 enthusiasts, needed more feedback than just a single turn, I decided to try each setting for 20 laps (approx 30 minutes).

I'll quote his original post here for reference if anyone else wants to try this. My results will follow his quoted post.

Well, since my question in Greyout's thread got swamped by a mod/poster war, I'll have to post this here. I think that, in my copy, the suspension tuning goes the opposite of what is canon on this forum. That is, that softer rear settings, induce MORE oversteer (which is opposite of what is canon on this forum). Do I just have a bugged copy, or is something else happening?

I did the following test, and I can duplicate this with any car. There are three settings, and the results are below each. I absolutely encourage any of you to duplicate these settings, and try to duplicate my results, or debunk them.

The settings will be done across, so you can see the differences easily, and they'll go SETUP 1 (which is Default Settings), SETUP 2, SETUP 3, and finally below the settings, the results.

I made sure to take the corners as I always do, and for the big banked left-hander, I took it at 2nd Gear, around 61-63MPH, for consistency.

TEST

Car: RX-8 Type S(J) - FR 285HP (Completely Stock except for Racing Suspension)
Tires: S2
Track: Trial Mountain

SETUP 1 SETUP2 SETUP3

Springs f10/r10 f10/r15 f10/r6
Height 120/120 120/120 120/120
Bound f8/r8 f6/r8 f8/r6
Rebound f8/r8 f6/r8 f8/r6
Camber 2.0/1.0 2.0/1.0 2.0/1.0
Toe 0/0 0/0 0/0
Stability 4/4 4/5 5/4

RESULTS:

SETUP1 (Default): Slight oversteer, nearly neutral
SETUP2 (rear stiffer): Understeer, in all turns.
SETUP3 (rear softer): Oversteer, in all turns. Braking, mid-turn, exit


My question is, shouldn't Setups 2 and 3, have REVERSED results?

My reviews of each set-up.

SETUP1 (Default): Slight oversteer, nearly neutral very fun car to drive and repeatable fast lap times. (I agree with Maturin basically.)
SETUP2 (rear stiffer): Very well balanced and much more planted feeling has better corner speed through-out the turn by 1-4mph at least in every corner. Since it is much more stable and planted, it is easy to get on the gas sooner helping your run onto the following straight-away and your lap time. Very consistent fast laps are possible with this set up.
SETUP3 (rear softer): Rear end is WAY too soft and wallows around behind you. Almost any large turn of the steering wheel gives you nearly instant loss of rear lateral traction and rear end drifts become the norm as you try to maintain the racing line. Noticeably decreased cornering speeds in the neighborhood of 1-5mph. VERY inconsistent lap times, BUT you can occasionally turn in a decent lap time if the car happens to zig while you want it to. More often than not it zags instead of zigs. IF you could get the car to not drift through a turn (only happened a handful of times), it would understeer badly through the entire turn.

Lap Times:
SETUP1 (Default): Consistent low 1'38's and the occasionmal high 1'37. Best lap of the 20 laps was a 1'37.740.
SETUP2 (rear stiffer): Consistent high 1'37's with a best lap of 1'37.468
SETUP3 (rear softer): VERY inconsistent. Ranged from low 1'38's to low 1'40's. Best lap was a 1'37.553 with a couple dumb luck slides.

Keep in mind that none of these sessions were done trying to set the "ultimate" lap time. I was simply trying to go fast and clean to form some sort of pattern in the handling. I was driving using typical OLR rules (2 tires on, no touches), but of course in 60 laps there are several mistakes and I disregarded those laps' times for the comparison.

I saved the first 20 lap session, forgot to save the 2nd 20 lap session (easily repeatable though as it was a nice consistent set-up), saved the 3rd 20 lap session and I also saved the fastest lap of the 60 laps which was from the 2nd session. I can send the Max Drive or X-Port files to anyone that needs them.

I spent over 2 hours doing this and had no idea nor did I care what the outcome would actually be. I hope someone else would like to try the same thing and post their thoughts as well.

Also if anyone has problems getting the car to do what I say it does with me driving, I'd be happy to discuss that here with an open and helpful mind. Again, I can also send the full length replays or the fastest lap ghost for you to watch/chase.

Best regards,
Patrick "Tuff240"

 

[sukerkin]

Thanks for the input Tuff - that's the sort of results I experienced with my dips into the tuning soup (brief as they've been with Licenses to Gold and an AI so poor that I haven't yet had to spanner a car into performing any better than stock).

The experiments I performed centred around altering the rear springs within a +/- 50% range of stock and, I have to say, that I didn't achieve a definite sense that the variation made a great deal of difference to the handling. As I said above, some corners were taken easier with the springs one way and some another; sometimes a corner would deliver terrible plough understeer and another time lurid oversteer depending on how I handled the throttle and brake - not a stunning revelation .

It's good to hear that another driver got the same feel out of the settings suite and I'm now pretty much convinced that I shan't have to 'relearn' how to tune for the benefit of GT4 hew:.

 

[mrnelson]

Okay, I was feeling... <snip>
Best regards,
Patrick "Tuff240"

Tuff, Nice write up, but I don't see that you're really drawing any conclusions here... Consequently I'm going to try based on what you wrote:

My assumption based on what you have written is that you are essentially agreeing with the stated findings of Maturins original post, in that when you lowered the rear spring rate it made this particular car oversteer more often (Lets for arguments sake call this 'The Maturin Effect' )...

My question now is: Is this an error on the part of PD as Maturin is suggesting? Or is this simply an anomaly of this particular car?

To put it another way, can 'The Maturin Effect' be reproduced repeatedly on other cars with different characteristics?

If it can then Maturin may be right, if not then there must be some other forces in play, despite that fact that the original effect is repeatable (For whatever reason).

 

[Duke]

Most importantly the ability to separate theory from FACT. I listen to what my EYES say, not what I THINK they say. Even if I had ZERO percent complete, the last ability is most important

Once again, play the game, adjust the suspension one click at a time, or have a friend do it (blind), and tell me it isn't reversed.

If you can't do that, you're hopeless.

I also notice that M-Spec and the others who claimed it wasn't reversed have never again posted in this forum, as they have, no doubt, realized they are wrong, as have most other people.

Last warning about your attitude. Check your PMs.

 

[mugen_s2002]

I agree that the spring rates are revered. But it's no big deals, just swap your front and rear spring settings. I think this should be stickied.

 

[Greyout]

SETUP3 (rear softer): Rear end is WAY too soft... Almost any large turn of the steering wheel gives you nearly instant loss of rear lateral traction and rear end drifts become the norm as you try to maintain the racing line.

And this is where the game is wrong, thank you for the additional evidence.

with a super soft rear, the front is going to push off the track in an understeering mess!

 

[Greyout]

Hi Greyout,

I think it could be as simple as having the springs reversed. It's reasonable to assume that the graphics engine is a separate piece of code to the physics engine.

Lets assume that they are separate modules/classes. This would make their coding much easier to maintain and offer them the ability to change only the physics or graphics as necessary and also allow both sets of code to look at only one place to find any variables, spring rates, camber etc.

If the respective pieces of code look to the set up screen values to obtain the value of the springs then apply these values, it is a VERY SIMPLE coding error to apply the value of the front spring to the rear of the car and apply the rear spring value to the front in the physics engine while correctly applying these values in the graphics engine. End result, the graphic does not correspond to what the car behaves like.

Reasonable explanation for those of us who belive that the rates are reversed...
...I'll let those reading decide, as it is very difficult to prove without access to the code.

I find it VERY hard to believe that the body pitch, squat, & roll is governed by anything other then the physics model. Perhaps a different algorithm, and the two guys didn't confer with eachother.

The credits list "simulation algorithm" as being developed by one person.

 

[Greyout]

Wow the prelude is ridiculous! It really feels like an FR car from gt3 if the front springs are strong. With weak front springs the car feels like FF from gt3. 1000X more noticeable then anything with the RX8.

yes, with a soft rear & stiff front, you can drift sideways through any hairpin by just hurling the car into the corner at full throttle.

rediculous.

 

[Steve Gunnis]

I just asked a friend of mine to give it a shot.

He softened up the rear of the prelude, and stiffened up the front. He said it is the "oversteer king"

This is very bad.

Until I can go home and try this myself, I take back anything good I ever said about GT4 physics.

I haven't done anything so thorough in the way of a precise comparison but i keep finding that adjusting the settings of the cars has an unpredictable effect on the handling.

I am absolutely certain that the Caterham Fireblade fully modified (just shy of 300 bhp and weighing just over 300kg!) produces lift when driving at speed. Try taking it around the Nurburgring and find out, it's like a hovercraft! Not a good advert for what in reality is a car with a lot of mechanical grip and superb cornering.

 

[Greyout]

I Not clear on your "adjusting automatically" comment for the dampeners, could you please elaborate more on this for me?

With a super soft spring rate, a damper setting of 3/3 can be used, and they seem to control the spring motion fine. Pump up the spring rate to the max, and, again, the 3/3 setting will control the bound & rebound of the super stiff spring just fine. I think the 1-10 is an arbitrary value that moves up & down with spring rate.

Your .3 vs 3.0 vs 6.0 comment was a typical if more is good, too much is better.
Why not just put the largest cam in your motor you can possibly fit inside the valve cover/block or where ever it is on your paticular car? Do you also believe those "racing" stickers make your car go faster? (Not directly aimed at you, just trying to make a point.)

What I'm saying is that as you keep adding spring rate to one end, the physics error just gets worse and worse - it is never accurate, and then suddenly not. A tiny adjustment results in a tiny incorrect result. A big adjustment results in a big incorrect result.

When was the last time you read about them changing the spring rates by 500-1000ft/lbs in any given car to "adjust" it? They generally start with a "close" spring rate from their years of experience for that paticular vehicle and application and adjust it from there because they already know that "extreme" tuning is usually pointless.

Nationally, in the production car race series that I folllow, people increase their spring rates by HUNDREDS of lb/in at a time.

find online classifieds, and they are FILLED with:

"Hey, I have 400lb/in 7" springs off the rear of my integra, selling for $100, and I'm looking for 900 lb/in, anyone have any?

the well sorted cars, NATIONALLY, run rates in the 600F/1200R region, (the realtime TSX in the World Challenge runs rear rates of 3000lb/in! and when these cars & drivers started their careers with HPDE's and track/street cars, they were at rates of 200-300 lb/in... which is what most off-the-shelf street kits offer. so by the time they have their car fully sorted, they are running springs 4-5 times stiffer then they started out... not to mention the stock springs, which were in the 100-250 region!.

Were are talking about 2500lb+ production cars, with wheel rates that are significantly less then spring rates... not 400 lb carbon tubs with actuator arms attaching the shocks directly to the hub. changes in spring rates of 200, 300, 400, hell, 600 lbs AT A TIME are frequent & common!

Increasing a spring by 2 kg/mm at a time is a drop in the bucket, about as small an increment as a a real person would consider going through the hassle of swapping out...

The game is consistantly providing incorrect results for the most basic suspension adjustments for nearly all cars.

 

[Bad760]

First thankyou for taking the time to do a long test Tuff240.

Reading Tuff's results and comparing them to my own experience it almost exactly matchs my experience albeit with a different car.

I have found with almost all my cars that they seem to like a slightly higher spring rate in the rear than what they come with stock with the race suspension.

One key thing that I picked up on when reading Tuff's experience using Setup 3 (rear softer)

IF you could get the car to not drift through a turn (only happened a handful of times), it would understeer badly through the entire turn.

that is an almost an exact match to what I found, is that if you could get the rear to stay inline on corner entry and hooked up then the car would understeer badly.
This I am pretty sure does not happen with a too stiff rear setup, you will lose traction and just never get it back.

Now at the risk of sounding like a broken record this exactly matches what i said in my very first post when talking about testing this using my 1/10th scale RC race car

Now looking at a real world example, I race 1/10th scale RC touring cars at a national level.

Now I can tell you that when I put the hardest springs on the front and softest on the rear I most definitely get oversteer turning into and mid corner as the rear of the car wobbles around with such soft spring rates, but bad understeer out of the corner as the car squats and loads up the rears. I can't easily explain that as my understanding of roll and pitch moments and moving roll centres and roll axis isn't 100%.
With a stiffness bias to the front the car is very responsive to initial turnin but will push badly after that unless you put it and keep it in a slide

Here is one thought I had, now I found the 2 soft rear springs to have the same effect ingame and using my RC car, maybe the way we have to control the cars ie. basically from a third person perspective, we have no seat of the pants feelings from the car to tell us what it is doing, we only know vaguely what the car is likely to be doing from many repeated laps and observing from outside the loop, is having some effect on the handling characteristics we are observing.

I have done some crewing on speedway super modified cars and helped the driver with his setup, and after observing the race I have talked to the driver afterwards and said that I thought it looked like he had some oversteer, but quite surprising to me he said he actually had bad understeer and was trying to drive around it resulting in the oversteer that I observed.

Greyout

I think you are still getting hung up on the numbers that PD put on the spring rate sliders, my personal thoughts are they just put numbers on the sliders to make us feel better, there are no units on the rollbar settings or indeed the shock settings.

Looking at 2 very different cars I have, the (newly won) XJ220 LM & the Autobianchi A112 Abarth, the spring rates for the XJ220 vary from 8 to 20 (prob not exact but close enough), and the Abarth from 4 to 12.

Now I if the spring rates are linear I would have expected the rates on the XJ220 to be well in the order of a factor of 10 larger than the Abarth but they are not even twice the rate.

Looking at that example it is quite possible that the spring rates are not linear in scale but possible on a logarithmic scale.

 

[Greyout]

hmmm, that is possible, and it would be nice if it was true.

I will do further testing with my prelude tonight.

even if the scales were off, it doesn't explain why the car does what it does when the sliders are at their extremes... but I'll start from scratch, force myself to ignore the numbers, and see what happens.

 

[rk]

Looking at that example it is quite possible that the spring rates are not linear in scale but possible on a logarithmic scale.

I LIKE that theory. It seems to me that logarithmic scaling would more easily lend itself to Greyout's belief that the dampers are relative.

 

[Greyout]

still very strange that PD would go through the trouble of putting real-life units on the slider's, but none of the others (except camber), if they weren't going to attempt to make them in the same ballpark.

Edit: maybe the value is actually wheel rate?

 

[tuff240]

Tuff, Nice write up, but I don't see that you're really drawing any conclusions here... Consequently I'm going to try based on what you wrote:

Thanks, look forward to hearing your thoughts.

My assumption based on what you have written is that you are essentially agreeing with the stated findings of Maturins original post, in that when you lowered the rear spring rate it made this particular car oversteer more often (Lets for arguments sake call this 'The Maturin Effect' )...

My question now is: Is this an error on the part of PD as Maturin is suggesting? Or is this simply an anomaly of this particular car?

To put it another way, can 'The Maturin Effect' be reproduced repeatedly on other cars with different characteristics?

If it can then Maturin may be right, if not then there must be some other forces in play, despite that fact that the original effect is repeatable (For whatever reason).

Yes and No.
I agreed with his findings on the first set-up, the default set-up. I thought the car didn't oversteer as much with the 2nd set-up due to being more "properly" balanced. It also would hold a tighter line in the turns and would never push unless the car was being driven past it's limits. It's limits were higher than both set-up 1 and 3.
I agree that the car is a drift king in set-up #3, but it's not because the rear is "stiffer" (the backwards slider theory). Quite the opposite. It is so soft that it can't properly maintain grip and therefor slides all about the place as if the rear suspension is barely attached to the car.
If you look at my average lap times you will clearly see what works best and what doesn't work.
Set-up 1 is probably good for around a 1'37.2xx - 1'37.5xx fastest lap with me driving.
Set-up 2 I'm sure I can get into the 1'36's with fairly easily.
Set-up 3 is probably some were around a 1'37.0xx - 1'37.2xx with a lot of luck as it doesn't handle consistently and you are constantly trying to regain control of the overly soft rear end.

I believe, but have yet to test it, that it should be roughly the same for all cars. They have a limit to which the suspension can be tuned to and it's not near the ends of the sliders regardless of what the measurements say on the sliders.

Does that make sense?

 

[tuff240]

And this is where the game is wrong, thank you for the additional evidence.

with a super soft rear, the front is going to push off the track in an understeering mess!

Not true.
Think of it this way. Flatten your rear tires to about 5-10 psi each. Go drive your car. Is there more grip in a straight line? Yes, because the sidewalls of the tires are soft and flex. Now go hang a turn like this and see how much lateral grip you have, even though the rear suspension is now softer. Before someone says, "tires aren't springs", tires ARE part of the suspension system and contribute to it's softness or hardness as much as anything else.

(Disclaimer: don't actually try this test with your real car, it can be dangerous and I'll not be responsible for anyone's accidents.)

 

[tuff240]

With a super soft spring rate, a damper setting of 3/3 can be used, and they seem to control the spring motion fine. Pump up the spring rate to the max, and, again, the 3/3 setting will control the bound & rebound of the super stiff spring just fine. I think the 1-10 is an arbitrary value that moves up & down with spring rate.

Okay, I understand better now, thank you.
With my limited tuning of my own cars you seem to be on to something here. I'll pay closer attention to this in the future and see if it holds true. 👍

What I'm saying is that as you keep adding spring rate to one end, the physics error just gets worse and worse - it is never accurate, and then suddenly not. A tiny adjustment results in a tiny incorrect result. A big adjustment results in a big incorrect result.

I didn't find this to be the case entirely. I felt as if it did go in the right direction, but then all of a sudden hits this big NO-NO area and she is squirely as all hell.

Nationally, in the production car race series that I folllow, people increase their spring rates by HUNDREDS of lb/in at a time.

find online classifieds, and they are FILLED with:

"Hey, I have 400lb/in 7" springs off the rear of my integra, selling for $100, and I'm looking for 900 lb/in, anyone have any?

the well sorted cars, NATIONALLY, run rates in the 600F/1200R region, (the realtime TSX in the World Challenge runs rear rates of 3000lb/in! and when these cars & drivers started their careers with HPDE's and track/street cars, they were at rates of 200-300 lb/in... which is what most off-the-shelf street kits offer. so by the time they have their car fully sorted, they are running springs 4-5 times stiffer then they started out... not to mention the stock springs, which were in the 100-250 region!.

Were are talking about 2500lb+ production cars, with wheel rates that are significantly less then spring rates... not 400 lb carbon tubs with actuator arms attaching the shocks directly to the hub. changes in spring rates of 200, 300, 400, hell, 600 lbs AT A TIME are frequent & common!

Yes, but what I am saying is AFTER they have their spring rates sorted, they do not make huge changes. Maybe PD has sorted the spring rates for us and they only require slight adjustment to tailor the car to your preference?

The game is consistantly providing incorrect results for the most basic suspension adjustments for nearly all cars.

IF you go by the numbers on the sliders that they provide, then I agree. I never go by the numbers they provide. Always on feel and test driving. And I feel that they go in the right direction from my experiences.

 

[rk]

(Disclaimer: don't actually try this test with your real car, it can be dangerous and I'll not be responsible for anyone's accidents.)

"I don't know, officer, thats how I found him, just sitting there, with the controller in his hand, no sign of struggle...."

 

[sukerkin]

Just to chime in on the Dampers, I've always worked with the proviso that PD gave us 'magic' dampers in the GT series i.e. that they rescale to match the spring rates so all you have to worry about are their relative values.

Tuff's assessment of the Spring Rate Mystery is the same as my own. In fact, he's neatly tied together the ideas that those of us on the "It's okay really" side of the wall have expressed 👍.

I'll keep looking in here for news and updates but, for me, I'm just going to get on with spannering my cars and see how I feel in a year or so .

 

[Shmak]

Hey all, first post on this thread, but i have been following it avidly and i must say i have learned a great deal about suspension, weight transfer, etc. and i thank you guys for that. Theres alot of good reading in here.

Alright lemme say right off that im not here to profess my boundless knowledge about real-world racing or springrates, because im no gearhead race wizard. Call me an enthusiast, not a professional. So basically what i did was what Maturin outlined at the beginning, with some slight changes to the procedure.

I felt as if it did go in the right direction, but then all of a sudden hits this big NO-NO area and she is squirely as all hell.

Rather than repeat the experiment exactly for simply another confirmation of Maturin and Tuff's results (i figured they were true and very similar), I decided to find the NO-NO Zone =]
So i took my stock RX8 Type-S to Trial Mountain for a good flogging with this strategy in mind: Decreasing the rear spring rate an increment at a time until i felt a drastic change in the handling characteristics. Result? I didn't find it. Now comes the evidence since i like to do things in reverse:


I did a number of laps with each setup until i completed four clean laps, no tapping, lawn-mowing, etc. I didn't really have that much time today to do more than that, and in retrospect i would have more convincing evidence, with the same result.

Setup #1 - Default Race Suspension - 10f/10r
I don't have to describe yet again how the stock car feels since Tuff and Maturin illustrated a better picture than i could, and i don't like doing pointless work. So, neutral it is. I posted the fastest lap with this setup, and i feel it probably is the fastest of all the settings i tried in the test. Oh and the first lap is a bit slow, but i was warming up and it only took me like 1 or 2 laps to get into the groove, so that says something for how nice it is in this state of tune.

Lap 1 - 1'40.756
Lap 2 - 1'39.942
Lap 3 - 1'38.399
Lap 4 - 1'38.916

Setup #2 - Custom Race Suspension - 10f/8r
This setup caused some oversteer that was most noticable in the high speed turns after the starting grid. Getting a tire or two off the course in the apex would mean some countersteer was in order to correct the slide. Regardless, i did ok and posted consistant times with this setup since im no stranger to a bit of oversteer.

Lap 1 - 1'39.247
Lap 2 - 1'39.155
Lap 3 - 1'39.697
Lap 4 - 1'38.862

Setup #3 - Custom Race Suspension - 10f/6r
In this test, the car behaved much like the previous setup only more so. I could get the tail to come around rather easily, though i don't think it was drifto champion material. From some of the posts i was expecting a good deal more oversteer than i actually saw. Times suffered, tho not by all that much. It was more difficult to post consistant times than both pervious setups.

Lap 1 - 1'39.027
Lap 2 - 1'40.370
Lap 3 - 1'39.106
Lap 4 - 1'39.748



So now i got to thinking that, if there was a NO-NO Zone, it would have to be between the 10 and 8 setting, because that was where the car seemed to change the most. Now i would have liked to do more tests but i was running out of time, so i only managed to work out 2 more laps, this time with the rear set at 9.

Setup #4 - Custom Race Suspension - 10f/9r
Nearly as nice as the default setting, this turned out to be pretty much neutral. There may have been a slight oversteer, but not much. A bit greater tendency to slide if i feighted in the opposite direction than stock. Overall i didn't get to have as much time with this setup as the others, so more testing is needed =]

Lap 1 - 1'38.675
Lap 2 - 1'38.928




Alright so now that all that is out of the way, here's one thing i definately didn't experience - understeer. None. The car went where i pointed it, i didn't feel any pushing at all. I know that if the NO-NO Zone does exist, it is probably between 8 and 9 on the spring, so i'll probably try that at a later date. But as things stand now, it seemed like a progression, albiet not a perfectly linear one.



One more thing here i wanted to throw a couple of pennies at:

I find it VERY hard to believe that the body pitch, squat, & roll is governed by anything other then the physics model. Perhaps a different algorithm, and the two guys didn't confer with eachother.

I know i started out this post explaining my "less than extensive" knowledge about the subject at hand, but i will say that one thing i do have extensive knowledge about is 3D modeling, animation, and to some extent, coding. In a perfect world the physics code would directly relate, and be proportional to, what happens in the 3D space you see on the screen. However the GT world, while so very good that millions of people spend countless hours there, is not perfect. I would be willing to bet a very large sum of money that the parameters of body-roll, pitch, etc, are only dependent on the shape of the car model in relation with the ground. There might be a slight possibility of adjustments within these parameters, but i haven't seen any evidence of it and frankly its really tough to tell if the body pitches more or less after adjustments in the settings. The real "physics" of the game are not controlling how the body of the car moves in the game, they are controlling how the wheels move in relation to the ground; with all the variables like power, weight, SPRING RATES, etc, taken into account.

alright wheew thanks for putting up with all that, i feel like i just gave birth.

-Shmak

 

[Duke]

Hi, Shmak, and welcome to GTPlanet. An excellent addition for your first post. I'm sure your contributions concerning the graphics end of things will make a big difference.

On the graphics note, it's been a week since I played. However, I have to note that I spent some time dialling in my RX-7 RS-R for use in the Japanese Championship. One of the steps I included was purchasing the race suspension, lowering, and stiffening the car. I drive from the inside view though I rarely have time to watch the replays. Despite the increase in power and acceleration, from the driver's view, the nose dip at each upshift was noticeably reduced over the stock suspension setup.

So I believe that the suspension settings are at least informing the rendered body motion if not exactly dictating it.